摘要:

5-14 SHENSTONE AND CUNDALL INFLUENCE OF TEMPERATURE XL.-The InJlueme ?f Temperatwe on the Composition and Solubility of Hydrated Calcium Szclrphate and of Calcium Hydroxide. By W. A. SHENSTONE and J. TUDOR CIJNDALL. I. SUCH facts as the extraordinary soliibility of silver nitrate at temperatiires above loo",* and the evidence of a distinct relation between the solubility of salts a t high temperatures and their melting points,* together with the circumstance that high temperature, though favourable to dissociation diminishes the solubility of only a few substances are apparently inconsistent' with the idea that in all cases the soliibility of salts in water is due to the formation of definite hydrates. Yet on the other hand even before the recent publications of Mendel6eff and others there was considerable reason for supposing that in many cases the solubility of anhydrous salts in water is f Tilden and Shenstone Phil.Trans. 1884 Part I ON HYDRATED CALCIUM SULPHATE ETC. 545 accompanied by and influenced by the formation of such hydrates.* And it has been supposed that the influence of high temperature in reducing the solubility of several salts is due to dissociation of soluble hydrated compounds the products of the dissociation in these cases being less soluble than the compounds from which they have been formed. This view receives some support from the fact that several of the salts in question for instance sodium sulphate and copper sulphate form well-known hydrates which are readily d ecom-posed on heating even in the presence of a large excess of water.? On the other hand however in the case of some othem such as sulphate of calcium the only known hydrates have been supposed to be comparatively stable even in dry air.As a satisfactory theory of solut.ion must be wide enough t o include an explanation of the peculiar behaviour of these salts we have thought it worth while to spend some time on the experiments described in this paper and we think that our results will be found to be a useful contribution to this side of the " solution question," although in the case of calcium hydroxide t,hey are at present partly of a negative character. 11. The In8uence of Temperature on Hydrated 0alciu.m 8ulphate.-The statements on this subject in works on chemistry vary consider-ably but all agree so far that they lead to the conclusion that a temperature above 100" is necessary to stmt the dehydration of the salt and that a considerably higher temperature is required for its complete desiccation.For example Hannay ( J . Clzem. Xoc. 1887 ii, 381) states that in dry air dehydration of calcium sulphate does not commence till a temperature of 118" is reached but that subsequently it proceeds at as low a temperature as 100" (Bar. = 760 mm.) until 15 per cent. of water has been expelled. Our results do not agree very well with any of these statements ; for in consequence of conducting our experiments with the special view of detecting small changes (viz. by employing it set of weights whose exact relations were known and by resorting to the method of vibrations in weighing) we observed at an early stage a peculiarity in the behaviour of the substance that has previously been over-looked.Experiment I.-A known mass of pure hydrated calcium sulphate of our own preparation was placed in a flask A and after the removal of hygroscopic moisture by means of a current of dry air was heated in a slow current of air which had been dried by means of phosphoruf; f It is not unlikely that in some cases for instance in that of calcium sulphate, -f We find this to be true in t'he case of CuS04,5H20 at temperatures above solubility depends entirely on the existence of one or more hydrated cornpounda. 100". VOL. LIlI. 2 546 SHENSTONE AND CUNDALL INFLUENCE OF TEMPERATURE Total loss per cent. by artificial CaS04,2H20.Temperature. pentoxide until its weight became constant a t 70° loo" and 150". A similar experiment was made on a portion of powdered selenite. Total loss per cent by selenite. I n these experiments the admission of moisture to the contentls of A during cooling and weighing was prevented by means of well-fitting stoppers B C and the t w o tubes were securely plugged with glass-wool to prevent the mechanical conveyance of particles of salt from A by the current of air. We assured ourselves of the efficiency of these precautions by repeated experiments. As hot water attacks glass vessels in the prolonged exposure necessary in these experiments to an extent sufficient t o interfere with the accuracy of the work and as paraffin is inconvenient to work with A was plunged into a copper-bath filled with shot the copper-bath being itself placed in a vessel containing water or paraffin.The temperature of A was determined by means of a thermometer whose bulb was immersed in the shot and in contact with A. TABLE I.-Showing the Results of Experiment I. I I ___- /---I- --70°C. . 100" c . 150" C . Low red heat . 20 *67 20.89 21 *C'r .-19'99 20.45 20 '67 ON HYDRATED CALCIUM SULPHATE ETC. 547 The formula CaSO4,2H2O requires 20.9 per cent. of water. It has frequently been observed by others that the total loss of water in drying this salt slightly exceeds that required by theory. The temperature 70" was selected as the starting point in this experiment because whilst that temperature is not too far below loo", the solubility of calcium sulphate at 70" is distinctly lower than at 35" which is probably the temperature of maximum solubility.Experiment 11.-This experiment was made at do" which is only slightly above the temperature of maximum solubility of calcium sulphate. The results obtained are given in Table 11. The same method as that described above was employed. TABLE 11. Water lost by 2.0460 gram of calcium sulphate at 40". Time. I G hours . . . . 30 . . . . . . . . 48 . . . . . . . . 72 . . . . . . . . 96 . . . . . . . . 120 . . . . . . . . 144 . . . . . . . . I . 0 *0008 gram 0-0068 ,, 0*0309 ,, 0-0376 ,, 0'0492 ,, 0.0600 ,, 0.0202 ), The loss in this case at the end of 144 hours amounted to about 3 per cent.but the change was not yet complete. Experiment III.-The above experiments seem to establish that, contrary to previous statements hydrated calcium sulphate parts with the greater part of its water of crystallisation a t 70" in dry air and that even at as low a temperature as 40" it is not absolutely permanent. Whilst we were making them we were led to think that the results of a careful examination of the rate of loss in equal periods of time would be interesting. Another experiment was therefore made at 70", in which powdered selenite was heated in A during periods of three hours in a current of dry air which was passed through the apparatus at an average rate of 111.6 C.C. per minute. The results of this experi-ment which aro given in Table 111 and curve No.I (p. 550) show that not only is the rate at which this salt dissociates a slow one but that i t is much slower in its earlier stages than afterwards.* We think that these two facts and especially the latter help to account for the divergent statements that have been made on this subject. f At higher temperatures the three-hour intervals between the weighings are too long to permit of the detection of this peculiarity in the behaviour of caloiuw sulphate. 2 P 548 SHENSTONE AND CUNDALL INFLTJENCE OF TEMPERATURE Owing to the fact that most salts part with their water of crystallisa-tion as rapidly during the earlier stages as afterwards (or eveE more rapidly) chemists frequently neglect slight changes in experi-ments of this kind. Thus in his careful experiments Hannay heated calcium sulphate for periods of 20 minutes only to the following temperatures 100°7 103"' 105" 110" 115"' and finding no perceptible loss till 118" was reached concluded that lower temperatures than this were without effect on it.TABLE I11 (Curve No. 1). Time. 3 hours 6 9 ) . . . . . . . . . 12 ) 15 18 21 24 27 30 33 36 Loss of water in dry air at 70". 0 -94 per cent. 2-86 ), 4.87 )) 7.25 ), 9-73 ), 12-87 :? 14 94 )) 18-20 ,, 19.14 ), 19.87 ,, 20'14 )) 16 -7.2 ,, Experiment IV.-This experiment shows even more markedly the slowness with which calcium sulphate responds to the influence of heat. Table IV gives the results obtained by heating a specimen of powdered selenite a t 100' in a water-oven during periods of three houm each.Only a very SIOW current of undried air was allowed to pass through the oven during the experiment. TABLE IV (Curve Xo. 2). Loss of water after 3 hours' heating was 0.04 per cent. ?? ? 7 6 77 7 0.075 7 7 7 7 7 9 9 ?7 7 7 0.85 9 9 7 7 9' 12 31 > ? 4.06 7 7 7 ) 9 7 15 7 7 7 7 8-30 7 7 ? ? '? 18 7 ) 7 7 11.25 9 , 7 7 7 7 21 7 ) > ? 13.86 7 7 7 7 7 7 24 7 7 , 14.69 ,, 7 3 7 7 29 9 7 ) 14-73 ,, 1 7 7 33 7 1 7 7 14.93 ,) 9 7 ,) 39 7 7 7 9 14-93 9 ON HYDRATED CALCIUN SULPHATE ETC. 549 Ezperirnent V.-The divergent results t o which we have alluded are, however partly to be attributed t o the circumstance that different specimens of calcium sulphate (CaSO4,2H2O) do not behave in exactly the same manner when submitted to identical treatment.Table V gives the results of exposing three different specimens of hydrated calcium sulphate to a temperature of 100" simultaneously under absolutely identical conditions. In respect to the total loss in undried air it will be observed that these results agree with those of other observers as well as could be expected under somewhat variable conditions. Loss of Waterper cent. at 100". Time. 2 hours 4 6 8 ) Artificia.1 CaSO4,2H2O. I -4.3 15 '0 15 *8 15.8 Selenite. Selenite, T. 1.3 7 - 8 11 -5 13.8 1 '0 5 '8 10'0 12-8 Xummaq.