摘要:

I204 MACKENZIE: THE ACTlON OF SODIUM MEETHOXIDE ON CXXVIIL-The Action of Sodium Nethoxide and i t s Homologues on Benxophenone Chlo&le and Bmxal Chloride. By JOHN EDWIN MACKENZIE, D.Sc., PI1.D. IN a previous communication to the Society (Trans., 1896, 69, 985), a description was givsn of the preparation of dimebhoxydi phenylmethane by the action of sodium methoxide on benzophenone chloride according to the equation (C,H,),CCI, + 2CH,*ONa = (C,H,),C(O*CH,), + 2NaC1, and of di-ethoxy- and dibeazoxy-diphenylmethane, using sodium ethoxideBENZOPHENONE CHLORIDE AND BENZAL CHLORIDE. 1205 and benzoxide respectively instead of methoxide. I n continuing this investigation, dipropyloxy-, diisobutyloxy-, and dihydroxy-tetraphenyl- methane have been prepared, and for the sake of comparison a number of experiments with benzal chloride have been carried out.The action of sodium methoxide and its homologues on benzal chloride was first investigated by Wicke (Anncden, 1857, 102, 356), who prepared dimethoxy-, diethoxy-, and diamyloxy-benzylidenes, the reaction pro- ceeding thus : C,H,*CHCI, + 2CH,*ONa = C,H,-CH(O*CH,), + 2NaCI. Some years later, Limpricht, in a research on the chlorine substitution products of toluene (Anncderh, 1886, 139, 319), repeated Wicke's work, but was unable to obtain products free from chlorine. This being so, and no record of the yield of the products obtained by Wicke being given, i t was thought advisable to try these experiments agzin under various conditions. Following Wicke's instructions, it was found that the reaction took place under the ordinary pressure as represented, but that the benzal chloride only disappeared on repeated treatment with sodium methoxide." On the other hand, when benzal chloride mas heated with sodium ethoxide under pressure, a different reaction took place, ethyl chloride, benzaldehyde, and sodium chloride being the products.The change may be represented thus : C,H5*CHC12 + C,H,*ONa = C2H,C1 + C6H5*CH0 + NaCl. By using the sodium compounds of different alcohols, the corresponding chlorides mere produced. That this reaction does not apply to phenols would appear from the work of Fosse (Compt. rend., 1900, 130, 725 and 1194), who obtained diphenoxyethylidene by heating ethylidene chloride and sodium phenate in sealed tubes at 120°, according to the equation,? CH,*CHCJ, + 2C,H,*ONa = CH,,*CH(O*C,H,), + 2NaCl.As in benzophenone chloride and benzal chloride both halogen atoms are attached to the same carbon atom, it was thought that itl would be interesting to see what happened when the halogen atoms * In the case of sodium benzoxide, the only product separated was stilbene, and that only in minute quantity, The reaction would thus appear to be expressed in part by the equation : 2C,H5*CHCI, + 4C,H;CH;ONa = 4NaC1 f C,H,*CH:CH-C',H, + 2CGH,*CH,*OH -t- C,H,*CHO. .t. That this should be so is rather curions in view of the fact that when benzal chloride and phenol are heated together, they form clihydroxytriphenylmethane according to the equation : and that benzophenone chloride gives n similar componiid with either phenol or s'oclinm phenoxidc.CGH,*CHCI, + BC,H,*OH = CGH,*CH(CGH,'OH), + 2HCl91206 MACKENZIE: THE ACTION OF SODIUM METHOXIDE ON are attached to different carbon atoms. I n the case of ethylene di- bromide, the reaction would be expected to take place thus : CH2Br*CH2Br + 2C,H5*ONn = CH,(O*C,H,)*CH,(O*C,H,) + ZNaBr, but no record of experiment showing this to be so is known t o the author. Diethoxyethylidene has, however, been prepared by Henry (Compt. rend., 1885, 100, 1007) from an intermediate product in this way: CH,I*CH,(O*C,H,) + C,H;ONa = CH,(O~C,H,)*CH,(O*C,H,) t NaI. On heating ethylene dibromide with sodium ethoxide under pres- sure, however, it was found that acetylene was produced, reaction taking place thus : CH,Br*CH,Br + 2C,H,*ONa = CH:CH + 2C,H,*OH + 2NaBr.The production of acetylene in a similar fashion, using sodium isoamyloxide instead of ethoxide, is recorded by Sawitch (Juhresber., 1861, 646). I . A c t i o n of Xodium AlkyZoxides o n Benxoyhenons CI'LZoride. Diln.o~~yZoxydipT~enzylmetl~url.le, (CGBs),C!O.C)H,*CHz'C)H,),. I n preparing this substance, 3.7 grams of sodium were dissolved in 40 grams of propyl alcohol, and to the cold product 19 grams of benzo- phenone chloride were added. The mixture was gradually heated to a temperature of 9 5 O , when a violent action took place, and then kept a t 120° for 7 hours, a t the end of which time the supernatant liquid still gave an alkaline reaction. The liquid was filtered from the salt which had separated, the latter being washed three times with small quantities of propyl alcohol.The filtrate mas then distilled under reduced pressure to remove the excess of propyl alcohol. The residue, which was a viscous, brown oil, was diluted by the addition of a little ethyl alcohol, filtered from some salt, and distilled, 7.9 grnma of a colourless oil boiling at 200-210° under 40 mm. pressure being col- lected. The yellowish, semi-solid, strongly alkaline substance remain- ing in the distilling flask was distilled with steam, From the milky distillate, crystals separated which melted a t 32-34O, and boiled at 204O under 40 mm, pressure. By cooling the fraction boiling at 200-210° under 40 mm. pres- sure in a freezing mixture, a white, powdery mass wasobtained, which on recrystallisation from light petroleum formed colourless, prismatic crystals melting at 33-34.5'.They amounted to nearly 1 gram. On analysis : 0.2026 gave 0.5982 GO, and 0.1576 H,O. C= $0.53 ; H= 8.64. C19H2402 requires C = 80.28 ; H = 8.46 per cent.HENZOPHENONE CHLORIDE AND BENZAL CEILORIDE. 1 20'9 Dipropyloxydiphenylrnethane is insoluble in water, but extremely easily soluble in methyl or ethyl alcohol, ether, benzene, light petroleum, $c. It is rather unstable, the faces of crystals very soon becoming dull. Well formed crystals are very difficult to obtain. The amount of the fraction boiling a t 2UO-21O0 under 40 mm. pressure corresponds to 35 per cent. of the theoretical yield. The preparation of this substance mas effected in the way previously described, the quantities taken being 3.7 grams of sodium, 41 grams of isobutyl alcohol, and 19 grams of benzopheaone chloride, When the sodium compound melted, a brisk action took place, but was not complete after heating to 130--150° for 7 hours, the liquid still show- ing an alkaline reaction.The salt was removed by filtration, and the liquid then distilled under diminished pressure. After removal of the excess of isobutyl alcohol, the temperature rose rapidly to 199O, and 16.5 grams of a thick oil were collected, having a boiling point between 199' and 210" under 35 mm. pressure. When placed in a freezing mixture, this oil became a thick jelly in which minute needles appeared on scratching, After standing at the ordinary temperature for 18 days, the small bunches of needles, which had grown, were filtered off, dried on a porous plate, and, as they showed no sharp melting point, dissolved in ether., The ethereal solution deposited silky needles after being kept in a desiccator for a week.The dried crystals, which weighed 0% gram, now melted a t 62--64O, but on exposure t o the air the melting point fell, and, as mill be shown later, the substance decomposed with the formation of benzophenone. A combustion per- formed a week after the separation of the crystals gave the following figures : 0.2682 gave 0.8313 CO, and 0.1657 H20. C = 84.5 ; H = GbS6. C,,H,,O, requires C = 80.76 ; 13 = 8-97 per cent. C13€Ilo0 ,, C=S5.71 ; €I=5*49 ,, The quantity being so small, no experiments could be carpied out to ascertain the reason for the difference in melting point between these crystals and those described below.The oil from these crystals was again distilled under a pressure of 35 mm., when eleven grams, or 44 per cent. of the theoretical quantity obtainable, came over between 203" and 215", mostly a t 210'. By cooling in a freezing mixture, small, diamond shaped plates crystsllised from the oil, which gradually became solid throughout. After drying on a porous plate, the solid melted a t 36-38', but the melting point was lowered by exposure to the air. From a n ethereal solution,120s MACKENZIE: THE ACTION OF SODIUM METHOXIDE ON crystals melting at 35-37", and from light petroleum, crystals melting at 35-36', were obtained. On analysis of the crystals melting at 36-38', the following numbers were obtained : 0,2041 gave 0.6017 CO, and 0,1644 H,O.C = 80.40 ; H = S.95. 0,2076 ,, 0.6131 CO, ,, 0.1669 H20. C=80.54; H=8*92. C,,H,,O, requires C = 80.76 ; H = 8.97 per cent, The following experiment is a further proof that the substance has the formula attributed to it. 0.2660 gram of the crystals in a platinum boat was placed in a desiccator over sulphuric acid and weighed every second day. The crystals soon deliquesced, then became entirely liquid, meanwhile steadily losing weight for nearly three weeks. A t the eud of the fourth week, the weight had become constant, and on introducing a particle of benzophenone, the reddish- brown oil crystallised. The loss in weight amounted to 0.10SO gram, or 40.6 per cent. The loss in weight caused by splitting off diiso- butylic ether from diisobutyloxydipheny1methane is 41.6 per cent.An analysis of the residual product proved i t to be impure benzophenone. C,3H,,0 requires C=S5*71 ; H=5.49 per cent. 0.1562 gave 0.4858 CO, and 0.0794 H,O. I n this respect, therefore, the dibobutyloxy-derivative agrees with the dimethoxy- and diethoxy-compounds. Diisobutyloxydiphenylmethane is exceedingly soluble in the ordinary organic solvents. Although i t crystallises more readily than the propyloxy-compound, it is difficult to work with in summer weather on account of its low melting point and ready dissociation. C = S4.82 ; H = 5-65. Attempt to prepare Diurrt y Zoxydiphen ylmethane. The quantities used in this experiment were 2.8 grams of sodium, 50 grams of amyl alcohol(b. p. 129*5-130.5"),and 13.6 grams of benzophenone chloride.The mixture was heated-after a violent action had taken place-in an oil-bath to 135-145' for 5 hours. Dry ether was then added to the still alkaline product, and the solution filtered from the salt. On Fractional distillation under 40 mm. pressure, 3 grams of oil boiling between 200' and 220", 10.2 grams between 220' and 235*, and 4.3 grams between 235' and 260° were obtained. The two latter portions formed a jelly when placed in a freezing mixture, but no crystals separated. On exposure to winter cold during the Christmas vacation, small groups of stellate needles were obtained, which after drying between filter paper melted at 66-67', Only a very small quantity was obtained, and further efforts to get more were fruitless. An analysis gave figures whichRENZOPHENONE CHLORIDE AKD EICNZAL CHLORIDE.120'3 lie between those required for the amyloxy-compound and benzo- phenone. 0.1268 gave 0.3887 CO, and 0.0745 H,O. C = S3.60 ; H = 6.53. C,,H,,O, requires C = 81-65 ; R = 8.87 per cent. C,,H,,O ,, C=85.71 ; H=5.40 ,, It is curious that this compound is the product of the action of sodium phenoxide on benzophenone chloride, and that no diphenoxy- compound could be isolated, Two methods of preparation are described. I n the first, sodium phenoxide was prepared by adding 4.6 grams of sodium to a solution of 18.9 grams of phenol in dry ether, long con- tinued heating and frequent shaking being necessary t o convert the sodium into sodium phenoxide (which is almost insoluble in ether) ; 23.7 grams of benzophenone ch!oride were then mixed with the pro- duct.On heating, no action took place until the ether was distilled off, when violent ebullition set in, vapours of phenol being evolved. The residue was heated for 1& hours in an oil-bath a t 11 5", and when cold extracted with ether, The ethereal extract was repeatedly shaken with water until the washings no longer had an alkaline re- action. From the first washings, phenol separated as an oil on the addition of hydrochloric acid, After drying the ethereal extract and distilling off the ether, there remained an uninviting, thick, brown oil, which would neither solidify on cooling in a freezing mixture nor on the introduction of particles of benzophenone or phenol. After trying to crystttllise it from alcohol, ether, chloroform, and other solvents, it was found that by the addition of light petroleum to the ethereal solution, small crystals separated, and after several days a product very like treacle filled the bottom of the beaker.This was spread on a porous plate and then dissolved in a large volume of chloroform and boiled under a reflux condenser with animal charcoal to decolorise it. Repeated boilings reduced the colour of the solution to a light yellow, and on the addition of light petroleum, light yellow, sandy crystals separated. After several recrystallisations, the substance softened a t about 260" and melted a t 285-2879 Analysis showed that the substance had the peculiar composition of 2 molecules of ether combined with 1 of dihydroxytetraphenyl- methane." 0.1330 gave 0.3862 GO, and 0.0943 H,O.C = 79.19 ; H= 7.S9. C,,H,,0,,2C,H,o0 requires C = 79.20 ; H = 8-00 per cent. * Bseyer has obtained dichloral pcroxidc hydrate with one niolecule of ether of crystallisation, C4H4C1604,C4H1,,0 (Bey., 1900, 34, 2482).1210 MACICENZIE: THE ACTION OF SODIUM MlWIIOXIIIE ON The ether of crystallisstion was expelled by heating in a steam oven. A portion of the substance, which had already lost i n weight by standing in an exhausted desiccator for several days, lost more than 20 per cent. by heating, the theoretical loss being 29.6 per cent. The tesults of the analysis of a portion of the substance so obtained were : 0.1418 gave 0.441 2 C'O, and 0 -01300 I€,O. C,5H2002 requires C = 85.22 ; H = 5.68 per cent. The following method of preparation WAS found to give much better results: 6.1 grams of sodium dissolved in 130 grams of phenol and 31.6 grams of beneophenone chloride were heated in a water-bath until hydrogen chloride ceased to come off, which was at the end of 22 hours.The excess of phenol was then distilled off under 40 mm. pressure a t 130-140°, and the residue, mixed with water, repeatedly extracted with ether, The ethereal solution was washed with caustic soda solution and then with water, dried, and boiled for 6 hours with animal charcoal, After filtration and concentration, the solution on cooling became almost solid. Tile greenish-brown, crude substance so obtained weighed 61 grams, or 91 per cent. of tho theoretical quantity, After further boiling with animal charcoal and recrystallisation, the crystals melted at 284-385".Qualitative experiments show that benzophenone chloride and pheuol react directly with production of. the above product, but no quantita- tive experiment has yet been performed. Dihydroxytetraphenylmethanc is a colourless, crystalline substance which dissolves very easily in ether, easily in alcohol, and moderately in chloroform, but only sparingly in light petroleum. It is soluble in caustic soda without coloration, and is reprecipitated by the addition of an acid. I t does not give the bromine colour reaction mentioned by Russanoff for the corresponding dihydroxytriphenylmethane. By heating the substance with its own weight of fused sodium acetate and four times as much acetic anhydride, an acetyl derivative was obtained, wliicb, after recrystallisation from acetone, melted at 170-171".C = S4.85 ; H = 6.26. Analysis showed it to be the diacetyl compound. 0.2194 gave 0.6386 GO, and 0.1202 H,O. C = 79-38 ; H = 6.08. C,,U,,O, requires C = 79.81 ; I€ = 5.60 per cent. Action of Ethyl Alcohol on Benxophenone. Prom the easy dissociation of the above compounds, it was thought possible that they might be formed directly from benzophenone and the corresponding alcohol, but this proved not to be the case, as the following experiments showed. Five grams of benzophenone were heated with 20 grams of ethylBENZOPHENONE CHLOItIDE AND I3ENZAL CHLOP,IDE. 1 211 alcohol in a water-bath for 3 hours and allowed to stand overnight. No crystals havicg appeared, most of the alcohol was distilled off.The residual oil did not crystallise on standing, but on the addition of a particle of benzophenone, a rapid growth of crystals took place. After drying they melted a t 48-49', and were evidectly unchanged benzophenone. A further crop of crystals from the mother liquoi- brought the amount recovered up to 4% grams. Action of 1 per cent. Solutioiz of Hydrogen Cldoi-itle i i z HetlyZ Alcohol on Benxophenone. As E. Fischer (Bey., 1897, 30, 3053 ; lS9S, 31, 545, 1989) mentions that the use of 1 per cent. alcoholic solutions of hydrogen cbloride is particularly adapted to the production of sldals, and only infers that it is not applicable for the production OF ketals, the following experi- ments were performed. These shorn that the process is inapplicable in the case of benzophenone.Five grams of bonzophenoue were dissolved in 100 C.C. of 1 per cent. solution of hydrogen cliloride in methyl alcohol, and the mixture allowed t o stand for 5 days. Most of the alcohol was then removed by distillation, and the residue crystsllised on cooling. The crystals were separated from the mother liquor, which afforded a second crop on standing, the amount recovered being 4.9 grams. The crystals melted at 48-49' (benzophenone m. p. as0), hence the benzo- phenone was unacted on. A similar experiment in which 5 p t m s of bmzophenone and 40 c.c, of 1.5 per cent, solution of hydrogen chloride in methyl alcohol were heated in a sealed tube a t a temperature of 75-90' for 12 hours also resulted in the recovery of the whole of the benzophenone unchanged.D i m e t ? ~ o x ? / d ~ ~ ~ ? ~ e n ~ l ~ ~ e t ~ ~ c ~ ~ e . Action of N i t k Acid on D i i n e l ? ~ o x ~ c ~ i ~ ~ ~ e 7 ~ ~ ~ ~ ~ ~ t ? ~ u n e . -The following experiment was performed in the hope of obtaining the nitro-deriva- tive of dimethoxydiphenylmethane, but dissociation took place, and dinitrobenzophenone resulted, Two grams of the powdered crystals were slowly added to 25 C.C. of fuming nitric acid cooled by ice, the crystals dissolving apparently without change. After standing for a day, the solution mas poured on to crushed ice, by which means a white, curdy precipitate was formed. It dissolved easily in hot ethyl alcohol, and from the solution there separated simultaneously pale yellow leaflets and needle-like crystals, neither of which showed a constant melting point.As this might be due to a The weight of dried precipitate was 2.1 grams.1212 MACRENZIE: THE ACTION OF SODIUM METHOXIDE ON mixture of isomerides, analyses of different portions of the substance, which had been kept in desiccators until of constant weight, were made. 0.3082 gave 27.9 C.C. moist nitrogen at 1 3 O and 757 rnm. N = 10.66. 0.2287 ,, 20.4 C.C. 9 9 13" ,, 759 mni. N- 10.52 C,,H,0,N2 requires N = 10.30 per cent. As dinitrobenzophenone exists in several modifications, further efforts were made to separate tho possible isomeric forms. From a fairly concentrated nitric acid solution, glistening crystals resembling sand mere deposited. They melted at 189-190', and crystallised from hot glacial acetic acid in fan-shaped groups of needles, thus agreeing with the properties of 4 : 4'-dinitrobenzophenone (Stadel, Ber., 1894, 27, 2110).On heating the mother liquor from the above experiment and diluting it with hot water, a second crop of crystals consisting of rosettes and needles was obtained. Recrystallised from glacial acetic acid, they softened at 137Oand melted a t 149", thus conforming with the de- scription of the properties of 3 : 3'-dinitrobenzophenone. Neither of these substances is appreciably volatile with steam, and, both are very sparingly soluble in ether. Di~~~enylmetlLyZeneanilid~, (C,H,),C:N*C,H,.-This substance was formed when dimethoxydiphenylmathane was heated with three times its weight of aniline. At about 60', the solid had all dissolved, and a t 175" crystals began to separate and a slight ebullition occurred.Atter being kept at lS0" for 5 minutes, the product mas allowed t o cool, filtered with the aid of a pump, and the residue mashed with dry ether. From a hot methyl alcoholic solution of the residue, glistening, yellow plates separated, showing a melting point OC 113-113*5°; Rohde gives 112-113' (Ber., 1892, 25, 2056). 11. A c t i o n o f S o d i u m A l k y l o x i d e s on Benaccl Chloride u n d e v the o r d i n w y P r e s s u y e . Action of #odium &fethoxiJe." According to Wicke's instructions (Arcnalert, 1857, 102, 366), 23 grams of sodium were dissolved in 250 C.C. of methyl alcohol, 80.5 grams of benzal chloride added to the solution, and the mixture heated in a water-bath for 15 hours.As it was thought possible that methyl chloride might be formed, this being the case when the action takes place under pressure, an apparatus for collecting gas was attached t o * As the products obtained in these experiments were not all of the same char- acter, they will be described nndcr the hending of the sodium derivative of the alcohol which acted 011 beuzal chloride.BENZOPHENONE CHLORIDE AND 1;lCNXA L CHLORIDE. 121 3 the end of the reflux condenser, but no gas was found t o be evolved. After removing the alcohol by distillation, the residue, which was alkaline, was mixed with water, and the oil which separated extracted by ether. The ethereal extract was dried over calcium chloride, the ether removed, and the residue subjected to fractional distillation under diminished pressure.I n this way, a colourless oil which dis- tilled between 190" and 2 10' under the ordinary pressure was obtained. On testing the various fractions between 190" and 210" for chlorine, it was found t o be present i n all. Only after heating this oil with fresh quantities of sodium methoxide i n alcoholic solution several times, could i t be obtained free from chlorine. In another experiment,. potassium was substituted for sodium, and zinc dust and alcoholic potash were used to remove the last traces of chlorine, as described under sodium ethoxide. I n this way, 1 2 grams of an oil boiling between 180' and 210' were obtained free from chlorine. Supposing i t to be pure dimethoxybenzylidene, this would be a yield of 15 per cent.of the theoretical. Analysis of the portion boiling at 194-196' gave the following figures : 0.1671 gave 0.4345 CO, and 0.1160 H,O. C,H,,O, requires C = 71.06 ; H = 7.89 per cent. Dimethoxybenzylidene is a colourless, limpid oil, with a n odour of geranium. It boils at 194-196', Fischer (Bev., 1898, 31, 549) giving 19So, and Wicke 208O, as its boiling point. The last is probably in- correct, as Wicke gives no analysis, and his product probably contained unchanged benzal chloride. C= 70.91 ; H = '7.71. Action of #odium Ethoxide. In this experiment, 23 gramsof sodium were dissolved in 230 grams of ethyl alcohol, and to the cold solution 80.5 grams of benzal chloride were added. The mixture was heated in a water-bath for 24 hours, no violent action taking place, but salt gradually separating.At the end of this time, the liquid mas still alkaline. Having dist,illed off most of the alcohol, the residue was mixed with water and extracted three times with ether. The ethereal solution mas washed with water until i t showed a neutral reaction, dried over calcium chloride, filtered, and the ether evaporated. The residue mas then distilled under a pressure of 45 mm., nearly t h e whole coming over between 90° and 175". On redistilling this under the ordinary pressure, 3.6 grams were collected below 206", 59.3 grams between 206" and 220', and 6.3 grams between 220° and 300'. A s all these fractions contained chlorine, those boiling up t o 220' were added to a solution of 9 grams of sodium in 100 grams of alcohol, and the mixture heated on the water-bath for 17 hours.A1214 MACKENZIE: THE ACTION OF SODIUM METHOXIDE ON Separation of salt again took place, and the liquid darkened in colour. The product was treated as before, and 51-1 grams of a colourless liquid boiling at 135-140' under 75 mm. pressure mere obtained, which, under tbe ordinary pressure, distilled between 300' and 220'. As the various fractions still contained chlorine, they were heated a third time with sodium ethoxide (4.5 grams sodium in 45 grams alcohol) for 16 hours, and subsequently treated as before. The fractions collected were: 6.2 grams a t 212-215'; 13.3 grams at 215--217'; 12.6 grams a t 217-219O; 4.3 grams a t 219-222'. As they all still showed the presence of traces of chlorine, the action of zinc dust and alcoholic potash was tried on the two latter .fractions. Sixteen grams of the oil mixed with 5 grams of potassium hydroxide dissolved in 20 grams of alcohol, diluted with water to make x solution, ancl 5 grams of zinc dust mere allowed t o stand at the ordinary temperature for five days, and then heated under a reflux condenser for an hour in a mater-bath. The alcohol having been removed by distillation, the residue mas mixed with water, extracted with ether, dried, and the ether expelled.The resulting product now distilled at 216' to 220°, chiefly a t 217', 13 grams being so obtained. I n order to make certain of the absence of chlorine, n Carius estimn- tion was carried out. 0,5890 gave 0.0004 AgCl and ash. It is very curious that Wicke makes no mention of the difficulty of removing the chlorine compounds in this reaction.On the other hand, Limpricht, who repeated Wicke's work, but heated the mixture of benzal chloride, sodium methoxide, and alcohol at 140°, was unable to obtain products free from chlorine, the amount of the latter varying between 7.5 and 18.7 per cent. The absence of chlorine having been established, the liquid mas once more fractionally distilled, and 7.5 grams of oil boiling at 216-217" (uncorr.) * were collected, Wicke, with whom Fischer agrees, men- tions 222' as the corrected boiling point of diethoxybenzylidene. A combustion T of this portion gave the following figures : Ash = 0.0001. * The temperatnres throughout this investigation are uiicorrected. t The combustion of this substance was a matter of some difficulty, because, on heating it apparently splits off ethyl ether, which, if allowed to pass over rapidly, Causes the percentage of carbon to come out too low.The following analyses of portions (I and I1 boiling a t 217-219", 111 a t 216-220", and IV a t 216-217") which were free, or as nearly as possible free, from chlorine illustrate this fact. I. 0'3745 gave 0.9706 COz and 0'2933 H,O. C=70'68 ; H=8.70. 11. 0.1690 ,, 0.4397 CO, ,, 0'1360 HzO. C=70*90; H=8'94. 111. 0'6398 ,, 1'6868 CO, ,, 0.5056 H,O. C=71.93 ; H=S*77. IT. 0.5438 ,, 1'4243 CO, ,, 0'4255 H,O. C=71'43; H=8*67- In the above four analyses, the combustion was carried out a t an ordinary rate, an C,,H,,O, requires C = 73-33 ; H = 8 $8 per ccnt.UENZOPIIENONE CHLOItlDE AND EENZAL CHLORIDE.121 5 0.24 gave 0.645 GO, and 0.2 H,O. C = 73-29 ; H = 9.25. C,,HI,O, requires C: = 73.33 ; H = S.58 per cent. 8 Diethoxybenzylidene is a colourless liquid with a fragrant odour. It is not soluble in water, but is miscible with the ordinary organic solvents. It is stable in the presence of alkalis, but is readily decom- posed by acids. With a saturated solution of sodium bisulphite i t soon yields the beazaldehyde compound. Assuming that the fractions 215-222", weighing 30.1 grams in all, consisted of pure diethoxybenzylidene, the yield would be 33 per cent. of the theoretical. This is, therefore, not so convenient a method as E. Fischer's for the preparation of this substance. Action of Sottiurn Bemoxiclc. The quantities used in this experiment were 4.6 grams of sodium, 50 grams of benzyl alcohol, and 16.1 grams of benzal chloride. The mixture was heated in an oil-bath at a temperature of 206-210' for 5 hours, during which a quantity of solid matter separated.When cold, a large voliime of ether was added and the solution filtered, the salt being washed several times with ether. After removal of the ether, the yellow oil which remained was distilled under a pressure of 55 mm., fractions being collected between 100" and 270". The residue in the distilling flask was a viscous mass. The last fraction of distillate, namely, that boiling at 200-2'i0°, smelt of benzaldehydo, and contained some chloride. On distillation under the ordinary pres- sure, the temperature steadily rose t o 300'. A further effort t o obtain a constant boiling liquid under a reduced pressure of 60-65 mm.was also ~ n ~ u c ~ e s ~ f u l , the distillate heing collected in the following frac- tions : up to 1 1 5 O , 9.3 grams; 115-120", 12 3 grams ; 120-195', 11.9 grams; 195-260", 5.3 grams, and 360-300', 6.8 grams. The first two fractions were found t o be free from chlorine, and as they distilled at 195-202' under 749 mm. pressure, were probably benzyl alcohol (b. p. 204'). By cooling the last fraction in a freezing mixture, a small quantity of crystals separated. These were filtered off, dried on a porous plate, and then melted at 112-115'. A s the presence o€ stilbene and benzoic acid, which both melt at 120°, was suspected, the following tests mere performed. The crystals did not dissolve i n solutions of either sodium hydroxide or carbonate, nor did they react with litmus, hour to an hour and three-quarters being taken between tho introduction of tho substance and the removal of the absorption apparatus.In the combustion mentioned in the text, the time was extended to two hours and a half. This ob- servation was also made by Dr. A. J. Walker when burning dirnethoxybenzylidene. The other portions all contained chlorine.1216 MACICENZIE : THE ACTION Ok' SODIUM METHOXIDE ON but they decolorised a solution of bromine in carbon disulphide, thus indicating the absence of benzoic acid, and the presence of stilbene. They were then purified by recrystallisation from hot ethyl alcohol. The glistening leaflets, of which only a minute quantity was obtained, melted sharply at 120', and on analysis gave the following figures : C = 93.02 ; H = 8.65.0.0316 gave 0.1078 CO, and 0.0246 H,O. C1,H,, requires c! = 93.33 ; H = 6.67 per cent. With the idea of removing any benzoic acid, and possibly chlorine compounds, from the fractions 195-260' and 260-300°, an ethereal solution of them was shaken with aqueous solutions of sodium car- honatle and hydroxide, dried, and, after the removal of the ether, distilled under 85 mm. pressure. I n this way, 5.5 grams were ob- tained, distilling between 200' and 240'. On mixing with light petroleum and cooling in a freezing mixture, there separated some crystals, which when dry weighed 0.11 gram. As they resembled the crystals of stilbene above mentioned, the bromide was prepared.An ice-cold ethereal solution of bromine was immediately decolorised by an ethereal solution of these crystals. After standing 4 hours in the cold, the silky needles which had been deposited from the soln- tion, were filtered off and dried on a porous plate. The weight of crystals obtained mas 0.124 gram, and they melted a t 236-237'. As stilbene dibromide melts a t 237', this experiment confirms the results of the analysis. From.the mother liquor of the stilbene, no liquid of constant boiling point could be isolated, and it still contained a considerable quantity of chlorine. The action of sodium benzoxide on benzal chloride would thus appear to be a rather complicated one, the formation of stilbene only taking place in very small quantity. Action of Phenol o n Benxal Chlode.As it had been found that benzophenone chloride acted directly on phenol, the same result was expected in the case of the above sub- stances. A mixture of 55 grams of phenol and 16.9 grams of benzal chloride was heated gently at first, then to 120' for 10 hours, when hydrogen chloride ceased to come off. The loss in weight of hydrogen chloride was 7 grams, or 95 per cent. of the theoretical. From the dark brown residue, phenol was distilled off under 50 mm. pressure a t 100-107', the temperature being allowed t o rise to 210'. On removing the capillary tube from the ruby-red, transparent jelly remaining in the flask, a sharp click was heard, and crystals shot out radially from the centre. The weight of crystalline solid was 24 grams, or 87 per cent.of the theoretical. After boiling with animal charcoal and re- crgstallisi ng from chloi oform, the colourless crystals of dihydroxy-BENZOPHENONE CHLOlZlDE AND BENZAL CHLORIDE. 1217 triphenylmethane melted at 160-1 61". As mentioned by Russanoff (Ber., 1889, 22, 1944), when gently warmed with bromine water, washed, and dissolved in alcohol, this substance gives a beautiful, blue colour on the addition of caustic alkalis. When heated with acetic anhydride and fused sodium acetate, it affords a diacetyl derivative, which crystallises from acetone in colour- less crystals melting at 10s-110'. I n this respect, therefore, i t also agrees with the product obtained by Russanoff by the condensation of benzaldehyde and phenol by means of sulphuric acid. 111. Action o f Sodium Alkploxides o n Benxal Chloride uiacler Pressure in Sealed Tubes.Action of 8odium Methoxide. In this experiment, 41.4 grams of benzal chloride were added to a solution of 6 grams of sodium in 60 grams of methyl alcohol, and the mixture heated a t 100-105" for 6 hours. On the tube being opened, only a slight pressure of gas was noticed, but a considerable quantity of a white salt had separated. The tube was again sealed and heated a t 150' for 3 hours; on reopening, a strong pressure of gas was observed, and the liquid contents were faintly acid to litmus. After standing for a few minutes, the liquid began apparently to boil, and methyl chloride was briskly evolved for more tlian an hour. It may be noted that a corresponding result was obtained with the other alcohols used under similar conditions.The residue was filtered with the aid of the pump, and the liquid thus obtained was distilled under a pressure of 75 mm., the fractions collected being 21.7 grams below 35', and 24 grams between 35' and 105', chiefly 100-105'. On redistillation under the ordinary pressure, nearly 20 grams of crude methyl nlcohol, boiling between 66' and 70", and 23 grams of crude benzaldehyde, boiling between 175' and 195', were obtained. The crude benzaldehyde so obtained corresponds to a yield of 87 per cent. of the theoretical. From the residue, a small quantity of a crystalline acid melting at 131" was obtained (benzoic acid melts a t 121"), probably formed by the oxidation of the aldehyde. Action of Sodium Ethoxide. This experiment was carried out in a similar manner to the previous one, the quantities taken being 4.6 grams of sodium, 47 grams of ethyl alcohol, and 32 grams of benzal chloride.The mixture was heated at 150-160' for 7 hours. No pressure of gas was noticeable on opening the tube, but on heating to 55" n large volume of gas was VOL. LXXIX. 4 01218 MACKENZIE: THE ACTION OF SODIUM METHOXIDE ON liberated. The gas, which measured 2-25 litres, mas collected in a gas holder. After passing it through two wash-bottles containing sulphuric acid, some of the dry gas was liquefied in U-tubes immersed in a freezing mixture. About four C.C. of the colourless, very mobile liquid which was obtained in this way evaporated very rapidly when removed from the freezing mixture, The vapour burned with a green edged flame, and was evidently ethyl chloride. The volume of gas measured was about half that which should 'theoretically have been obtained.The contents of the tube were next filtered with the aid of the pump, and after distilling off the unchanged alcohol from the filtrate, the temperature was raised to 210°, the oil which came over amounting to nearly 23' grams. The residue was dark brown in colour and resembled pitch. It did not give evidence of the presence of chlorine as shown by the sodium test. On heating alone, it gave off a very acrid odour. A solution obtained by boiling it with water and filtering hot, deposited glistening leaflets, which melted at 121' (benzoic acid melts at 121'). On redistilling the oil, the temperature rose rapidly to 175' and be- tween 175' and 185' more than 12 grams, and between 185' and 210' 5.5 grams, came over.On shaking with a cold saturated solution of sodium bisulphite, both these fractions were shown t o consist mainly of benzaldehyde, and the presence of only a small quantity of benzal chloride in the latter fraction was proved by the tests for chlorine. Act ion of Sodium Propyloxide. I n this experiment, 4.6 grams of sodium, 50 grams of propyl alcohol, and 32.2 grams of benzal chloride were heated at 150'for 7 hours. No gas escaped on opening the tube. The tube was then connected with a condenser, to which two U-tubes, immersed in a freezing mixture, were attached. It was heated in the outer tube of a V. Meyer vapour density apparatus filled with water.When the temperature OF the water rose to 55', bubbles of gas began to come off, and after heating for an hour and a quarter, during which time the temperature gradually rose to 97", all the gas seemed to have been evolved, The liquid, con- densed in the U-tubes, weighing 11.4 grams, was then fractionally distilled, a Linnemann column being used. The temperature, which rose to 43" before any liquid distilled over, remained constant a t 46" for some time, and then rose rapidly to 90'. The fractions collected were 43-48' (chiefly 46O), 4.4 grams; 48-97' (chiefly 90-94'), 6.4 grams. The former was a colourless, mobile, strongly refractive and pleasant smelling liquid resembling propyl chloride in all its properties (prop91 chloride boils at 46.5'). A yield of 4.4 grams of propyl chlorideUENZOPHENONE CHLORIDE AND BENZAL CHLOXIDE.1219 corresponds to 28 per cent, of the theoretical. The latter portion was chiefly propyl alcohol. The residue in the tube was mixed with about 250 C.C. of water and extracted with ether eight times. The ethereal extract, which was neutral to litmus, was dried over calcium chloride, and, after expelling the ether, was distilled, 26 grams of a mobile liquid coming over below 105O and 18.5 grams of an oil between 175" and 530'. The first portion consisted mainly of propyl alcohol, whilst the last had a stjrong odour of benzaldehyde, but was found to contain a considerable quantity of chlorine, I n order to get a rough estimate of the quantity of benzaldehyde present, the last portion was shaken with a saturated solution of sodium bisulphite, and the crystalline compound thus formed filtered with the aid of the pump, washed twice with ethyl alcohol, and dried on a porous plate.The weight of the dry bisulphite compound was 9.6 grams, or 23 per cent. of the theoretical. Action of Xoclium Benxoxide. I n this experiment, 4.6 grams of sodium dissolved in 50 grams of benzyl alcohol and 32 grams of benzal chloride were heated a t 150-160° for 11 hours. On opening the tube, slight pressure was noticeable, a combustible vapour escaping. A small quantity of glistening leaflets, which had crystallised in the upper part of the tube, proved to be insoluble in cold, but readily soluble in hot, water, and also in caustic soda, from which they were reprecipitated by the addition of hydrochloric acid.After drying, the crystals softened at 90' and melted at 11S0, agreeing generally therefore with the pro- perties of benzoic acid, The contents of the tube were then filtered, and the oil thus obtained subjected to fractional distillation under 60 mm. pressure, the temperature being allowed to rise to 140°, a t which point crystals appeared in the condenser, The fractions were then distilled under the ordinary pressure, and 7-2 grams mere col- lected between 162' and 1 7 6 O , and 20 grams between 176" and 178'. As the last fraction was expected to be benzyl chloride, chlorine esti- mations were made with the following results : C1= 21.5. C,H,Cl requires C1= 28.06 per cent. 0.2673 gave 0.2330 AgCl. 0.2207 ,, 0*1918 ,, C1=21*5.AS the liquid probably contained benxaldehyde, it was shaken with a saturated solution of sodium bisulph ; the colourless crystalline substance so obtained was filtered off, and proved to be the benzalde- hyde bisulphite compound. The oil was then separated by the addition of water and extraction with ether. After drying the ethereal extract and removing the ether, the residue was distilled under a pressure of1220 ACTION OF SODIUM METHOXIDE ON BENZOPHENONE CHLORIDE. 70 mm., when it came over between looo and llOo. Unfortunately some was lost, but of the remaining 8.7 grams, 1.S grams distilled below 176', and 5.7 grams at 176-177O under the ordinary pressure. The latter portion showed all the properties of benzyl chloride (b. p. 179"), and a chlorine determination gave satisfactory figures.02635 gave 0.2967 AgC1. C1= 27.9. C,H7C1 requires C1= 28.06 per cent. I n another experiment, in which the same quantities were used, the components were thoroughIy mixed by stirring with a glass rod before sealing off the tube. After heating at 150-155O for 11 hours, the sodium chloride which had separated mas filtered off, with the aid of a pump from the brown liquid,-washed with a little benzyl alcohol, and dried. It weighed almost 12 grams, the calculated quantity being 11 *7 grams. From the liquid obtained by distillation of the filtrate under 50 mm. pressure, 18.2 grams of sodium bisulphite compound were separated, corresponding to a yield of 43 per cent. of the theoretical. After repeating the distillation and treatment with sodium bisulphite, 11 *S grams of benzyl chloride, or 46 per cent, of the theoretical quan- tity, distilling at 175-176O under 748 mm.pressure, were obtained. An estimation of chlorine gave the following figures : C1= 27.5. C7H,C1 requires C1= 28.06 per cent. 09165 gave 0.2403 AgCl. IV. N o t e on the Analysis of Benxczl and Benxgl Chlorides. As Wicke states that the chlorine in benzal chloride is completely precipitated by the addition of an alcoholic solution of silver nitrate, it was thought that in the case of this compound and of benzyl chloride the Carius method of estimating halogens might be replaced by the more direct process. The following results, however, show that the precipitation is very incomplete in the case of benzyl chloride (I), and only partially complete in that of benzal chloride (I1 and 111). I. 0.3280 gave 0.3623 AgC1. C1= 22.4. 11. 0.6302 gave 1.0907 AgCl. Cl=42*98. C,H,Cl requires C1= 28.06 per cent. 111. 0.4226 ,, OT314 AgCl. C1= 42.97. ' C7H,CI, requires C1= 44.0'3 per cent. An attempt was also made to estimate the chlorine in benzal chloride by reduction with sodium amalgam and precipitation of the sodium chloride by silver nitrate in the usual way. The figures ob- tained in two experiments were :DIARYLOXYISOPROPYLPHOSPHOROUS ACIDS. 1221 I, OT012 gave 0.4654 AgC1. C1-16.5. 11. 1.3776 ,? 0,9345 AgC1. C1= 16.8. C7H,C12 requires C1= 44.09 per cent. Both the above methods were therefore inapplicable, and the Carius method had to be resorted to. Action, of Xodium Ethoxide on Ethylene Dibromide under Presswe. A mixture of 23.5 grams of ethylene dibromide and 5.75 grams of sodium dissolved in 57.5 grams of ethyl alcohol wa8 sealed up in a tube and, after remaining a t the ordinary temperature for 2 days, during which a quantity of salt separated, was heated at 120-130' for '7 hours, On the tube being opened, a gas possessing all the pro- perties of acetylene escaped under slight pressure. This gas burned with a brilliant, white, luminous flame, decolorised bromine water, forming, oily drops having a peculiar odour, and produced a deep red and a yellowish-white precipitate in ammoniacal solutions of cuprous chloride and silver nitrate respectively, both of which were explosive when dry. The filtrate from the salt distilled at R temperature of 68-70', and i n this way nearly all the alcohol was recovered. The author desires to express his thanks to Dr. A. Jamieson Walker for carrying out the experiments on the action of sodium methoxide and of isobutyloxide on benzal chloride under the ordinary pressure. The latter, having unfortunately yielded negative results, are not recorded here. BIRKBECK INSTITUTION, LONDON.