-The results we have obtained show that both in dry and moist air hydrated calcium sulphate is less stable than has been supposed. Its peculiar behaviour under the influence of heat,* suggests the idea that in the case of this substance we have to deal with molecular aggregates of great stability and that it is only after the gradual breaking up of these that dissociation can take place.It will not perhaps be unreasonable in future to place calcium sulphate with those salts whose diminished solubility in hot water may possibly be due to dissociation of definite hydrates. It is true that calcium sulphate is thrown down from a hot solution at a much more rapid rate than that at which dehydration occurs even in perfectly dry air at similar temperatures. But if there be any truth in the above suggested explanation of the slow rate at which the solid salt dissociates this circumstance is of less importance since it is not unlikely that in the liquid state there is a comparatively simple state of affairs in regard t o molecular aggregation and moreover the liquid condition is more favourable to the rapid progress of change than the solid state.It will be noticed that the curves fail to afford any support to the idea that other hydrates of calcium sulphate exist besides that to which we give the formula CaSO,,B&O. * Zinc sulphate behaves in a somewhat similar manner. See Hannay loc. cit 550 SKINNER AKD RUHEMANN THE ACTION OF IV.-In$uence of Temperature o n the Composition and Solubility of Culciunz Hydroxide. Our experiments with this substance are much fewer than in the Case of calcium sulphate. A specimen of pure calcium hydroxide, dried a t 16" in air free from carbon dioxide lost only 0.3 per cent.of moistmure after prolonged heating to temperatures ranging from 70" to 150" in a current of air thoroughly dried by means of phosphorus pentoxide. This led us to doubt the accuracy of the statements that have been made as to its solubility in hot water especially as all experiments on the subject, so far as we are aware have been made in Fessels of glass which might possibly be attacked by the hydroxide as it is at high temperatures by calcium sulphate (Tilden and Shenstone Zoc. cit.). An experiment was therefore made to test this point. This experiment was made with the platinum tube employed for similar work by one of us in conjunction with W. A. Tilden in 1885 (Proc. Roy. Xoc. vol. 38 p. 331). The utmost care was taken and a carefully prepared specimen of the hydroxide was employed. We found that a t 15U0 3081 parts of solution contained only one part of calcium hydroxide. A t 19" one part of hydroxide was found to be present in 640 parts of solution. No donbt therefore remains on this point; calcium hydroxide is very decidedly less soluble in hot water than in cold but we have a t present no information as to the cause of its diminished solubility

ISSN:0368-1645    

DOI:10.1039/CT8885300544

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

550 SKINNER AKD RUHEMANN THE ACTION OF XLL-The Action of Phenylhydra.zine on Urea and some of its Derivatives. By SIDNEY SKINNER B.A. and S. RUHEMANK Ph.D. IN this paper we give an account of the action of phenylhydrazine on certain compounds nearly related to urea. I n the first part several substances are described which complete the series of semicarbazides and carbazides both of oxy- and thio-carbamides. The difference between the carbarnides and these substances which contain groups of two atoms of nitrogen united directly is shown by the fact that the latter yield coloured compounds when treated with a mild oxidiaing agent such as copper sulphate or mercuric chloride. The latter part of the paper is devoted to a description of th PHENYLHYDRAZINE ON UREA. 551 reaction of phenylhydrazine with parabanic acid and the comparison of this reaction with that which takes place with alloxan under like conditions.I n the cold phenylhydrazine behaves as ammonia does wikh parabanic acid forming the corresponding normal salt but on boiling with water a hydrazide of oxaluric acid is produced. This reaction is not analogous t o that with ammonia at the temperature of boiling water as that is said to produce the ammonium salt of oxaluric acid. Diphen y 1 curbmid e. When a mixture of 21 mols. of phenylhydrazine and 1 mol. of ethylic carbamate is heated over a small flame until the evolution of ammonia ceases a viscous brown product remains which crystallises after some days; crystallisation may however be at once brought about by adding excess of ether.This compound diphenylcarbazide is in-soluble in ether sparingly soluble in hot water easily in hot alcohol, and is best recrystallised from dilute alcohol. It melts at 151" and gives a deep red coloration with ammonia. The formula CO(NH*NH*CsH5) requires the following values :-Found. Theory. -7 -7 I. 11. C, 156 64.46 p. c. 64-02 Hi4 6.43 - 14 5.80 N4 56 2314 - 22.92 0 . 16 6.60 -- -Its formation takes place in the following way :-+ C2H,*OH. I f the ethereal solution from which the diphenylcarbazide has separated is allowed to stand other crystals come down ; the yield of these however is very small if the experiment is carried out as directed. The meltling point of theae crystals is 172" which is the same as that of phenylsemicarbazide a substance originally obtained by Fischer (Annalen 190,113) from potassium isocyanate and phenyl-hydrazine.Its formation is easily explained thus :-NH Co<NH2 OCnH5 + NH2*NH*C6H6 = CO<NHTNHC6H5 + C2H5*OH. We have also obtained diphenylcarbazide directly from carbamide by the action of an excess of phenylhydrazine 552 SKINNER AND RUHEMANN THE ACTION OF Pellizzari (Gazzetta 16 SOO) and more recently Pinner (Ber. 20, 2358) have described the action of carbamide in slight excess on pheny lhydrazine or its hydrochloride and have obtained Fischer's phenylsemicarbazide (melting point 172"). From these results it is evident that both diphenylcarbazide and phenylsemicarbazide may be prepared either from ethylic carbarnate or from carbamide.In fact, by heating diphenylcarbazide with carbamide phenylsemicarbazide results and conversely diphenylcarbazide is formed on heating phenylsemicarbazide with phenylhydrazine. It also follows that one amido-graup of carbamide is equivalent in its reaction with phenyl-hydrazine to the ethyl-group of ethylic carbarnate. Diphen y lsemicar baxide. When equivalent quantities of monophenylcarbamide and phenyl-hydrazine are heated together ammonia is evolved and a product is obtained which becomes solid on cooling. This is washed with ether to remove excess of the hydrazine boiled with water and the insoluble residue crystallised from alcohol. Rosettes of needles melting at 170-171" separate from the hot alcoholic solution. This substance is diphenylsemicarbazide; it is insoluble in ether and water but - -NH-C H dissolves readily in hot alcohol.The formula CO<NH.x6H.5c 6 5 requires :-Found. Theorj. f--J'- -3 r---7 I. 11. - CI3 156 68.72 68.51 H, 13 5.73 6-29 N3 . 42 18.50 - 18.79 0 16 7-04 -- -The reaction takes place in the iollowing way :-This substance is a derivative of oxycarbamide corresponding with the thiocarbamide-derivative CS<NH.N6H.b6H, obtained by Fischer by the action of phenylthiocarbimide on phenylhydrazine. It would doubtless be formed by a similar reaction from phenyl isocyanate and phen yl hy drazine. NH*C H Phenylsei?Lithiocarbazide. We expected by heating a mixture of equivalent quantities of phenylhydrazine and monophenylthiocarbamide to obtain Fischer' PHENYLHYDRAZINE ON UREB.553 diphenylsemithiocarbazide to which we have just referred. On carrying out this experiment however ammonia nitlrogen benzene and aniline were evolved and a white solid remained; this is phenylsemithiocarbaxide. I t is insoluble in ether scarcely soluble in boiling water but comes down in pinkish crystals from its solution in hot alcohol. The These crystals have a melting point of 190". formula CS<N~~NH,c,H5 NH requires :-Found. Theory. r-- 7 I. 11. 111. rA- 7 - - C7 . . . 84 50.30 p. C. 50.56 Hg. 9 5.39 , 5.86 S . . 32 19.16 ,, - -- 19.02 -NB . . . 