ISSN:0368-1645    

DOI:10.1039/CT9017901204

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

DIARYLOXYISOPROPYLPHOSPHOROUS ACIDS. 1221 CXX1X.-Action of the Chlorides of Phosphorus on Aromatic Ethers of Glycei-ol. Dimryloxyisopropyl- phosphorous Acids. By D. R. BOYD. SYMMETRICAL glycerol diphenyl ether, OPh*CH,*CH(OH)*CH,*OPb, was originally prepared by Rijssing (Ber., 1886, 19, 63) from u-di- chlorohydrin. Lindeman (Bey., 1891, 24, 2147) has since obtained both the diphenyl and di-ptolyl ethers more conveniently by using epichloroh ydrin. These compounds appear to be the only representatives of the diary1 ethers of glycerol which have been described, and their properties have VOL. LXXIX. 4 P1222 BOYD: ACTION OF THE CIILORIDES OF PHOSPHORUS ON not been very completely investigated. I recently had occasion to study the action of the chlorides of phosphorus upon the diphenyl ether, and the results obtained in this and some similar cases are recorded in the present paper.When glycerol diphenyl ether is treated with phosphorus penta- chloride, the corresponding diphenoxyisopropyl chloride is formed. OPh*CH,*GH(OH)*CH,*OPh 4 OPh-CH,*CHCl*CH,*OPh. If, on the other hand, phosphorus trichloride is used, and the pro- duct of the reaction treated with water, a large yield of diphenoxy- isopropylphosphorous acid is obtained. CH(CH,*OPh),*OH + PCI, = CH(CH,*OPh),*O*PCI, + HCl. CH(CH2*OPh),*O*PCI, + 2H20 = CH(CH,*OPh),*O*P(OH), + 2HC1. Similar results follow if glycerol phenyl p-tolyl ether or the d i p tolyl ether is substituted for the diphenyl compound. The behaviour of alcohols towards phosphorus trichloride has been investigated by various chemists (Wurtz, Menschutkin, Kowalewsky), who have shown that either an ester of phosphorous acid, for example, C,H,*O*P(OH),, or the corresponding chloride, C2H,*O*PCl,, is formed according to the proportion of alcohol used.More recently, Jaroschenko (Chem. Cent?.., 1897, ii, 334) has suggested the employment of this reaction as a means of distinguishing between primary, secondary, and tertiary alcohols. According to this author, primary alcohols react with phosphorus trichloride to give phosphorus compounds of the type R*CH,*O*PCI,, the yield in the case of isobutyl alcohol being 78 per cent. of the theoretical amount (compare also Kowalewsky, Chent. Centr., 1897, ii, 333). Secondary alcohols, on the other hand, yield unsaturated hydrocarbons according to the equation : 3CH,*CH(OH)*CH, + PCI, = 3CH3*CH:CH, + 3HCl + P(OH)3, the yield of propylene obtained from isopropyl alcohol being 80 per cent.of that required by theory. Milobendski (Chem. Centr., 1899, i, 249), however, has been unable to verify this observation in the case of isopropyl alcohol. He finds, on the contrary, that when phosphorus trichloride acts on this alcohol, only a very small quantity of propylene is formed, and that the main reaction proceeds according to the equation : 3C,H,O + PCl, = P(O*C,HT),*OH + C,H,C1 + 2HC1. I n view of these conflicting statements, a study of the action of phosphorus trichloride upon the glycerol diary1 ethers acquires addi- tional interest. From the observations recorded in the present paper, it is evident that some secondary alcohols at least behave precisely in the fashion which has been recognised by Jaroschenko as characteristieAROMATIC ETHERS OF GLYCEROL.1223 of primary alcohols. The use of phosphorus trichloride as a reagent for the recognition of the primary or secondary character of an alcohol must therefore be regarded as of very doubtful value, The diaryloxyisopropylphosphorous acids here described are sub- stances with a marked tendency to crystallise, and show a some- what high degree of stability when compared with other derivatives of phosphorous acid of the same type already known. They undergo no change when left exposed to moist air, and can even be crystallised from boiling water. Solutions of their ammonium salts may be boiled for a long period without any decomposition taking place.The com- pounds, however, are quickly hydrolysed by heating with caustic potash. EX P E R IY EN T A L. Actiort of Phosphorus Pentachloride on s-Glycerol Biphenyl Ether. Formation of Diphenoxyisopropyl Chloride, C,H,*O* CH,*CHC1*CH2*O*C,H,. The glycerol diphenyl ether used in this and the following experi- ment was prepared by Lindeman’s method. It melted a t 80--81°.* Twenty-four grams of the ether (1 mol.) were mixed with 22 grams of phosphorus pentachloride (1 mol.). I n a few minutes, a vigorous reaction took place, resulting in the formation of a yellow liquid. This was poured into water and heated with dilute caustic soda solution until the smell of phosphorus oxychloride had disappeared. The alkaline liquid was then extracted with ether, and the ethereal solu- tion dried over potassium carbonate.On evaporation of the ether, an oil was obtained which was distilled under reduced pressure. The distillate, on standing, solidified. Jt was dissolved in light petroleum, from which, on cooling, it separated in large, transparent, oblique prisms melting at 3i0. The yield was 7.5 grams, or about 30 per cent. of the theoretical amount, On analysis : 0.1534 gave 0.3862 CO, and 0.0848 H20. C = 68.66 ; H = 6.19. 002092 ,, 0.1156 AgC1. C1= 13-67. C,,H,,O,CL requires C = 68.55; H = 5.77 ; 01 = 13.50 per cent. * In this connection, it may be mentioned that an unsuccessful attempt was made to prepare as-glycerol diphenyl ether from P-dibromohydrin. When this substance was treated with a mixture of sodium phenate and melted phenol, a satisfactory yield of a diphenyl ether was obtained, but this proved, on investigation, to be the same compound that results from a-dichlorohydrin or epichlorohydrin, namely, the symmetrical ether.This is no doubt to be explained by supposing that epibromo- hydrin is formed as 311 intermediate product by the action of the sodium phennte on the 8-dibromohydrin. 4 P Z1224 BOYD: ACTION OF THE CHLORIDES OF PHOSPHORUS ON The substance dissolves very easily i n ether, alcohol, and other organic solvents, and in small quantity can be distilled without decom- position under the ordinary pressure. Action, of Phosphorus 17ricl&~ids m s-Glycerol Diphenyl Ether. E'ormation of Diphenoxy isoprop ylphosphorous Acid.CH( CH2*O*C6H,),*O*P(OH),. I n each experiment, 13 grams (3 mols.) of the diphenyl ether and 9 grams of phosphorus trichloride (4 mols.) were used. The mixture was heated in the water-bath for about half-an-hour until no more hydrogen chloride was evolved, The resulting colourless liquid, con- sisting of the chloride of diphenoxyisopropylphosphorous acid, together with tbe excess of phosphorus trichloride, was cooled and then poured into a litre of ice-cold water, A somewhat vigorous reaction took place, with liberation of hydro- chloric acid. After stirring for a short time, a white, viscous mass wi s obtained, which, on standing, became solid. I n the first experiments, this product was extracted repeatedly with boiling light petroleum, in which the unchanged glycerol diphenyl ether dissolves, whilst the phosphorous acid is practically insoluble.It was afterwards found that a much more convenient method, and one giving a pure product, consists in treating the above-mentioned viscous mass a t once with a considerable volume of dilute ammonia solution. On standing some hours, the whole of the diphenoxyisopropylphosphorous acid dis- solves, leaving behind any unchanged glycerol ether. I n this operation, it is necessary t o use a rather large quantity of water, as otherwise the ammonium chloride which is formed, if any phosphorus tri- chloride should have escaped decomposition in the previous treatment with water, causes precipitation of ammonium diphenoxyisopropyl- phosphite. On acidifying the ammoniacal solution with hydrochloric acid, an oily precipitate of diphenoxyisopropylphosphorous acid was obtained, which soon changed to a crystalline mass.This was filtered off, and washed well with water containing some hydrochloric acid. The washed pro- duct was dried at 100' and crystallised from ethyl acetate, from which it separated in beautiful, prismatic needles, or radiating groups of these, melting at 119-120'. The yield was 9 grams, or about 55 per cent. of the theoretical amount. On analysis : 0.1839 gave 0.3923 CO, and 0,0928 H,O. C = 58.18 ; H = 5.66. 0.6867 ,, 0.2535 Mg,P,OF. P = 10.28. C,,H170,P requires C = 58.40 ; H = 5.57 ; P = 10.06 per cent. Diphenoxyisopropylphosphorous acid is slightly soluble in coldAROMATIC ETHERS OF GLYCEROL. 1225 water, giving a liquid mitb a faint acid reaction ; from this solution, it is reprecipitated on addition of a little hydrochloric acid." It is moderately soluble in boiling water, and, on cooling the solution slowly, separates in we31-developed, prismatic needles similar t o those obtained from ethyl acetate.It is very easily soluble in dilute aqueous am- monia, and if t o a concentrated solution some ammonium chloride is added, the ammonium salt of the diphenoxyisopropylphosphorous acid is immediately precipitated in the form of an oil. This oil dis- solves at once on addition of more water, and no hydrolysis occurs, even on prolonged boiling OF the solution. The acid is also readily soluble in cold caustic soda solution, but on boiling the solution quickly becomes turbid from separation of the glycerol diphenyl ether.The liquid now contains phosphorous acid, and after acidification and subsequent filtration is found to reduce mercuric chloride solution. The substance dissolves very easily in alcohol, and somewhat less so in benzene, chloroform, acetone, or hot ethyl acetate, It is insoluble in ether, if free from alcohol, or in light petroleum. Glycerol PhenyZ p-ToZyZ Ether, C,H,* O*CH,*CH(OH)*CH,*O* C,H,*CH,. This substance was obtained by an adaptation of Lindeman's method for the preparation of the symmetrical ethers. A solution of p-cresol and sodium ethoxide in alcohol was treated with the theoretical amount of glycidol phenyl ether, and the mixture boiled for some hours in a reflux apparatus. The product was then cooled, poured into water, and the resulting solid precipitate washed with water, dried, and crystallised from alcohol.It formed white leaflets, which after several crystallisation8 melted at 73.5-76'. Repeated crystallisation did not alter the melting point. The sample analysed was obtained by hydrolysis of its phosphorous acid and sub- sequent crys tallisat ion. 0,2071 gave 0.5636 CO, and 0.1323 H,O, I n properties, the substance closely resembles the diphenyl and diptolyl ethers already described. It can be distilled under reduced pressure without decomposition, and may be crystallised conveniently either from alcohol or light petroleum. C= 74.22 ; H = 7.16. C,,HI,O, requires C = 74.37 ; H = 7.04 per cent. ie Autenrieth (Ber,, 1897, 30, 2371) draws attention to the same phenomenon in the case of acids of the type of diphenylphosphoric acid, and Wurtz (AnnaZen, 1846, 58, 75) records a similar behavionr on the part of amylphosphorous acid.1226 DIARYLOXYISOPROPYLPHOSPlXOROUS ACIDS Phenoxy - ptolytoxyisopropy I Chloride, C,X,*O* CH,- CHCl*CH2*O*C,H4*CH3.Molecular proportions of glycerol phenyl ptolyl ether and phos- phorus pentachloride were mixed and the product of the reaction treated exactly as in the case of the preparation of diphenoxyiso- propyl chloride. The substance crystallised from light petroleum in clusters of transparent plates of well-defined form melting a t 609 On analysis : 0-1624 gave 0*4130 CO, and 04895 H20. 0'2075 ,, 0.1055 AgCI. Cl=12*57. In solubility, volatility, &c., the substance closely resembles tho C=69*36 ; H=6.18. C,6H,p02C1 requires C = 69.41 ; H = 6-27 ; C1= 12.82 per cent.corresponding diphenoxy-compound. ~he~oxy-p-toEy~oxyisop~opyEp~~o~pho~ous Acid, C€T,*C,H4*O*CH,*CH( CH,*O* C,H,)*O P( OH),. Twenty grams of glycerol phenyl p-tolyl ether were heated with 16 grams of phosphorus trichloride and the product treated as in the case of the diphenyl compound, The substance crystallised from ethyl acetate in radiating clusters of needles very similar to those formed by the diphenoxy-derivative, and melted a t 106-107°. The yield was 16 grams, or about 65 per cent. of the theoretical quantity. On analysis : 0.1991 gave 0.4339 CO, and 0.1087 H20. 0.5528 ,, 0.1945 Mg,P207. P = 9-79. I n aolubility and general properties, the substance is very similar to the corresponding diphenoxy-compound. Its ammonium salt, which was obtained in the form of silky crystals, is very soluble in water and is precipitated from a concentrated solution on the addition of ammonium chloride.Di-ptolytoxyisopropyl Chloride, CH,*C,H,*O*CH,* CHC1* CH,*O* C, 8,*CH3. The glycerol di-p-tolyl ether used in the two following experiments was prepared from epichlorohydrin and p-cresol (Lindeman, loc. cit.). It melted at 88O. The ditolyl ether and phosphorus pentachloride were mixed in molecular proportion, the containing vessel being immersed in cold water in order to moderate the vigour of the reaction. The resulting liquid was treated with hot caustic soda solution and then extracted with ether as in the previous cases. On evaporation of the C = 59.44 ; H= 6.12. C,,H,,O,P requires C = 59.59 ; H = 5-96 ; P = 9-60 per cent.AUTOFERMENTATIOX AND LIQUEFACTION OF PRESSED YEAST. 1227 ether, the residue solidified. Distillation in a vacuum mas therefore omitted and the substance crystallised at once from light petroleum. It separated in small but well-developed, transparent rhombohedra melting at 70'. 0.1665 gave 0.0514 AgC1. The properties of this substance are exceedingly eimilar to those of C1 = 12.09. C17H190,C1 requires C1= 12.1 9 per cent. the diaryloxyisopropyl chlorides already described. Di-p-toylyylox~isop~~o~~yl~~os~ho~o~s Acid, CH(CH,* 0. C,H,aCH,),*O*P(OH)2. This substance wasprepared in a manner quite analogous to that employed in the two previous corresponding cases. It crystallised from ethyl acetate in a very similar fashion, the crystals melting at 111-112°. On analysis : 0.4712 gave 0.1597 Mg,P,07, I n general properties, this substance ,resembles its two lower homo- logues very closely. It is precipitated from its aqueous solution on addition of hydrochloric acid, and its ammonium salt is precipitated on addition of ammonium chloride. The study of these and some allied compounds is being continued. P= 9.43. CI7H,,O,P requires P = 9.23 per cent. CHEMICAL DEPARTMENT, HARTLEY COLLICGE, SOUTHAMPTON,

ISSN:0368-1645    

DOI:10.1039/CT9017901221

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

AUTOFERMENTATIOX AND LIQUEFACTION OF PRESSED YEAST. 1227 CXXX-Auto fermeiztation and Liyue faction of Pressed Yeast. By ARTHUE HARDEN acd SYDNEY ROWLAND. IF a sample of washed and pressed yeast be kept in an open vessel, it will, in course of time, be observed to become darker in colour, and to change its dry, powdery condition, until, passing through all stages of pastiness, it finally becomes a thick liquid. In the course of a series of experiments on expressed yeust juice, it was found advisable to study this phenomenon, especially with regard to the influence of temperature upon it and upon the accompanying phenomena of evolution of carbon dioxide and absorption of oxygen, points which have not hitherto received attention from the authors1228 HARDEN AND ROWLAND : AUTOFERMENTATION AND who have described the liquefaction of yeast, or have studied the absorption of oxygen and evolution of carbon dioxide by yeast suspended in water, PFeparatiorz of Yeast.-The yeast employed in the following experi- ments was top yeast obtained from an English brewery.It was freed from wort by means of a small filter press, and washed with water until the washings were quite colourless. The pasty mass was then removed from the filter press and submitted to pressure in a hydraulic press. I n this WAY, the yeast was obtained as a friable, white mass, containing about 30 per cent. of solid matter at looo, and capable of being crumbled between the fingers. In$zcence of Temperature on Rate of Lipuefccction (Autoplasmolysis). -The rapidity with which liquefaction is accomplished varies greatly with the temperature, and also depends on the condition of the yeast, the length of time for which it has been kept, and the temperature to which it has been exposed.The following numbers apply to a sample of yeast which was skimmed on February 15th, washed and pressed on February 19th, and then a t once employed for the experiment. I n this case, liquefaction a t the ordinary te-mperature was delayed for more than two weeks, whilst a t 50' it occurred within so short a time as 1-14 hours, intermediate times being required at 26" and 39O. Temperature. Time of liquefaction. 14O 16 days. 26 53 hours. 60 1.25 hours, 39 5 9 ) These experiments were carried out in an atmosphere of carbon dioxide, so as to avoid any complication due to absorption of oxygen and consequent rise of temperature (see p.1231). Evolution of Carbon Dioxide (Autofermentation of Glycogen).-When yeast is preserved, the glycogen which is present in the cells gradually undergoes fermentation with production of carbon dioxide and alcohol. This phenomenon occurs both in the presence and in the absence of air, but in the former case it is accompanied by an oxidation process in which oxygen is absorbed. In order to ascertain the inffuence of temperature on the evolution of carbon dioxide alone, and to measure the extent of this evolution, the yeast was examined in an atmosphere of carbon dioxide or nitrogen, the nature of the indifferent gas being found to be immaterial. For this purpose, the washed and pressed yeast was rubbed into a fine powder and placed in a flask closed by an indiarubber stopper carrying two tubee, through which a current of carbon dioxide was passed to displace the air.The flask was then placed in an incubator a t the desired temperature and connected withLIQUEFACTION OF PRESSED YEAST. 1229 20 minutes .................. 4 0 , , .................. 1 hour ........................ 1 ,, 20 minutes ......... 2 hours ..................... 3 ,, ..................... an apparatus for collecting and measuring the evolved gases. This consisted simply of a bottle containing brine covered with a layer of oil, and connected by a syphon tube wibh a second graduated bottle, in which the brine displaced by the gas was collected and measured a t regular intervals of time.The following table and the curves on p. 1230 show the characteristic results thus obtained a t four different temperatures (50°, 39*, 2 6 O , and 14') with equal portions of a sample of yeast which contained 31.45 per cent, of solid matter a t 100'. One hundred grams of yeast :were taken in each case, and the gas was measured at atmospheric temperature and pressure over brine. 190 450 790 950 950 960 Table showing the rate of evolution of cadon dioxide by yeast exposed The time to dzferent temperatures in an indzyevmt atmosphere. of Eipwfaction is shown by the lcwger type. -____ 39". 110 210 330 475 905 1880 228 0 2400 2590 2590 26". 90 165 225 290 400 530 680 1505 2500 2695 2720 2730 14". 80 115 140 173 210 250 275 390 530 610 775 880 1320 1840 2128 2128 ~ ~~ I C.C.of carbon dioxide evolved at Time. I ____-- 1 50". ..................... .................... .................... ..................... ..................... ..................... ..................... ..................... ..................... ...................... These numbers and curves show, in the first place, that a t 50' the evolution of carbon dioxide commences with great rapidity, but is sud- denly interrupted by the liquefaction of the yeast, although micro- scopical examination reveals the presence of abundance of glycogen in the cells. I n the three other cases, however, the total volume of gas evolved does not differ very greatly, although there is a great difference between the rates a t which it is evolved. The maximum volume is produced at 2 6 O , and amounts to 2730 c.c., which corresponds to about 5.3 per cent.of the weight of the pressed yeast, or 16.8 per cent'. of the dry yeast present. It is to be noted that the evolution of gas ceases some time before liquefaction occurs. A t 3 9 O , the rate of1230 HARDEN AND ROWLAND : AUTOFERMENTATION AND evolution is considerably greater, but the total volume is slightly less, the shape of the curve suggesting that in this case, as a t 50°, the auto- fermentation is interrupted by the liquefaction of the mass. At 14", the rate of evolution is extremely slow, and the total volume only about 75 per cent. of that evolved at 2 6 O . This may possibly be due to the gradual exhaustion of the fermentative power of the cells. In every case, the yeast after liquefaction was capable OF growth in wort, although the samples which had been exposed to the higher temperatures commenced to develop only after a considerable time.3200 2800 2400 2000 %, 2 % 1600 1200 800 400 0 1 2 3 4 5 7 8 9 Time in days. The arrowhead shows time of liqzctfaction. It will be noted that the processes of liquefaction and evolution of carbon dioxide are interdependent in so far as evolution of gas never proceeds after liquefaction has occurred, although, on the other hand, the cessation of gas evolution does not necessarily imply immediate liquefaction. Relation of Alcoho2 to Carbon Dioxide produced by Autofemmntation of Glycogen.-The production of carbon dioxide by yeast kept in an atmosphere free from oxygen appears to be due t o a true alcoholic fermentation, inasmuch as alcohol is -produced in the characteristicLIQUEFACTION OF PRESSED YEAST. 1231 proportion to the carbon dioxide.Thus 100 grams of yeast containing 31.7 per cent. of solid matter gave, a t 37', 2160 C.C. of carbon dioxide a t 18' and 766.5 mm. pressure, or 4.01 grams, together with 3.61 grams of alcohol, allowance being made for the amount of alcohol originally present in the yeast. Hence the ratio of alcohol to carbon dioxide is 1 : 1.1, which agrees closely with the ratio usually found in the ordinary alcoholic fermentation, namely, 1 : 0.96. The slight deficit of alcohol is probably due to the over-estimation of the original alcohol of the yeast, which would include the amount formed during the heat- ing up of the water with which it was distilled.Absoiptivn of Oxygen.-The fact that yeast when exposed to the air absorbs oxygen is a well-established one, and the relation of this phenomenon t o the production of carbon dioxide by autofermentation has been studied by Schutzenberger (" Les Fermentations "), and by Grbhant and Quinquaud (Art%. sc. nat. Botccnique, 1889, p. 269, quoted by Duclaux, Trucit5 de Microbiologie, 3, 231), who examined the yeast suspended in pure water. The general result of these researches was that the amount of oxygen absorbed increases with the tempera- ture, the maximum obtained being 9.6 C.C. per gram of dry yeast per hour at 50°. The ratio of carbon dioxide to oxygen (respiratory quotient) was also found by Grbhant and Quinquaud to increase from 1.06 at 1 4 O to 4.5 at 46'.As these experiments had all been carried out with yeast suspended in water, it was thought advisable to re-examine the phenomenon as i t occurs in pressed yeast, since in this condition each cell is entirely dependent on the material contained within its walls, and complica- tions due to alimentary functions are eliminated. For this purpose, a current of air or oxygen was passed over the yeast at a known uniform rate, and the resulting mixture of gases was collected at equal intervals of time, measured, and then passed through potash and again measured. A record was thus obtained for successive equal intervals of (1) the volume of oxygen supplied, (2) the carbon dioxide evolved, and (3) the oxygen absorbed. I n order to effect this, oxygen was maintained at a constant pressure by means of a hydro- statically balanced valve in a gas-holder containing dilute caustic soda solution.The gas was then pumped through the yeast, contained in a glass cylinder, by means of two oscillating glass cylinders working in mercury, from which the gas was alternately discharged to the yeast and admitted from the reservoir, constancy of direction in the stream of gas being attained by a three-way tap changed over a t the end of stroke by a gravity trip gear. The varying pressure of the brine column contained in the collecting vessel was counterbalanced by means of a mercury valve arranged in such a manner that the pres- sure on the gas in the delivery tube of the pump remained constant,1232 HARDEN AND ROWLAND : AUTOFERMENTATION AND so that each stroke of the pump delivered exactly the same volume of gas.Under these circumstances, the phenomena observed were of the same general character as those described by previous observers. It was found almost impossible t o keep the temperature of the yeast constant during the course of such an experiment, owing to the large amount of heat evolved by the oxidation process, and in most cases, therefore, no attempt was made to do this, but the rise of temperature was observed by a thermometer inserted in the mass of yeast. I n a current of nitrogen at the temperature of the air, on the other hand, no rise of temperature was observable, the autofermentation of the glycogen being very slow at this temperature and there being no oxidation, to which the rise appears to be mainly due.CURVE 11. 6 12 18 94 30 36 42 48 54 Equal times ; pedods of Jive minutes. Nom.--In the m e of the curve showing the temperature efect, the ordinates represent degrees of temperature. The typical course of such an experiment, carried out with freshly pressed yeast in a current of oxygen, is shown by the accompanying curve (Curve II), which applies to 69-1 grams of yeast containing 27 per cent. of solid matter. The temperature gradually rose from 16.5' to 41*35O, and then slowly fell t o 22-45', at which point the experiment was discontinued, 4.6 hours after its commencement. During this time, 1103 C.C. of oxygen mere absorbed and 2148 C.C. of carbon--dioxide evolved, this being an average of 3.47 C.C.of oxygen and 6.76 C.C. of carbon dioxide per gram of fresh yeast per hour, or 12.85 C.C. of oxygen and 25.03 C.C. of carbon dioxide per gram of dry yeast per hour. This amount of oxygen, which represents the average of the whole experiment, is con-LIQUEFACTION OF PRESSED YEAST. 1233 siderably greater than the maximum amount observed by Schutzen- berger, which amounted to 9.6 C.C. and mas observed a t 50'. The respiratory quotient was 2-25 a t the highest temperature observed, and gradually fell to 1, the average being 1.94. The great ease with which gases penetrate the cell walls of yeast in this condition and come into equilibrium with the cell contents is illustrated by a phenomenon which was observed during these experi- ments. When yeast is allowed to stand for a short time, the cell contents become saturated with carbon dioxide.If now a measured volume of some indifferent gas be passed in, the partial pressure of the carbon dioxide being thus lowered, a large amount of the dissolved gas is at once liberated, so that there appears to be a sudden evolution of gas. Thus on passing 51 C.C. of nitrogen into 87 grams of pressed yeast contained in a cylinder connected to two gas burettes, no less than 90 C.C. of gas were at once obtained. When the yeast has been freed from carbon dioxide by a current of air or nitrogen, and carbon dioxide is then passed in, a very rapid absorption occurs, and in two or three minutes the yeast is again saturated. As the autofermentation of the glycogen in the absence of air had been found to correspond with normal alcoholic fermentation, a com- parison was instituted between the amount of carbon dioxide evolved in the presence of oxygen and in its absence, in order to obtain, if possible, some information as to the chemical action OF the oxygen, (1) One hundred grams of fresh yeast at 39' in absence of oxygen gave 1730 C.C.of carbon dioxide. One hundred grams of the same sample in a current of oxygen at 39' gave 2090 C.C. of carbon dioxide, 844 C.C. of oxygen being absorbed. Ratio of excess of carbon dioxide evolved in presence of oxygen to the oxygen absorbed = 2090 - 1730 = o,43. 844 (2) One hundred grams of fresh yeast at 39' in absence of oxygen gave 2160 C.C. of carbon dioxide, and in a current of oxygen gave 2370 C.C. of carbon dioxide, 635 C.C.of oxygen being absorbed. Ratio of excess of carbon dioxide to oxygen absorbed = 2370 - 2160 = o,33. 635 I f the oxygen oxidised the glycogen completely to carbon dioxide and water according to the equation C,H,,O, + 60, = 600, + 5H20, the amount of carbon dioxide evolved by the oxidation process would be three times that evolved by the normal fermentation process from the same weight of glycogen according to the equation C,H,,O, + H20 = 2C0, + 2U2H60, and hence the difference between the volumes of carbon dioxide1234 AUTOFERMENTATION AND LIQUEFACTION OF PRESSED YEAST. evolved in presence, and in absence, of oxygen should be two-thirds of the volume of the oxygen absorbed. As, however, the ratio of excess of carbon dioxide to oxygen absorbed was invariably found t o be considerably less than two-thirds, it appears probable that carbon dioxide and water are not the sole products of the oxidation.In view of the large amount of carbon dioxide evolved by yeast when it is exposed to a current of oxygen, an experiment was made to ascertain the limit of this evolution. Twenty-five grams of yeast, containing 31.1 per cent. of solid matter, were exposed to a current of oxygen at the temperature of the air, and the carbon dioxide absorbed in caustic potash and weighed. In 12 days, 3.7422 grams of carbon dioxide were collected, so that 1 gram of dry yeast gave 0.4812 gram of carbon dioxide=0.131 gram of carbon. Since dry yeast contains about 50 per cent. of carbon, it follows that in this case 26 per cent.of the carbon of the yeast was evolved as carbon dioxide. Microscopical Appearunce.-Coincident with the series of changes culminating in the liquefaction of the yeast, the following series of structural changes was observed microscopically. The freshly pressed yeast consists of large cells, with a small vacuole and granular proto- plasm, staining a deep brown with iodine. As the evolution of carbon dioxide proceeds, the vacuole increases in size, the brown stain obtained with iodine diminishes, and just before liquefaction there is usually no glycogen left in the cell. After liquefaction, the cells have no vacuole and are shrunken, the cell walls being crumpled and the cell substance highly granulated and contracted to a centrally aggregated mass, floating in a small amount of a clear fluid.No brown reaction with iodine is, as a rule, obtainable, and although in the case of yeast liquefied at SO", the brown stain is obtained, the cell does not in other respects differ from the normal char act er. It therefore seems probable that the liquefaction of the yeast is due to the discharge of the contents of the vacuole, and that the progressive increase in the size of the vacuole results from the accumulation of some substance produced along with carbon dioxide from the glycogen. O'Snllivan and Tompson (Trans., 1890, 57, 872) have described the liquefaction of yeast, but did not attribute the liquefaction of the mass to the discharge of the vacuolar fluid. On the contrary, they state that '' A microscopical examination at this stage shows that the yeast cells have shrivelled up into a comparatively small bulk, whilst their outline is irregular and ill-defined. The cell wall has almost entirely disappeared, but the large majority of the cells are unbroken. The vacuole occupies practically the whole of the interior of the cell, This point, however, requires Further investigation.SUEOXIDE OF PHOSPRORUS. PART 11. 1235 and the granulations are very marked, being, in fact, by far the most distinct feature of it.” I n all the numerous samples which have come under our observation, however, the phenomenon occurs as we have described it above, and the whole progress of the change, terminating in the extrusion of the contents of the vacuole has been watched on the hot stage. The cell wall, moreover, can be quite readily distinguished throughout the process. Our thanks are due to Mr. W. J. Young for some assistance in the experimental portion of the work. JENNZR INSTITUTE OF PREVENTIVE MEDICINE.

ISSN:0368-1645    

DOI:10.1039/CT9017901227

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

SUEOXIDE OF PHOSPRORUS. PART 11. 1235 CXXXL-Non-existence of the so-called Suboxide of Phosphorus. Parat 11. By CHARLES HUTCIIENS BURGESS and DAVID LEONARD CHAPMAN. IN a previous paper (Chapman and Lidbury, Trans., 1899,75,973), it was claimed : firstly, that the grounds adduced by previous investigators for the existence of a definite suboxide of phosphorus having the formula P40 are insufficient ; secondly, that the so-called suboxide of phosphorus, prepared by their methods, has properties identical with those of red phosphorus ; thirdly, that when the substance is carefully purified and analysed, the percentage of phosphorus is invariably higher than that required by the formula. Amongst the several ‘‘ suboxides ” prepared and examined by us was one recently obtained by Michaelis and ,Pitsch (Bey., 1899, 32, 337) by precipitating the red solution which results from the action of aqueous alcoholic potash on white phosphorus, with dilute hydro- chloric acid.The percentage of phosphorus found by us in the sub- stance was 90.5, which is 2 per cent. higher than that required by the formula P40, and in its properties the “suboxide” resembled the other preparations, A complete account of the experiments of Michaelis and Pitsch did not appear until several months after their first publication on the subject (Annalen, 1899, 310, 45). I n this paper? the authors lay claim to having prepared a substance free from hydrogen and other impurities, and containing the theoretical per- centage of phosphorus required by the formula, P40. It is moreover supposed to differ from amorphous phosphorus in its behaviour towards aqueous alcoholic potash.I n the present communication, we shall explain why Michaelis and1236 BURGESS AND CHAPMAN: NON-EXISTENCE OF THE Pitsch’s results cannot, in our opinion, be regarded as proof of their conclusions, and shall describe experiments which confirm the views already expressed by Chapman and Lidbury.” The Composition of the so-called Suboxide. Our analyses show : firstly, that the percentage of phosphorus in the ‘‘ suboxide ” prepared by Michaelis and Pitsch’s method varies from 86 per cent. to 93 per cent.; secondly, that hydrogen is always present in considerable quantity ; thirdly, that other impurities, amongst which is carbon, are also present. The explanation of the striking difference between these results and those of Michaelis and Pitsch is, we believe, to be found in the method of analysis employed by them to estimate the hydrogen.I n the first place, the substance was gently heated before the analysis for hydrogen was made, in order to drive off the water which they and previous observers had found to be present. The anthors evidently regard this moisture, the presence of which was directly proved by heating with copper oxide, as entirely derived from the atmosphere during manipulation, but if this view as to its source is incorrect, then the process of heating can only result in removing before analysis part of the water which it is their object to find, Some idea may be gained as to the rate at which moisture is absorbed from the air from the following experiment.0.5946 gram of the substance was introduced into an open, wide-mouthed tube, and the rate of increase in weight observed. I n 10 minutes it gained 0*0006 gram, in 35 minutes 0.0014 gram, and in 135 minutes 0.0036 gram. Another point in connection with their experiment deserves atten- tion, The hydrogen in the previously warmed suboxide was estimated by heating it with lead oxide in a combustion tube, and driving the resulting water by means of a current of dry air into a, weighed calcium chloride tube. During the heating of the mixture of suboxide and lead oxide, a cloud was formed, which was so difficult to control that it could not be prevented from entering the calcium chloride tube. If the cloud were due to phosphorus pentoxide, and this does not seem unlikely, it would, unless the utmost precautions were taken t o cause it to combine with the lead oxide, retain a large proportion of the water in the combustion tube.Again, there is no mention of the lead oxide having been heated while the current of dry air was drawn through, a precaution which certainly seems necessary. By carefully washing and drying the substance, prepared with all the precautions given by Michaelis and Pitsch, Chapman and Lidbury * Michaelis and Arend (Annalen, 1901, 314,2d9) have recently published a paper on the same subject, to which we shall also have occasion t o refer later,SO-CBLLED SUBOXIDE OF PHOSPHORUS. PART 11. 1237 found that the phosphorus exceeded by 2-3 per cent.that required by the formula P,O. Michaelis and Arend, in reply, state that the solu- tion should be cooled t9 Oo, and the precipitation of the red solution effected with acetic in the place of hydrochloric acid, and that under these circumstances the substance will not contain an excess of phos- phorus. From our point of view, the acetic acid is only another possible source of impurity, and it is not at all surprising that the percentage of phosphorus should have been by this means reduced. We have in the present research made no serious attempt to free the red phosphorus from this impurity, but we have simply adopted Michaelis and Arend’s method of preparation, and shown by analysis that the substance obtained cannot have the formula P,O. Estimation of the Phosphorus in the so-called Suboxide.-The specimen was weighed out into a Geissler flask, and dissolved in a small quantity of dilute nitric acid by warming on the water-bath.As soon as the solution was complete, strong nitric acid was alIowed to flow down the condensing tube together with a few C.C. of hydrochloric acid, and the mixture heated on the water-bath for 12 hours. The contents of the flask were then washed out into a large porcelain basin, and the excess of acid evaporated off, I n order to be quite certain that no error was introduced from the action of the acid on the glass, the phosphoric acid was first precipitated with ammonium molybdate. The ammonium magnesium phosphate obtained from this in the usual way was dissolved in hydrochloric acid, and reprecipi- tated by the very slow addition of ammonia from a burette with constant stirring, 10 C.C.of magnesia mixture being added before the whole was left to stand, Estimation of the Hydrogen in the so-called Su6oxide.The method employed consists in distilling the specimen, whereby phosphorus vapour, steam, hydrogen, and phosphoretted hydrogen are formed, The phosphorus vapour is made to combine with copper, and the water is decomposed by red hot aluminium, EO that it is thus possible to obtain all the hydrogen as gas. To avoid the absorption of moisture during manipulation, a soft glass tube, B, was closed at one A B end, and another tube, A , was ground into the other end. A was drawn out to a fine capillary which communicated with the air. The specimen can be kept for days in such a bottle without any appreciable alteration in weight.The weighing bottle was dried in an air-bath, the ‘‘ suboxide ” rapidly introduced, and the stopper, A , inserted, the weight of the bottle having been previously obtained. After finding VOL. LXYIX. 4 Q1238 BURCIESS AND CHAPMAN: NON-EXISTENCE OF THE the weight of the specimen, the hydrogen was estimated in the following manner :- A hard, Jena glass tube of 8 mm. internal diameter was closed at one end, and the bottle, A , which contained I' suboxide," dropped to the bottom. A glass rod, B, was then introduced, and about one-half of the remainder of the tube was first tightly packed with clean copper gauze, C, and then with rolls of aluminium foil, D. The surface of the aluminium foil had been previously cleaned by warming with ether for many hours.The Jena tube was fixed in a horizontal position, and communicated through a phosphoric oxide tube with a continuous Sprengel pump. It was thus left, with the pump working, until a good vacuum had been obtained. The part of the tube containing the copper and aluminium was then heated to a temperature at which the aluminium just began to melt. A carefully chosen tube will stand the pressure of an atmosphere at this temperature. During this heating, a little gas was pumped out from the aluminium and copper, but the volume rapidly diminished, and was soon D C B A negligible. On heating that part of the combustion tube which contained the " suboxide " with a Bunsen burner, hydrogen was evolved in considerable quantity, and continued to come off until all the phosphorus had volatilised.The gas was collected at the pump, and retained for analysis. The residue remaining in the bottle, which contained the suboxide, was a perfectly black, non-volatile substance, .and was proved to contain both carbon and phosphorus," I n two experiments, the substance was heated in the same way as described above, with the excoption that no copper or aluminium was introduced into the combustion tube. The amounts of hydrogen were in these cases also far too large to allow of the substance having the formula P,O. Examination of the Gas EztoZued.-The samples of gas which had been collected at the pump were transferred to a eudiometer andexploded with * This residue will not burn in oxygen even when strongly heated.I n one experiment, it was shown to contain carbon by heating it with lead chromate in a Combustion tube and collecting the carbon dioxide in potash.SO-CALLEb SUBOXTDE OF PHOSPHORUS. PAKT 11. 1239 excess of oxygen. I n several cases, the contraction occurring was too large for pure hydrogen. This was apparently due to the presence of some hydrocarbon, since the gas remaining after explosion was in these cases partly absorbed by potash, The improbability that the substance examined is the oxide P,O is just as great whether the gas contained a hydrocarbon or consisted of pure hydrogen. Pwpamtion of the Samples.-SnmpZe I was prepared by precipitating the red solution which results from the action of aqueous alcoholic potash on white phosphorus with very dilute hydrochloric acid.The details given by Michaelis and Pitech (Annalen, 1899, 310, 56) were observed, the only variation being that the hydrochloric acid was kept in constant rotation by means of an automatic stirring apparatus. After allowing one quantity of the red solution to pass through the filter paper, the hydrochloric acid was left to stand for some time, in order to regain the temperature of the laboratory, before another quantity was prepared and filtered. As only a small amount of the substance was prepared and the time taken in its preparation was considerable, we are inclined to think that the low percentage of phosphorus is due to the action of the caustic alkali on the filter paper. The washing and drying were performed as described by Michaelis and Pitsch.The complete analysis shows that the substance cannot be a suboxide, P,O. The clear red solution was allowed to run from a separating funnel, drop by drop, into very dilute hydrochloric acid, which was kept stirred as before. The acid was cooled from time to time with cold water. The precipitate was washed successively with water, alcohol, and ether, and then with carbon disulphide, which has been shown to remove ordinary phosphorus completely from such a preparation (Chapman and Lidbury, Zoc. c&, p. 976), should i t happen to contain any. It will be seen from the analytical numbers that the amount of phosphorus is 4.3 per cent. higher than that required by the formula P,O, also that the black residue left on distillation in a vacuum is much smaller than in sample I.The sample wad completely soluble in aqueous alcoholic potash. Xarnple I11 was prepared exactly according to the new directions given by Michaelis and Arend (Zoc. cit., p. 263), the utmost precautions being taken to keep both the red solution and the precipitating acid at 0'. The percentage of phosphorus is still 1.5 per cent. higher than that required by the formula P,O, A'amyde I T was prepared from ammonium hypophosphite in the following way (Michaelis and Arend, loc, cit,, p. 266). Thirty grams of ammonium hypophosphite were dissolved in 100 grams of glacial acetic acid, and 45 grams of acetic anhydride were gradually added. Xccmple I1 was prepared without employing filter paper. The red solution was prepared from sample IV.4 Q 21240 BURGESS AND CHAPMAN : NON-EXISTENCE OF THE The mixture was warmed on the water-bath until a precipitate began to appear. It was then cooled, another 45 grams of acetic anhydride were added, and tbe mixture was heated again on the wnter-bath. Finally, the whole was poured into excess of water, filtered, washed, and dried. We experienced great difficulty in removing acetic acid from this precipitate by washing. The analysis shows that the sub- stance cannot be the oxide, P,O. Sampls Y was prepared from sample IV by warming for some time on the water-bath with dilute hydrochloric acid. This removed the im- purities to such an extent that the amount of phosphorus rose 1 per cent. Xample YI was prepared from the red solution, obtained by dissolving sample IV in aqueous alcoholic potash, by precipitating with hot hydro- chloric acid (one volume of strong hydrochloric acid to two volumes of water).Analytical Results.-The analytical results obtained were : Sample. 1. 11. { 111. { IV. { v. VI. Per- centage uf P. a6 7 92'87 92.81 90'01 86 5 0 ~ 7 . 5 ~ 89.75 C.C. of hydrogen per 0.1 gram of substance. 11.14 8.87 8-13 7.05 3-63 7 *55 4 '72 7-51 Contraction Found 1 C.C. 17.06 13.35 12.17 contraction 7 -66 12.97 7'43 Calculated for hydrogen, C.C. 16-71 13'31 12-19 not found 5-45 11.33 7-07 Residue per 0.1 gram. Gram. 0.0059 0-0013 0'0029 0'0052 0-0045 Formula, as- suming that the substance is a chemical com- pound, and neglecting residue. Since 0.1 gram was ahout the amount of substance taken, the hydrogen is calcu- In calculating the formula in the last column, no allowance is made for the residue, The second value for the hydrogen with samples I11 and I V was obtained when It lated as c.c., and the residue as grams per 0.1 gram of substance.and therefore the number attached to the oxygen is somewhat too large. the substance was distilled in a tube which contained no copper or aluminium. was smaller becalise the water vapour was not decomposed. In this experiment, the residue was heated with a solution of potash, and then This residue gave, on combustion with lead chromate, 0'0006 gram of carbon. a This does not represent all the hydrogen which can be obtained by heating alone, since during the experiment the stopper came out of the little bottle, and ~ o m e of the " suboxide " was blown through the tube by the escaping hydrogen.* The absorption which occurred on the addition of potash after explosion was 0.77 C.C. The residue gave, on combustion with lead chromate, O*OOQQ gram of carbou. washed with water, proving that a considerable portion is insoluble in potash.60-CALLED SUBOXIDE OF PHOSPHORUS. PART 11. 1241 Michael+ und Pitsch's Pure and Impure Suboxides. Michaelis and Pitsch distinguish between impure suboxides, which are supposed to contain red phosphorus and solid phosphoretted hydro- gen, and p w e suboxides, free from these substances. The following are their analytical numbers for the impure preparations : P 90.35; 90.1 89.80; 89-72 90.48 90.89 91.85 per cent. H 1-73 0.3 1.36 0.95 1.95 ,, The calculated percentage of hydrogen in the compound P,H, is 1-58, and therefore some of the impure suboxide specimens contain more hydrogen than the solid hydride of phosphorus to which the impurity is supposed to be due.Again, there is nothing in the methods of preparation of the impure and pure substances to suggest such a marked difference in composition as the authors claim for them. For example, a pure suboxide containing no hydrogen is obtained by the action of acetic anhydride on ammonium hypophosphite, and an im- pure substance, containing a large percentage of hydrogen, by the action of acetyl chloride on hypophosphorus acid. Our analytical numbers afford a strong oonfirmation of the view already expressed that the '' suboxide of phosphorus " is only impure red phosphorus.The Red Xolution of Phosphovus in Aqueous Alcoholic Potash.--When ordinary phosphorus is dissolved in aqueous alcoholic potash, a red solution is obtained. The solution, when first formed, is apparently quite clear, but on allowing it to remain at the temperature of the laboratory, it rapidly decomposes with evolution of hydrogen and phosphoretted hydrogen, and loss of colour. If a strong solution is allowed to decompose, it becomes muddy, and a brown solid slowly settles to the bottom, When the solution is kept at Oo, the same changes take place, but much more slowly. On warming on the water- bath, the decomposition proceeds very rapidly, and no brown solid is formed. The point to be borne in mind is that the red solution itself, when separated from the phosphorus from which it is obtained, is at the ordinary temperature very unstable, and readily decomposes with evolution of hydrogen and phosphoretted hydrogen.Now, some stress has been laid by Michaelis and Pitsch upon the supposed fact that ordinary phosphorus is soluble in aqueous alcoholic potash with evolution of hydrogen, whereas the '' suboxide " dissolves in it without liberation of this gas, which would indicate, if the observation were correct, that phosphorus must be partially oxidised before solution can take place. On performing comparative experiments, we find that the 4' suboxide '' and ordinary phosphorus dissolve in aqueous alcoholic --1242 BURGESS AND CHAPMAN : SOX-EXISTENCE OF THE potash at the ordinary temperature, in both cases with evolution of considerable quantities of hydrogen.A t Oo, the ‘( suboxide ” dissolves very much more rapidly than ordinary phosphorus, and in neither case is an appreciable quantity of hydrogen given off. The hydrogen can, therefore, in all cases be regarded as derived from the decomposition of the red solution, and certainly affords no evidence of the state of oxidation of the substances dissolved. No conclusions can be drawn from the relative rates of solution of the two substances, since the particles of the one are so small that their shape can scarcely be seen under a microscope (one-sixth inch objective), whereas the granules of the other can readily be seen with the naked eye. If ordinary phos- phorus could be obtained as finely divided as the “suboxide,” there is every reason for thinking that the red solution mould be formed at least as readily in the one case as in the other.The red solution may be precipitated either by neutralisation with an acid, or by the addition of an ammonium salt. The colour of the precipitate obtained with a strong acid is light yellow or green, with a weak acid it is a darker green, and with ammonium chloride it is still darker. The dark precipitates, when warmed with a strong acid, become bright yellow, indicating that the dark colour is probably due to the presence of a base in the precipitate, which can only be com- pletely removed by a strong acid. The substances obtained in the absence of any base are always bright yellow, such, for example, as the ‘‘ suboxide ” formed by the action of acetic anhydride on hypophos- phorus acid.It may here be mentioned that the brown solid, obtained by the decomposition of the dark red solution, becomes bright yellow when warmed with hydrochloric acid. Michaelis and Pitsch assert that certain specimens of impure “ sub- oxide” leave a residue of red phosphorus when dissolved in aqueous alcoholic potash. All our preparations, whether they contain 94 per cent. or only 86 per cent. of phosphorus, are completely soluble in this reagent, and a precipitate is formed only on allowing the resulting clear red solution to stand. Concerning the nature of the red solution, it may be pointed out that the presence of alcohol greatly accelerates the solution of flowers of sulphur in potash, persulphides being formed, By analogy, we are led to suspect that the solution of phosphorus in the same reagent contains a perphosphide.This supposition, if correct, would account for its colour, and for the precipitation of phosphorus on the addition of an acid. The potassium phosphide is soluble in alcohol with forma- tion of a deepred solution, but the reaction is so violent that it is attended with considerable decomposition,SO-CALLED SUBOXIDE OF PHQSPBOBUS. PART 11. 1243 Solubility of Red Phosphorus in, Aqueous Alcoholic Potash. Besides establishing a very close relationship between the so-called suboxide of phosphorus and red phosphorus in other respects, Chapman and Lidbury have shown that Pedler’s phosphorus (obtained by the action of sunlight on a solution of phosphorus in carbon disulphide) is, like the “suboxide,” soluble in aqueous alcoholic potash.This form of phosphorus was used because it can easily be obtained in a fine state of division. Michaelis and Arend find that this phosphorus contains, as might be expected, both carbon and sulphur, and they believe that some oxygen is also prosent, which is derived from the wash-water by the substitution of oxygen for gulphur. By using carbon tetrachloride in the place of carbon disulphide as a solvent for the phosphorus, they obtained, by the action of sunlight, a substance which they were unable to dissolve in aqueous alcoholic potash. It is not, however, necessary to consider the ex- periments of Michaelis and Arend on this point in detail, since the com- plete solubility of red phosphorus in aqueous alcoholic potash is so easily proved that it cannot for a moment be doubted. To establish this fact, the following experiments were per- formed.The apparatus employed to prepare the red phosphorus is shown in the accompanying diagram. The tube B was partially filled with red phos- phorus, which was prevented from entering A by means of a tight plug of glass wool. The red phosphorus, before being introduced into the tube, was washed in turn with water, alcohol, and ether, and dried in a vacuum over phosphoric oxide. The T-piece, B, was fused on to a tube, which communicated through a phosphoric oxide tube with an automatic Sprengel pump in such 4 manner that A and B were horizontal. After exhaustion, the phosphorus was very slowly dis- tilled into A .During the distillation, a little hydrogen was evolved which was pumped out of the apparatus after sufficient phosphorus CLASS W O O L .1244 SUBOXIDE OF PHOSPHORUS. PART 11. had come over. The tube A was finally fused off at E and F, and the phosphorus was distilled into the end remote from the tube D. The ordinary phosphorus may be completely reconverted into red phosphorus by passing the silent discharge through the vapour. This was done by connecting one pole of an induction coil with copper wire wrapped round the middle of the tube A, and the other pole with mercury con- tained in D. The conversion takes place only slowly a t the ordinary temperature on account of the low pressure of the vapour; it is, however, accelerated by heating the tube to 100' in an air-bath.The red phosphorus was deposited over the inner surface of the tube. When it was thought that the conversion was complete, the tube was opened under carbon disulphide, and allowed to remain in contact with this liquid for Bome hours. The carbon disulphide did not leave any residue of phosphorus on evaporation. The red phosphorus was finally removed from the walls of the tube, ground in a mortar, col- lected on a filter paper, and washed with ether. On treatkg the product with aqueous alcoholic potash, a deep red solution passed through the filter paper, and this gave a voluminous precipitate with hydrochloric acid. A residue consisting of much larger grains dis- tinctly visible to the naked eye remained bebind, which was rendered soluble by regrinding.The same experiment may be performed with commercial red phos- phorus. The sample used by us was in the form of a powder, and did not contain ordinary phosphorus. It was reduced to a fine powder by grinding in an ordinary porcelain mortar. An agate mortar cannot be used for this purpose as its surface is so smooth that the pestle slides over the particles. The fine powder, after being washed successively with hydrochloric acid, alcohol, and ether, was readily soluble in aqueous alcoholic potash, giving a considerable quantity of a deep red solution, which was then precipitated by hydrochloric acid. The residue re- maining on the filter paper was easily rendered soluble by regrinding. By repeating the process of grinding several times, all the phosphorus, with the exception of a small quantity which could not be removed from the filter paper, was coaverted into the red solution. Conclusions. From the experiments described in this paper, and from the facts established by Chapman and Lidbury, we conclude : (1) That no suboxide of phosphorus having the formula P,O has ever been prepared, because the percentage of phosphorus is variable, and because the latest substance, described as having the composition P,O, contains other elements in addition to phosphorus and oxygen, hydrogen being present in considerable quantity.ACTION OF AMMONIA ON METALS AT HIGH TEMPERATURES. 1245 (2) That the substance described as a suboxide of phosphorus is impure red phosphorus, because the properties of both are the same, and because direct analyses have shown that the impurities in the alleged suboxide (regarding it as red phosphorus) are such as might be expected from the methods of preparation. THE OWENS COLLEGE, MANOHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9017901235