42 25.14 , - - 25.57 The reaction by which this substance is produced takes place in two stages. During the first ammonia is evolved and diphenylsemi-thiocarbazide is formed thus :-CS<NH.c6H NH2 + NH,*NH*C6H5 = cs<xH'c6H5 NH'NH*C6H5 + NH,.The product of this stage however, cannot be separated for the second begins before the first is complete, and in it phenylhydrazine converts the diphenylsemithiocarbazide into phenylsemithiocarbazide :-That this reaction actually takes place was shown by a direct The formation of aniline probably occurs in the following way with experiment on some diphenylsemithiocarbazide. the direct production of phenylsemithiocarbazide :-+ CgHci'NH2. Pellizzari (Quxxetta 16 200) has described a substance which he calls a phenylsemithiocarbazide formed by the action of phenyl-hydrazine on thiocarbamide. He states that it melts at 200-201". If it does and has the same percentage composition as our substance, it is probably an isomeride in which the phenyl radicle occupies a different position.We hope to settle this point by preparing some of this substance and comparing it with our own 554 NHGH, C o < ~ ~ . ~ ~ . ~ ~ -NH*NH-C,H, C o < ~ ~ - ~ ~ ~ ~ ~ ; SKINNER AND RUHEMANN THE ACTION OF Wine-red destroyed by ammonia and hydro-chloric acid. Violet colour ammonia makes it scarlet. Ferric chloride gives a red colour and an excess destroys it. Colour Reactions. NH, S < ~ ~ o ~ ~ ~ ~ ~ ; If a drop of dilute copper sulphate solution is added to a solution of any of these carbazides or semicarbazides an intense colorat,ion is produced. So intense and distinctive are these colorations that they may be used as qualitatire tests.The following colours are very characteristic :-A few drops of copper sulphate solution produce :-Deep blue not destroyed by ammonia. NH*C,H Green not destroyed by ammonia. A solution of copper sulphate added to monophenylcarbamide or monophenylthiocarbamide solution gives no colour reaction. Hence it follows that the production of the colour is characteristic of the substituting hydrazine-group which is necessary to form the carb-azide or semicarbazide. This colour is due to the oxidising action of copper sulphate for ot,her compounds of similar oxidising action produce colour reactions. Thus when mercuric chloride is added to diphenylcarbazide it acquires an intense violet colour very like that produced with copper sulphate. Pheny lurazole. When a mixture of biuret and phenylhydrazine is heated over a small flame ammonia is driven off and on cooling the whole mass solidifies.If this is extracted either with alcohol or with water, bundles of crystalline needles separate from the hot solution as it cools. After a second crystallisation from alcohol these have a melting point of 260". Their aqueous solution when treated with copper sulphate and potash does not give the " biuret reaction," but on adding potasli or ammonia a red coloration is produced. A determination of the nitrogen in these crystals gave 23.9 per cent. A compound of the formula CsH,N30 requires 23.72 per cent. of nitrogen. Such a substance has recently been prepared by Pinner (Ber. 20 2358) by heating one part of phenylhydrazine hjdrochlo-ride with one and a half parts of carbamide; his product had a melting point of 262" and it is therefore identical with ours.Thi PHENYLHYDRAZINE ON UREA. 555 substance which Pinner has named phenylurazole is formed in oui-reaction in the following way :-CO-NH H0N.H CO*NH = N H / 1 + 2NH:. ‘CO-NCsHS NH/ + I ‘CO-NH H.N*CsH5 I t s formation in this way from biuret suggests the idea t,hat in Pinner’s reaction biuret is first formed and it then produces the urazole by reacting with the phenylhydrazine. Diphenylcarbaxide Mercurochloride. An aqueous solution of mercuric chloride added to an alcoholic solution of the diphenylcarbazide gives at first a deep violet colour, and as the alcohol becomes more dilute a precipitate is formed. This precipitate is collected and recrystallised from hot alcohol.The crystals are flat plates which do not melt b u t decompose suddenly a t 135”. A drop of the alcoholic mother-liquor placed on filter-paper produces a deep violet stain. Analysis showed the crystalline substance to be a double compound of the composition CO(NH*NH-C6H5)z,HgClz. Found. Theory. 7- 7 r - w I. 11. 111. CIS - - 156 30.40 p. C. 31.04 H i d . 14 2.73 , 5-00 - 10.99 - N* 56 10.91 ,, 0 16 3-11 ,, Hg. 200 38.99 , - - -C1 - . 7 1 13-83 ,, - -- - -- 13-87 When this double compound is boiled with water in which it appears to be insoluble a liquid tarry substance is formed which floats on the surface and mercurous chloride falls t o the bottom. This viscons tmry substance on cooling becomes a brittle black solid which contains chlorine.It is soluble in alcohol and on addition of ammonia brings down a violet precipitate of the base which contains no chlorine. An excess of ammonia dissolves the coloured substance, whilst potash makes it red. The dry colour base is soluble in glacial acetic acid with a red coloration. Evidently then the action of mer-curic chloride is to oxidise the diphenylcarbazide to the hydrochloride of a colour base which is easily precipitated by ammonia. Pheqlhydrazine Parabanate. A solution of phenylhydrazine hydrochloride has no action on 556 SKINNER AND RUHEblAKN THE ACTION OF solution of parabanic acid but on adding sodium acetate to this mixture there is an immediate separation of crystalline leaves which analysis proves to be phenyl hydrazine parabanate.Evidently the reaction takes place quite simply ; thus :-C303N2H,,H,0 + 2CsHgN2,HC1 + 2NaC2H302 = C30sN2H,,2( CsH,N,)H20 + 2NaC1 + 2C2H402. The same substance may also be prepared by shaking a mixture of the free base with an aqueous solution of the acid. It is quite insoluble in alcohol and ether and melts at 170" with decomposition. When boiled with a very large quantity of water it dissolves and at the same time undergoes decomposition with formation of a hydrazide. The substance contains 1 mol. H,O just in the same way as parabanic acid does. We are inclined to consider this molecule as one of water of crystallisation. The formula C3O3N,H2,2 (C,H,N,),H,O of the substance dried at 100" requires the following values :-Found.Theory. r--A--7 r-- 7 I. 11. C15 . 180 51-73 p. c. 51-23 51.99 H, 20 5.73 , 5.50 5.80 - - NG 84 24.13 ,, 0 64 18.39 , - -Oxalzwhydraxide. When phenylhydrazine parabanate is boiled with a very large excess of water it dissolves slightly and on cooling a yellowish, ramiform crystalline substance separates. This is oxalurhydrazide. It is very slightly soluble in water quite insoluble in alcohol arid ether and melts with decomposition at 215". Th'e reaction takes place in the folloming manner :-NH* CO C 0 *N H*NH* C6H5 NH( C6H,Tli12)-c0 'NH( (&HEN,) *c 0 co/ I ,H,O = c o < ~ ~ 2 + HzO + CGHsN,. The substance reduces a copper sulphate solutioo with a green coloration. Our analysis gave the following numbers :-Found. Theory.1 I. 11. 7-HI,. 10 4.50 , 4.91 -- C9 . 108 48.64~. c. 48.24 N4 56 23.22 , - 25.11 0 3 . . . 48 2164 ,, . - PHENYLHYDRAZINE ON UREA. 557 An attempt was made to obtain this same substance from oxaluric acid. The latter was prepared from parabanic acid according to Liebig's directions ; it was then dissolved in watler and treated with sodium acetate and phenylhydrazine hydrochloride solutions. The crystalline silvery plates which immediately separated were collected and well washed with water. The analysis and comparison of this sub-stance with phenylhydrazine oxalate showed that they were identical, so that the following reaction takes place between oxnluric acid and phenylhydrazine hydrochloride :-NH*CooCooH + 2C6H,Nz,HC1 + 2NaCzH3O2 + H20 = c o < ~ ~ , Aniline hydrochloride in presence of sodium acetate gives with parabanic acid a reaction similar to that with phenylhydrazine hydro-chloride and produces aniline parabanate as a precipitate of slender needles ; these melt about 250" with decomposition.It may also be directly prepared by shaking aniline with an aqueous solution of parabanic acid. Pheiaylhydrazine-allsxan. The reaction between alloxan in aqueous solution and phenyl-hydrazine hydrochloride in presence of sodium acetate has lately been described by Pellizzari (Gazzetta 17 254). He has stated that the reaction takes place in the following was :-That is to say that the hydrazine reduces the alloxan to alloxantin, and this he explains by the supposition of the formation of an inter-mediate substance consisting of 2 mols.of alloxan and 1 mol. of phenylhydrazine but he has not isolated this substance. We found some time ago that this substance might be easily prepared by mixiag cold alcoholic solutions of alloxan and the free base ; in a short time a reaction begins and a substance is precipitated which is extremely unstable for if the vessel be slightly warmed an evolution of nitrogen begins. To pour the liquid on a filter-paper is sufficient to start its decomposition The determination of the composition of this substance by combustion appeared hopeless and so the following method was adopted. Experiments were made to find the quantity of free nitrogen which a definite weight of alloxan would give and they proved to our satisfaction that 1 mol. of alloxan yields 1 mol. o 558 EDELEANU SOME DERIVATIVES OF nitrogen ; it is probable therefore that the intermediate substance has the composition The alloxantin is formed by the reaction of this substance with the excess of alloxan thus :-i ' i ;N;H.C,H 5 j . Note on a Phenyl-piper?ll-thiocarbamide. This is a crystalline substance prepared by adding phenyl isothio-It is easily recrystallised from alcohol and exanate to piperidine. melts at 103-104". NH'C6H5 requires the following numbers :- NC5Hio The formula CS< Theory. r--7 r--h- -3 I. 11. C, - 144 65.45 per cent. 65.42 Hls 7-83 - 16 7-27 N . 28 12.72 , - 23-05 S 32 14.54 Found. - -University Laboratory Cnrnbridg e, March 1888

ISSN:0368-1645    

DOI:10.1039/CT8885300550

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

558 EDELEANU SOME DERIVATIVES OF XLII.-Xonze Derivatives of Phennylmethacrylic Acid. By L. EDELEAXU P1i.D. IN the Berichte for 1887 (p. 616) I described some derivatives of phenylmethacrylic acid and phenylisobutyric acid and I have since obtained some further derivatives. PuranitrophenyZisobutyric A c i d C,H,(NQ2)*CH2.CH(CH,).COOH. Phen-j-lisobutyric acid obtained by Conrad and Bischoff’s method, is gradua11S added in small portions to six times its weight of nitric acid sp. gr. 1.52. On pouring the mixture into cold water the nitro PHEN YLMETHACRYLIC ACID. 559 acid is precipitated and after several crystallisations from alcohol forms small prisms melting at 121". I t is rzadily soluble in alcohol and acetic acid but only very slightly in benzene and light petroleum.Analysis gave-ClO-bNO4- I. 11. - C 57-42 5 7-45 H . . . . 5.26 5.43 N . . . . . . 6.70 - 6.88 0 . . . . 30-62 -- -The acid forms salts with the alkalis and with barium and strontium, all of which dissolve readily in water. The silver salt is very insoluble. Its analysis gave dried at loo" 34% per cent. Ag. CloHl,NO, requires 34-21 per cent. Ag. Oxidation with permanganate yielded an acid which was identified as paranitrobenzoic acid. Along with the paranitrophenylisobutyric acid of melting point 121" is an acidPrhich remains liquid at the ordinary temperature and could not be crystallised even on cooling to a low temperature. It forms salts which resemble those of paranitrophenylisobutyric acid but they are less stable. The silver salt contains 1 mol.H,O and is decom-posed at 100" ; dried over sulphuric acid it gave 32.49 per cent. Ag ; theacid C,oH,,N04 + OH requires 32.33 per cent. On oxidation this acid yields orthonitrobenzoic acid. The liquid acid is therefore, orthoni trophenylme thacrylic acid. In order if possible to obtain this nitro-acid in a crystalline state, I nitrated the methyl salt C6H5*CHz*CH(CH3).COOCH,; it is a liquid boiling at 232". Analysis gave-CllHl,% C . . . . . . 74.16 H 7-86 74.35 7.90 This was dropped slowly into fuming nitric acid sp. gr. 1.54 pre-cipitated by much water and crystallised from ether. The product separated in long prisms melting at 76" easily soluble in ordinary solvents. The analysis shows that in this case it is converted into a dinitro-derivative.The results were as follows:-C11Hl2N,O,. I. IT. - C . . . . . . 49.25 49.26 H 4-59 - . . . . 4.48 N 10.45 - 10.45 0 35.82 - -560 SOME DERrVATIVES OF PHENYLMETHACRYLIC ACID. On warming this nitro-derivative with sulphuric acid for a few minutes and diluting with water the acid is liberated and forms colourless six-sided prisms somewhat flattened. It melts a t 89" and is very soluble in ordinary solvents. Analjsis gave-C,,HlONZO,. I. 11. C 47.24 47.09 -H 3.92 4-1 1 N . . 11-02 - 11.20 O . . . . . . 37.80 ---Nitroami~7ophenylisobutyric Acid, is obtained from the dinitro-acid by reduction with ammonium sulphide. It crystallises from hot water in bright-red plates which melt a t 138". MOZ*CsH3( NHZ) CHz*CH(CHS)COOH, Analysis gave :-CIOH,2N@.4.I. Jr. - c 53.57 53-40 H 5.36 5.48 N 12-50 -0 . . 28.57 -12.68 - -AmidomethyZhydrocarbosty1.i1 C,HlZN,O. On boiling the nitroamidophenylisobutyric acid with ammonium sulphide for two hours a substance was obtained which no longer dissolved in ammonia. It crystallised from water in slender needles which melted a t 216", and dissolved with great difficulty in alcohol and light petroleum. Analysis gave-c 10HIZNZO * I. Ir. - c 66.18 68.30 H 6-82 7.01 N 15-91 - 15.95 o 9.09 - --The formation oE this compound leads to the conclusion that one of the nitro-groups in this d~nitrophenylisobu.tyr~c acid is ortho to the fatty part wllilst the second nitro-group is either para or meta. An experiment in which paranitro~henylis~butyric was heated with fuming nitric acid produced the same diuitro-acid as above described. The second nitro-group is therefore in the para-position to the methane residue SATURATED AND UNSATURATED BIBASIC ACIDS. 561 The following formulaa may therefore be given as expressing the constitution of these four compounds :-CH2.CH (CH3) .COOCH3 CH2'CH(CH3) 'COOH PI \/ NO2 NO2 Paraorthodinitrophenyliso-butyric acid. 0 Methyl paraoythodinitrophenyliso-butyrate. CH2*CH (CH3) CO OH CH,.CH(CH3)\ /\ NH-/" \/ NH2 I IN* \/ NH2 Paramido-orthonitrophenylisobutyric Paramidomsthylhydrocarbo -acid. styril. Chemical Laboratory, Artit 1 ery Co I leg e Woo lw ich

ISSN:0368-1645    

DOI:10.1039/CT8885300558

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

SATURATED AND UNSATURATED BIBASIC ACIDS. 561 XLII1.-On the Magfietic Rotatory Power of some of the Saturated an'd Unsaturated Bibasis Acids and their Derivatives; also of Mesityl Oxide. By W. H. PERKIN Ph.D. F.R.S. NEARLY a year since I brought before the Society an account of some experiments upon the magnetic rotatory power of the ethereal salts of maleic and citracoiiic acid and their isomers (Proc. 1887-8 p. 98), but owing to a desire to re-examine these substances when prepared by at process different from that previously used and to extend my experiments on unsaturated compounds and also to determine the magnetic rotation of some of the saturated bibasic compounds running parallel with them I delayed sendirig in any detailed account of my experiments until this additional work was completed.So far as the re-examination of the ethereal salts of the unsaturated acids is con-cerned it will be found that the numbers now given do not vary appreciably from those given last year except in the case of ethylic itaconate which was a little too high owing to impurity in the pro-duct examined. Before considering however the bearing of the results which have been obtained it will be most convenient first t o give the YOL. LIII. 2 562 PERKIN SATURATED AXD UNSATURATED t. 1 sp. rotation. details of the preparation properties and magnetic rotation of the substances examined. Mol. rotation. Malonic Acid. 23 5" 23 -5 23 *5 23.5 23.0 23 -0 This was examined in aqueous solutions the proportions corre-sponding to 1 mol.of acid to 4 mols. of water (C,H404 + 4H20). This is a supersaturated solution at ordinary temperatures. The density determinations gave-0 * 9537 0 -9543 0 *9546 0.9555 0.9605 0 *9536 15" 15 d7 1.2543, 23 *o 0.955'7 Average 23'2 1 0.9553 23.0 1 0 -9.545 -~-20" 20 d-" 1.2514, 25" 25 d 1.2488. The following are the numbers obtained for the magnetic rota-tion -I--/-- -7 -460 7.465 7 -467 7 '474 7 '514 7 *466 7 -47'7 7 -468 7 *474 -4 *OOO Malonic acid . . . . . . . . . . . . . . . . 3 *474 Propyl Xuccinate. This ether which does not appear to have been previously described, was prepared by passing gaseous hydrochloric acid through a hot mix-ture of succinic acid and about twice as much propyl alcohol as was necessary for the formation of the ether ; when partially saturated with hydrochloric acid it was gently boiled so that more succinic acid might go into solution and again partially saturated with acid, this operation being repeated until all the acid had disappeared ; it was then well saturated with hydrochloric acid and allowed to stand about 24 hours.At the end of this time the product was heated and the unchanged propyl alcohol dist'illed off. The crude ether was diluted with ordinary ether and. the solution mashed with water and sodium carbonate after which it was dried over anhydrous potassiu BlBXSIC ACIDS AND THEIR DERIVATIVES. 5 63 carbonate and distilled. The propy 1 succinate thus prepared came over within about half a degree but on taking the densities of dif-ferent fractions they were not found to agree quite so closely as was desired ; the product was therefore carefully fractioned and was obtained boiling practically constant at 250.8" (corr.) when distilled and collected in two fractions.These gave densities fairly close to each other viz. :-15" 15" Fraction I. d- 1.0063, 15" 15 , 11. d- 1.0061, The densities found for the other temperatures were-4" 4" d- 1.0157 25" 25" d- 0.9986. Propyl succinate is a colourless oil boiling without decomposition ; when cooled in ice and hydrochloric acid it solidifies to a crystalline mass which fuses below 0". The following numbers were obtained for its magnetic rotation :-t. 10 *3O 10 *3 10 -3 13.0 13.0 Average 11.4 Sp. rotation.idol. rotation. I-- --0 -9324 0 -9343 0 -9345 0.9285 0'9316 0 a 9323 --10 *353 10'373 10 * 377 10 *340 1.0 -374 10 *363 -____-Succiw y 1 Ch lor ide . This was prepared in the ordinary way by means of succinic acid and phosphorm pentachloride. After the oxjchloride of phosphorus formed has been mostly distilled off it is best to fraction the product under reduced pressure otherwise carbonisation takes place to a con-siderable extent especially if a Wurtz flask is used with a neck suffi-ciently long to contain the thermometer scale in the vapour and the distillation is conducted slowly. The chloride of succinyl used boiled a t 150-152" (corr.) a t 214 mm. and was a bright jellow liquid. At 760" it boiled at 190-192" (corr.). The deiisity determinations gave the following results :-2 Q 564 t.PERKIN SATURilTED AND UNSATURATED Sp. rotation. Mol. rotation. 4" d- 1.4252, 4" 10" d- 1-4178, 10" 15" 15" d- 1.4123, 20" goo d - - 1.4073, 25" 85 30" 30 d- 1.4028, d- 1.3809. I-- ---- I 10 *4" 10.0 10 -0 10 -0 9 -0 9 *2 9 . 