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

ACTION OF AMMONIA ON METALS AT HIGH TEMPERATURES. 1245 CXXXI1.-The Action of Ammonia on Metals at High Tempeq*a t ures. By GEORGE THOMAS BEILBY and GEORGE GERALD HENDERSON. TEN years ago, while one of the authors was engaged in developing an industrial process which involved the passing of large volumes of ammonia gas through metal tubes at a red heat, some striking obser- vations were made. In the first place, the statement of Rameay and Young (Trans., 1884, 45, SS) that ammonia is decomposed into its elements with great rapidity by red hot iron was amply confirmed. When a current of ammonia at the rate of 4 litres per minute was passed through an iron tube 12.5 mm. in diameter and heated a t 810° for 300 mm. of its length, only 27 per cent. of the ammonia escaped decomposition, 73 per cent., or nearly three-fourths of the whole, being decomposed, The velocity of the current through the heated part of the tube was about 1.5 metres per second, so that the ammonia molecules were only exposed to the hot metal for one-fifth of a second.Various observers had found that, for equal surfaces, copper has much less action on ammonia than iron. Experiments were accordingly made, using a solid drawn copper tube instead of an iron one. Under similar conditions of temperature and ammonia current, the quantity of ammonia decomposed by the copper tube in a given time was only about one-third of the quantity decomposed by the iron tube. This result was, so far, encouraging, and an attempt was made to use copper tubes for the industrial operation.However, after exposure t o ammonia at a temperature of 800" for a few hours, the tube became so short and brittle that i t could not bear its own weight without breaking, The next step taken was to strengthen the copper tube by slipping over i t a sleeve pipe of iron, which fitted tightly and gave the necessary strength to resist bending or breaking. Thus protected, the copper tube could not break or crumble away, but it was soon found that it tended to close up until only a very small amount of gas could pass through it, Examination showed that the walls of the copper1246 BEILBY AND HENDERSON: THE ACTION OF tube had become very much thickened, and being unable to expand outwards, owing to the sleeve of iron, had expanded inwards until the bore of the tube was nearly closed.Observation with the microscope showed that the copper had become spongy and disintegrated through- out. It retained its colour, and, to a certain extent, its metallic lustre, but it appeared as if it had been in the fluid state, and blown up into a sponge by innumerable minute gas bubbles. Not only was the copper acted on, but the iron sleeve pipe had been reached and pene- trated by the ammonia molecules. The iron pipe had becomeas brittle as hardened steel, so that it could be shattered by a blow with a hammer, and showed a bright, silvery fracture. Under the micro- scope, the iron also exhibited a spongy structure. At this time, a number of other metals and alloys were experimented with, in the hope that something might be found which would resist the action of ammonia at a high temperature.Nickel, silver, platinum, gold, as well as a variety of alloys, were tried, but in every case the metal acquired the same spongy structure, and its strength and tenacity became seriously deteriorated. No metal we have tried is able to resist the attack of the ammonia molecule at a high tem- perature. To the already long list of the formidable properties of the nitrogen atom must now be added this power of attacking and disin- tegrating the most massive and refractory of metals, not even the noble metals being proof against its assaults. In the case both of the iron and thecopper tubes, it was found that under uniform conditions the quantity of ammonia decomposed re- mained fairly constant. While the continued action of ammonia tends todisintegrate the copper more and more, the greater surface thus exposed does not appear to add sensibly to the decomposition of ammonia by a given mass of metal.During the whole life of the protected copper tube (about 150 hours), the amount of ammonia decomposed did not vary much from 1 gram per minute. On the total life of 150 hours, this amounted to 9000 grams. This quantity of ammonia was many times the weight of the copper which decomposed it. It was evident, therefore, that the amount of ammonia decomposed was not in any way limited to what would be required to form a nitride or a hydride of copper. Examination of the decomposed gases showed that, on the average, the nitrogen and hydrogen were present in the proportion of 1 : 3 by volume.On the other hand, the appear- ance of the metals after exposure to ammonia clearly indicated that the melting point of the metal had been lowered by the action, and, therefore, that chemical combination between the metal and one or other of the gases had taken place at some stage in the operation. To produce a spongy mass? the metal must have been, at any rate, in a plastic or semi-fluid condition, but the struCture rather suggested thatANMONIA ON METATS AT RIGH TEMPERATURES, 1247 the metal had been suddenly cooled while in the act of boiling, bubbles in every stage of formation and bursting being fixed in the solidified metal. A spongy state may be produced in a material which is merely plastic, but this appearance of boiling could only be found in a material which had been fairly fluid.The temperature of the experi- ment was far below the melting point of copper or iron, therefore a t some stage in the operation a more fusible compound must have existed. As everything pointed to the continuous formation and de- composition of some compound of the metal with ammonia or one of its constituent elements, some preliminary experiments were made to ascertain how far combination was taking place. Rolls of fine wire gauze of copper and of iron were heated in a porcelain tube a t 800°, and a current of ammonia a t the rate of 65-7 litres per minute was passed through the tube for 70 minutes. The following results were obtained, Weight of copper gauze before treatment, 42-04 grams ; after treatment, 43.92 grams-a gain of 1.82 grams, or 4.47 per cent, Weight of iron gauze before treatment, 18.87 grams ; after treatment, 20.02 grams-a gain of 1.15 grams, or 6.09 per cent.The iron gauze had become so brittle that it could not be bent without breaking, Its colour was bright silvery-grey, and under the microscope the spongy structure mas very well marked. The copper gauze had become equally brittle. I t s colour was a bright pink, and its surface was so completely disintegrated that metallic lustre had disappeared. Under the microscope, the bubble structure was very obvious. With both metals, the diameter of the wires had increased two or three times. As already stated, a number of other metals were exposed to ammonia at a red heat. Although the energy of the action varied to some extent, all without exception were attacked in the same may, and became spongy and disintegrated.Even in the case of those metals, for example, gold and platinum, which did not show any obvious increase in weight through absorption of nitrogen, the appearance under the microscope was the same, and indicated that the action of ammonia had produced a certain degree of fluidity. This was shown in an inter- esting way when wires of different metals were twisted together and then heated in a current of ammonia. I n many cases it was found that these metals had flowed together; thus, iron and copper, iron and gold, gold and platinum, gold and silver, became fused together. I n the case of iron and gold, the gold sometimes flowed over the surface of the iron, forming a complete plating.Up to this point, the investigation of this matter had been prosecuted mainly with the object of finding a suitable material for making tubes to resist the action of ammonia a t a red heat. Two years ago, the authors began a more systematic examination of the behaviour of various metals under the action of ammonia. The scope of the inves-1248 BEILBY AND HENDERSON: THE ACTION OF tigation was not restricted to the study of the chemistry of certain nitrides, but was intended to cover the physical as well as the chemical action of gases on metals a t high temperatures. The remarkably energetic action of ammonia on all metals at a high temperature, and the interesting physical changes in the metals brought about by this action, very naturally suggest that this particular case of the mutual action of gases and metals may supply a key to the study of the whole subject.It is not possible to examine the specimens of various metals which have been subjected to this action without being impressed with this view of the phenomenon and its probable bearing on the whole question of the occlusion of gases by metals, and the permeability of metals by gases. The general method of experiment followed has been to pass a current of dry ammonia gas over the metals in the form of rod, wire, sheet, or foil, or sometimes in a fine state of division. The metals were placed in a porcelain tube, glazed inside and outside, and heated in a gas furnace to varying degrees of redness. The temperature was determined sometimes by the melting of pure salts and sometimes by a Le Chatelier thermo-junction. In the experiments carried out at temperatures below 500°, the tubes containing the metal mere heated in a Meyer air-oven, As a general rule, a very rapid current of ammonia was passed through the tube, since experience showed that it was desirable that the gas should be present in large excess.After each experiment, the specimen of metal was left to cool in a current of ammonia before removal from the tuba Preliminary experiments proved that little or no decomposition of the ammonia resulted from passing the gas through a glazed porcelain tube 50 em. in length and 12.5 mm. i n internal diameter, even at a temperature of 850O. Many series of experiments were carried out in which the conditions were varied with respect t o the state of aggregation of the metal, the velocity of the current of ammonia, the temperature to which the metal was heated, and the duration of the experiment.The results of the numerous experiments are summarised in the following para- graphs. Iron. In January last, Mr. G. J. Fowler published an exhaustive paper on the formation of iron nitride by the action of ammonia on finely divided, freshly reduced iron (this vol., p. 285). Our independent con- clusions as t o the formation and decomposition of iron or copper nitride (arrived at nearly ten years ago as a result of working on an industrial scale), namely, that formation of the nitride occurs in presence of excess of ammonia molecules, whilst decomposition takes place when hydrogen molecules are present in excess, are aompletely confirmed byAMMONIA ON METALS AT HIGH TEMPERATURES.1249 Fowler's experiments with iron. We do not, therefore, propose to publish results which are simply a repetition of his, but as the con- ditions under which many of our experiments were carried on were different, we give a summary of our conclusions. In the experiments upon iron, the metal was used in the form of fine gauze, wires of different thickness, or rods. The general results of a large number of trials under varying conditions were as follows. When iron in the compact state is heated in a current of ammonia under the necessary conditions, it is more or less completely converted into a nitride of iron of the formula Ee4N2,* which possesses character- istic properties of its own.A nitride of this forniula contains 11.13 per cent. of nitrogen. We obtained products containing up to 10.59 per cent. of nitrogen, although, if the conditions were not favourable, smaller proportions of the nitride were formed. The essential conditions for the formation of nitride of iron by the direct action of ammonia on iron in the compact state are, first, the presence of ammonia in large excess, and second, a sufficiently high temperature. If these conditions are satisfied, the action takes place with remarkable rapidity. An iron rod one-quarter of an inch in diameter was penetrated to the centre in 30 minutes when heated to bright redness in a rapid current of ammonia. Unless care is taken to ensure the presence of a large excess of ammonia, very little or absolutely none of the nitride is obtained, but at the same time, the ammonia is more or less completely decomposed into its elements and the physical properties of the iron undergo an extraordinary change. It becomes highly lustrous and very brittle, and when examined under the microscope exhibits no trace of crys- talline structure, but only the porous or spongy structure already referred to.It is evident that, under the conditions of our experi- ments, nitride of iron is not stable except in presence of excess of ammonia, and that the great alteration in the structure of the iron, even when no nitrogen is permanently fixed, is due to the continuous formation and decomposition of the nitride. Nitride of iron can be produced from the compact metal within a fairly wide range of temperature.According to our experiments, the formation of the nitride begins somewhat below 450", although the action is very slow at that temperature, and the nitride can also be produced a t the highest temperature attainable in our furnace (850-900°). There is, however, no reason to suppose that the latter temperature represents the highest limit at which the formation of nitride is possible. The most favourable temperature depends largely upon the state of aggregation of the iron, and particularly upon the * The formation of this nitride was first established by Stahlschmidt (Ann. Phgs. Chem., 1864, [ii], 125, 37).1250 BEILBY AND HENDERSON: THE ACTION OF surface exposed to the action of the ammonia.Thus, using a fine wire of 0.3 mm, diameter, the action proceeded most rapidly, and the largest proportion of nitride was obtained at a temperature somewhat below 650°, but when thicker wires or rods were used the most suitable temperature was found to be 800-8850°. As regards the properties of nitride of iron, our results generally corroborate those of Fowler. The nitride is very readily soluble in dilute hydrochloric or sulphuric acids, and it was proved by analysis that the whole of the nitrogen is then liberated in the form of ammonia. When heated to redness in a current of hydrogen, it is completely decomposed into iron and ammonia, and it is also decom- posed when exposed t o the action OF steam at a red heat. I t can, however, be heated to a high temperature in a current of ammonia without undergoing any change.Iron gauze or mire, when converted into nitride, acquires a silvery-grey colour and retains its external form, but the surface is penetrated by innumerable cracks and acquires a peculiar, ( ( blistered ” appearance, whilst in the case of the thicker wires the surface is also dotted over with crater-like openings with raised edges, as if bubbles of gas had forced their way through a fused or semi-fused mass. The product is so brittle that it can easily be broken into fragments with the fingers, and crushed to powder in a mortar. Under the microscope, the powder appears to consist of aggregates of lustrous, silvery particles, more or less spherical in form, which evidently had aolidified from a fused, or at least pasty, state.When experirnentswiththickwiresor rods were interrupted after passing the ammonia for short periods, a core of unaltered iron remained, whilst the outermost part was wholly converted into nitride. Pure iron is rendered hard and brittle like steel by the absorption of small quantities of nitrogen. Tubes of malleable iron, alter exposure for 7 days to the action of ammonia at 800°, became so brittle that they could be broken like porcelain by a blow with a hammer, and a rod of charcoal iron was made so hard that it could be used as a drill. It appears not improbable, in the authors’ opinion, that some at least of the effects on the structure and properties of iron and steel which are at present attributed to other elements may in reality be due to the presence of traces of nitrogen, The conflicting statements of earlier observers regarding the action of ammonia on iron a t high temperatures can be reconciled if it is remembered, first, that although the physical properties of the metal are altered, no nitride is permanently formed unless the necessary condi.tions are observed; and second, that the proportion of the metal converted into nitride in a given time is dependent on the state of aggregation of the iron, as well as on the temperature and the quantity of ammonia present,AMMONIA ON METALS AT HIGH TEMPERATURES. 1251 Colialt. I n preparing cobalt nitride, we used the metal in the form of the powder obtained by reducing pure oxide of cobalt with hydrogen. When heated at a high temperature in ammonia, cobalt behaved similarly to iron as regards the decomposition of the ammonia into its elements, but no nitride was formed. At a temperature of about 500', a slight increase in the weight of the metal was noted, and at a some- what lower temperature the metal combined slowly with nitrogen until finally a product containing 10.33 per cent.of nitrogen was ob- tained. A nitride of cobalt of the formula Co4N, contains 10.63 per cent. of nitrogen, hence the conversion of the cobalt into nitride was practically complete. The formation of nitride of cobalt can only proceed within :much narrower limits of temperature than that of nitride of iron, even when, as in all our experiments, ammonia is present in large excess. Thus, for example, a sample of cobalt which gained in weight slowly when heated in ammonia at 500°, lost again when the temperature was raised to 600'; The most favourable tem- perature for starting the formation of the nitride appears to be about 470'; once the absorption of nitrogen has begun, the temperature may with advantage be lowered somewhat below this point.Nitride of cobalt was obtained as a dull greyish-black powder. Under the microscope, the particles of powder are seen to be composed of aggregations of minute particles which are all more or less lustrous and to some extent spherical in form, a3 if they had been at any rate in a semi-fluid condition. The nitride dissolves rapidly and completely in dilute hydrochloric and sulphuric acids with formation of a cobalt- ous salt, and analysis showed that all the nitrogen is set free as ammonia.It is completely decomposed when heated t o redness in hydrogen, the nitrogen being eliminated as ammonia, and it is also decomposed, slowly but completely, when heated in a current of steam. Nickel, h some of our experiments, the nickel was used in the form of wire 2 mm. in diameter, When the wire was heated in ammonia at a high temperature (800--850"), no increase in weight was noted, but the ammonia was, to a large extent, decomposed into its elements, and the appearance of the metal mas greatly altered. The surface became quite dull at first, and was soon penetrated by an irregular network of cracks, and the metal became quite brittle. When the temperature was lowered to about 600°, the metal began to gain in weight slowly, and after several hours' heating in a rapid current of ammonia, an in- crease of 5 per cent.in weight mas attained. By dissolving some of the12.52 EEILBY AND HENDERSON: THE ACTION Ol! product in dilute sulphuric acid, and estimating the ammonia liberated, it was proved that this increase was due to the formation of nitride of nickel. After this treatment, the surface of the wire was found to be penetrated by cracks and fissures, spreading in all directions, and the metallic lustre had quite disappeared. Under the microscope, the product was seen to be composed of minute, closely adhering particles, which were silvery in appearance, and all more or less spherical in form. Nitride of nickel, apparently, cannot be obtained at temper- atures much above 600' ; at about 550°, it is produced fairly rapidly, but it is of advantage to lower the temperature somewhat once the process has started.As in the case of iron, the essential conditions for the formation of nitride of nickel are the presence of ammonia in excess and a suitable temperature ; under other conditions, no nitrogen is permanently fixed by the metal, but the ammonia is largely decomposed, and the properties of the metal are profoundly modified, owing to the con- tinuous formation and decomposition of the nitride. The range of temperature within which nitride of nickel can be formed appears to be much narrower than in the case of iron, but, on the whole, there is great similarity in the behaviour of the two metals when exposed t o the action of ammonia at high temperatures.In order to prepare nickel nitride, finely divided nickel, obtained by reduction of the oxide with hydrogen, was heated in ammonia at about 500'. The metal gained in weight steadily but slowly until a product was obtained which, on analysis, was found to contain 7.5 per cent. of nitrogen. In none of our experiments was the metal induced to combine with a higher proportion of nitrogen than this. The formula Ni,N requires 7.36 per cent,, and the formula Ni,N,, 8.74 per cent, of nitrogen, and hence it appears that the nitride of nickel obtained in our experiments differs in composition from the nitrides of cobalt and iron. It was produced as a dull black powder, which was shown by the microscope to consist of aggregates of very minute, roughly spherical particles adhering closely together.It is readily soluble in dilute hydrochloric and sulphuric acids, and resembles the nitrides of cobalt and iron in its behaviour when heated in hydrogen and in steam, Little or no nitride is obtained below 400'. Copper. Copper, like iron, is very sensitive to the action of ammonia at high temperatures, and there is considerable similarity in the behaviour of the two metals." I f the ammonia is in large excess, the copper is con- verted, a t least partially, into a nitride, which, however, is only stable * The statements of earlier observers regarding the action of ammonia on copper at high temperatures are very contradictory.AMMONIA ON NETALS AT HIGH TEMPERATURES. 1253 under definite conditions, and is readily decomposed into its elements.Hence no nitride is formed when copper is heated in ammonia unless a large excess of the latter is present, but on the other hand, the am- monia is decomposed into hydrogen and nitrogen (although the amount of the decomposition is only about one-third of that effected by iron under similar conditions), and the metal suffers a very marked change in its physical properties. It loses most of its metallic lustre, acquires a pink colour, develops much the same spongy structure as has been described in the case of iron, and becomes extremely brittle. Examina- tion with the microscope leads to the conclusion that the metal has been in a t least a semi-fluid state, and has been rendered porous and spongy by the escape of numerous minute bubbles of gas.The am- monia penetrates into the metal very quickly. For example, a copper rod, one-quarter of an inch in diameter, was attacked through to the centre when heated in a current of ammonia for 30 minutes. But disintegration of the metal goes on almost indefinitely. Copper exposed to the action of a,mmonia for seven days a t 800' became reduced to a fine, spongy powder. I n our experiments, the metal was used in the form of gauze, wire, foil, and rod. The maximum quantity of nitrogen fixed in any experi- ment was 4.5 per cent. A nibride of copper of the formula Cu,N contains 6.86 per cent. of nitrogen. The nitride is very easily decom- posed by heating in hydrogen, and apparentiy can only exist within a comparatively narrow range of temperature.The change in the physical properties of the metal, even when no nitrogen is retained by it, is no doubt to be attributed in this case also to formation and de- composition of the nitride. Silver, Bold, and Platinum. I n our experiments with silver, gold, and platinum, the metals mere used both in the form of wire and in the spongy state. They were heated in ammonia at temperatures varying from 400' up to nearly 900°, b u t in no case was the formation of a nitride indicated by any increase in the weight of the metal, however rapid the stream of am- monia through the tube. In every instance, however, the ammonia suffered decomposition into its elements, although to a far smaller extent than with the metals of the iron group, and the physical pro- perties of the metals were altered, to some extent in all cases, and very markedly in the experiments conducted at temperatures from 750' upwards." * '' Ammoniacal gas is scarcely acted on in an ignited porcelain tube when clean and empty, but more readily when it contains fragments of porcelain ; with still greater facility when it contains platinum, silver, or gold wire : more easily still when it contains copper wire, and most quickly and conipletely when iron.wire is VOL. LXXlX. 4 R1254 BEILBY AND EENDERSON: TBE ACTION OF‘ When heated in ammonia a t 800°, the polished surface of fine silver wire acquired a ‘‘ frosted ” appearance, and when examined with the microscope the wire was found to be covered all over with minute rounded blisters or bubbles, while there was also very distinct evidence of “spitting.” The elasticity of the metal was also very greatly reduced.Gold wire was also greatly changed in appearance by exposure to the action of ammonia at 800°. The colour was changed, and the entire surface of the wire was seen under the microscope to be closely covered with small blisters or protuberances which appeared to have solidified after partial fusion. When precipitated gold was similarly heated in ammonia, the brown masses shrank together and became much more compact, the colour changed to light yellow, and metallic lustre made its appearance. The microscope showed that the product was composed of roughly spherical particles which adhered closely, When a current of ammonia was passed at the rate of 2 litres per hour over gold heated at 800°, fully 10 per cent.of the gas was decomposed. When platinum wire was heated in ammonia at 800°, the surface of the metal became duller, less lustrous, and showed a more or less blistered appearance under the microscope. I n most cases, a fine, black deposit was formed on the surface of the metal. The deposit was sometimes closely, sometimes loosely, adherent, but could be rubbed off easily with filter paper or cotton wool. On examination, it was found to be nothing but platinum black, which clearly had been formed by disintegration of the surface of the compact metal. When a rapid current of ammonia was passed over platinum wire heated at 800°, the gas was decomposed to the extent of about 8 per cent. The elasticity of both gold and platinum, like that of silver, is reduced to an enormous extent by exposure to a current of ammonia at high temperatures, and the resistance of each metal to the passage of an electric current is perceptibly increased.Comparison of our experiments on silver, gold, and platinum with those on the metals of the iron group and on copper, leads to the con- clusion that the very marked change in the physical character of the former metals, which is produced by the action of ammonia on them at high temperatures, is likewise due to the formation of metallic nitrides, which, however, are quite unstable, even in presence of a great excess of ammonia, and therefore readily decompose into metal and nitrogen, The continuous formation and decomposition of these nitrides would, of course, account for the observed disintegration of introduced.These metals, for the most pad, do not undergo any observable alteraa tion in weight ; but copper and iron become brittle, while gold and platinum remain perfectly unchanged.”-GnaEI,rN, Hartdbook of Chernislrv, vol. II., p. 421.AMMONIA ON METALS AT HIGH TEMPERATURES. 1255 the metals under the attack of strongly heated ammonia. The instability of these nitrides probably arises from their temperatures of formation and decomposition lying close together. It seems not im- probable that the formation of spongy deposits on the outside of platinum crucibles heated by Bunsen burners, as well as the disinteg- ration of the platinum wires of pyrometers exposed to furnace gases, may, sometimes at least, be accounted for by the presence of traces of ammonia in the furnace gases.Conclusions. A number of other metals, including aluminium, zinc, tin, and lead, and many different alloys, for example, brass and aluminium bronze, have also been examined with regard to their behaviour when subjected t o the action of ammonia at temperatures below their melting points. In every case, changes in the physical structure of the metals and alloys similar to those already described have been observed, and the ammonia has been decomposed to a varying extent into nitrogen and hydrogen. It would be tedious and unprofitable to describe our experiments in detail; suffice it to say that they all tend to confirm the following general conclusions at which we have arrived.Metals in general, when exposed to the action of ammonia at high temperatures, are either converted into nitrides-wholly or partially- or else profoundly changed in their physical properties, even although no nitrogen is permanently fixed by the metal. The changes include alterations in the colour, lustre, tenacity, elasticity, and electrical conductivity of the metals, and are caused by the disintegration of the metal due to the continuous formation and decomposition of unstable nitrides. When the altered metals are examined under the microscope, it is seen that these nitrides must be more fusible than the metals, for a characteristic spongy structure, due to the escape of innumerable minute bubbles of gas from a molten or pasty mass, is clearly visible in all cases.The maximum absorption of nitrogen by each metal is determined by (1) the state of aggregation of the metal, (2) the tem- perature, (3) the excess of ammonia, (4) the time. Nitrides can hardly be obtained by the direct action of ammonia on metals a t high tem- peratures unless an excess of ammonia is present, since all are easily decomposed into metal and nitrogen by heating in hydrogen. If we follow the action closely, for example, in the case of copper, it appears probable that it begins by the ammonia molecules attacking the surface molecules of the metal and forming a fusible nitride. If a plentiful excess of ammonia molecules are present to overpower the hydrogen molecules which result from the decomposition of the ammonia, a theoretical absorption of nitrogen takes place. But the 4 ~ 21256 EENDERSON AND CORSTORPHINEI .” nitride which is formed, being fusible at the temperature of formation, penetrates into the copper, and the further action tends to take place at some distance from the surface, where the ammonia molecules are fewer, and the hydrogen molecules are relatively more numerous. At a certain distance from the surface, a point will be reached at which the ammonia and the hydrogen molecules so exactly balance each other that no nitrogen is absorbed, or rather that, as soon as a molecule of nitride is formed, it will be immediately decomposed with evolution of nitrogen. The hydrogen resulting from the decomposition of the ammonia, together with the nitrogen from the decomposition of the nitride, force their way to the surface of the fluid nitride, causing the appearance of boiling-the particular structure which ia found in all metals which have been acted on by ammonia. It is clear that some such explanation as this is necessary if we are to account for the continuous and practically constant decomposition which takes place at a given metallic surface, and for the disintegration of the metal itself. We hope to extend our investigations on the action of gases on metals in the near future, We take this opportunity of expressing our thanks to Messrs. P. W. Tainsh, A.I.C., and F. W. Watson, B.Sc., Nobel Company’s Prizemen, and B. G. McLellan, A.I.C., Research Student in the Glasgow and West of Scotland Technical College, for much assistance in the experimental part of this investigation. We are also greatly indebted to Messrs. Johnson and Matthey, London, for their courtesy in preparing and placing at our disposal the pure gold and platinum which we required. GLASGOW.

ISSN:0368-1645    

DOI:10.1039/CT9017901245

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1256 EENDERSON AND CORSTORPHINEI .” CXXXII1.- Condensation of Bend with Dibenzyl Ketone. By GEORGE GERALD HENDERSON and ROBERT HENRY CORSTOBPHINE, B.Sc. IN the course of his researches on the synthesis of pentacarbon rings, Japp has shown that benzil and acetone unite, in presence of a small quantity of aqueous caustic potash, to form the aldol’ condensation product acetonebenzil, COPh*CPh(OH)*CH,*CO*CH,, and that when acetonebenzil is treated with an excess of the same reagent, it is con- verted, by elimination of the elements of water, into anhydracetone- benzil (Japp and Miller, Trans., 1885, 47, 21; Japp and Burton, Trans., 1887, 51, 420 ; Japp and Lander, Trans., 1897,71,123). Japp ultimately came to the conclusion that anhydracetonebenzil is a closedCONDENSATION OF BENZIL WITH DIBENZYL KETONE.125'7 chain compound, namely, a diphenylcyclopentenolone of the formula YPh-CR Cph(oH).c~,>co~ and on substituting dibenayl ketone for acetone, we obtained results which support this view. Benzil condenses readily with dibenzyl ketone in presence of aqueous caustic potash, yielding a substance of the formula C29H2202, which, from its general character, appears to be a t e t i . a p ~ n y l c y c l o ~ ~ t ~ n o l ~ e , a derivative of 1 : 2 : 4 : 5-tet~raphenylcyclopentene. The reaction may be represented by the eq.uation : QOPh CH,Ph yPh= CPh >CO + H,O. COPh -t CH,Ph>Co = CPh(OH)*CHPh An aldol condensation product is doubtless formed in the first in- stance, but we did not succeed in isolating it, although the conditions of the reaction were variously modified with that object in view.The general behaviour of the new compound is in accordance with the formula given above, the chief point of difference being that the com- pound does not combine additively with bromine to form a dibromide, as might be expected from its constitution, but yields a very un- stable substitution derivative. On the other hand, it responds to Baeyer's test for non-saturation, as it rapidly changes the colour of a solution of potassium permsnganate in the cold in presence of excess of sodium carbonate. The existence of a hydroxyl group in the com- pound is proved by the formation of an acetyl derivative, as also by the action of phosphorus pentachloride and of alcoholic hydrogen chloride on it, when an unstable chlorine derivative of tetraphenyl- cyclopentenone is obtained in each case by replacement of the hydroxyl group, The compound yields a crystalline oxirne, and, although i t does not react readily with phenylhydrazine itself, a hydrazone was prepared by heating it in alcoholic solution with p-bromophenylhydrazine. When cautiously oxidised with chromium trioxide in acetic acid solution, it yields benzoic acid and a neutral crystalline compound, C28H2004, which possibly may be isobend, ;C;'Ph*O*COPh CPh.O*COPh' By partial reduction of diphenylcyclopentenolone with hydriodic acid, diphenylcyclopentenone, CPh.CH,>CO, is obtained (Japp and Burton, loc.cit.), but tetraphenylcyclopentenolone behaves somewhat differently with reducing agents, and does not give the expected gPh*CH, Q P h Y CPh tetraphenylcyclopentenone, CHph.cHph>"o. When it is heated under atmospheric pressure with hydriodic acid and red phosphorus, it gives a crystalline compound of the formula C29H240, which appar- ently does not contain a carbonyl group, as it could not be induced to1258 HENDERSON AND CORSTORPHINE : form either an oxime or a hydrazone. On the other hand, the compound yields an acetyl derivative, and it also reacts readily with phosphorus pentachloride and with alcoholic hydrogen chloride, giving in each case the same chZorotetr~p7~enyIcyclo~entelae, C,,H23CI ; the presence of a hydroxyl group in the compound is thus proved. With bromine, it gives, not an additive product, but a bromine derivative, C2,H2$r*OH ; on the other hand, it quickly reduces potassium permanganate in presence of sodium carbonate, and hence appears to be unsaturated.We there- fore conclude that this reduction product must be a tetmphenylcyclo- CPh =CPh CPh(OH)*CHPh pentenol, of which the formula must be either I >CH,, or >CH-OH. CPhL-CPh CHPh*CHPh more probably, I When tetraphenylcyclopentenol is heated, under pressure, with hydriodic acid and red phosphorus a t 170-180°, it undergoes further reduction, and a mixture of two hydrocarbons is obtained. One of these has the formula C29H24, and is in all probability 1 : 2 : 4 : 5-tetra- QPh=CPh phen y lc y clopentene, CHPh.CHPh>CH2. The other hydrocarbon is apparently identical with the 1 : 2 : 4 : 6-tetraphenylcyclopentane, QHPh*CHPh cHph,cHph>CH2, obtained by Wislicenus and Carpenter by the QPh( OH) - CHPh reduction of the pinacone, cph(oH).CHph>CH2’ which they pre- pared from dibenzoyldiphenylpropane (Annalen, 1898,208,223). The formation of the latter hydrocarbon justifies the view that the substance obtained by condensing benzil with dibenayl ketone is a closed chain compound containing a pentacar bon ring.EXPERIMENTAL. Tetraphenylcyclopentenolone. A mixture of 50 grams of benzil, 50 grams of dibenzyl ketone, and 100 C.C. of 33 per cent. aqueous caustic potash was heated gently on a water-bath, the contents of the flask being frequently mixed by vigorous shaking. After about half an hour’s heating, the melted layer which floated upon the top of the aqueous solution began to solidify; when the whole had turned solid, the alkaline liquid was poured off, and the mass ground up in a mortar and then washed with water until quite free from caustic potash, The crude product was dark in colour, and even after repeated crystallisation from alcohol the crystals still retained a purple coloration, Part of the colouring matter was removed by washing the product with a little benzene, and the last trace got rid of by severnl crystallisations from benzene andCONDENSATION OF BENZIL WITH DIBENZYL KETONE. 1259 finally from alcohol.The yield was very satisfactory. The following results were obtained on analysis of the purified crystals : C,,H,,O, requires C = 86$6 ; H = 5.47 per cent. 0-2166 gave 0.6854 GO, and 0.1128 H,O. A cryoscopic determination of the molecular weight, benzene being used as solvent, gave a result in accordance with the foregoing formula.C = 86.19 ; H=5*78, Wt. of Wt. of CXJH22O2 substance. solvent. Depression. Mol, wt. mol. wt. 0.1822 18.815 0 . 1 2 O 394 402 Tetraphenylcyclopentenolone crystallises from alcohol in clusters of long, colourless, lustrous prisms which melt a t 208O. It is readily soluble in benzene, and fairly readily in boiling alcohol, but only sparingly so in ether, and is almost insoluble in light petroleum, It dissolves in cold concentrated sulphuric acid, giving a solution of a beautiful, intense violet colour which quickly changes to red ; from this solution, even after heating, it is precipitated by water un- changed, except that i t is now coloured purplish-red. When a drop of a solution of potassium permanganate is added to an alcoholic solution of tetraphenylcyclopentenolone previously mixed with a few drops of aqueous sodium carbonate, the colour of the permanganate is very quickly discharged.The oxime, C,,H,,O:N*OII, was prepared by gently heating tetra- phenylcychpentenolone in alcoholic solution with the calculated quan- tities of hydroxylamine hydrochloride and sodium acetate, evaporating to dryness, extracting with ether, evaporating the ether, and recrys- tallising the product from alcohol. It crystallises in small, colourless plates which melt a t 1 6 7 O and are fairly easily soluble in alcohol, The following result was obtained on analysis : 0.2863 gave 8.6 C.C. moist nitrogen a t 21' and 766 mm. Tetraphenylcyclopentenolone does not react readily with phenyl- hydrazine.When an alcoholic solution of the two substances was heated for some time under a reflux condenser, no change took place; when the solution was heated in a sealed tube at 150°, a tarry mass was produced; and when a methyl alcoholic solution was heated at 100' for several hours in a pressure bottle, a small quantity of a yellow, crystalline substance was obtained which contained no nitrogen and was not further examined, However, by substituting p-bromophenyl- hydrazine for phenylhydrazine, the desired result was obtained. A solution in methyl alcohol of the calculated quantities of tetraphenyl- cychpentenolone and p - bromophenylhydrazine was heated at 100' N = 3-53, C29H,,0,N requires N = 3.35 per cent.1260 HENDERSON AND CORSTORPHINE : in a pressure bottle for some hours, the solution filtered and evaporated, and the residue crystallised several times from alcohol.The p-bromophen ylh ydraxone, C2,H2,0: N,H C,H,Br, was thus obtained in the form of short, colourless prisms, which were fairly readily soluble in alcohol: it melted at 168-169'. The following results were obtained on analysis : 0.2338 gave 0.6286 CO, and 0.1015 H20. 0.2653 ,, 0.0870 AgBr. Br= 13.95. C,,H,70N2Br requires C = 73.55 ; H = 4.73 ; Br = 14.01 per cent, C = 73.32 ; H = 4.82. The acetyl derivative of tetraphenylcyclopentenolone was obtained by boiling it with excess of acetic anhydride for some hours, pouring the mixture into water, neutralising the acid with sodium carbonate, and extracting with benzene.On evaporation of the benzene, i t separated in prisms of a dark reddish-purple colour. Repeated crys- tallisation from benzene, alcohol, and other solvents failed to remove the last traces of the colouring matter, but the crystals, although coloured, melted sharply at 218', and the melting point was not altered by recrystallisation. The substance is easily soluble in benzene, but only sparingly so in alcohol. The following results were obtained on analysis : 0.2408 gave 0.7388 CO, and 0.1132 H,O. Action of Bromine, Phosphorus Pentachloride, and Alcoholic Hydrogen Chloride on ~~tr~p~en~Zcyclo~~tenoZone.--When solutions of tetra- phenylcyclopentenolone (5 grams) and of bromine (2 grams) in chloro- form, all carefully dried, were mixed, hydrogen bromide was slowly evolved.The mixture was left under a bell jar along with a dish containing soda-lime until the reaction was completed, and on subse- quent evaporation of the chloroform, small, dark red crystals were deposited. By recrystallisation from a mixture of benzene and light petroleum, the substance was obtained in colourless crystals, which were found t o contiain bromine, but no satisfactory analysis could be made because it is very unstable, decomposing at the ordinary tem- perature with evolution of hydrogen bromide. Such results as were obtained indicated that the substance was probably a monobromo- derivative of tetraphenylcyclopentenolone. A colourless, crystalline product containing chlorine was formed by gently warming tetraphenylcyclopentenolone with phosphorus penta- chloride, but it could not be purified for analysis on account of the readiness with which it decomposed.The same substance, or at least one which possessed the same appearance and properties, was produced by the action of alcoholic hydrogen chloride upon tetraphenylcyclopent- C = 83-67 ; H = 5.22. C3,H2,0, requires C = 83.78 ; H = 5.41 per cent.CONDENSATION OF BENZIL WITH DIBENZYL KETONE. 1261 enolone. This unstable compound was probably a monochloro-derivative of tetraphenylcyclopentenone, judging from the results of approximate estimations of the chlorine contained in it. Oxidation of 2'etraphenylcyclopentenoZone.-Oxidation proceeded steadily when an acetic acid solution of chromium trioxide was slowly added t o a concentrated solution of tetraphenylcyclopentenolone in glacial acetic acid, the mixture being kept cold during the process.The mixture was then poured into water, and the solid which separated was collected on a filter, washed with water, and finally warmed with a solution of sodium carbonate. A portion went into solution, but part remained undissolved in the sodium carbonate, and was removed by filtration. The alkaline solution was acidified and extracted with ether ; on evaporation of the ether, crystals were deposited which were easily recognised as benzoic acid, The residue, insoluble in sodium carbonate, was crystallised from benzene, from which it separated in the form of colourless crystalsmelting a t 164-165'. The substance, which is neutral in character, is readily soluble in benzene, but only very sparingly so in alcohol.The following results were obtained on analysis : 0.2049 gave 0.6035 CO, and 0.0877 H,O. C = 80.32 ; H = 4.75. 0.1893 ,, 0.5591 CO, ,, 0.0806 H,O. C=80.55 ; H = 4.73. C2sH,,0, requires C = 80.0 ; H = 4.76 per cent. A determination of the molecular weight by the cryoscopic method, benzene being used as solvent, gave a result in conformity with the foregoing formula. Wt. of wt. of ~,H,OO, substance. solvent. Depression. Mol. v mol. wt. 0.1571 13.612 0.1 4 O 404 420 The only substance of the formula C,,H,,O, which in any way re- sembles in physical properties the substance described above is isobenzil, flPh*o*CoPh of which the melting point is stated to be 1 5 0 O (Klinger, CPh 0 COPh' Ber., 1891, 24, 1265). When tetraphenylcyclopentenolone was heated on the water-bath with chromium trioxide, glacial acetic acid being used as solvent, the only product which could be detected was benzoic acid.Attempts were also made to oxidise tetraphenylcyclopentenolone with sodium hypobromite, but these mere unsuccessful, no change taking place. 2'etraphenylcyclopentenoZ. A mixture of 10 grams of tetraphenylcyclopentenolone, 15 grams of red phosphorus, and 60 C.C. of aqueous hydriodic acid (b. p. 126') was boiled under a reflux condenser for 3 hours, After coolisg, the acid1262 HENDERSON AND CORSTORPHINE : solution was poured o f f and the solid residue was ground in a mortar, thoroughly washed with water, and dried. The crude product was dissolved in benzene, and the solution agitated successively with aqueous sulphurous acid, aqueous sodium carbonate, and water, and then dried with calcium chloride. On concentration, nearly colourless crystals were obtained, the dark colouring matter present in the crude product being readily soluble in benzene, The substance, after puri- fication by recrystallising several times from alcohol, afforded the following results on analysis : 0.2003 gave 0.6605 CO, and 0.1069 H,O.The molecular weight was determined by the cryoscopic method, Wt. of Wt. of Ca9H24O C=89*93; H=5*92. C2,H2,0 requires C = 89.69 ; H = 6-18 per cent. benzene being used as solvent. substance. solvent. Depression. Mol. wt. mol. wt. 0.1537 15.223 0.1 3 O 380 388 From these results, and from the properties of the substance described below, it is seen to be tetraphenylcyclopentenol. It crystallises from benzene, in which it is readily soluble, in colourless, lustrous needles, which melt at 162'.It is' sparingly soluble even in boiling alcohol, and not at all readily soluble in ether. An alcoholic solution of this substance, rendered alkaline by the addition of a few drops of aqueous sodium carbonate, quickly changes the colour of potassium perman- ganate solution. Two grams of tetraphenylcyclopentenolone were dissolved in 10 grams of glacial acetic acid, 0.5 gram of red phosphorus and 0.25 C.C. of hydriodic acid were added, the mixture was boiled for three hours under a reflux con- denser, and finally the product was separated and purified by the method already described. We had expected to obtain tetraphenylcyclopentenone by reducing tetraphenylcyclopentenolone with hydriodic acid, and therefore we attempted to prepare an oxime and a hydrazone from the product.However, it could not be induced to react with either hydroxylamine, phenylhydrazine, or p-bromophenylhydrazine, in whatever way the conditions were modified. This fact, together with the other properties of the reduction product, led to the conclusion that the oxygen which it contained must be present in the form of a hydroxyl group, that is, it must be a tetraphenylcyclopentenol. The acetyl derivative of tetraphenylcyclopentenol was prepared by heating it with fused sodium acetate and excess of acetic anhydride for some hours. The mixture was then poured into water and the insoluble portion collected on a filter, washed with water, dried, The same substance was obtained in a different way.CONDENSATION OF BENZIL WITB DIBENZYL KETONE.1263 and crystallised from a mixture of benzene and alcohol. It crystallises in short, colourless, lustrous prisms, which melt at 181-182'. It is very readily soluble in benzene, but much less readily in alcohol. The following results were obtained on analysis : 0,2429 gave 0,7726 CO, and 0.1268 H,O. C= 86-72 ; H= 5-80. 0.2236 ,, 0.7126 00, ,, 0.1195 H,O. C=86*91 ; H=5*94. CS1HS6O2 requires C = 86.51 ; H = 6-04 per cent. Action, of Bvomine on, Tetraphenylcyclopenteno2.-Five grams of tetra- phenylcyclopentenol were dissolved in chloroform and a solution of 2.3 grams of bromine in chloroform was added; the substances were all thoroughly dried before use.Hydrogen bromide was evolved a t once and the reaction proceeded fairly rapidly. The mixture was left under a bell jar, which also contained soda-lime, until the action had ceased, the chloroform was then evaporated off, and the residue recrys- tallised from a mixture of benzene and light petroleum. After several crystallisations, monobromotetraphenylcyclopentenol, C,,H,,Br *OH, was obtained in a state of purity, It forms colourless, prismatic crystals, which are easily soluble in benzene; its melting point is 215'. 0.1700 gave 0.0690 AgBr. C,,H2,0Br requires Br = 16.95 per cent. A c t h of Phosphorus Pentachtoride and of Alcoholic Hydrogen Chloride on Tetraphenglcyclopenteno2.-When a mixture of tetra- phenylcyctopentenol with the calculated quantity of phosphorus penta- chloride was gently heated a vigorous action took place.The product was treated with water, and the insoluble portion dissolved in ether, On evaporation of the ether, dark red crystals were deposited, which were finally obtained free from colouring matter by repeated crystal- lisation from a mixture of benzene and light petroleum. Analysis showed the substance to be a monochZorotetraphenyZcyclopentene. It crystallises in colourless prisms which melt at 181'. It is freely soluble in benzene and fairly so in alcohol, from which it can be crys- tallised without decomposition. 0.1685 gave 0.0599 AgC1. C1= 8-79. C,,H,,Cl requires C1= 8.72 per cent. When tetraphenylcyclopentenol is treated with alcoholic hydrogen chloride, the same chlorine derivative of tetraphenylcyclopentene is obiained.About a gram of tetraphenylcyclopentenol was mixed with alcohol previously saturated with hydrogen chloride, and the mixture agitated at frequent intervals until the greater part of the solid had gone into solution. After some hours, the solution was filtered, the filtrate mixed with water, and the precipitated solid collected Br = 17-27.1264 CONDENSATION OF BENZIL WITH DIBENZYL KETONE. and crystallised from alcohol. The crystals melted at 18l0, and a mixture of them with the substance obtained by means of phosphorus pentachloride melted sharply at the same temperature. Tets.ap~enyZcyclop~t6n~ am? Tetraphenylcyclopntan8. Tetraphenylcyclopentenol is reduced when heated in a sealed tube with hydriodic acid and red phosphorus, giving a mixture of two hydro- carbons in varying proportions.The temperature must be carefully regulated in order to obtain a satisfactory result ; thus, up to 160° hydriodic acid had little or no action ; at 210°, the product was a tarry mass, which did not invite further treatment ; at 175', a white powder mixed with a little of an oil was obtained; at a temperature of nearly 190° the oil was the chief product, and only a little of the white powder was present. In order to obtain both the oily product and the white powder, the following conditions were finally adopted. Three grams of tetra- phenylcydopentenol, reduced to a fine powder, were mixed with 5-5 grams of red phosphorus and 30 grams of hydriodic acid (b. p. 1 2 6 O ) , and the mixture was heated in a sealed tube at a temperature of about 180° for some hours. The product, after removal of the acid liquid, was crushed to powder, thoroughly washed with water, dried, and then extracted first with boiling ether and next with boiling benzene. The ether dissolved all of the white powder, but only a little of the oily substance, which is sparingly soluble in that solvent; the benzene extract contained the greater part of the oily substance. Each ex- tract was agitated successively with aqueous sulphurous acid, aqueous sodium carbonate, and water, and then dried with calcium chloride. From the ethereal solution a white powder was obtained on distilling off the ether ; this substance was purified by recrystallisation from ether, from which it separates as a white, crystalline powder. It melts with decomposition above 300°, and is easily soluble in benzene but only very sparingly so in alcohol. Analysis showed that it is a, hydrocarbon of the formula C29H24, and in all probability the un- saturated compound, 1 : 2 : 4 : 5-tetraphenylcyclopmtene. 0.1379 gave 0,4721 GO, and 0.0806 H,O. On evaporation of the benzene solution, the other hydrocarbon was obtained in an oily condition, but it separated in crystals from a mixture of alcohol and acetone. It melts at S0*5-S1°, which is bhe melting point given by Wislicenus (Zoc. cit.) for 1 : 2 : 4 : 5-tetraphenyl- cyclopentane. C = 93.37 ; H = 6.49. CBH24 requires C = 93.55 ; H = 6.45 per cent. GLASGOW AND WEST OF SCOTLAND TEWNIUAI, COLLEGE,