5 9 *7 11 -0 12 *o 13 '0 14 -0 1.1893 1 *1888 1 . l W O 1 -1879 1 * 1966 1 1996 1.1957 1.1951 1 *1901 1 *1946 1 -1871 1 *1916 ' '7'224 1 7.219 7 -209 '7 214 ' 7.261 7 '280 7 *255 7 '256 '7.234 7.267 7-227 7.265 Pyrotartaric Anhydride and Chloride. The method given for the preparation of pyrotartaric anhydride consists in heating pyrotartaric acid with phosphorus pentasulphide (Bottinger Ber.11 1352). At first it was intended t o prepare it by heating pyrotartaric chloride with the acid but the yield of chloride obtained was very unsatisfactory as carbonisation took place to a considerable extent. The chloride boiled at about 210-220" under 760 mm. and a t about 158" at 214 mm. If the operation had been conducted from the first under reduced pressure probably a more satisfactory yield might have been obtained. The process which was found to work well for the production of the anhydride consists in digesting the powdered acid with an excess of acetyl chloride until all action is over and slowly fractioning the product when the anhydride is eventually obtained as a rather thick colourless oil, boiling constantly at 247.4 (corr.). This boiling point is lower than that of succinic anhydride which is given as 250" whilst that of glutaric anhydride is given as 282-287".Pyrotartaric anhy-dride has little or no odour ; it sinks as an oil in cold water but when agitated wit,h hot water it soon dissolves yielding a perfectly clear solution. Ih remains flnid even if cooled down to near 0" and has been described as an oil but if rubbed with a glass rod crystaliisation set BIBASIC ACIDS AND THEIR DERIVATIVES. 365 in and it soon becomes a white confused crystallised mass. This fuses at 31*5-32" but not sharply. The relative density determinations gave-6.5" d g 1.2458, 15" 15 2 5" 25 a7 1.2378, d L 0 1.2303, 40" 40" d- 1.2203, 55.8" 55.8" a- 1.2122. F T O ~ these t,he following Orne densities were deduced :-t.I d. I Difference. O0 10 20 30 40 50 60 1 * 2526 1 *2422 1 2318 1.~214 1 *2110 1 -2006 1 *1Y02 0*0104 0 *0104 0 -0104 0 -0104 0,0104 0 -0104 The determinations of the magnet%! rotation gave-t. -9 * 4 O 9 *o 9 .o 8 - 5 17 * 2 16.3 Average 11.6 ~-Sp. rotation. 0 -9323 0.9335 0 -936'3 0 .9383 0 *9259 0 9371 0 *9338 --Mol. rotation. -4 -750 4 '755 4 '76'7 4 977 4 -744 4 -789 4 -764 The following were made at higher temperatures :-t. I sp. rotation. I M ~ L . rotation. 47 'so 49 -4 50 *9 52 *1 Average 50.0 0 *go96 0'9104 0 *go75 0 -9079 0 -9088 4 '738 4.74.3 4 *730 4 -737 4 *737 566 Sp. rotation. PERKIN SATURATED AND UNSATURATED Mol.rotation. --Glutaric Acid. This acid was prepared from the cyanide of trimethylene which is obtained on digesting bi-omide of trimethylene with cyanide of potassium and alcohol. The cyanide was purified by distillation and then saponified with aqueous potash. The reaction takes place easily, ammoniit being evolved very freely on heating the mixture. The resulting solution was acidified with hydrochloric acid and the glutaric acid taken up with ether it is necessary to agitate the solution many times siiccessively with fresh quantities of ether before all the acid is taken up. In one operation the acidified mixture was evaporated t o dryness before extraction with ether but the acid obtained was coloured and difficult to get quite pure.The acid obtained from the ethereal solution was dried over the water-bath and crystallised from benzene. This was found to be a convenient solvent glutaric acid being moderately soluble in it when boiling and but slightly so when cold. After two crystallisations it was obtained in white non-deliquescent plates melting a t 96-97". Rebout gives 96.5" (Ann. Chern. Phys. [ 5 ] 14 501). Thv strongest solution of this acid which could be con.reniently used for the examination of its magnetic rotation was in the propor-tion of 1 mol. of acid to 10 mols. of water (C5H804 + lOOH,). Two such solutions were made for the second the acid was recrystnl-lised from water. They had the following densities :-1 *0001 1 '0008 1 *0005 0 -9992 0.9933 0 -9992 0 *9980 0 -9987 -Sol.I. Sol. 11. 4" 41° d- 1.1224, .-15" 15 25" 25" d- 1.1166, d- 1-1126, 1 -O 15 d& 1.1162. The following numbers were obtained f o r the magnetic rota-tion :-Solution I. t. 12.6" 13 '0 13 '0 13'3 13 *6 13.6 14 -2 Average 13.3 -I__ I 15 509 15 -521 15 * 516 15 * 500 15 -410 15 -502 15 *500 15 -49 BIBASIC ACIDS AND THEIR DERIVATIVES. 567 t. ~-16 -4O 16.4 16 *4 1i; '4 16 -4 Average 16.4 So lukion II. Sp. rotation. 0.9911 0 -9949 0 '9934 0 *9946 0.9970 0 *9942 ----Mol. rotation. -15 -428 15.488 15 -465 15 -483 15 -492 15.47'1 These numbers are as close as could be expected ; the average of the molecular rotation less the molecular rotation of 10 mols.of water, should give that of glutaric acid thus :-Average mol. rot. of C,He04 + lOOEl- = 15.482 Less molecular rotation of 100H . . . . = 10*000 Molecular rotation of glutaric acid . . . = 5.482 Ethyl Glutamte. The ethyl compound of glut,aric acid was prepared by saturating its alcoholic solution with hydrochloric acid. The ether after being separated by means of water was washed with sodium carbonate, dried with potassium carbonate and distilled. It nearly all came over at 236" (corr.) a little of the first and last being rejected. Rebout gives 236.5-237' (corr.) as the boiling point he observed. The density determinations gave :-20° 4 O d- 1-0382, 4 O 2uo 25" 10" 10 2 5 O 900 15" 15 30° d- 1.0243, d- 1.0204, d o c 1.0167. a- 1.0327, d7 1.0284, The following are t'he numbers obtained for the magnetic rota-tion : 5 68 PERKM SATURATED AND UNSATURATED t.Sp. rotation. t. Mol. rotation. 12.6' 12 -6 12 -6 12 *9 12 -9 12 *9 11 -3 11 *3 11 -3 11 -3 12 '0 13 '3 13 -6 13.9 11 '2O 11 '2 11 *3 11 -5 12.0 Average 11.4 Arerage 12.5 0 *9773 14 -423 0 '9782 14.436 0 -9802 14 '46'7 0 -9829 14 *508 0.9791 14.459 0 -0795 14 -459 ----Sp. rotation. 0 -9219 0 -9232 0 a9235 0 -9250 0.9259 0 *9d51 0 -9206 0 *9221 0 9243 0 *92S3 0.9221 0 -9240 0 -9195 0 -9214 0.9231 Mol. rotation. 9 -345 9.357 9 '361 9.379 9'388 9 -380 9'322 9 *337 9 -359 9 *359 9 -342 9'372 9 -329 9.350 9.356 Ethyl Sebate.The specimen examined was the same as that described in my previous The following fresh measurements were paper (Trans. 1884 518). obtained for its magnetic rotation :-Maleic Anhydride. This was prepared by the process described by me in a paper brought before the Society some years since (Trans. 1881 561) and consists in digesting maleic acid with acetyl chloride and decomposing the resulting aceto-maleic anhydride by distillation. Considerable quantities were made and the process was found to work very satis-factorily. It was found safest t o use a good excess of acetyl chloride, otherwise if too little be used fumaric acid will be formed and come over with the last portion of maleic anhydride. The latter should be distilled three or four times to ensure the complete decomposition of the aceto-maleic anhydride and fraction off the acetic acid formed BIBASIC ACIDS AND THEIR DERIVATIVES.569 t. Sp. rotation. ---I__-23 '0" 0 *9219 24.0 0.9204 24 - 5 0 *9204 25 -0 0 *9801 Average 24 *1 0 -9207 --___-I__-The boiling points of these preparations were taken with different thermometers and gave :-I 199.5" corr. ; 11 200" corr. ; 111 200" corr. ; so that practically the boiling point of maleic anhydride may be taken as 200". Maleic anhydride may be crystallised from absolute alcohol if the operation be conducted quickly but if left t o stand afterwards the crystals gradually disappear. This substance being solid its magnetic rotation was determined from its solutions in acetic acid acetic anhydride and oitraoonic anhydride.Mol. rotation. 9.502 9.494 9.498 9 -408 9 *498 Solution of BIaleic Anhydride in Acetic Acid. The acetic acid solution was made in the proportion of 2 mols. of acetic acid to 1 mol. of maleic anhydride 2C2H40 + CaH203. This solution was a supersaturated one and the anhydride crystallised out on standing but after warming the solution remained free from crystals sufficiently long for the required determination. The acetic acid used was perfect'ly free from water. The density determinations gave the following numbers :-loo 10" a - 1.1880 1 7 O 17" d- 2.1804, 25" 25 dF0 1.1733. The magnetic rotation found was as follows :-Solzction of Maleic AnLydridc! in Acetic Anhydride, The solution of maleic anhydride i n acetic anhydride was in the proportion of 5 mols.of maleic anhydride to 2 mols. of acetic anhydride 5C4H203 + %4H@3. This forms a supersaturated solu-tion which sometimes will remain liquid for a long time but is ver 570 PERKIN SATURATED AND UNSATURATED 1 *2142 1.2019 1 *1896 1 *1772 uncertain in this particular. Its relative density determinations gave the following numbers :-t . 6%" 6.6" d- 1.2781, Sp. rotation. Mol. rotation. 60" 60" d- 1.2345, 32" 0.9972 31 I 0.9999 98" 98" d- 1.2158. 25" 25 d- 1.2595, 30 .661 30 '733 30 *645 From these the following true densities were deduced :-10" 20 30 40 50 d. 1 -2740 1 -2622 1 * 2503 1 -2383 1 2263 Difference. -I---0 '0118 0 -0119 0.0120 0 -0120 t. 60" 70 80 90 100 Difference.0 -0121 0.0123 0 -0123 0 * 0124 0 *0124 The magnetic rotation gave the following numbers. Owing to the tendency of the solution to crystallise the determinations had to be made at a rather high t,emperature. This will make the results prob-ably a little low :-Average 30'7 I 0'9975 1 30.651 Less mol. rot. of 2 mols. C4H603 8.564 Mol. rot. of 5 mols. C,H,O . . 