ISSN:0368-1645    

DOI:10.1039/CT9017901256

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

TBE FORM OF CHANGE IN ORQANIC COMPOUNDS. 1265 CXXX1V.-The Form of Change in Organic Com- pounds, and the Furiction of the a-Meta-orientating Groups. By ARTHUR LAPWORTH. IN a paper published in the Transactions of the Society some time ago (Trans., 1898, ’73, 445), the author showed t h a t a very large number of changes and interactions in organic chemistry could be represented by forms, deducible from two simple types, which may be termed the ay- and up-rules. A critical examination of what is really essential to the applicability of these rules shows that the whole matter rests solely on the assumption that isomeric change is due, not to mere interchange of the position of atoms or groups in a molecule, but in general to a series of migrations, apparent or real, and that only one atom or group migrates at a time.With such an assumption, it is easy to show that there is no way of avoiding the conclusion that if the production of ring compounds is excluded and no change of valency occurs, the migration must be representable by a strict application of the uy-rule; if, on the other hand, change of valency does occur a t any part of the molecule, then the ap-rule must come into play at that point. It is of no consequence how the migration is effected, as the principle simply precludes a direct interchange of groups, and the representation of undissociated compounds by illegitimate formulae. The author was greatly influenced by the apparent simplicity of the stereochemical view of the mode of transference suggested in his first paper (pp. 448 and 452), but is no longer able to regard explanations based on such principles as of any real value.Occasion has already been taken to point out (Proc., 1901, 17, 2) that in applying the author’s ay- and &-rules, the intermediate positions which were assigned to a migratory group in its trans- ference must not be regarded as real resting points, but rather as representing the various possible positions of the group in the line between its initial and final positions of attachment. An explanation which appears capable of explaining, amongst other things, the very general applicability of the rulesis one based on the assumption that change in organic chemistry is largely due to the occurrence of a dissociation between singly bound groups and subservient to the following law ; the state of dissociation between, two singly bound atoms which leads to isomeric change, exists d y once in the molecule at any instant. A dissociation of the character which the above conception de- mands is found in weak electrolytes, and, in tbe author’s opinion,1266 LAPWORTH : FORM OF CHANGE IN ORGANIC COMPOUNDS, it is to electrolytic dissociation, often doubtless in extremely minute amount, that the majority of changes in organic compounds may be most probably assigned.This view, which the author has now held for a long time, and arrived at from a consideration of the prevalent forms of change, receives support in the recent ap- pearance of the papers of Euler (Bey., 1900, 33, 3202) and of Zengelis (Ber., 1901, 34, 198), who, apparently from entirely differ- ent considerations, have been led to put forward a similar sug- gestion with regard, more particularly, to the hydrolysis of esters and sugars.On this principle, the simplest possible case of isomeric change may be imagined to consist in the dissociation of a molecule X-Y at a point between two singly bound atoms into two groups, 2 and k, each of which is capable of becoming attached to one univalent atom or group to form an undissociated chemical molecule capable of free existence. The groups 2 and ? will, as a rule, be oppositely charged ions. Now the principle governing the possible modes in which X and * may again become mutually attached appears to be that the resulting, now undissociated, molecule X*Y shall be immediately re- presentable by a legitimate formula through a mere adjustment of the conventional I ‘ bindings.” * In order to avoid misconception, it must be pointed out that this adjustment takes place in general along.an already existing line between the initial and final positions of mutual attachment of one group to another, a single binding becoming a double one, a double one a treble one, or vice versd, or a single binding may altogether disappear. The converse of the last change, namely, the formation of a single binding where none existed before, is probably to be found only in cases where the formation of ring compounds is thereby in- volved; even here, however, it usually appears possible to trace exactly similar laws. It should be made clear that the dissociation of X*Y may be followed, not by a reunion of X and Y, but, in presence of other dissociated groups, by the union of these groups with others to form compounds which are not isomeric with the original substance.To illustrate the application of the preceding principles, a case of substitution, namely, the action of bromine on phenol, which appears to * Possibly the formation of the new compound is preceded by an actual re; adjustment of the bindings in the molecule. Thds it is probable, for instance, that a dissociated group i*B:C*D:E niay change to A:Bb6*D:E or A:B.C:D*k, so that the a?- and aS-rules and their stereochemical explanations may apply to the altera- tion of the position of free affinity in the dissociated group, and these changes may be successive, although no intermediate compounds are formed.b 4AND FUNCTION OF THE a-META-ORIENTATIXG GROUPS. 1267 be fairly simple, may be considered. The bromine may be imagined to dissociate slightly into Br and Br, and the weakly acid phenol as usual into H and O*C,H,, the bromination consisting in the union of Br and O*C,H,, the possible products are those in which these two groups (otherwise preserving their original characteristics so far as the relative positions of atoms contained in each are concerned) are mutually attached, so that by merely altering, if necessary, the bindings in the above-mentioned sense, a legitimate formula is at once obtained for the compound C6H,0Br. This is possible at the oxygen atom, a t the carbon atoms 2- and 4-, but not a t the carbon atoms 1- or 3..The possible products are therefore : - + -k - + - OBr 0 0 H A P H / j H >< H+H HI1 lKB' Or HI1 IIH \/ HI IH H H \/ H Br unless it is supposed that ring compounds such as : 1-0 0 might be produced, a possibility which is sufficiently remote to require no further remarks. The law relating to dissociated groups may be stated more strictly than on p. 1265 as follows. The ions of organic compounds usually possess onEy one point of free valency, which is merely another way of stating that they are usually weak electrolytes, and therefore form only univalent ions. Following out the recently advanced conceptions of Abegg and Bodlander (Zeit. ccnorg. Chem., 1899, 20, 453), a complex ion may be considered to arise from the union of a simple ion with a neutral component, and, conversely, a complex ion may break down into a simpler one and a neutral component, It should follow, therefore, that a molecule, X*Y*Z, may become dissociated into ions, say, X and Y*Z, and that afterwards the ion Y*Z may become further simplified into a neutral component Y and the ion Z , the latter carry- ing away the free affinity and the charge.A law similar to that just formulated will hold for the latter process, namely, that the neutral component Y shall be at once representable by a legitimate formula through an adjustment of the bindings in the sense already explained.1268 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, It will follow in general that a simple ion will be the more readily eliminated from a complex ion of a given type if it has a large ‘‘ electroaffinity ” (Abegg and Bodlander, loc.cit.), and it may be pointed out here that,, in most simple cases where two groups are withdrawn from a molecule, the product of their union is a recognised electrolyte. In illustration of this point, the author’s conception of the breaking down of acetone cyanohydrin, CN*CMe,*OH, under the influence of alkali may be alluded to. Here the dissociation probably occurs first between the hydrogen atom and the oxygen of the hydroxyl group, since it must in any case be supposed that all alcohols are feebly dis- sociated in this way. The ions are therefore H and CN*CMe,*b, and in the negativelycharged ion the CN group is known to have a large electroaffinity for the negative charge ; it is, moreover, in such a position that its removal will result in the formation of a molecule at once representable by the legitimate formula CMe,:O.The function of the alkali is doubtless to provide hydroxyl ions in the presence of which the concentration of the hydrogen ions of the cyanohydrin is greatly diminished, and the dissociation of the cyanohydrin con- sequently raised to a corresponding extent. With this brief introduction, it is possible to proceed to some special cases t,o which these principles apply, and, in order to be able to deal generally with some of these, the following rule, easily deducible from what has been said, may be stated. If, durifig a reaction, a group X might be expected to unite with an atom R, in the complex R,*Rp:R,, then the product may contctin, not only substances with the compkx R,X-R,:R,, but also, and, sometimes exclusiuely, those with R,:R,*R,X and thei9* tautome& forms.Some important forms of interaction may be a t once mechanically deduced from the expansion of the simplest type of addition at a double binding, A:B + X*Y = AX-BY, and it is easy to show that the general equations may be true if read in either sense. - I- . Firstly, expanding B we obtain : A:B,-B,:B, + x + ir f-f AX~I~,=B,:B, + + t-, AX~B,:B,*B,Y (R), easily seen t o be the form to which so much importance has been attached by Thiele. ,!!econdly, expanding Y only : f i AX*& + $,*Y :Y % i*BdY,-Yp:Ya + k f l A:B + X+ 3?,*Ys:Y,, @ %X*B*YY*YB Y, (S). This form is not translatable in terms of Thiele’s rule, but is oneAND FUNCTION OF THE a-META-ORIENTATING GROUPS.1269 which will probably be found t o be the basis of many reactions as yet imperfectly understood, and one or two cases where it appears directly applicable may be discussed. It is, no doubt, the type of change involved in the Claisen reaction in its simplest form, as, for example, when sodium ethoxide acts on a mixture of acetone and ethyl oxalate, a condensation which is perhaps the result of the follow- ing series of changes. The ions Na and CW,:CM& of the sodium derivative of acetone, CH,:CMe*ONa (Freer, Amer. Chem. J., 1891, i3, 322), unite with a carbonyl group of the ethyl oxalate. As sodium shows very little tendency to form complex ions, ibis perhaps the negative ion which first becomes attached to the ethyl oxalate (compare, however, Proc., 1901, 17, 95) : - + s a + CJ3,:CMe.b + O:C(OEt)*CO,Et .t-f $a + 6 * C(OE t)(CO,E t)*CH,*CMe:O.The components on the right are the ions of the sodium compound, NaO*C(OEt)(C0,Et)*CH2*CMe:0, which, by loss of alcohol, affords the stable sodium compound, NaO*C(C02Et):CN*CMe:0, as the actual product. As anything like an adequate discussion of the details of this reaction would occupy a very large amount of space, the author con- fines himself a t present to the foregoing remarks. The reaction between aldehydes and the metallic-derivatives of iso- nitro-compounds doubtless proceeds in accordance with this type. Thus with pot a ssium isoni t ropropane and f ormaldeh y de, K + bNO:CMe, + CH,:O ++ K + O:NO*CMe,*CH,*b f-f O:NO*CMe,*CH2*OE. Thirdly, expanding both B and Y, we obtain the form thus roughly expressed : X*Ya*Yp:Y, + A:Bu*Bp:BY ++ AX*Bu:Bp*B,*Yy9Yp:Ya .- (T). This doubtless includes, amongst others, the cases of interaction of +unsaturated esters and ketones with ethyl sodio-malonate, -cyano- acetate, and -acetoacetate. Thus with methyl acrylate and ethyl sodiocyanoacetate : Na*O* C( OEt) :CH*CN + 0: C(OMe)*CH :CH, + Na*O*C( OMe) : CH* CH,. CH(CN) C( OEt): 0. In his first paper, dealing with the subject of isomeric change (Zoc. cit., p. 455), the author referred briefly to the case of meta-substitution VOL. LXXIX. 4 s1270 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, in the benzene series, using the case of the sulphonation of nitro- benzene by way of illustration, and showed that the most probable mode in which the change might be supposed to occur was that the acting agent united in the first instance with the side group, and that elimination of a substance then took placo by removal of a hydrogen atom in the nucleus (necessarily the rneta-atom, unless it is supposed that ring compounds like those depicted on p.1267 are produced) with a group attached to the side chain. The initial stages were mostly similar to those usually assumed to take place when nitromethane, for example, is converted into a salt of its iso-form by a metallic hydr- oxide; subsequently, in the benzene derivative, the hydrogen atom is removed, not from the a-position, but from the related y-position. That is to say, the benzene compound was supposed to be converted into a derivative of its tautomeric form corresponding with the iso-forms of fatty nitro-compounds, and this was then converted into the rneta- substitution derivative by isomeric change in accordance with the ay-rule.The first actions assumed, written in the usual form, may be compared thus : (1) Caustic potash acting on a fatty nitro-compound, :CIPNO:O + HOK + : c H ~ N o < ~ ~ --+ :C:NO~OK + HOH. (2) Sulphuric .acid acting on nitrobenzene (S = SO,H), -CH-~X~*NO:O + HOS -+ :CH*~:C.NO<E,H ---f :C:b*6:NO*OS + H OH It was not perceived at the time when this view was put forward that, if thers be any truth in.the conception, then those groups which, in the aromatic series, are the characteristic meta-orientating groups should be capable of reacting on the tautomeric normal and iso-forms >CH*R and >C:RH when in attachment to a >CH group. The fact that the groups, NO,, CO*R, and CN, do possess both properties is a t least very striking (compare Hantzsch and Veit, Ber., 1899, 32, 607, and Hantzsch and Osmund, ihid., 34l), and as regards the only other meta-orientating group, namely, SO,*R, the experiments of K8tz (Bev., 1900, 33, 1120) are sufficient to show that its properties are similar to those of the other three groups, more especially as it was found that the compound Ph*SO,*CH(SO,Et), behaved as a strong acid.It may be remarked that the foregoing groups in the fatty series render the a-hydrogen atom, and in the benzene series the related 7-hydrogen atom, replaceable, so that it appears probable that the formation of large quantities of meta-di-derivatives is due in general to the occurrence of changes very similar to those occurring in the fatty series, the relationship being expressed by the ay-rule.AND FUNCTION OF THE a-META-ORIENTATING GROUPS. 1271 It may be argued that substitution by direct attack in the nucleus is possible, and that therefore meta-derivatives may be formed in this way.Doubtless they are thus produced to a certain extent in all cases; nevertheless, it seems impossible to believe that such widely different groups as N(CH&, CH,, C1, and CH,CI, should render the ortho- and para-hydrogen atoms directly replaceable, and that the others, NO,, CN, &c., should have precisely the opposite effect by a mere exertion of an attractive or repulsive influence. I n the author's opinion, so far as direct substitution in the nucleus is concerned, all groups may be presumed to have an ovtho-paw orientating influence, due, perhaps, io considerations like those sug- gested by Thiele, and the formation of msta-substitution derivatives in quantities preponderating over those of the ortho- and par-deri- vatives combined, must be attributed to an entirely different pheno- menon.The formation of ortho- and para-substitution products simul- taneously from an ordinary benzene mono-substitution derivative C,H,*X by an agent PQ is perhaps due to the formation of inter- mediate compounds of the types X P and H Q related by the ay-rule, and yielding by loss of HI? the benzenoid o~tho- and pwa-derivatives, C,H,XQ.In consequence, were X of a nature capable of exerting a steric hindrance on the formation of such an intermediate compound, the action would be hindered, but without, of course, preventing the para-hydrogen atom from being removed as easily as the meta-atom. If, therefore, in the fatty series, the group X*b:Q forms additive products with difficulty, then it is to be expected that substitution in the compound C,H,*X will also be difficult. Such an example is found in tert.buty1- benzene. Since, then, it appears that the function of the characteristic meta-orientating groups in the benzene series is probably quite similar to that which they exercise in the fatty series, it should follow that the similarity could be traced, not only in the effect which they exercise in the simplest cases of substitution, but in more complex reactions.One of these, applicable to many fatty compounds in which they occur, is the Claisen reaction, the course 4 s 212’72 LAPWORTH: FORM OF CHANGE IN ORGAKIC COMPOUNDS, of which has already been discussed (p. 1869). Now, in order that this action may occur, it is necessary that two hydrogen atoms should be present a t the a-carbon atom, and it happens that in benzenoid ketones, esters, &c., where the carbonyl group is in direct attachment to the nucleus there is no hydrogen at the a-position; proceeding, therefore, t o the related point, the y-position, only one hydrogen atom is present as a rule, namely, the meta-hydrogen atom, but in some cases there is a stable CH, group a t the y- or y’- position outside the ring.Such a substance is found in 0- or p - methylbenzophenone or ethyl 0- or p-toluate, but not in the corre- sponding meta-derivatives. Whilst these compounds react only with the greatest difficulty, if at all, those containing the more reactive nitro-group, as, for example, 0- and p-nitrotoluenes, are capable of taking part in the Claisen reaction. Thus Reissert found (Be?*., 1897, 30, 1030) that the methyl group in these two compounds was attacked, but that no reaction occiirred in the case of the meta-nitrotoluene; he asserts, also, that ethyl oxalate is the only ester which can be used. The author has con- firmed Reissert’s statement regarding the inactivity of the meta- compound, but has found that amyl nitrite may be used in place of ethyl oxalate, and yields the oximes of 0- and p-nitrobenzaldehydes ; no doubt other esters might also be used, provided that the product were a sufficiently stable sodium derivative.The reaction is evidently a particular case of y- or meta-substitution, in which the meta-position is outside the ring, that in the ring being excluded from the type of reaction. It may be supposed, as in other cases, that a, compound of the type CH,:F*F:NO*ONa is produced, having a constitution analogous to that of the quinoneoximes on the one hand, and to the isosulphate of nitro- benzene (p. 1270) on the other. The iso-derivative then reacts with ethyl oxalate, as follows (compare p. 1269) : C0,Et *C](OE t)*ONa -+ C0,Et *C(OEt):O CH,: ?* <:NO*ONa CH, *?: -NO:O -+ that is, in accordance with the reaction expressed by A:B+X*Y, in which Y is expanded twice.As such a reaction should, in turn, be applicable to similarly con- stituted fatty compounds, it seemed that it might be possible to con- dense ethyl oxalate, hc., with open chain substances of the type *CH,*CR:CR*X (X = NO,, CN, SO,R, CO*R) at the y-position instead of at the a-position, as usual.AND FUNCTION OF THE a-META-ORIENTATING GROUPS. 1273 Compounds of the above type and containing no a-hydrogen atom are difficult to obtain in large quantities. Experiments were most successful with ethyl crotonate, and the results justify the prediction, as ethyl y-oxalocrotonate may be obtained, under the proper conditions, in fairly large amount. It is a matter of little difficulty to trace the course of the reaction in the above manner.The number of possible condensation products in such cases, and the fact that some of them may be formed with greater ease than the y-oxalo-derivatives, may obviously render the isolation of the latter a matter of great difficulty. That the ethyl oxalocrotonate is not the a-derivative is shown by the marked difference between its properties and those of other a-oxalo- esters and ketones. It affords a black instead of the red to violet coloration with ferric chloride which a-derivatives usually give, and its stability towards hydrolytic agents is incomparably greater than that of such compounds ; whilst the a-oxalo-esters decompose into oxalic acid on the one hand, and pyruvic acids and carbon dioxide on the other, the new substance does neither ; when boiled with alkalis, it gives no oxalic acid, and with acids it suffers hydrolysis and the product loses water, being converted into a substance which is evi- dently a ring compound, CH<~E$~>co2H, a change which would be impossible with an a-oxalocrotonic ester.Finally, the idea that the substance might be a P-oxalo-ester may be at once set aside, as it is impossible to find a suitable formula for such a substance. The condensation of ethyl crotonate with ethyl oxalate in the above way might, at first sight, be attributed to the presence of the group CJ&*bC*, but that this is not the case is shown by several facts. Thus ethyl a-methylacrylate, which is isomeric with ethyl crotonate and contains that group, gives no indication of forming a similar compound.Again, other unsaturated esters containing the grouping *CH,*CR:CR, should behave in a similar way, bnt examination of the ester of camphorenic acid, which also contains this grouping, showed that no condensation occurred, The power of two such pairs of doubly-bound carbon atoms in attachment to a CH, group to render the reaction a possible one is unquestionable (Thiele, Ber,, 1900, 33, 666), but with those substances which contain only one such pair, there is almost certainly a sharp line of demarcation, both in the fatty and in the aromatic series, between the two classes represenced respectively by the formulse *CH,*6:6* and *CH,*d:c'*X (where x = co, &c.).1274 LAPWORTH: FORM OF CHANGE IN ORGlANlC COMPOUNDS, EXPERIMENTAL.Action of Sodium Ethoxide and Amyl Nitrite on 0- and p-Xitrotoluenes. Amyl nitrite has little or no action on 0- or p-nitrotoluene in presence of alcoholic sodium ethoxide, but if the anhydrous ethoxide is used there is little difficulty in isolating the oxime of 0- or p-nitro- benzaldehyde respectively from the product. The mode of treatment found most suitable was as follows. Sodium (2-3 grams) was di&olved in 12 times its weight of alcohol, and the excess of the latter afterwards got rid of by distillation in a stream of hydrogen at about 180°, the removal being completed in a vacuum at this temperature, The residue was covered with about 200 C.C. of thoroughly dried and purified ether, and a mixture of amyl nitrite and o-nitrotoluene was then slowly poured in, the temperature being at first kept down by means of a freezing mixture.The whole, after remaining a few days at the ordinary temperature, was poured on crushed ice, the resulting aqueous solution being separated, extracted twice with pure ether, and freed from the latter by a current of air. On adding dilute hydrochloric acid to the solution, a fairly copious precipitate of solid matter separated. This was collected, dried, and crystallised from benzene. 0.2097 gave 0.3878 CO, and 0-0710 H,O. The substance melted at 95-96O and had all the appearance and properties of o-nitrobenzaldoxime. I n order to complete its indentifi- cation, it was heated for some time with concentrated hydrochloric acid, the liquid being then extracted with ether and the latter evaporated.A residue of solid matter remained, which had the properties of o-nitrobenzaldehyde, and on dissolving it in dilute acetone and adding a few drops of dilute sodium hydroxide, rapid darkening ensued, followed by a deposition of indigo. With p-nitrotoluene, the yield of oxime is not so good, but no difficulty was experienced in isolating it. The crystalline substance obtained melted at 128--12Q0, and when heated with pure p-nitro benzaldoxime, its melting point was not depressed, 0 1505 gave 0-2'780 CO, and 0.0515 H,O. C = 50.3; H = 3.8 per cent. With m-nitrotoluene, no evidence of the formation of an oxime could be obtained, and no positive result ensued, even when in this case ethyl oxalate was substituted for amyl nitrite.As condensation with ethyl oxalate almost invariably takes place more readily than with C = 50.4 ; H = 3.8. CIH,O,N, requires C = 50.7 ; H = 3.7 per cent. On analysis :AND FUNCTION OF THE WMETA-ORIENTATING GROUPS. 1275 amyl nitrite, it may be concluded that m-nitrotoluene behaves alto- gether differently from the 0- and pcompounds in this regard. Experiments were made in which amyl and ethyl formates and nitrates were substituted for oxalates and nitrites. With the formates, reaction certainly occurs, but on treating- the product from o-nitro- toluene with water, a crystalline, neutral compound separates, and only a small quantity of any acid substance could be detected. Theneutral substance crystallised from alcohol in nearly colourless prisms melting at 121°, and gave the following results on analysis : 0.1148 gave 0.2577 CO, and 0.0492 H,O.The substance was identified as 2 : 2'-dinitrodibenzyI, C = 61.2 ; H= 4.7. C,,H,,0,N2 requires C = 61-7 ; H = 4.4 per cent. which, it is interesting to note, has been obtained only on one previous occasion, namely, on treating o-nitrophenylpyruvic acid, the product from o-nitrotoluene, ethyl oxalate and sodium ethoxide, with alkali (Reissert, Ber., 1897, 30, 1039). As the substance is not formed when ethyl formate is omitted in the above reaction, it appears highly probable that it owes its origin to a condensation product of o-nitro- toluene and ethyl formate, which, judging from the properties of p-nitropheng lacetaldehyde, would be a highly unstable substance (Lipp, Ber., 1886, 19, 2647).Experiments with other o- and p-Substituted 5!'oluemes.--In endeavour- ing to extend the above observations, ethyl 0- and p-toluates were treated with ethyl oxalate and sodium ethoxide under several condi- tions. Here it was found that small quantities of unstable, acidic substances were produced which were ketonic in their nature and gave blue to violet colorations with ferric chloride. These substances were possibly the condensation products sought for, but good numbers were not obtained when they were analysed, owing t o the small quantities hitherto isolated, and the consequent difficulty of ensuring their purity. With 0- and p-toluonitriles, violent reactions took place, but rapid decomposition ensued, black, amorphous masses being deposited, and this occurred also in absence of ethyl oxalate. It is hoped that further experiments with 0- and p-methylsulphones and ketones will give more definite results.I n none of these cases, however, is it to be expected that such definite results will be obtained as with the compounds containing the highly reactive nitro-group.1276 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, Condensation of Ethyl Crotonata with Ethyl Oxalate. Formation of Ethyl crotonate and ethyl oxalate condense in presence of anhydrous sodium ethoxide suspended in ether or toluene. The liquid slowly becomes bright yellow in colour as the ethoxide dissolves, and after the lapse of a week, a yellow, microcrystalline deposit settles on the walls of the containing vessel. A considerable quantity of the product remains dissolved, however, and the whole should be poured into ice- water containing an excess of dilute acetic acid, the ethereal solution separated, washed, and extracted repeatedly with dilute sodium car- bonate.The crude ester may be isolated by acidifying the alkaline extract with acetic acid and extracting with ether, which should after- wards be allowed to evaporate spontaneously. The oxalo-derivative may also be obtained by adding a mixture of the two esters to the calculated quantity of sodium, cut into thin sheets, and covered with a considerable quantity of absolute ether. In all cases, the presence of a very small quantity of water is sufficient to completely prevent the formation of the desired product, and the yield never exceeds 40 per cent.of the theoretical amount. The ester is best purified by dissolution in cold dilute sodium car- bonate, powdered sodium acetate being afterwards added to the soh- tion. The sodium compound then separates as a voluminous mass of needles which may be separated by filtration, washed with dilute sodium acetate solution, and afterwards decomposed by dilute hydro- chloric acid. The nearly white ester which separates is dried, and crystallised from a mixture of benzene and light petroleum. A speci- men of the ester was analysed. Ethyl y- Oxdocrotonccte, C0,Et *C( OH) : CH* CH : CH* C0,Et. 0.2265 gave 0.4684 CO, and 0.1336 H,O. C = 56.4 ; H = 6.6. C,,H1,O, requires C = 66.0 ; H = 6.6 per cent. Ethyl y-oxalocrotonate is a nearly colourless solid. It dissolves very readily in all organic media with the exception of light petroleum in which it is sparingly soluble, even when hot; it is nearly insoluble in water.It crystallises from a mixture of ethyl acetate and light petroleum in small, transparent prisms, and from light petroleum in fan-shaped aggregates of plates or isolated, short, compact prisms or tablets. When these are examined in convergent polarised light, an optic axis of a biaxial interference figure is seen to emerge obliquely with regard to the field. When melted on a glass slip beneath a cover-glass, it solidifies sud- denly on cooling in bundles of fine needles interspersed with irregularly arranged patches of indistinct crystalline structure.AND FUNCTION OF THE U-META-ORIENTATING GROUPS. 12'77 That the ester exists in the enolic form, C0,Et *C(OH):CH*CH:CH*CO,Et, is shown by the fact that it is a fairly strong acid; it expels carbon dioxide rapidly from dilute solutions of sodium carbonate, and if a moderately strong solution is made, the yellow sodium derivative crys- tallises out.From its solution in alkali, the ester is precipitated on addition of acetic acid. The presence of the enolic grouping in the substance is also shown by the fact that its dilute alcoholic solution is coloured an intense brownish-black on addition of ferric chloride, and this coloration is not discharged by the addition of a very large excess of strong mineral acid ; with ferrous sulphate, no marked coloration is produced. Attempts to prepare the acetyl and benzoyl derivatives of the ester resulted in the formation of white, amorphous masses, which did not dissolve at once in dilute sodium carbonate solution.They were slowly decomposed by water and moist solvents, however, and could cot be made to crystallise. The ester cannot be purified by distillation, even under reduced pressure, as it rapidly decomposes ; it boils at 180' under the ordinary pressure, losing a certain amount of alcohol, and affording, for the most part, a carbonaceous mass. A small quantity of an oily substance distils over and a phenolic odour becomes apparent, but the majority of the distillate is probably the ester of the coumalincarboxylic acid described later. On warming the compound with soda, it dissolves rapidly, and if the alkali be strong, separation of a red, oily sodium salt ensues.The salt dissolves on shaking, however, and the solution becomes intensely yellow. On acidifying the diluted liquid after boiling for a consider- able time, little or no oxalic acid could be detected when the highly purified ester was used. When hot hydrochloric acid is used in the hydrolysis, the liquid, a t first slightly yellow, becomes colourless as the substance dissolves, and here again no carbon dioxide or oxalic acid could be detected as a product of decomposition. When the substance is warmed with solutions of aniline, or hydr- mines in dilute acetic acid or in alcohol, yellow precipitates are slowly produced j the aniline derivative is readily obtained in a crystalline form, but has not as yet been closely examined.The molecular weight of ethyl oxalocrotouate in acetic acid was determined by the cryoscopic method. The mean of three concordant measurements was 225, the number calculated for a substance having the formula C,,H,,O, being 214.1278 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, Action of #odium Ethoxide on a Mixture of Ethyl P-Bthoxybzctyrocte and Ethyl Oxakate. CH,*CH(OEt)*CH:C(OEt)*ONa might be regarded as a probable step in the formation of ethyl oxalocrotonate, sodium ethoxide was allowed to act on a mixture of ethyl /3-ethoxybutyrate and ethyl oxalate under the conditions found to be most advantageous for the production of that substance. It was found that it was eady to obtain some quantity of ethyl oxalo- crotonate in this way, but the yield, a5 compared with that obtained directly from ethyl crotonate, was small, and it is probable that the compound CH,*CH:CH-C(OEt),*ONa is the true intermediate sub- stance if any such is produced a t all, although it is manifestly im- possible to determine this with any degree of certainty.I n order to obtain evidence as to whether the compound The sodium derivative of ethyl oxalocrotonate, C0,Et C( ONa): CH* CH* CO,Et, is formed when the ester is dissolved in sodium carbonate or sodium hydroxide solution. It is not very readily soluble in cold water, and quite sparingly so in solutions of more soluble sodium salts. It forms long, yellow needles which have straight extinctions in polarised light, their directions of greatest length and elasticity being coincident.A specimen crystallised from a solution of sodium acetate was washed with water and analysed after drying over sulphuric acid in a vacuum. C,oHl,O,Na requires Na = 10.0 per cent. 0,3962 gave 0.1143 Na,SO,. Na=9*4. When this substance is washed with ether which has not been specially dried, it slowly decomposes and the ether on evaporation yields the nearly pure ester, indicating that the substance is hydro- lytically decomposed by water to a very considerable extent. The coppev derivative, (C,oHl,O,),Cu, is produced when an aqueous solution of copper acetate is added to the ester dissolved in alcohol; the blue solution of the copper salt becomes yellowish-green, and finally an amorphous greenish-brown precipitate is formed, which may be separated and washed with dilute alcohol.It is soluble in alcohol or ether, and could not be obtained in a crystalline condition ; on treat- ment with acids, it yields the pure ester. A specimen, after drying at looo, was analysed : 0,3635 gave 0.634 CuO. C20H,60,,Cu requires Cu = 12.9 per cent. With dilute aqueous soIutions of the sodium derivative, solutiona of soluble calcium, barium, nickel, or cobalt salts give no precipitates ; C = 12.8.AND FUNCTION OF THE U-META-ORIENTATING GROUPS. 1270 mercuric chloride throws down a bulky precipitate insoluble in ether. In somewhat concentrated solutions, calcium chloride forms a white, flocculent precipitate insoluble in ether j the silver compound is precipi- tated on adding silver nitrate, but rapidly darkens in the light, deposit- ing metallic silver.y- Oxalocrotonic Acid, C0,H C( OH) : CH- OH: CH. C0,H. This substance may be obtained in small quantities by the following process. The sodium derivative of the diethgl ester is finely powdered and triturated in a mortar with a 30 per cent. solution of sodium hydroxide, the liquid being added in small quantities and the temper- ature kept low. The solution, which is reddish-yellow in colour, is allowed to remain at the ordinary temperature for several hours until a small quantity, when diluted and acidified with acetic acid, gives no precipitate. The whole is then diluted with several times its bulk of water, cooled in ice, acidified with a large excess of sulphuric acid, and extracted about 20 times with ether, the latter being dried over calcium chloride and evaporated.The substance may be purified by crystallisation from a large bulk of ethyl acetate. 0,3721 gave 0.6264 CO, and 0,1194 H,O. The basicity of the acid was determined by titration with N/10 caustic soda, with phenolphthalein as indicator; the end point is difficult to determine precisely, owing to the deep colour of the result- ing sodium salt. The numbers obtained as the equivalent varied from 82-85, that required for a dibasic acid, CGH606, being 79. y-Oxalocrotonic acid is sparingly soluble in water and organic media in general, and is nearly insoluble in benzene, chloroform, or petroleum; it is most abundantly dissolved by acetic or formic acid or methyl or ethyl alcohol, none of which, however, deposits the substance in a well crystallised form.As usually obtained from aqueous or alcoholic solutions, it forms a bright yellow, microcrystal- line mass, and it is not easy to ascertain whether it is a uniform sub- stance or a mixture of tautomeric forms, but the author inclines towards the latter view. The cold aqueous solution of the acid is coloured intensely brownish- black by a solution of ferric chloride, indicating the presence of an enolic form, whilst on addition of hydrazine acetate immediate yellow precipitates are obtained, indicating that a ketonic form may be present. Hydroxylamine and semicarbazide, however, do not afford sparingly soluble derivatives ; with a solution of the former, the yellow colour of the solution becomes much less intense. C=45*8; H = 3 5 CGHGO, requires C = 45.6 ; H = 3.8 per cent, It melts and decomposes at about 190'.1280 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, Cournalin-karboxylic Acid (a-P~rone-d-curbox~~~c Acid), cO>O.CH- CHKCH:C( C0,Et) When diethyl oxalocrotonate is heated with acids, or when the free acid is heated at its melting point, ring formation ensues and a coumalin- carboxylic acid is formed, The most advantageous mode of preparation consists in boiling the ester with excess of fuming hydrochloric acid until complete dissolution has taken place, the liquid being then heated with animal charcoal, filtered, and evaporated to dryness on the water-bath. For further purification, the residue is triturated with enough strong hydrochloric acid to form a paste, transferred to porous earthenware to drain, and then recrystallised two or three times from dilute acetic acid. On analysis : 0.2337 gave 0.4410 CO, and 0.0592 H,O.C,H,O, requires C-51.43; H= 2.8 per cent. The equivalent of the acid as determined by titration with caustic soda was 140, or exactly that required for a monobasic acid having the formula C,H,O,. The acid dissolves somewhat sparingly in hot water, alcohol, acetic acid, acetone, or ethyl acetate, and was prmtical1y insoluble in benzene, chloroform, or light petroleum. It crystallises best from hot, strong hydrochloric acid, When heated, it melts and decomposes slightly a t 227-22S3. The crystals from hydrochloric acid are rectangular, transparent plates, or long, transversely striated needles which show a tendency to become twinned.Heated beneath slips of glass, it sublimes slightly before melting, and on cooling solidifies rapidly, forming for the most part a microscopic mass of indistinct structure, but here and there, especially among the sublimed parts, large, well-formed crystals may be seen ; in these crystals, the extinction in polarised light is straight, and the directions of greatest elasticity and length are at right angles. On slow sublimation, as during its analysis by the combustion method, it sublimes in brilliant needles. A dilute solution of the sodium salt gave no precipitates with salts of barium or calcium. A nearly white precipitate was produced on addition of lead acetate, and this dissolved readily in acetic acid ; with ferric chloride, a copious, flocculent, brown precipitate was formed, and with mercuric chloride a small quantity of an insoluble salt was precipitated. A cold aqueous or alcoholic solution of the acid gave no coloration with ferric chloride.On warming the aqueous solution of the acid with silver nitrate and a drop of ammonia, rapid blackening ensues and a brilliant mirror is formed on the walls of the tube. This is doubtless due to the C= 51.5 ; H e 2.8.AND FUNCTION OF THE a-META-ORIENTATING GROUPS. 1281 hydrolysis of the acid to oxalocrotonic acid, as the solution of the acid, when made alkaline with ammonia, warmed, and afterwards acidified gives a very distinct brown coloration with ferric chloride. When the acid is heated rapidly in a test-tube, a distinct odour of coumalin becomes noticeable, and this substance appears to be formed in small quantity when the calcium salt of the acid is heated strongly in a stream of hydrogen.The aqueous distillato in the latter case, on addition of ammonium sulphate, becomes milky, and a small quantity of a nearly colourless oil is deposited. This, after extraction with ether, had the properties of coumalin so far as the small quantity obtained would permit them to be observed. Thus, i t gave a bluish- red coloration with ferric chloride, and evolved an odour resembling that of crotonaldehyde when warmed with alkalis. It may be observed that. the odour and colorations were directly compared with those afforded by coumalin made from mslic acid in accordance with the directions given by Pechmann (Anncden, 1891, 264, 305), and no difference could be detected. The acid shows little or no tendency to yield a pyridone derivative when treated with ammonia, but when its ammonium salt is strongly heated with lime, or even alone, a powerful odour of pyridine is evolved, and the distillate affords a perbromide closely resembling that of this base; the large quantity of ammonia and the small quantity of the basic substance in the distillate have hitherto prevented the isolation of any pure pyridine derivative.-This ester is most easily obtained by the method used by Pechmann in preparing the ester of the isomeric acid, as the properties of the acids and their esters are very similar (Zoc. cit., 279). It is purified by crystallisation from light petroleum. Bthyl CoumaZi.n-6-carl1oxyZate, CH<cH:C(Co,Et)>O.CH- CO 0.3808 gave 0.7948 CO, and 0.1672 H,O. C = 56-8 ; H = 4.9. C,H,O, requires C = 5'7.1 ; H = 4% per cent, The ester is readily soluble in water and in most organic media with the exception of light petroleum, in which it dissolves only sparingly when cold. It crystallises from hot light petroleum in beauti- ful, thin, rectangular plates melting at 59-60', The crystals, in polarised light, show interference colours of high orders, and have straight extinction, their directions of greatest length and elasticity being at right angles. After melting, the substance solidifies to opaque masses of long, flattened needles or thin plates. When covered with 15 per cent. aqueous ammonia, the substance first dissolves, and on stirring, a mass of beautiful, white crystals separates.These disappear on warming, however, and on treatment1282 LAPWORTH: FORM OF CHANGE IN ORGANIC COMPOUNDS, with potash, yield a yellow solution which gives the tests for the salt of oxalocrotonic acid; the ester, therefore, is not the ethyl pyridone- carboxylate which it was hoped would be produced. No other method of treatment tried gave any basic substance whatever. Action of Amyl Formate and Nitrite on Ethyl Crotmunte. Amyl formate and nitrite both react with ethyl crotonate in pre- sence of sodium ethoxide or metallic sodium suspended in dry ether, yielding acidic products in considerable quantity. These are possibly the y-substituted derivatives sought for, but no attempts to obtain them in a pure form have as yet been successful, nor has any better result been achieved by endeavouring t o isolate the corresponding acids.The isonitroso-compound is converted into a basic substance on reduction with sodium amalgam, and it is hoped that by means of this prodnct the nature of the original reaction may be finally ascertained. Action of Ethyl Oxakate on EtlTlyZ a-Methykacrykate, Ethyl a-methylacrylate was made by heating ethyl a-bromoiso- butyrate with diethylaniline, as recommended by Howles, Thorpe, and Udall (Trans., 1900, "7, 947), but was isolated by distilling the resulting mixture and fractionating the portion which passed over below 160°, a method which appears t o afford a somewhat better yield than that recommended by these authors. The ester was treated with ethyl oxalate in presence of sodium ethoxide and also of sodium and ether, and even under the conditions most advantageous for the formation of ethyl oxalocrotonate, no corre- sponding oxalyl derivative was obtained, even in an impure condition.This was shown by the fact that, after shaking out the product with water and acidifying the aqueous extract with acetic or hydrochloric acid, no precipitate was produced, and no black coloration was developed on addition of ferric chloride, It is thus established with some degree of certainty that the forma- tion of ethyl oxalocrotonate is not to be accounted for by the proximity of the negative double binding CH,*I):V, for this is also present in ethyl a-methy lacrylate. Negative results were also obtained on endeavouring to condense ethyl oxalate with ethyl camphorenate, which contains the grouping CH,*CH:CH.AND FUNCTION OF THE a-META-OHLENTATING GROUPS.1283 Applicution of the Claisen Beaction to othe~ Compounds containing the G;rozcping C H, 6 : 6- C 0. On treating ethyl dimethylacrylate, CMe,:CHeCO,Et, with ethyl oxalate in presence of sodium and ether or of sodium ethoxide, the bright yellow colour which is characteristic of the early stages in the preparation of ethyl oxalocrotonate a t once appears, and if, after a few seconds, the mass is treated with water and the aqueous extract acidified, a colourless oil separates in small quantity, and, on adding ferric chloride to a solution of this in ether, an intense black colora- tion ensues. If, however, the treatment with sodium or with sodium ethoxide is allowed to continue, the liquid becomes green, and, on adding water, a dark-red, aqueous solution is obtained, which deposits a comparatively small amount of an oil on addition of acetic acid. I n both cases, a small quantity of a brown copper compound, resem- bling that obtained from ethyl oxalocrotonate, may be obtained, but no crystalline substance is produced on decomposing this. Phorone, CMe,:CH*CO*CH:CMe,, reacts very readily with ethyl oxalate in presence of sodium ethoxide, and a large yield of an oily or resinous product is obtained. This affords a black coloration with ferric chloride, and gives a brown, copper salt ; it does not yield oxalic acid on alkaline hydrolysis, but gives a sparingly soluble, pulverulent acid which forms an orange-red solution in alkalis. Benzylidenemesityl oxide, CMe,: CH* CO*CH: CHP h, also reacts, al- though somewhat less readily, with ethyl oxalate under the conditions described, and a similar compound is produced. This, as well as the preceding ketone, also reacts with amyl formate or nitrite, but the products are equally uninviting, Camphorone gives exactly similar derivatives. Although the products have not yet been obtained in a pure form, it appears probable from these results that there is a line of demarca- tion between those esters and ketones which contain the grouping *CH2*&6*CO* and those which do not. The difficulty of obtaining pure substances is due, in part, to the fact that the products are readily decomposed by distillation, even in a vacuum, and also, doubtless, to the readiness with which the up-unsaturated esters and ketones undergo decompo- sition and polymerisation under the conditions of experiment, as has been shown by Pechmann and others (Be?., 1900, 33, 3329, &c.), so that, unless the condensation with the oxalate is sufficiently rapid the product is likely to be of a very mixed character. The investigation of the foregoing compounds is being continued,1284 LAPWORTH AND LENTON: THE CONSTITUTION OF and it is intended that the behaviour of ethyl tetrolate, ethyl a-ethyl- crotonate, &c., towards ethyl oxalate should be examined. The author desires to express his best thanks to the Research Fund Committee of the Chemical Society for a grant which has largely de- frayed the cost of the preceding investigation, and with the help of which it is being continued. CREMICAL DEPARTMENT, SCHOOL OF PHARMACY, BLOOMSBURY SQUARE, LONDON, W.C.

ISSN:0368-1645    

DOI:10.1039/CT9017901265

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1284 LAPWORTH AND LENTON: THE CONSTITUTION OF CXXXV.-The Constitution of Camphanic Acid and of Bromocccmphoric Anhydride. By ARTHUR LAPWORTH and WALTER HENRY LENTON. ONE of the most interesting points in connection with the problem of the constitution of camphor and its derivatives is to be found in the behaviour of ordinary bromocamphoric anhydride on hydrolysis. When that substance is boiled with water, especially in presence of sodium carbonate, the anhydride ring is broken, and the bromine atom is simultaneously removed. The product consists for the most part of the lactonic product, camphanic: acid, but a certain amount of an un- saturated monobasic acid, lauronolic acid, is also produced, its mode of formation being represonted empirically by the equation, co C8H1,Br<CO>0 + H20 = G,H,,*CO,H + HBr + GO,.The researches of Fittig and his pupils on brominated acids have brought to light the fact that the removal of carbon dioxide and hydrogen bromide from such compounds by the aid of dilute aqueous alkalis is associated exclusively, or nearly so, in open-chain com- pounds, with P-bromo-acids, and, generalising from this fact, Aschan (Ber., 1894, 27, 2114) and others have concluded that in bromo- camphoric anhydride the bromine atom must occupy the @position with regard to one of .the two carboxyl groups. Acceptance of this view, however, is rendered difficult, for the fol- lowing reasons. Saturated carboxylic acids, on bromination, invariably yield a-bromo-acids. Fittig’s observations have reference to the behaviour of /3-bromo-acids. Combining these conclusions, we arrive at the view that bromocamphoric acid must be both an a- and a /3-bromo-acid, that is to say, it must contain the grouping CO,H 6Br*c*CO,H, and be a bromosuccinic acid.Hence it mustCAMPHANIC ACID AND OF BROMOCAMPHORIC ANHYDRIDE. 1285 follow that camphanic acid belongs to that unstable group of com- pounds, the p-lactones, of which but few are known, a view which it is almost impossible to reconcile with the great stability of the lactone ring, for hydroxycamphoric acid is unable t o exist in the free state, being at once converted into camphanic acid. Another fact which militates against the probability of the existence of the group CO2H*kBr*o*C0,H in bromocamphoric acid is the fact that lauronolic acid, which, according t o this view should contain the grouping CO,H*&b, is not an ap- but a &unsaturated acid, as is shown by its ready conversion into and formation from campholactone and the corresponding hydroxy-acid.Other chemists, desiring t o maintain that camphoric acid was a derivative of succinic acid, and either ignoring the work of Volhard and others, or attaching less significance t o it than to Fittig's observa- tions, have assumed that camphanic acid is a y-lactonic acid. This assumption necessitates the additional one that camphoric acid either becomes brominated at a point which is not in the a-position with regard to a carboxyl group, or that the brominat'ion follows the usual course, and that the hydrolysis of the bromo-anhydride has involved a change of a type otherwise quite unknown, and representable as follows : *?H *q yBr*CO,H + YH*CO,H 1 + HBr.I n the hope of being able to prove that the mistake had arisen in generalising too hastily from the behaviour of brominated open chain acids, we have made a long series of experiments with bromocamphoric anhydride and camphanic acid. It was clear from the first that the investigation would be more than usually diacult, for had any straightforward method been available, so important a problem would scarcely have remained for so long a time unsolved. It was soon found that any views based on the assumption that the change of bromocamphoric anhydride to camphanic acid involved an unusual change of configuration must be set aside, as the reverse change may be effected with great ease by merely warming camphanic acid on the water-bath with phosphorus pentnbromide. The next point t o be proved was that camphanic acid was derived from an a-hydroxy-acid.For this purpose, and for a, long time without success, we sought a method of removing the carboxyl group which was presumed to be attached to the same carbon atom as the hydroxyl group. The removal of a carboxyl group from an a-hydroxy-acid is, as a rule, a fairly easy process, and in a large number of cases may be achieved by such simple means as heating with strong acids, or with *9*C02H *q--co-o VOL. LXXIX. 4 T1286 LAPWORTH AND LENTON: THE CONSTITUTION OF I CH,*Q*CO*NH, I ?Me2 chromic acid or lead peroxide in presence of diliite acetic acid. Tn the present case, however, it would appear that the absence of the actual hydroxyl group itself, which is altered by its participating in the formation of the stable lactone ring, renders the usual oxidation processes entirely ineffectual.Attempts were also made to oxidise the product in which the lactone ring is opened (obtained by boiling the acid with excess of alkali); these were more effectual, but as the oxidation went too far, the experiments gave no useful result. Eventually, however, the nitrile of camphanic acid was prepared in the hope that, like the a-hydroxynitriles, it would prove to be unstable towards alkalis. For this purpose camphanamide was required as an intermediate product and it was obtained by the following methods. Camphanic acid was heated with phosphorus trichloride and the product poured into ammonia; a small quantity of the amide mas thus obtained, but the process was tedious and the yield unsatisfactory.The amide was obtained much more easily, however, by a modification of Wreden’s method. Wreden heated bromocamphoric anhydride with ammonia in closed tubes, and obtained a substance which he took to be the imide of hydroxycamphoric acid (Amalen, 1872, 163, 339), but which is identical with the amide made by the above process, behaves neither as a hydroxy-compound nor as an imide, and, as our subsequent work showed, must be regarded as camphanamide. The action is represented by the equation CH,+CN CH,*F:O + H 2 0 + I ?Me2 $?Me, co 0 C,H,,Br<CO>O + ZNH, = NH,Br + NH2*CO*C,H,,<b0. The heating in sealed tubes was found to be unnecessary, as it was sufficient to leave the finely-powdered bromoanhydride with strong ammonia for several hour6 at the ordinary temperature in order to effect its almost complete conversion into the amide.The amide was then converted into the nitrile by heating it with a mixture of phosphorus trichloride and pentachloride. A waxy nitrilolactone was thus produced, which, on treatment with strong alkalis, .was resolved into hydrogen cyanide and camphononic acid (Lapworth and Chapman, Trans., 1899, 75, 1000). As this is a y-ketonic acid, the investigation has afforded an apparently incontro- vertible proof of the views which we hold of the relationship of bromo- camphoric acid and camphanic acid to camphoric acid itself. The course -of the changes involved may be represented by the scheme,CAMPHANIC ACID AND OF BHOMOCAMPHORIC ANHYDRIDE.1287 and i t may be worth while to point out that a combination of the above facts with those already known about camphononic acid (Zoc. c k ) is in itself sufficient to decide almost conclusively the true constitution of camphoric acid. Thus, it has been shown that camphononic acid has one or other of the two formulae, CH,*$!O CO--C)H, I p e 2 and I $!Me2 UH,*CMe*CO,H CH,* CMe*CO,H and of these, in reality, only the former can be deemed worthy of serious consideration, for the acid yields hydrazones, a semicarbazone, and an oxime only with difficulty, does not unite with hydrogen cyanide, and cannot be reduced by such energetic treatment as with sodium and boiling amyl alcohol.Such a behaviour is altogether unknown in simple ketones and ketonic acids which contain the group- ing *CH,*CO*CH,*, present in the second of the above formule; the properties of such an acid would approach more nearly those of cam- phonic acid (Trans., 1900, 77, 454), which has a constitution of that kind. The first of the above formulae, therefore, apart from any views as to the constitution of camphor or camphoric acid, is the only possible which is character- ised by an exceptionally feeble tendency to form additive complexes (compare Trans., 1901, 79, 379). I n extending the foregoing observations, we have succeeded in devising a second method of converting camphoric acid into cam- phononic acid, through camphanamide as the intermediate stage.In this method, advantage was taken of the fact that the additive com- pounds of ammonia with aldehydes or ketones are easily broken down under the influence of alkalis or acids. In order to obtain the analogous compound of cnmphononic acid, the amide of camphanic acid was subjected to the action of sodium hypobromite and excess of sodium hydroxide. It was expected that the CO-NH, group would, as usual, be converted into the NH, group, and that an unstable aminohy droxy-acid of the for mula one, containing as it does the grouping "\ C-C*C:O, c/ I $Me2 CH,*CMe*CO,H would be produced which would at once break down into ammonia and camphononic acid. As a matter of fact, by this process, large quan-1288 LAPWORTH AND LENTON: THE CONSTITUTION OF tities of the ketonic acid may be prepared, and in a shorter time than by any of the methods hitherto discovered.EX PE R IJI EN TAL, The camphanic acid used in these experiments was prepared from bromocamphoric anhydride by boiling it with potassium acetate dis- solved in glacial acetic acid, and removing the potassium bromide from time to time by filtration, in accordance with Aschan's directions (Actu SOC. scient. fenn., 21, No. 5, 1). Dry camphanic acid is best made by heating the hydrated crystals in a flask a t ZOO0, a stream of air being occasionally drawn through the flask to remove the steam. On cooling, i t is noticed that the whole sets to a semi-transparent mass of crystals, and that this after- wards becomes opaque; this change is due t o dimorphism, and is most easily observed in the following way.The camphanic acid is melted on a microscope slide beneath a cover glass; on cooling, the substance sets rapidly to R transparent isotropic mass the structure of which is difficult to distinguish, but consists of n conglomeration of crystals resembling ammonium chloride ; almost immediately afterwards, the appearance of the second, doubly refract- ing, ordinary modification is noticed, the field now becoming distinctly crystalline, Camphanic acid is very stable towards most, and especially towards acid, oxidising agents. Thus, when heated with lead peroxide and acetic acid, it does not afford any appreciable quantity of carbon dioxide. It is very slowly attacked by nitric acid, however, and is practically converted into camphoronic acid, the intermediate com- pounds, if any, being less stable towards the agent than camphsnic acid itself.Attempts were made to obtain a ketonic acid. by boiling the cam- phanic acid with excess of potash to hydrolyse the Iactone ring, and the resulting solution of the potassium hydroxycamphorate was diluted and partially neutralised by means of a stream of carbon dioxide. A 2 per cent. solution of potassium permanganate was then run in, and :M it was found t h a t decolorisation occurred only very slowly, excess of the oxidising solution was added, and the whole allowed to remain for several days at O o ; the solution was then decolorised by means of sulphurous acid, heated, filtered, and evaporated. On acidifying and extracting the residue with ether, a n oily mixture was obtained, which soon deposited a considerable quantity of crystals of uualtered cam- phanic acid ; the remaining portion gave a very small deposit when warmed with a solution of phenylhydrazine acetate, but the amount of t h i s was iubufficient to be of any value for further investigation.CAMPHANIC ACID AND OF BROMOCAMPHORIC ANHYDRIDE.1288 Experiments were then tried with campholactoniz acid, which is usually supposed to be closely related t o camphanic acid, as it was possible that it might be the hydroxy-acid corresponding with cam- phononic acid. It was made by hydrolysing purified campholactone, and formed beautiful, white crystals melting a t 146'. The purified acid was dissolved in sodium carbonate solution, cooled to 0' and treated in the usual manner with dilute potassium permanganate, which a t first was instantly decolorised, but when n comparatively small quantity had been added, retained its colour for a long time.The products, isolated in the usual way, contained substances of a ketonic character, but the insoluble phenylhydrazones obtained from it, curiously enough, mere insoluble in dilute sodium carbonate, and were, therefore, not simple hydrazones of ketonic acids. From this it would appear that campholactonic acid is not genetically related to cam- phononic acid in the simple manner commonly supposed.* I n attempting to obtain camphanamide, the first experiments were made with the object of preparing it from the chloride of camphanic acid. For this purpose, the dry, finely powdered acid was heated in a flask with a large excess of pbosphorus trichloride for several hours, the excess of the latter boiled off, the residue dissolved in ether to render it more easy to manipulate, and the ethereal solution gradually poured into strong aqueous ammonia, which was kept a t Oo and shaken con- tinuously.A small quantity of a white, pulverulent substance separated, which was collected by filtration, washed, and crystallised from methyl alcohol, when i t separated in brilliant prisms melting at 160°. When warmed with dilute soda, the substance slowly dissolved, and on acidifying the resulting solution, a sparingly soluble acid separated. This melted a t 160°, with evolution of water vaponr, solidified im- mediately, and afterwards melted a t the same temperature as the original amide.The properties of the two foregoing substances resembled very * The author has suggested the formula 1 as a probable one for lauronolic acid (Brit. Assoc. Report, 1900, 327). Jf this is correct, then the formula for the corresponding y-hydroxy-acid, namely, campholactonic acid, would be CH,'CMe ZMe C H , ~ M ~ *CO,H """~,"G'j 1 1 CH,*UMe--CO1290 LAPWORTEI AND LENTON: THE CONSTITUTION OF closely those of the compound obtained by Wreden from bromocam- phoric anhydride by heating i t with ammonia in closed tubes (Zoc. cit.), and it was thought, therefore, that a better yield might be obtained by his process. On repeating his experiments, it was found that the componnds were, in fact, identical, and, moreover, that it was un- necessary to employ heat during the process, as, when the hromo- anhydride was sufficiently finely powdered, a marked development of heat occurred spontaneously on adding it t o ammonia. We have, therefore, used the following process in preparing the amide.The anhydride is powdered as finely as possible, passed through a fine sieve, and projected, in small quantities a t a time, into a flask containing strong aqueous ammonia (sp. gr. O*SSO), which is agitated during the whole time to prevent the formation of lumps. I n the course of 24 hours, the powder is converted into a mass of minute needles, which may be collected at the pump, washed, and crystallised from methyl alcohol or acetone. On analysis : 0.1947 gave 0.4377 CO, and 001371 H,O. C=60*8 ; H=7.8.0.2390 ,, 13.9 C.C. moist nitrogen a t 13O and 750 mm. N = 6.8. C,,H,,O,N requires C = 60.9 ; H = 7.6 ; N = 7.1 per cent. Camphanamide has all the properties ascribed to it by Wreden (Zoc. cit.). It dissolves sparingly in water, cold alcohol, or ethyl acetate, more readily in hot methyl or ethyl alcohol or acetone, and separates from the last-named solvent in beautiful, transparent prisms of calcite-like lustre. The crystals are apparently of rhombic symmetry ; in crushed frag- ments, in convergent polarised light, a wide biaxial figure is occasion- ally seen. The melted substance solidifies readily in long needles, flattened in a direction perpendicular to the optic axial plane. The directions of greatest length and elasticity are at right angles to one another, That the compound is in reality an amide, and not, as Wreden sup- posed, a hydroxyimide, is shown by the fact that it does not behave like an imide in any way, and gives no silver compound on treatment with ammonia and silver nitrate.Its identity with the substance obtained from the chloride of camphanic acid tells in favour of the view that it is an arnide. Further, and perhaps more conclusive, evidence is afforded by the fact that it was not found possible, even with Franchi- mont’s mixture of acetic anhydride and sulphuric acid, to prepare an acetyl derivative, the substance remaining unattacked after treatment for several hours at 130’. Camphnamic Acid, NH,*CO*C,H,,(OH)*CO,H.-This compound is easily prepared by warming powdered camphanamide with 10 per cent.sodium hydroxide solution, and, after precipitation with hydrochloricCAMPHANIC ACID AND OF BROMOCAMPHORIC ANHYDRIDE. 1291 acid, may be crystdlised from dilute alcohol. A specimen was analysed, after exposure a t 100' for 9 hours. 0-2172 gave 0.4529 CO, and 0.1613 H,O. The substance, when crystallised from dilute alcohol, contains 1 ruol. of water of crystallisation. It dissolves somewhat readily in alcohol, is sparingly soluble in ethyl acetate, and ingoluble, or nearly so, in benzene or light petroleum. From a mixture of methyl alcohol and ethyl acetate, it separates in beautiful, transparent prisms of consider- able size, which have a brilliant lustre, a well-marked plane of cleavage, and readily break up into thin plates. The double refraction is weak.The melting point of the substance is difficult to determine with any certainty, owing to the difficulty of getting rid of the water of crystallisation and the readiness with which the acid is converted into the lactone. When slowly heated, it melts at 160', as stated by Wreden, but when the tube containing it is plunged into sulphuric acid at 155O, fusion does not occur until a temperature of 165-166O is reached. I n all cases, an effervescence, due to the escape of water- vaponr, accompanies the fusion, and the residue soon solidifies, the mass melting once more a t 20S0, the melting point of camphanamide. A dilute solution of the ammonium salt gives no precipitate with solutions of calcium or barium salts; a white precipitate is produced with warm basic lead acetate, and with ferric chloride a nearly white precipitate is formed, which, on warming, disappears, the whole becoming reddish-brown.C=56.S ; H=8.2. CI,,Hl70,N requires C = 56.0 ; H = 7.9 per cent. Action of Behgdrating Agents on Camphanamide. 0 Camphanonitvile, CN*C,H,,<b, . Camphanamide is not easily converted into the corresponding nitrile ; zinc chloride, phosphoric oxide, or phosphoric sulphide either pro- duced no effect on it or converted i t into a charred mass. By the following process, however, n small quantity of the desired product may be obtained. The finely powdered amide is placed in a flask, uncovered, with a large excess of phosphorus trichloride, one molecular proportion of phosphorus pentachloride is added, and the whole heated on the water- bath until the particles of the amide are no longer distinguishable. The flask is ther, cooled, and the contents are poured slowly on to powdered ice which is kept well stirred.Chloroform is then added, the whole well shaken, and the chloroform extract shqken repeatedly with very dilute sodium carbonate solution, dried with calcium1292 THE CONSTITUTION OF CAMPHANIC ACID. chloride, and evaporated to dryness. The green or greenish-black, oily residue is extracted repeatedly with large quantities of light petroleum, and the waxy material which separates from the hot solu- tions crystallised several times from the same solvent, until it melts at 135'. A specimen dried in a vacuum was analysed: 0.2345 gave 0.5777 CO, and 0.1506 H20. C = 67.2 ; H = 7.1.CI,H,302N requires C = 67.0 ; H = 7.3 per cent. Camphanonitrile forms soft, fern-like crystals resembling those of ammonium chloride, which aggregate on pressure to a waxy, camphor- like mass. Melted on a slip of giass, it solidifies rapidly and com- pletely, forming skeleton crystals whose branches are rectangularly arranged, the whole being completely isotropic. The highest melting point observed for the substance was 135-137', but was never quite sharp, and it is possible that this temperature is a few degrees too low. When heated slowly at a higher temperature, the substance distils, apparently without much decomposition, and the vapour has an odour resembling that of raspberries. The nitrile dissolves in about five times its weight of sulphuric acid without decomposition, and if the solution is mixed with an equal bulk of fuming acid (25 per cent, SO3) and the mixture poured into ice, a small quantity of nearly pure camphanamide is obtained, showing that no structural change has been involved in the action of dehydrating agents on the amide.Action of Alkalis on Camphanonitrile. Tormution, of Canaphononic Acid. When camphanonitrile is covered with 20 per cent. aqueous potassium hydroxide, no immediate effect is observed, but if the whole is warmed or allowed to stand for some time the solid slowly disappears and a clear solution is finally obtained. On acidifying this solution, efferves- cence occurs and a strong odour of hydrogen cyanide becomes perceptible, the actual presence of this substance being easily shown by the usual tests. When the strongly acidified solution is extracted with chloroform in the usual way, a transparent, waxy mass remains on evaporating the extract.This substance crystallises from ethyl bromide in small prisms melting at 228' and has all the properties of camphononic acid. On analysis : 0.3713 gave 0.8583 CO, and 0.2760. In order to obtain icirther proof of the identity of the acid, it was This crystallised from metbyl alcohol in C = 63.1 ; H = 8.1. C,HI,O, requires C = 63.5 ; H = 8.2 per cent. converted into the oxirne.THE CHLORODIRROMO- AND DICHLOROBROMO-BENZENES. 1293 large, transparent rhombohedra which rapidly became opaque on ex- posure to the air, and as the substance melted at 186-187' the identity of the acid with camphononic acid was certain. Action of Sodium Hypobvomite and Sodium Hydroxide 0% Camphanamic Acid. Eighteen grams of ths amide were dissolved in 100 C.C. of 10 per cent. sodium hydroxide solution by the aid of warmth ; t o the resulting liquid 13 C.C. of bromine dissolved in 350 C.C. of sodium hydroxide were added, and the whole was heated on the water-bath for an hour. The excess of hypobromite was removed by means of sodium sulphite, and the liquid then acidified and evaporated to dryness, any unaltered amide which separated during this process being removed from time t o time. The residue was then extracted with dehydrated methylated spirit, and the extracted matter shaken with chloroform several times, the extract being evaporated to dryness, A waxy or oily residue remained, which was first triturated with ethyl bromide and afterwards crystallised from the same solvent. The substance thus obtained consisted almost entirely of pure carnphononic acid, as was proved by the methods j u s t described. By the treatment of 55 grams of camphanamide in this may, the recovered amide being repeatedly subjected to the same process, a quantity of pure camphononic acid weighing 17 grams mas finally obtained, and the process occupied only a few days. CHEMICAL DEPAKTMENT, SCHOOL O F PHARMACY, BLOOMSBUILY sQUAItE, W.C.

ISSN:0368-1645    

DOI:10.1039/CT9017901284

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

THE CHLORODIRROMO- AND DICHLOROBROMO-BENZENES. 1283 CXXXV1.-The Chlomdibromo- and Dichlm-obronzo- benzenes. By WILLIAM HOLDSWORTH HURTLEY, D.Sc. (Lond.). ACCORDINU t o theory, there should be twelve trisubstituted benzenes containing either one atom of chlorine and two atoms of bromine, or two of chlorine and one of bromine. Six of these are unsymmetrical in structure, two symmetrical, and four vicinal. Of these twelve, the two symmetrical compounds have been obtained by Hantzsch, Schleis- sing, and Jager ( B e y . , 1897, 30, 2334) ; the s-chlorodibromobenzene by the transformation of the acid s-tribromobenzenediazonium chloride ; and the s-dichlorobromobenzene by the transformation of the same compound on standing and warming. The s-chlorodibromo- vor,. LXXIX. 4 u1204 RURTLEY: THE CHLORODIBROMO- AND benzene was also obtained by them from 3 : 5-dibromoaniline, by re- placing the amino-group by chlorine.I n this paper, the preparation of all the twelve chlorobromobenzenes fromanilines of knownconstitution is described. The unsymmetrical com- pounds were all obtained by replacing the amino-group in di-halogen amines by chlorine or bromine, and, for this purpose, Gattermann’s well-known method (Ber., 1890, 23, 1222) was employed. Several of the unsymmetrical compoiinds were also obtained by replacing the amino-group in tri-halogen anilines by hydrogen. Tbe symmetrical and vicinnl compounds were prepared by replacing the amino-group in the corresponding chlorobromoanilines by hydrogen, by the method first described by Griess (8nnc61?en, 1866, 137, 67).Any unsymmetrical tri-halogen benzene can be prepared from acet- anilide by introducing two halogen atoms, wherr a compound of the Ax results, where X, and also Y, may be either chlorine NHAc li Y or bromine. On hydrolysing the acetyl derivative and replacing the amino-group by chlorine or bromine, the desired compound is obtained. Further treatment with a halogen converts the 2 : 4-halogen anilines into the symmetrical tri-halogen compounds, from which the sym- metrical chlorodibromo- or dichlorobromo-benzenes are obtained by removing the amino-group. Thus : 9 \ Y x()x \/’ Y where X, and also Y, may be either chlorine or bromine. Two, and only two, tri-halogen anilides are obtained when a meta- halogen anilide is treated with chlorine or bromine. One of these has a higher melting point, is less soluble in alcohol, 50 per cent.acetic acid, or benzene, and is formed in much larger amount than the other. The substance of higher melting point has the halogens in the positions 2 : 4 : 5 ; this is proved : (a) By hydrolysing the acetyl derivative and removing the amino- group, when an unsymmetrical tri-halogen benzene results. ( b ) By the fact that the same anilide is obtained as principal pro- duct on introducing one halogen atom into the 3 : 4-halogen anilide. The other anilide may have the halogen atoms in the positions 2 : 3 : 4, 3 : 4 : 5 , or 2 : 3 : 6. It is produced together with a larger amount of the isomeric 2 : 4 : 5-compound when one halogen atom entersDICHLOROBROMO-BENZENES.1295 into the 3 : 4-di-balogen anilide, and, on removing the amino-group, does not yield an unsymmetrical tri-halogen benzene. Hence it is not a 2 : 3 : 6-derivative. It is not a dimeta-derivative, because, apart from the improbability of the formation of such a compound, I have shown that on brominating m-dicbloroacetanilide the product is not identical with that which results on chlorinating m-bromoacetanilide, although both yield the same dichlorobromobenzene. The anilide having the lower melting point must therefore be a 2 : 3 : $-derivative. Thus we have : NHAc NH2 NH2 Y/\ 1 Ix +- '\/ Y Y \/ Y NHAc ,/ \/ Y A i" \ NHAc "w /\Y ' Ix \/ Y /\Y li. Y If this scheme is correct, we should obtain as final products the on brominating m-chloroacet- compounds anilide; the first compound should be identical with that prepared by replacing the amino-group in 2 : 4-dibromoaniline by chlorine, and tho second with that formed on replacing the amino-group in 2 : 6-dibromo- aniline by chlorine.The quantities of the tri-halogen benzenes at disposal for the deter- mination of chemical and physical properties were about 3 grams each in the case of vicinal derivatives, and about 10 grams in each of the others. The vicinal compounds crystallise in well-defined, rhombic plates, the symmetrical in long, slender prisms, and the unsymmetrical in short, thin prisms. The chlorodibromo- and dichlorobromo-benzenes are very soluble i n benzene, ether, chloroform, o r petroleum, but less so in alcohol, from which they can all be readily crystallised.The unsymmetrical com- pounds are very slowly volatile in steam, in which, however, the sym- metrical and vicinal derivatives volatilise readily. The vicinal and unsymmetrical compounds have a characteristic bromobmzpne-like odour, whilst the symmetricJ derivatives have a very faintly mouldy one. The melting and boiling points of these tri-halogen benzenes show interesting regularities ; these constmts, with those of the trichloro- and tribromo-benzeses;, are collected in the following table : p , B r Br/\ Br \/c1 , I IC1 and Br \/ This has been shown to be the case. 4 U 21296 HURTLEY: THE OHLORODIBROMO- AND Trichlorobenxenes. Tv-ibr omo benze ne8. M. p. €3. p. M, p. B. p. 1:2:4 16" 213" 1:2:4 44' 275O 1:2:3 53 218 1:2:3 87 - 1:3:5 63 208 1:3:5 120 271 Dichlorobromobenze~es.Chorodibromobenxenas. C1:Cl:Br M. p. B. p. C1:Br:Br. M. p. B. p. 1 :3:4 36" 256' 1:2:4 27 258 1:2:5 40.5 259 1:2:3 73.5 264 v { ~ ~ ~ ~ ~ 65 242 { 1:2:6 69.5 265 8 1:3:5 77.5 232 1:3:5 99.5 256 A consideration of this table shows that the melting point depends on both the nature and position of the substituents, whilst the boiling point depends more on the former than on the latter. Thus, the melting point of 1 : 3-dichloro-2-bromobenzene is 32' higher than that of 1 : 4-dichloro-2-bromobenzene, whilst the boiling points differ only by 7" ; the melting point of I-chloro-2 : 3-dibromobenzene is 33Ohigher than that of 1-chloro-2 : 5-dibromobenzene, whilst the boiling points differ only by Fie; the melting 'points of the symmetrical compounds are much higher, but their boiling points are slightly lower, than those of the unsymmetrical derivatives.The symmetrical compounds have the highest melting point, the vicinal are intermediate, and the un- symmetrical have the lowest melting poinf ; this is also true for the trictloro- and tribromo-benzenes, I n the case of the boiling points, the vicinal compounds boil at the highest temperature, the unsymmetrical are intermediate, and the symmetrical compounds have the lowest boiling points. This order applies to the trichlorobenzenes and also to the trimethylbenzenes. The boiling point of the vicinal tribromobenzene is not given in Beil- stein's Hundbuch, and those of the unsymmetrical and symmetrical compounds are given as 275" and 278" respectively. As the sym- metrical tribromobenzene would be expected to conform to the same rule as the other compounds, and boil at a lower temperature than the unsymmetrical derivative, I made a specimen of this substance by removing the amino-group from symmetrical tribromoasiline, and purified the product by crystallisation from alcohol and distillation in a vacuum ; it boiled a t 271' under 765 mm.pressure, thus conforming t o the rule. f 1 :2 :4 24.5' 237" as{ 1:3:4 25 235 1:4:2 33 235 60 243DICHLOROBROMO-BENZENES. 1297 Ex P E RI ME NT A L. 1 : 2 .Dic~~loro-4-bronaobenxer~e. This compound was prepared from 2chloro-4- bromoacetanilide, which was obtained from p-bromoacetanilide by the method described by Chattaway and Orton (this vol., p. 820). The base from the 2-chloro-4-bromoacetanilide was dissolved in a large excess of concentrated hydrochloric acid (ten times the calculated quantity), some water added, diazotised at 0' with sodium nitrite, and the solution of the diazochloride added to freshly made, well washed, precipitated copper.This product was extracted with chloroform, filtered, the chloroform removed by distillation, and the residue dis- tilled in a vacuum. From the non-volatile portion, by washing with ether, a substance having all the properties of an azo-derivative was isolated ; it is being examined. The 1 : 2-dichloro-4-bromobenzene was again distilled in a vacuum, when i t boiled constantly at 124" under 33 mm. pressure, with the oil-bath a t 234'. When crystallised from alcohol, i t formed short prisms melting at 24.5'.It boiled a t 237O under 757 mm. pressure. This and all the other boiling points under atmospheric pressure, described in this paper, were determined by Siwoloboff's method (Bey., 18S6, 19, 795). 0.1787 gave 0.3757 AgCl + AgBr and 0.2553Ag. C1= 30.63; Br = 36-74, C,H3Cl,Br requires C1= 31 -38 ; Br = 35-40 per cent.* 1 : 3 - Dich loro-4-bromo benzene. The amino-group in 2 : 4-dichloroaniline was replaced by bromine exactly as above described, except that hydrobromic acid was used in place of hydrochloric acid. Gattermann states that a mixture of sulphuric acid and potassium bromide can be added to the diazo- chloride in place of hydrobromic acid, but in this preparation a better yield resulted when the latter was used. On distilling the copper mix- ture in a current of steam, it was found that the product came over very slowly, and, subsequently, extraction with chloroform was used instead of this process. On distillation in a vacuum, the dichlorobromobenzene boiled at 1 1 1 O under 21 mm.pressure, with the oil-bath at 130'. It crystallised in clusters of small, white prisms which melted at 25" and boiled at 235' under 751 mm. pressure. * The mixed silver salts were weighed in a small Gooch crucible ; this was then placed in a small Rose crucible and heated in a stream of dry hydrogen. In the above analysis, the mixed chloride and bromide was only 0*0002 too high and the silver 0*0008 too low ; as these errois are in opposite directions they make the found percentages of chlorine and bromine show considerable divergence from the calcu- lated values, This occurs in two or three cases in the present paper.1298 HURTLEY: THE CRLORODIBROMO- AND 0.1586 gave 0.3350 AgCl + AgBr and 0.2291 Ag.C1= 32.05; Br = 34.71. C6H,CI2Br requires C1= 31.38 ; Br = 35.40 per cent. This compound was also prepared by removing the amino-group from 2 : 4-dichloro-5-bromoaniline (p. 1302). 1 : 4-DiclJo~*o-2-bromobenxene. 2-Bromo-4chloroaniline was employed for the preparation of this compound. p-Chloroacetanilide was dissolved in glacial acetic acid, and to the solution one molecular proportion of bromine dissolved in acetic acid was added, along with some fused sodium acetate. The product so obtained was precipitated by water, crystallised from alcohol, and hydrolysed, and the amino-group of the resulting aniline replaced by chlorine.After extraction with chloroform and removal of the latter by distillation, the residue was distilled in a vacuum. Prom the non-volatile portion an azo-compound was isolated by wash- ing with ether. The distillate was redistilled, and came over a t 119" under 26 mm. pressure, with the bath at 141". 1 : 4-Dichloro-2-bromo- benzene crystallised from alcohol in short prisms, melted at 33', and boiled a t 236" under 751 mm. pressure. 0.2812 gave 0.5898 AgC1+ AgBr and 0.4014 Ag. C1= 30.87; Br = 36.13. CGH,Cl2Br requires C1= 31 *39 ; Br = 35-40 per cent. This compound was also obtained by removing the amino-group from 3 : 6~dichloro-4-bromoaniline (p. 1301), 1 -Chloroh3 : 4-dibromobenxene. On replacing the amino-group in12- bromo-4-chloroaniline by bromine, only a very poor yield of this compound was obtained.Accordingly, another method of preparation was used : 3 : 4-dibromoacetanilide was prepared by dissolving m-bromoacetanilide in glacial acetic acid, and adding the calculated amount of bromine, also dissolved in glacial acetic acid. After precipitation by water, and crystallisation from alcohol, a pure product was obtained (compare Korner, Gazxetta, 1874, 4, 330). This was hydrolysed, and the aminogroup re2 placed by chlorine, the rest of the process being exactly similar to that already described. Under 19 mm. pressure, the new compound distilled at 121°, with the bath at 141O. As the distillate was slightly green, it was distilled in steam, and three times crystal- lised from alcohol.1-Chloro-3 : 4-dibromobenzene cryatallised in short prisms, which melted at 35.5", and boiled at 256" under 760 mm. pressure.DICHLOROBROMO-BENZENES. 1299 0.2232 gave 0.4285 AgCl + AgBr and 0.2665 Ag. C1= 12-68 ; Br = 59.83. C,H,C1Br2 requires C1= 13.11 ; Br-59.14 per cent. This compound was also obtained by replacing the amino-group in 2-chloro-4 : 5-dibromoaniline by hydrogen (p. 1305). l4Idoro-2 : 4-dibromobenxene. The amino-group in 2 : 4-dibromoaniline is easily replaced by chlorine, and the new compound is obtained in a pure condition in exactly the same way as the preceding-substance. Under 41 mm. pressure, and with the bath at 152", it boils a t 139' ; its melting point is 27", and it boils at 258' unaer 757 mm. pressure. 0'1878 gave 0.3593 AgCl + AgBr and 0-2240 Xg. C1= 13.04 ; Br = 59.04.C,H,C1Br2 requires C1= 13.1 1 ; Br = 59.14 per cent. This compound mas also obtained by eliminating the amino-group from 3-chloro-4 : 6-dibromoaniline (p, 1304). 1-Chloro-2 : 5-di6romobenxene. p-Dibromobenzene was prepared by brominating benzene in presence of iodine (Jannasch, Ber., 1877,10,1355), and nitrated by careful addition of fuming nitric acid, the mixture being kept cool during the process. The p-dibromonitrobenzene was reduced by tin and hydrochloric acid, the amino-group in the resulting aniline replaced by chlorine, and the 1-chloro-2. : 5-dibromobenzene purified as above. It distils a t 121' under 24 mm. pressure, with the bath at 150". Another method employed for its preparation was as follows.3-Bromo- 4-chloroacetanilide mas prepared from m-bromoacetanilide by trans- formation of the nitrogen chloride of the latter, and separated from the 3-bromo-6-chloroacetanilide formed at the same time by hydrolping the mixed anilides with alcohol and sulphuric acid and distilling the product in steam, when 3-bromo-4-chloroaniline remained behind as sulphate. This salt was decomposed, and the aniline purified by distillation in steam and crystnllisation from chloroform. After acetylation, the resulting anilide was brominated, yielding 2 : 5-dibromo- 4-chloroacetanilide which, on hydrolysis and removal of the amino-group, gave 1 -chloro-2 : 5-dibromobenzene. This chlorodibromo-derivative melts at 40.5' and boils at 259' under 764 mm, pressure. 0.1701 gave 0.3299 AgCl+ AgEr and 0.2065 Ag, C1= 13.85; Br = 58.69 C6H,C1Br, requires C1= 13.1 1 ; Br = 59-14 per cent.1300 HURTLEY: THE CHLORODIBROMO- AND 1 : 3-Dichloro-5-bromobemxene.2 * 4-Dichloro-6-bromoaniline was prepared by a d d i q a glacial acetic acid solution of the calculated amount of bromine to a solution of 2 : 4-dichloroaniline in the same solvent, in presence of fused sodium acetate. The product was precipitated by water and crystallised from alcohol. The amino-group, in this and all other cases referred to in this paper, was removed as follows. The aniline was treated with sulphuric acid 01 such a strength that it dissolved fairly readily on warming. The solution, cooled to O", was saturated with nitrous fumes from arsenious oxide and nitric acid (sp. gr.1*35), and the resulting green liquid poured into excess of alcohol. On warming, the 1 : 3'di- chloro-5-bromobenzene crystallised out and was purified by distillation in steam and two crystallisations from alcohol. p-Bromo- aniline, dissolved in glacial acetic acid, was saturated with chlorine, made alkaline, and distilled in steam. The 2 : 6-dichloro 4-bromoaniline so obtained WAS crystallised from alcohol and the amino-group removed as just described. 1 : 3-Dichloro-5-bromobenzene crystallises in long, slender prisms having a very faint, rnouldy odour, melts at 77.5', and boils at 232' under 757 mm. pressure. Hantzsch (Zoc. cit.) gives its melting point as This compound was also obtained by the following method. 82 -84'. 0.1680 gave 0.3538 AgCl -I- AgBr and 0.241 1 Ag.CI = 31.25 ; Br = 35-83. C,H,Cl,Br requires C1= 31.38 ; Br = 35.40 per cent. 1-Chloro-3 : 5-dibrornobenxene. A glacial acetic acid solution of p-chloroaniline was treated with a solution of 2 mols. of bromine in the same solvent, in presence of fused sodium acetate. The resulting 2 : 6-dibromo-4-chloroaniline was pre- cipitated from the solution by water, crystallised from alcohol, and the amino-group removed as already described. To purify the product, it was distilled in steam and crystallised twice from alcohol. This compound was also prepared in a precisely similar manner from o-chloroaniline. 1-Chloro-3 : 5-dibromobenzene closely resembles the symmetrical dichlorobromobenzene. It melts at 99.5' and boils at 256" under 757 mm. pressure. 0.1660 gave 0.3216 AgCl+ AgBr and 0.2011 Ag.CI = 13.63; Br = 58.89. C,H,CLBr, requires C1= 13.11 ; Br = 59.14 per cent. This compound was also prepared from 3 : 5-dibromoaniline (10 grams Hantzsch (Zoc. cit.) gives the melting point as 96'.DI CH LOROBROMO -BENZ EN ES. 1301 of which Dr. Chattaway lzindly gave me for this purpose) by replacing the amino-group by chlorine. 1 : 3-Dicl~o~o-3-bromobenxene. m-Chloroacetanilide was dissolved in glacial acetic acid and the solu- tion treated in presence of fused sodium acetate with the calculated amount of bromine also dissolved in acetic acid. On precipitating the product by water and crystallising from alcohol, pure 3-chloro-4-bromo- acetanilide was obtained. This substance was dissolved in glacial acetic acid and saturated with dry chlorine, when a crystalline solid separated.The solid and the mother liquor were worked up separately as follows. The solid was principally a mixture of nitrogen chlorides; so it was dissolved in alcohol and a little ammonia added to decompose them. Prom this solution crystals melting a t about 170" separated ; they were recrystallised until they melted constantly at 189'. The mother liquor from the crystals, melting a t 170°, was precipitated by water and the precipitate crystallised from alcohol, when a product melting a t about 135" resulted, which was recrystallised until it melted constantly at 138.5'. The mother liquor was precipitated by water and the product dissolved. in alcohol, some ammonia being added for bhe reason just given. The crystals thus obtained melted at about 132" ; and by repeated crystal- lisation from alcohol were separated into a small quantity of the anilide melting a t 189O, and a second anilide melting constantly a t 138.5'.3 : 6-Dicliloro-4-brontoacetaniZ~~e crystallises in thin prisms and is sparingly soluble in alcohol, benzene, or 50 per cent. acetic acid. It melts a t 189'. 0.2143 gave 0.3596 AgCl+ AgBr and 0.2454 Ag. C1= 25.13 ; Br = 28.16. C,H,ONCI,Br requires C1= 25.06 ; Er = 28.26 per cent. 3 : 6-DichZoro- 4-bromoaniZine, obtained from the anilide by hydrolysis It is readily with alcohol and sulphuric acid, crystallises in needles. soluble in alcohol, petroleum, or ether, and melts a t 91". 0.2144 gave 0.4218 AgCl+ AgBr and 0.2875 Ag. C1= 29.23; Br = 33.33. C,H,NC12Br requires C1= 29.43 ; Br = 33.19 per cent.The constitution of this aniline, and therefore t h a t of the anilide also, was proved by removing the amino-group, when 1 : 4-dichloro- 2-bromobenzene was obtained. 2 : 3-l)ichlo~o-4-b~omoacetacnilide is far more soluble in alcohol, benzene?1302 HURTLEY: THE CHLORODIBROMO- AND or 50 per cent. acetic acid than the isomeric unsymmetrical anilide. It crystallises in prisms and melts at 138.5O. 0.2150 gave 0.3602 AgCl + AgBrand 0,2453 Ag. C1= 24.75; Br = 28.68. C8H,0NC12Br requires C1= 25.06 ; Br = 28.26 per cent. 2 : 3-DichZoi~o-4-bronro~niline is readily soluble in alcohol j benzene) petroleum, or ether ; i t crystallises in needles. and melts at 77.5O. 0.2344 gave 0.4688 AgCl+ AgBr and 0.3198 hg. C1= 29.50; Br = 33-27.CGH4NC12Br requires C1= 29.43 ; Br = 83.19 per cent. 1 : 2-Di'chZoro-3-b~*omobenoene.-The amino-group in the preceding compound was removed by the method already described and the product purified by distillation in steam and crystallisation from alcohol. From dilute alcohol, it crystallises in leaflets, but from absolute alcohol in well defined, rhombic plates. It melts at 60' and boils at 243' under 765 mm. pressure, 0.1501 gave 0.3130 AgC1+ AgBr and 0.2131 Ag. C1= 30*75; Br = 35.79, C,H3C12Br requires C1= 31.38 ; Br = 35040 per cent. 1 : 3-DichZoro-2-brornobenxene. m-Bromoacetanilide was chlorinated in glacial acetic acid solution and the two anilides which resulted were separated exactly as in the case of the preceding compound. 2 : 4-Dichloro-5-bromoacettlnilide crystallises in short prisms and melts at 198'.0.2280 gave 0.3774 AgCl + AgBr and 0.2574 Ag. C1= 24.72 ; Br = 27-88. C,H,ONCl,Br requires C1= 25-06 ; Br = 28.26 per cent. 2 : 4-Dichloro-5-6romoaniline crystallises in flattened prisms, melts at 86", and distils at 163' under 16 mm. pressure, 0.2436 gave 0.4811 AgCl + AgBr and 0-3269 Ag. Cl = 28.77; Br = 34.53. C,H4NClaBr requires C1= 29.43 ; Br =.33.19 per cent. The constitution of this aniline was proved by removing the amino- group when 1 : 3-dichloro-4-bromobe~zene mas obtained. 2 : 4-Dichloro-3-b~omoacetccnili&e cryst.allises in prisms from alcohol and in long, fine needles from benzene. 0.2013 gave 0.3405 AgCl + AgBr and 03322EAg. C1= 25.21 ; Br = 28-59. C,H,ONCl,Br requires C1= 25.06 ; Br = 28-26 per cent.It melts at 138'. 2 : 4-D;chZol.o-3-~1.omoa~iline crystallises in plates which melt at 78O. It distils at 172' under 22 mm. pressure.DICHLOROBROMO-BENZENES. 1303 0'2090 gave 0.4083 AgCl + AgBr and 0,2778 -4g. C1= 28.69; Br = 33.74. C,K4NCl2Br requires C1= 29.43 ; Br = 33.19 per cent. 1 : 3-DichZo~.o-2-61.oniober~xene is produced on eliminating the amino- group from the last-mentioned compound, It resembles the preceding vicinal dichlorobromobenzene, melts at 65*, and boils at 242' under 765 mm. pressure. 0.1489 gave 0.31 17 AgCl+ AgEr and 0.2126 Ag. Cl= 31.24; Br = 35.32. C6H,C12Br requires C1= 31.38 ; Br = 35.40 per cent. Dry p-nitroaniline was added to dry benzene and treated with dry chlorine, when much heat was developed and the benzene appeared to boil owing to the escape of hydrogen chloride.The yield of 2 : 6-dichloro- 4-nitroaniline is quantitative, and this method of chlorination is more convenient than that employed by Witt (Ber., 1875, 8, 143), namely, treatment of a hydrochloric acid solution of p-nitroaniline with potass- ium chlorate. In the 2 : 6-dichloro-4-nitroa~iline, the amino-group was eliminated and the resulting 3 : 5-dichloronitrobenzene reduced by tin and hydrochloric acid. By acetylation of the base, 3 : 5-dichloroacet- anilide was prepared and this was treated with one molecular propor- tion of bromine in presence of fused sodium acetate. On addition of a little water to the acetic acid solution, a solid melting a t 215' separ- ated, which, after being twice crystallised from acetic acid, melted constantly at 220'.0.1994 gave 0.3337 AgCl + AgBr and 0.2272 Ag. C1= 24.69; Br = 28.75 C,H,ONCl,Br requires C1= 25.06 ; Br = 28.26 per cent. On hydrolysis, the anilide yielded an aniline which was purified by distillation in steam and crystallisation from alcohol. This base crystallised in rather long needles and melted at 1299 0,2099 gave 0.4130 AgCl+ AgEr and 0.2812 Ag. C1= 29.17; Br = 33.75, C6H,NCl2Br requires C1= 29'43 ; Br = 33.1 9 per cent. From this aniline by elimination of the amino-group 1 : 3-dichloro-2- This compound was also 6btained by the following method. It formed short prisms. bromobenzene was obtained, 1-CI~loro-2 I 6-dibromobenxene. Prom m-chloroacetanilide, by bromination, there was first prepared ~-chloro-4-bromoacetanilide in pure condition, and from this by treat; ment with one molecular proportion of bromine, a mixture of the unsymmetrical and vicinal chlorodibromoacetanilides resulted.These ahilides were separated in a precisely similar manner to those described under 1 : 2-dichloro-3-bromobenzene.1304 THE CHLORODIBROMO- AND DICHLOROBROMO-BENZENES. 3-Chloro-4 : 6-dibrmoacetanilide crystallises in thin prisms and melts at 174". 0.2593 gave 0.4108 AgCl + AgBr and 0.2562 Ag. C1= 10.67 ; Br = 48.81 C8H60NClBr2 requires C1= 10.82 ; Br = 48-84 per cent. 3-Chloro-4 : 6-dibromoaniline has been obtained by Wheeler and Valentine (Amev. Chem. J., 1899, 22, 270). Its constitution is proved by removing the amino-group, when it yields 1-chloro-2 : 4-dibromo- benzene. 3-chloro-2 : 4-dibromoacetanilide crystallises in prisms melting at 152". 0.2192 gave 0.3480 AgCl +AgBr and 0.2169 Ag.C1= 10.75; Br = 49-06. C,H,ONClBr, requires C1= 10.82 ; Br = 48.84 per cent. 3-Chloro-2 : 4-dibromoaniline crystallises in plates which melt at 88". 0.1'772 gave 0.3231 AgCl +AgBr and 0.2016 Ag. C1= 12.52; Br = 56.05. C,H,NClBr, requires C1= 12-42 ; Br = 56.02 per cent. 1-ChZoyo-2 : 6-dibromobenzene, obtained from the last-mentioned com- pound by replacing the amino-group by hydrogen, closely resembles the preceding vicinal chlorodibromobenzenes. This compound was also obtained from 2 : 6-dibromoaniline, for which I am indebted to Dr. Orton, by replacing the amino-group by chlorine-a reaction which goes very smoothly. It melts at 69.5' and boils at 265" under 760 mm.pressure. 0.1780gave 0.3419 AgCl +AgBrand 0.2133 Ag. C1= 13-17; Br= 59.08. C,H,C1Br2 requires C1= 13.1 1 ; Br = 59.14 per cent. 1 -ChZo~o-2 : 3-dibvomobenxene. m-Bromoacetanilide was treated with one molecular proportion of bromine and the 3 : 4-dibromoacetanilide, which is by far the principal product, was purified by two crystallisations from alcohol. The glacial acetic acid solution of this product was saturated with chlorine and the unsymmetrical and vicinal anilides isolated in exactly the same way as the corresponding chloro bromoanilides. 2-Chloro-4 : 5-dib~omoacetanilide crystallises in needles and melts at 198'. 0.2091 gave 0-3343 AgCl + AgBr and 0.2090 Ag. C1= 1195 ; Br = 48-67. C,H60NClBr, requires C1= 10-82 ; Br = 48.84 per cent. 2-Chloro-4 : 5-dibromoamiline melts at 93" and crystallises in flat- tened needles.ACTIVE COMPOUNDS FROM INACTIVE SUBSTANCES. 1 305 0.2060 gave 0.3757 AgCl + AgBr and 0.2344 Ag. C1= 12.51 ; Br = 56-08. C6H,NC1Br, requires C1= 12-42 ; Br = 56-02 per cent. Replacement of the amino-group by hydrogen gave 1-chloro-3 : 4- dibromobenzene. 2-Chloro-3 : 4-dibl.on~occcetanilide crystallises in fine needles from benzene and melts at 1469 0.2287 gave 0.3649 AgCl+ AgBr and 0.2275 Ag. C1= 10.84; Br = 49.23. C,H60NClBr, requires CI = 10-82 ; Br = 48.84 per cent. 2-ch!oro-3 : 4-dibromoaniline crystallises in plates and melts at 9 1'. 0.2165 gave 0.3928 AgCl + AgBr and 0.2450 Ag. C1= 12-13; Br = 55.87. C,H,NClBr, requires C1= 12.42 ; Br = 56.02 per cent. 1 -ChZoro-2 : 3-dibrornobenxsne, obtained from the preceding compound by removal of the amino-group, closely resembles the other vicinal chlorodibromobenzenes. It melts a t 73.5' and boils at 148' under 23 mm. and a t 264O under 754 mm. pressure. 0,2029 gave 0.3881 AgCl+ AgBr and 0.2415 Ag. C1= 12.69; Br = 59.57. C,H,CIBr, requires c1= 13-11 ; Br = 59-14 per cent. I have much pleasure in stating that Dr. Orton drew my attention to the fact that the chlorodi bromo- and dichlorobromo-benzenes had not been prepared, and in acknowledging the help I have received from the advice and criticism of both Dr. Chattaway and Dr. Orton. The examination of these compounds is being continued, and the preparation of some of the chlorobromotoluenes, several of which have been obtained, has also been undertaken. CHEMICAL LABORATORY, ST. BARTHOLOMEW'S HOSPITAL AND COLLEGE.