22 -08'7' -~ 7 7 1 mol. , 4.417 Solution of Maleic Anhydride in Citraconic Anhydkde. Maleic anhydride dissolves easily in oitraconic a.nhydride ; the pro-This solution The density deterrnina-portions used were equimolecular CaH203 + C5H40s. deposits maleic anhydride in cold weather. tions of this solution gave BIBASIC ACIDS AND THEIR DERIVATIVES. ~~ ~ t.I sp. rotation. 571 Mol. rotation. 15" 15 d< 1.2983, 19 -5" 19 -0 18 -5 18 -0 d2'1 1.2938, 20 1 *1206 10 -101 1-1198 10 *091 1'1216 10 '103 1.1193 10.080 25" 25 dp0 1.2896. t. I Sp. rotation. The magnetic rotations gave the following numbers :-Mol. rotation. 12.1" 1 1.1250 10.6 1.1262 9-75 1 1.1296 ;;? ~ 1.1296 1 -1275 9 . 0 ~ 1.1269 Average 9.94 1 1.1275 --i___-10 '0'75 10.090 10 *lo5 10 -103 10 '081 10 * 076 10 * 088 Average 18.8 I 1.1203 I 10.069 } 5.527 Less mol. rot. of specimen of CjH403 used . Mol. rot. C4H203. 4.542 A second solution of maleic anhydride in citraconic anhydride was also examined the citraconic anhydride used as the solvent being that purified with phosphoric anhydride and described further on in this paper ; the proportions used were equimolecular.The density determinations of this product gave-15" 15" d- 1.2992 d1'" 1.3039, 10" 25" 25O d- 1.2946. These numbers are slightly higher than those obtained with the previous preparations owing to the density of the citraconic anhydride used being higher. The magnetic rotation gave the following numbers :-I- -.- 372 I 26 *Oo 1 '0972 26 .O 1'1002 26 -0 1 -0981 26 *O 1 -0975 24.0 1 -0994 24.0 1 '1028 23 *O 1 * 1002 23 *O 1 *0999 Average 24-8 1 -0994 PERKIN SATURATED AND UNSATURATED 13 '609 13 *646 13 *621 13 *644 13 -628 13 * N O 13.627 13 -624 13 -633 ---Maleic Acid. The acid being solid and not easily fusible had to be examined in solution.The strongest solution it was found pi-i~ctical to use was in the proportion of 1 mol. of maleic acid to 8 mols. of water (C4H404 + 80H2). This was a supersaturated solution and the acid was deposited to some extent on standing. I t s density determinations gave-15" 13" (1- 1.1694 20" 'Lo d- 1-1676, 25" 25" d- 1-1656. The magnetic rotation found was as follows :-t. 1 sp. rotation. 1 Mol. rotation. Ethyl Maleate. Several experiments were made on the preparation of this com-pound which it may be useful to describe. Attempts were first made to produce it directly from alcohol and maleic anhydride but to get a neutral ether it is necessary to employ a high temperature; the mixture was therefore heated in sealed tubes at 180-190" for four or five hours but in this way the product obtained consisted chiefly of ethyl fumarate.Maleic anhydride was then digested with alcohol, the mixture cooled in ice and salt and saturated with hydrochloric acid gas previously cooled by passing through a worm placed in a freezing mixture; a t this low temperature the action did not take place and it was necessary to allow the product to attain a tempera-ture of 18" or 19" to induce etherification. The product obtained consisted chiefly of ethyl maleate but it contained ft little ethy BIBASIC ACIDS AND THEIR DERIVATIVES. 573 fumarate and a small quantity of some chlorine addition product. As these methods did not yield satisfactory prodncts recourse was had to the process of preparing this ether from silver maleate by acting on it with ethyl iodide.In carrying this out the silver salt was added to an excess of ethyl iodide little by little the heat of a water-bath being applied t o set up the reaction after each addition ; the product was then digested on the water-bath for a short time. The ethyl maleate was then extracted from the silver iodide by means of dry ether and the ethereal solution distilled until the residual liquid had attained a temperature of about 160" this was then fractioned under reduced pressure. The ethyl maleate thus prepared came over at 180.5 (cow.) at 212 mm. it also boiled at 223.5" at 760 mm. (Anschutz found 225'). The following has been found the most satisfactory method of testing ethyl maleate for small quantities of ethyl fumarate.About 2 or 3 C.C. of the ether are saponified with alcoholic potash to which some wafer has been added the mixture is then diluted with water and the alcohol boiled off. After cooling dilute hydrochloric acid is added in excess and if no fumaric acid crystallises out the solution is treated with ether which will remove every trace of fumaric acid but scarcely any maleic acid so that on evaporation the former if present will be found t o constitute most of the residue. Neutral salts of maleic acid give with ferric salts it red solution similar to that formed by an acetate but fumarates give a bulky, pale-brown precipitate ; probably these reactions might be used for testing the purity of ethyl maleate but in this case it is especially necessary to saponify the ether with alcoholic potash diluted with water otherwise apparently an addition product is formed with the ethyl maleate which yields a potash salt precipitating ferric salts in a similar way to fumarates.It was found to be free from ethyl fumarate. The relative density determinations of ethyl maleate gave-10" 10 d-o 1.0780, 15" 15" d- 1.0735, 20" 20" 25" 25" d- 1.0695, d- 1.0658. The following numbers were obtained for the magnetic rotation of this compound : 574 PERKIN SATURATED AND UNSATURATED 1-0861 1 -0856 1 '0842 1 -0857 1 -0857 1 -0879 1.0877 1.0878 1'0i30 1 -0502 1 *0702 1 '0725 --t. -PI 12 -oo 11 - 6 11 -6 11.6 12 .5 12 * 5 12 - 5 11 *o 10 -5 23 .O 23 ' 0 22 *o 22 -0 ---~ t.Sp. rotation. Sp. rotation. 1 Mol. rotation. 9 -64.9 9 $37 9.632 9.620 9 -640 9 -640 9.660 9 -646 9 *643 9 -608 9 *582 9 -576 9 -596 Average 15.1 I 9-625 Ethyl Fwnarate. The first specimen examined was prepared by saturating a mixture of alcohol and fumaric acid with gaseous hydrochloric acid the mixture being heated now and then until the acid disappeared. The ether was washed first with water and then with sodium carbonate, dried and fractioned. It boiled a t 219- 220" (corr.) but contained R small quantity of chlorine from the formation of ethyl chloro-succinate. Dr. Purdie also observed the formation of ethyl chloro-succiriate when preparing ethyl furnarate 'hy this method though he evidently obtained more of it than I did probably on account of continuing the application of heat to the mixture whilst passing the hydrochloric acid (Trans.1881 39 346). The density determination gave-d ' z 1.0623, 15" 2 5" 25" d' 1,0539. The magnetic rotation determinations gave-I--- -9 * 5 O 9 *5 12 -8 12 *8 Average 11.1 --1 -124.7 10.073 1.1231 1 10.064 1 -1251 10 -145 1 -1250 10.112 1 . 1 2 7 ~ j 10.165 --___ As this ether was not quite pure other experiments were made on its preparation and it was found that etherification might b BIBASIC ACIDS AND THEIR DERIVATIVES. 575 effected by heating the acid and alcohol in a sealed tube to a high temperature. The proportions used were one of fumaric acid to three of absolute alcohol the mixture being heated at 180-190" for seven or eight hours.The excess of alcohol was then distilled off and the ethyl fumarate washed with water and sodium carbonate dried and distilled ; it boiled at 219.3" (corr.) Its density determinations gave-20" 2 0" d- 1.0535 1.0626, 10" 15" 15 d- 1.0578 25" 25 d- 1.0496. As might be expected these densities are somewhat lower than The magnetic rotations found were as folIows :-those of the ether containing chlorine. t. 10.0" 10 *o 10 -5 10.5 22-5 21 -7 21 - 5 Sp. rotation. 1.1256 1 '1280 1 * 1253 1 '1232 1.1135 1'1133 1 * I 126 Mol. yotation. 10.119 10.150 10 -130 10 '111 10 -119 10.111 10.103 Average 15.2 1 1.1202 1 10.120 The numbers are therefore almost identical with those obtained with the previous less pure specimen of ethyl fumarate ; the influence of a small quantity of ethxl chlorosuccinate would only very slightly reduce the rotation.The rotation of ethyl chlorosuccinate deduced from other compounds which have lately been examined is 9.72 or very close to that number. Fuinaryl Chloride. This was prepared from fumaric acid by means of phosphorus It was obtained as a pale-yellow fuming liquid boiling Its density determinations gave-pentachloride. at 161-164". 15" d-" 1.4202, la 25' 25" a- 1.4095. 20" 80 d- 1.4149, The following numbers were obtained for its magnetic rotation : 576 PERKIN SATURATED AND UNSATURATED t. --17 .OJ 17 *o 16 '8 16 *8 14 '3 13.9 13 *2 t. Sp. rotation. --1 '4579 1 *4567 1 *4564 1 *4579 1 '4641 1 -4652 1-4637 Sp.rotation. ---Average 15'6 1 1.4607 15 *5" 17 *O 18.5 14 .O 13 * 5 14 .O 22.0 21 -5 21.0 23 *5 Average 17 *7 Mol. rotation. 1 *lo14 1-1125 1-1113 1-1113 1 '1 141 1.1100 1 '1014 1 *lo11 1.1011 1 * 1039 1 -1068 ---8 *739 8 '732 8.729 8 '738 8 -758 8 "763 8 -769 8 * 747 Citraconic Anhydride. This was prepared in the ordinary way by the distillation of citric acid. It was fractioned many times. The product selected for examination boiled at 213.5-214" (corr.). Its density determinations gave-4" 4 d- 1.2605 15" 15 Go 1-2493, 20" 20" d- 1.2450 10" 10" d- 1.2540, 25" 25" d- 1.2409. The following numbers were obtained for its magnetic rotation :-I Mol.rotation. --5 *488 5 '547 5 '548 5.530 5 '544 5.525 5 -512 5 -509 5 *494 5 -519 5 -522 --As these numbers were not so high as was expected it was thought that the citraconic anhydride might contain some citraconic acid ; it was therefore heated with phosphoric anhydride up to its boiling point. As the latter was apparently a good deal hydrated and also blackened the citraconic anhydride was decanted and heated with fresh phosphoric anhydride this operation being repeated a thir BIBASIC ACIDS AND THEIR DERIVATIVES. 