ISSN:0368-1645    

DOI:10.1039/CT9017901293

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

ACTIVE COMPOUNDS FROM INACTIVE SUBSTANCES. 1 305 CBXXVI’I.-Expe?.irnents on the Production of Optically Active Compounds from Inactive Substances. By J. B. COHEN and C. E. WHITELEY. THE withdrawal of one of us from this research has made i t desir- able to publish the results of our experiments as far as they have gone. In addition to the three well known methods devised by Pasteur For obtaining optically active compounds from inactive asymmetric1306 COHEN AND WHITELEY: PRODUCTIOX OF OPTICALLY materials, many new processes have in recent years been proposed. These methods may be said to consist in subjecting the material to an unsymmetrical action of either a physical or chemical nature. Among the physical processes may be mentioned the crystallisation of the inactive material in a magnetic field which Pasteur tried without success and which has since been repeated by Boyd (Landolt, Optische Drehungsvermogen, p.I1 I) and others with similar results. Kipping and Pope have employed the method of crystallisation of a racemic compound from a solvent containing an active substance in solution (Proc., 1898, 14, 113) and obtained evidence of its effect in promoting the deposition of a larger proportion of one of the enan- tiomorphs. Among the chemical processes are the following. The selective hydrolysis of glucosides was effected by E. Fischer, by means of enzymes (Zeit. physiol. Chem., 26, 60); the fractional esterification of an inactive acid in combination with an active alcohol, or the reverse process, namely, the partial hydrolysis of an ester composed of an inactive acid and an active alcohol, was successfully employed by Marckwald and McKenzie (Bey., 1899,32, 2130; 1901, 34, 469) and Walden (Ber., 1899, 32, 3617); the rate of hydrolysis of cane sugar effected by d- and Lcamphoric acid was investigated by E.Fischer with negative results (Ber., 1899, 32, 3617). The formation of a new asymmetric carbon atom under asymmetrical conditions has also been studied by E. Fischerin the synthesisof the sugars. It isthis process which has especially attracted our attention. E. Fischer (AnrzccZen, 1892, 270, 64) has shown that in the synthesis of one sugar from another by the addition of hydrogen cyanide to the lower member, a new asymmetric carbon atom is introduced which may give rise to two stereoisomeric compounds represented as follows : Although the two new groups are optical antipodes, the two iso- merides are not necessarily so as a whole, and are not always produced in equal quantities.Fischer has found, for example, thgt d-glucose forms two cyanohydrins in very unequal quantities (Zoc. cit.), whilst in the case of d-mannose only one of the two possible cyanohydrins is produced (Hartmann, Annalen, 1892, 2’72, 190). It is clear, there- fore, that the asymmetric molecule exerts its influence on the space configuration of the newly added asymmetric carbon group. I n these examples, it is impossible to determine exactly the influence of the active part of the original molecule on the activity of the new group, seeing that the latter cannot be detached from the molecule. As the formation of active substances in living organisms is probablyACTIVE COMPOUNDS FROM INACTIVE SUBSTANCES.130'7 closely connected with their production from other active substances from which they are afterwards removed, the idea occurred to us to attempt to produce a new asymmetric carbon atom in an already active compound from which the originally active group could be sub- sequently detached. A number of reactions readily presented themselves, such as the reduction, bromination, or hydroxylation of esters composed of an unsaturated acid and an active alcohol, or the reduction of a ketonic ester of an active alcohol, the alcohol being afterwards removed by hydrolysis. These reactions may be represented as follows : (X stands for an atom or group not being hydrogen, A indicates the active alkyl or aryl group, and C the new asymmetric carbon atom) : 1.*CH:CH*CO,A -+ *CHX*CHX*CO,A --+ *CHX*CHX*CO,H 2. *CH:CX.CO,A -+ *CH,*CHX*CO,A --+ *CH,*CHX*CO,H 3. *CO*CO,A -+ *CH(OH)*CO,A --+ *CH(OH)*CO,H Under 1, we have prepared the bromine derivatives of the amyl and menthyl cinnamates, and of dicinnamyltar taric acid and examined the action of various reagents on the dibromo-compounds. All these experiments, after a considerable loss of time, had to be abandoned. Although the dibromo-derivatives of amyl and menthyl cinnamates and of dicinnamyltmtaric acid could be readily obtained in a state of purity, they could not be directly hydrolysed without removing bromine, and all attempts to replace bromine by hydroxyl failed.Under 2, we have studied the reduction of the menthyl esters of mesaconic acid and a-methylcinnamic acid. Under 3, we have investigated the reduction of menthgl pyruvate. The results in all cases have been of a negative character, in spite of every care to avoid possible racemisation by conducting the critical steps in the reactions a t the ordinary temperature. EXPERIMENTAL. AmyZ Cinnamate. A few preliminary experiments were made with this compound with the object of introducing asymmetric carbon atoms into the acid portion of the ester in its combination with active amyl alcohol. The substance was prepared by heating together equal weights of cinnamio chloride find ordinary an yl alcohol u n t i l bydrogen chloride ceased to be evolved.The product was then wRshed with water, dried over1308 COHEN AND WHETELEY : PRODUCTION OF OPTICALLY calcium chloride, and distilled in a vacuum. It boiled at 186-1885 under 20 mm. pressure; d 2O0/2Oo=0*975. I n order to obtain the phenylglycerate, the amyl cinnamate was treated with dilute permanganate, but even in a freezing mixture it underwent oxidation to benzaldehyde and benzoic acid, and no trace of the dihydroxy-compound could be detected, It was then converted into the dibromo-derivative by adding one molecular equivalent of bromine dissolved in chloroform. The bromine was readily absorbed and the product, when purified, formed a colourless oil. All attempts to re- place bromine by hgdroxyl failed. It is a colourless oil with a faint odour of amyl alcohol.Menthyl Cinnamate. This ester was prepared with the same object as the amyl ester, and with equally fruitless results. It was obtained by heating together in the oil-bath at 140" equivalent quantities of cinnamyl chloride and menthol, and purified by adding sodium carbonate and distilling in steam. The residue was extracted with ether, dehydrated over calcium chloride, and the ether removed by evaporation. The ester formed a light yellow, viscid liquid which. did not crystallise. It was then converted into the dibromo-compound by the addition of the equivalent quantity of bromine in chloroform. The colour of the bromine slowly disappeared and after removal of the chloroform the dibromo-compound crystallised. After recrystallisation from glacial acetic acid, it formed colourless needles and melted at 84'. On analysis : 0.220 gave 0.1697 AgBr.Br = 36.1. C,,H2,0,Br, requires Br = 35.9 per cent. We were unsuccessful in all our attempts to replace bromine by hydroxyl, ethoxyl, or acyloxyl groups. ~~trr.abromodicinnam~~tartaric Acid. Dicinnamyltartaric anhydride is readily prepared by the method described by Freundler (Ann. Chirn. Phys., 1894, [vii], 3, 486). It was brominated in chloroform solution and the liquid product remain- ing, after removing chloroform, crystallised on the addition of a little water, forming colourless crystals of tetrabromodicinnamyltartaric acid. It was completely decomposed with alkalis, and with ammonia deposited crystals melting at 119O, which were identified as mono- br omocinnam ide, C6H,*CBr: CH* CO*NH,.ACTIVE COMPOUNDS FROM INACTIVE SUBSTANCES.1309 0.1316 gave 0.1073 AgBr. No hydroxy-derivative could be obtained from this substance. Br = 34-7. C,H,ONBr requires Br = 35.4 per cent. Mentlbyl Pyruvate. Thirty-one grams of pyruvic acid and 55 grams of menthol were heated under diminished pressure on the water-bath with a reflux condenser. The product was then distilled in a vacuum and the ester collected a t 136-140' under 22 mm. pressure. d 11.5°/40=0*9917 ; [ - 181 -7'. On analysis : 0.3153 gave 0.1249 CO, and 0.112 H,O. C=68.85; H=9*96. C,,H,,O, requires C = 69.03 ; H = 9.73 per cent. Mertthyl Lactate. After several trials with different reducing agents and under different conditions, the following process was found to give the most satisfactory result.Menthyl pyruvate (5- 10 grams) was reduced with constant stirring in the cold with four times the theoretical quantity of glacial acetic acid and zinc dust, the latter being added at intervals during 5-6 hours. The product was filtered and washed with dry ether, The filtrate was shaken in a separating funnel with water and excess of barium carbonate to remove the acetic acid, When all effervescence ceased, the product was filtered, and the ethereal layer removed from the filtrate and evapor- ated t o a syrupy consistency in a vacuum a t the ordinary temperature. The syrupy residue was mixed with the theoretical quantity of potassium hydroxide dissolved in methyl alcohol and left overnight in a vacuum a t the ordinary temperature, when complete hydrolysis was effected.Water was added to the dry product, which was extracted with ether to remove menthol, The aqueous solution of potassium lactate, which was free from pyruvate, was made strougly acid, evaporated to a gummy mass in a vacuum at the ordinary temperature, and the free lactic acid extracted several times with ether. On evaporation of the ether, the residue was boiled with water and zinc carbonate, and, from the filtrate, crystals of zinc lactate separated. Ten grams of menthyl pyruvate yielded about 3.6 grams of zinc lactate, or 50 per cent. of the calculated amount. The air-dried salt was analysed, with the following result : The stirring was continued for double that time, 1.4412, at 105O, lost 0,2612 H,O. 0.6032 gave 0.2017 ZnO. VOL. LXXIX. 4 x H20= 18.12.Zn = 22.00. (C3H,O,),Zn,3H,O requires H,O = 18-17 ; Zn = 21.98 per cent.1310 COEKEN AND WHITELEY : PRODUCTION OF OPTICALLY A saturated solution of zinc lactate in a 500 mm. tube gave a rota- Menthyl Mesueonate. The mesaconic acid was prepared by Fittig's method by the action of bromine on an ether-chloroform solution of citraconic acid. To prepare the mesaconyl chloride, 1O.S grams of the acid were mixed with 34.8 grams of phosphorus pentachloride, and heated on the water-bath until hydrogen chloride ceased to be evolved. The phosphorus oxy- chloride was then distilled off on the water-bath under diminished pressure, and the remainder (9.8 grams) consisted of the acid chloride. This was mixed with the theoretical quantity of menthol (18.3 grams) and heated to 130' on the oil-bath.The product was made alkaline with sodium carbonate solution and distilled in steam. The residue was extracted with ether and the ether evaporated. The product con- sisted of a thick liquid; d 17*6"/4O=0*9904; [u]E'~' -92.05". On analysis : tion of only 1'. 0.218 gave 0.5858 CO, and 0.2057 H,O. C = 73.28 ; H = 10.48. C,,H,,O, requires C = 73.89 ; H = 10.34 per cent. Menthyl Pyrotartvate. 23.6 grams of the mesaconic ester were dissolved in alcohol, and 50 grams of the aluminium-mercury couple added in small portions a t a time, a few drops of water being occasionally introduced. The operation lasted 6 weeks. The reduced product was then filtered, and further extracted from the excess of the couple and of aluminium hydr- oxide by means of hot alcohol.On evaporation of the alcohol, the liquid product,, which had d 1 1*S0/40= 0.978, and [u]:'~' - 71*6', was analysed, with the following results : 0.1830 gave 0.4910 CO, and 0.1769 H,O. C,,H,,O, requires C = 73.45 ; H = 10.88 per cent. The product was treated with the theoretical quantity of methyl alcoholic potash in the cold to effect hydrolysis, and then extracted with ether to remove the menthol. The solution of potassium pyro- tartrate was then acidified with hydrochloric acid and extracted with ether. On evaporating the ether, crystals of pyrotartaric acid separated, and had the correct melting point, namely, 112-1 13'. 7.1 grams of the menthyl pyrotartrate gave 2-37 grams of pure pyrotartaric acid. The acid was analysed, with the following results : C = 73.17 ; H = 10.82.0.1581 gave 0.263 GO, and 0.0855 H,O. 1.68 grams were dissolved in water and made up to 10 C.C. C =45*37 ; H = 6.04. C,H,O, requires C = 45.42 ; H = 6.06 per cent, TheACTIVE COMPOUNDS FROM INACTIVE SUBSTANCES. 1311 rotation in a 100 mm. tube was -5.5'. The substance was further purified by neutral ising with potash and extracting repeatedly with ether to remove any traces of menthol. 1.8 grams in 10 C.C. now gave a rotation of 4-4'. This small rotation can scarcely be regarded as undoubted proof of the formation of an optically active compound. Menthyl a-il~eth?lZcinnccn~cLte, G6H5* CH: C( CH,). CO,*C1,H, g. The a-methylcinnamic acid was prepared by the method described by Edoleano (Bey., 1887, 20, 61s). It was converted into the chloride by heating with an equal weight of phosphorus trichloride on the water-bath for an hour.The liquid was decanted from solid phos- phorus compounds and the residue rinsed out with ether, which was added t o the clear liquid; On distilling off the ether, the acid chloride solidified, and after recrystallisation from ether melted a t 48-50'. Ten grams of acid yielded 8 grams of acid chloride. An equal weight of menthol (8 grams) was added to the acid chloride and the mixture heated in the oil-bath at 120-130" for an hour. The product was made alkaline with sodium carbonate solution and distilled in steam until free menthol ceased to distil over. The residue was extracted with ether and dehydrated over calcium chloride. On removing the ether, the residue (12 grams) solidified. It WRS purified by dissolving in methyl alcohol, from which i t crystallised in large tablets melting at 50'.On analysis : 0.1568 gave 0.4567 CO, and 0,1314 H,O. C = 79.43; H= 9.38. C,,H,80, requires C = 79.92 ; H = 9.42 per cent. The rotation in a 30.48 mm. tube a t 58' was -20'44'. After various reducing reagents had been tried unsuccessfully, the aluminium- mercury couple was finally adopted, although its action is very slow. Five grams of the ester were reduced by a large excess:of the couple (40 grams) during 3 months, and 4 grams of pure crystallised menthyl a-methylhydrocinnamate melting at 37' were obtained. The purity of the product was determined by comparison with some of the pure menthyl ester prepared directly from a-methylhydrocinnamic acid, Four grams of the acid were warmed on the water-bath with 6 grams of phosphorus pentachloride, and the phosphorus oxychloride was then removed by distilling under reduced pressure from the water-bath.The residue distilled a t 160' under 30 mm. pressure. The distillate consisted of a pale yellow liquid which did not solidify. It was heated in the oil-bath at 140" with an equal weight of menthol and distilled in steam with the addition of sodium carbonate solution to remove menthol. The residue was extracted with ether and dehydrated over calcium chloride. On removing the ether, the menthyl ester solidified, 4 x 213 12 ACTlVE COMPOUNDS FROM INACTIVE SUBSTANCES. and after recrystallisation from methyl alcohol melted a t 36-38', in agreement with the above result.The menthyl ester obtained by reduction with the couple was hydrolysed with alcoholic potash in the cold as described in the other cases, and 0.75 gram of pure acid (m. p. 36-38O) dissolved in chloro- form and the rotation determined in a 200 mm. tube. The rotation was +4', which is of the same order as that observed in the other cases, and too small to be looked upon as positive evidence of optical activity. Our thanks are due to Dr. T. S. Patterson for kindlyplacing his polarimeter at our disposal. Reduction of the a-Methylcinnamic Esters. The great difference shown in the rate at which methyl and menthyl cinnamate undergo reduction on the one hand, and menthyl a-methyl- cinnamate on the other, suggested the possibility that the additional methyl group in the side-chain of the acid radicle retarded the action of the couple. In order to obtain further evidence, the methyl, ethyl, propyl, and isopropyl esters of a-methylcinnamic acid were prepared. The first three were obtained by Fischer and Speier's method, and the last by the action of isopropyl iodide on the silver salt of the acid. The specific gravitiea and melting and boiling points of them esters are as follows : Ester. d 15'/15O. M. p. B. p. - Methyl ...., .... - 3 9 O Ethyl ........... 1.049 - 155-160° (30 mm.). Propyl ......... 1.027 - 162-165 (25 mm.). isoPropyl ...... 1-026 - 155-160 (20 mm.). The method for determining the rate of reduction was to reduce 1 gram of the methyl ester and a proportionate quantity of the others in ethyl alcoholic solution with excess of the couple (1 gram) during the same period of time, to remove the alcohol, hydrolyse the product, and titrate the alkaline solution with standard permanganate, which rapidly oxidises the unsaturated acid but not the reduced compound. No difference could, however, be detected between the esters. They were all readily and completely reduced. Our thanks are due t o Mr. C. P. Finn for his help in carrying out some of these experiments on the reduction of the esters. THE YOHKSHIRE COLLEGE, LPEDS.

ISSN:0368-1645    

DOI:10.1039/CT9017901305

出版商:RSC    

年代:1901

数据来源: RSC