577 time ; altogether a considerable quantity of phosphoric anhydride was used. The citraconic anhydride was then decanted from the phosphoric anhydride and fractioned ; it commenced to distil at 213.5" (corr.) and about nine-teuths came over within a degree of this.This distillate was again treated with phosphoric anhydride and heated up to its boiling point for a short time with it, when the phosphoric anhydride was now only a little discoloured ; after decanting off the citraconic whydride it was again distilled when i t came over nearly constantly a t 213.5" a few drops a t the last which were rejected coming over at 215". Citraconic anhydride thus purified was perfectly colourless and a, more mobile fluid than the ordinary product. Its relative density determinations gave-4" 4" 15" 15" 20" 20" 25" 25" 25.92" 37.4" 37.4O d- 1.2617, d- 1.2504, d- 1.2461, d- 1,2420, d2%" 1.2418, d- 1-2335, 51.45" 51.45" d ~ _ _ 1.2246, d- 59.75" 1.2205, 59.75" E 1.2178, 65" 7 7.5" 77.5" d- 1.2119, d- 87'75" 1.2081, 8i.75" 98%" 98%" d- 1.2055.These numbers are avemges of two and in some cases of three The following true densities were deduced from determinations. them :-t. 0" 10 20 30 40 50 60 70 80 90 100 d. 1 *2659 1.2549 1 -2439 1 -2328 1'2218 1'2107 1.1997 1-1886 1 *1775 1 -1664 1-1553 ~~ Diff. 0*01:0 0 -0110 0 -0111 0~0110 0'0111 0 -0110 0-0111 0*0111 0.0111 0*0111 The following numbers were obtained for its magnetic rotation. YOb. LIII. 2 3 78 PERKlN SATURATED AND UNSATURATED 16 *5 1 7 . 0 17.5 Average 1 7 - 4 --Two series o€ determinations were made-one a t the ordinary temperature and oue a t a high temperature for reasons explained further on.-Series I Ordinary Temperature. t. t. 1 sp. rotation. Sp. rotation. -__--I-- -1 *Of393 1 .om0 1.0687 1 *0708 1 * 0708 1 *0714 1 *0717 .-1.1101 1.1131 1 * 1098 1.1137 1'1131 1.1107 1~1101 1 m 1 5 Mol. rotation. ~ 5 -535 5 -550 5.533 5.553 5.544 5.534 5.534 5,540 -It will be observed that the specific rotation of this purified citraconic anhydride is higher than that of the ordinary product but that the molecular rotation is practically the same. This is acrounted for by the increase of the density resulting from the purification. Series II. High Temperatures. I 60 '5' 64.7 66 * 2 617 *1 67.4 67 -7 Average 65.7 3101. rotation.~~ 5 *451 5.51 1 5 -461 5 *46l 5*4'75 5 -477 5 -473 Citraconic Anhydride a?zd Acetic Acid. This mixture was made to correspond to the analogous one con-taining maleic anhydride being in the proportions of 1 mol. of anhydride to 2 mols. of acetic acid. The density determinations gave -15" 15" d- 1.1459, 20" 20 25" d- 1.1413, dLp 1.1371 BIBASIC ACIDS AND THEIR DERIVATIVES. 5'79 t. I sp. rotation. The numbers obtained for the magnetic rotation were as follows :-Mol. rotation. 23'2" 23 *2 23 *2 23.2 Average 23.2 0 9294 10 -519 0 *9261 10.483 0 -9281 10 *506 0.9261 10.482 0 '92'74 10.498 -__---Citraconic Anhydride and Acetic Anhydride. This mixture was also examined so as t o compare the results with those obtained with maleic anhydride and acetic anhydride.The quantities used were in the proportion of 5 mols. of citrnconic anhydride to 2 mols. of acetic anhydride. The relative density determinations gave the following results :-6.7" dG7 1.2116, 15" 15" d- 1.2028, 25" 25 ' d- 1.1941, 59.8" 59.8" 64.75" 98.05" Y 8.05" d" 1.1704, d-- 64'75" 1.1676, d---- 1.1544. The true densities deduced from these are as follows :-t. 10" 20 30 40 50 60 70 80 90 100 1 * 2078 1 '1960 1 * 1844 1 *1730 1.1618 1 -1506 1 *1394 1 * 1283 1.1172 1 *lo61 Difference. 0 a 0 1 1 8 0 -0116 0'0114 0'0112 0.01 12 0 *0112 0'0111 0'0111 0~0111 0*0111 The following results were obtained for the magnetic rotation :-2 R 580 PERKIN SATURATED AKD UNSATURATED t .j sp. rotation. Mol. rotation. I--I-- ~-16 .O 15'5 15.5 15 -5 Average 15.6 1 -0192 35 9 8 2 1 -0198 36.003 1 *0198 36 '005 1 -0186 35 961 1-0193 35.988 -____I--Citraconic Acid. As this acid is solid it was found necessary to examine its solutions. The solution employed was made in the proportions of 1 mol. of citraconic acid to 2 mols. of water (C,H,04 + 20R2) and was prepared by mixing citraconic anhydride with water in the proportion of 1 mol. of anhydride to 3 mols. of water. The resulting product was a snpersaturated solution depositing part of the acid on standing. A solution of citraconic acid when evaporated on the water-bath decomposes and on adding water to it citraoonic anhydride separates as an oil.Crystallised citraconic acid kept over sulphuric acid under a bell-jar smells strongly of the anhydride. The density determinations of the above aqueous solution of citraconic acid gave the following results :-25 *on 25 '0 25 *O 25 -0 23 .o 23 '0 23 '0 Average 24 -1 cis 1.2419 15" 1 *1469 1-1471 1'1480 1.1496 1.1504 1.1625 1 -14992 1 *1491 ---d k g 900 1-2392,. 25" 25" d -1 1.2366, The numbess obtained for the magnetic rotation were a s follows :-t. I ~ p . rotation. 1 ~ 0 1 . rotation. 8.553 8 *555 8 -562 8 -573 8.572 8.689 8 -5fi4 8 -567 2 -000 --Citraconic acid 6.56 BIBASIC ACIDS AND THEIR DERIVATIV&S. 58 1 1.9 *O" 16 *o 17 '5 18 ' 8 . 21.5 20 *o Average 1.8 -4 Ethyl Citraconate.This was in the first instance prepared by saturating an alcoholic solution of citraconic anhydride with hydrochloric acid gas keeping the mixture cool. After standing a few hours the ether was separated by the addition of water washed wj th dilute sodium carbonate dried over potassium carbonate and distilled. Thus obtained it boiled a t 230.5 (corr.). The density determinations gaze-1 -0650 10 *524 1 -0705 10.563 1 *0651 10 '514 1 -0d3t3 10.510 1 * 0573 10.490 1.0598 10 -481 I .@636 10 '513 --- --15" 15 d- 1.0486 20" %UO d- 1.0445, 2 5" 25" d' 1.0414 The magnetic rotabion determinatious gave-t. I Sp. rotation Molrotation. i On treating this ether with alcoholic soda and testing the resulting product it was found to contain a little chlorine showing the presence of some chlorine addition product resulting from the union of the ethyl citraconate with the hydrochloric acid used in its.preparation. Experiments were therefore made to obtain t h i s ether in a purer condition by heating citraconic anhydride with absolute alcohol in sealed tubes. By employing a temperature of 120-130" for a day a considerable quantity of an oily product was obtained but as it mostly dissolved in a solution of sodium carbonate it was evidently the acid ether ; a temperature of about 180-200" was therefore used and niain-tained for six or seven hours; after distilling oif the alcohol the product was washed with sodium carbonate solution dried over potassium carbonate and distilled i t boiled almost constantly at 230.3".The deiisi ty determinations gave-15" 15" d- 1.0485 20° 2uo d- 1.0446, 2 5" 2 5 O d- 1.0401) 582 PERKIN SATURATED AND UNSATURATED The following numbers were obtained for its magnetic rotation :-t. --l o .0" 10 *4 10 -8 11 2 11 - 5 13 - 5 13-5 -.-Sp. rotation. 1 '0707 1 '0673 1 -0689 1 *0666 1.0695 1 -0497 I .0526 ----Mol. rotation. --10 *515 10'484 10 '503 10.453 10,514 10 *484 10 *513 -_.-Average 11.6 1 1.0636 1 10'499 Some time after these experiments were made a quantity of the ethyl citraconate used for them was saponified the solution acidified, and the liberated acid taken up with ether. On gently evaporating this citraconic acid was left as a syrupy liquid owing to the presence of a little water ; but after standing for several days it deposited sma,ll crjstals of a less soluble acid evidently either itaconic o r citraconic acid which had been formed by the high temperature used when preparing the ether it was therefore finally resolved to prepare some pure ethyl citraconate from silver citraconate and ethyl iodide.Silver citraconate comes down as a very bulky precipitate quite different in character from silver itaconate and does not become dense when heated to 100". It is difficult to wash unless a vacuum pump is used with a considerable reduction of pressure. It was dried at loo" and gradually added to a large excess of colourless ethyl iodide. The action did not set in quickly in the cold but when gently heated local boiling took place on each addition of the salt.After all the silver salt had been added the mixture was heated on the water-bath for a short time and the silver iodide collected on a filter and washed with ethyl iodide. The filtrate was then freed from ethyl iodide by distillation and the ethyl citraconate washed with sodium carbonate solutlion dried by means of potassium carbonate and distilled. The ethyl citraconate thus obtained boiled constantly a t 230.3" and was perfectly colourless. I t s density determinations gave-lr" 15" d 2 1.0468 4" 4" d- 1.G567, 10" 1 oo d- 1.0514, 25' 25 d- 1.0395. 20" 20" d- 1.0429, I t will be observed that the density of the ethyl cit,raconat BIBASIC ACIDS AND THEIR DKRIVATIVES. 583 Sp. rotation.prepared in this manner is slightly lower than that of the products previously described. The numbers obtained for its magnetic rotation are as follows :-Mol. rotation. t. 1 'OFiiS 1 *0689 1 - 0703 1 -0634 1 -0709 1 * 0682 18 -3" 18 -4 18'3 18 -4 17 *O 17 0 17 *O 8.349 8 -359 8 -370 8-371 8 -372 8,364 ----Average 17.8 Sp. rotation. 1 -0651 1 * 0655 1 - OR43 1 *0604 1 '0613 1.0632 1 * 0627 1 * 0632 Mol. rotation. 10 %40 10.543 10 *532 10 *494 10.492 10 -514 10 *507 10 *S17 The three specimens have therefore given numbers very close to each other the influence of the small amount of impurities in the two first being compensated to a great extent by the variation in density, &c The average of all the numbers gives 10.500 practically.Methyl Citraconate. This was prepared from silver citraconate and methyl iodide in the same way as the ethylic salt just described; it boiled very nearly constantly a t 210.5" (corr.) and was perfectly colourless. The density determinations gave-4" 4 10" 10" 1.1312, d- 1.1951, 15" 15" a- 1.1208, 20" 2U" 2 5' 25 30" 30" a- 1.1168, d 1.1131, d7 1.1098. The following are the numbers obtained for it,s magnetic rotation :-t. I 13.3' 13 -0 13 -0 12.6 12.6 Average 12. El81 PERKIN SATURATED AND UNSATURilTED Ethy 1 Itaconnte. The acid used in the following experiment was obtained from Kahlbaum. An attempt was made t o etherify the acid by means of alcohol and hydrochloric acid but as it seemed to rapidly form an additive product with the hydrochloric acid it was abandoned.The method employed for the preparation of ethyl funlarate already described was then adopted the mixture of itaconic acid and absolute alcohol being heated for seven o r eight hours a t 180-190". The ether thus prepared boiled a t 227*5-228" and its density determina-tions gave-7" 7" d- 1.0563 15" 15" d- 1,0490, 25" 2 5 O d- 1.0412. The magnetic rotation determined from 15 series of observations gave a wtoleczdar rotation of 10.630 the details of which it is useless to give as the ether made by the above process is evidently not pure. Suspicion was aroused on account of the rotation of the compound being higher than it was expected to be ; the impurity is probably due to ethyl mesaconate formed by the high tempemture employed.This ether was prepared more than 12 months since and kept in the dark but on redetermining its density it was found that a certain amount of change probably polymerisation had taken place. The 15" 15" density a t d' had increased to 1.0537 or 0.0047 and on distilling, about four-fifths came over a t 227.7-238" some higher boiling product being left behind. To obtain the ether pure the method of treating the silver salt with ethyl iodide was again resorted to. Silver itaconate is appa-rently crystalline and much more deiise than silver citraconate, moreover it is not so easily acted on by ethyl iodide as thht salt, and requires digesting with it for some time on the water-bath to complete the reaction.On distilling the ethyl itaconate prepared by this method about five-sixths came over below 230" leaving a residue which partly came over only after being strongly heated in fact the residue appears to consist of et,hyl itaconate more or less polymerised. The first portion of the distillate on being fractioned gave ethyl itaconate with a boiling point of 227 7-227.9". The density deter-minat.ions gave-d4" 1.0607 4" 10" 10" d- 1.0546 59 ,c BBIBASIC ACIDS AND THEIR DERIVATITES. ( 3 t . 15" 15" d- 1.0304, Sp. rotation. 20" LO" d6- 1.0464, . 25" 25" d- 1.0427. 1 * 0598 1 * 0601 1 *0601 1 -0607 1.0647 1 * 0640 1 '0647 1 -0620 -__-The following numbers were obtained for its magnetic rotation :-18 -oo 18 .O 18 .o 18 -0 1.7 * 0 17 .O 17 -0 Average 17.6 Mol.rotation. -I--10.449 LO *453 10 -453 10 ~45'7 10.491 10 -484 10 *484 10 *467 --I t will be seen that this etherprepared from the silver salt does not differ in boiling point from that obtained by heating itaconic acid with alcohol; its density however is slightly higher whilst the specific and molecular rotahions are appreciably lower. Etlql Alesaconate. This ether was prepared by saturating a mixture of alcohol and mesaconic acid with gaseous hydrochloric acid. The ether was washed with dilute sodium carbonate dried and distilled. It was free from chlorine. The boiling point was 228" (corr.). The density determinations gave the following numbers :-15" 15 20" 20° d- 1.0492, d- 1-0453, 4" 4 10" d 1-0598, 1.0539, 25" 85" d- 1.0415.The magnetic rotation determinations gave 5S6 PERKIN SATURATED AND UNSATURATED t . Sp. rotation. 14 *oo 14 *4 14 8 13.0 13.5 13 *5 14 -0 22 *5 22 .o 21 *5 1 -1406 1 '1397 1.1469 1 '1431 1 * 14'21 1'1322 1 '1Y20 1 -1340 1 -1393 1 '14<29 I--Average 16'3 t. ! sp. rotation. Mol. rotation. Mol. rotation. --11 *219 11 -229 11 -229 11.278 11 '244 11 ' 2 43 11 -240 11 -215 11 207 11 224 11 '233 --Xethyl Mesaconate. This was prepared by saturating a mixture of mesaconic acid and methyl alcohol with hydrochloric acid. The cther was washed with sodium carbonate. I t boiled at 205.5-206.5" (corr.). The density detcrminations gave-4" 4 d 1.1360, 10" 10 d- 1.1302, 15" 1 5" 90" mo d- 1.1253, d- 1.1207, The determinations of the magnetic rotation gave-I-- I--- --15 -2.14'3 14 .O 14 *O Average 14.4 --1.1631 9'073 1.1645 9 -077 1.1610 1 9 047 1 -1610 9 *047 1.1619 1 9.061 - --_1 Mesityl Oxide. Methyl Isobutenyl Ketone. The prodiict examined was obtained from Kahlbaum. It was dried by means of anhydrous potassium carbonate and repeatedly frac-timed. The specimen selected boiled at 129*5-130" (coi-r.). The density determinations gave BlBASIC ACIDS AKD THEIR DERIVATIVES. t. I sp. rotation. 587 Mol. rotation. 1.5" 15" d- 0.8612 4" 4" d- 023706, 11.6' 11.6 11 *6 11 *6 Average 11.6 25" 85" d- 0.8548.1 '2336 7 975 1 * 2366 7.794 1 -2333 7.773 1 -2333 7 * i 7 3 --- --1 -2342 '7 -778 The following numbers were obtained for its magnetic rotation :-I-- I -Observations on t h e Results obtained with Sutiirated Compounds. Malonic Xuccinic and Glutnric Compounds. From previous experiments (Trans. 1884 570) it appeared that succinic acid was tlre first member of the homologous series of the bibasic acids though from analogy it was more probable that it should commence with glutaric acid. The results obtained from the examination of glutaric acid given in this paper show that the latter supposition is apparently correct as its series constant is lower t,han that of ethyl succinate thus :-Molecular rotation of ethyl succinate . 8.380 Less CH2 x 8 = 1.023 x 8 8.184 Series constant.0.196 -Molecular rotation of ethyl glutarate 9.356 Less CH2 x 9 = 1.023 x 9 9.207 Series constant 0.149 Numbers obtained by a fresh examination of ethyl sebate give results a little lower than these previously obtained these give a series constant very nearly the same as that of.-ethyl glutarate thus-Molecular rotation of ethyl sebate . 14.459 Less CHz x 14 =.1*023 x 1 4 . . 14.322 0.137 The number previously obtained for the mol. rot. of ethyl sebat 588 PERKIN SATURATED AND UNSATURATED was 14.496 if this be averaged witkt the new results it gives 14.477, and this has a series constant of 0.155 so that there can be no doubt that glutaric and sebacic acids are true members of the homologous series. It is quite probable that a re-examination of ethyl suberate would also give somewhat lower numbers than those previously obtained and thus also would be found to have the correct series constant'.The molecular rotation required for this substance would be 12.425 the number found was 12.461 and a very small error in reading would cause this as the molecular weight of thc ether is high. The molecular rotation found for prop91 succinate also gives a lower series constant than ethyl succinate this is quite in accordance with other observations the propyl-groups usually having this influence. The series constant is much the same as that of ethyl glntarate and sebate. Molecular rotation of propyl succinate. . . . Less CH x 10 = 1.023 x 10 10.363 1'0.230 0.133 The molecular rotation of ethyl glutarate is nearly identical with methyl succinate (pyro tartarate) of ethyl which is 9347.The accompanying diagram shows the relative position of the molecular rotatioils of the ethers of the bibasic acids those of some of the isomeric compounds being also gisen. I n the diagram in my previous paper the homologous series was supposed to follow the direction which is indicated by the dotted line this is now substituted by the line starting from ethjl glutarate and following on to ethyl sebate. It is interesting to notice that in the case of the monobasic acids and ethereal salts that the molecular rotation drops from formic to acetic acid and again but in a less degree to propionic acid the true homologous series then cornmencing (see Diagram VI Trans., 1884 548).In the case of the ethers of bibasic acids we get this peculiarity to a greater extent the drop occurring three times before the true humohgous series commences. (See accompanying dis-gram.) The relationships of the rr-agnetic rotations of the ethers of the bibasic acids t o the acids themselvss have hitherto been only inferred from the results obtained from the examination of the monobasic acids and of their ethereal salts ; some experiments were therefore made in this direction but as the bibasic acids are solid and not easily fusible solutions had to be employed this makes accurate results more difficnlt to obhin. Two of the most soluble acids were taken Hmison S Sons. LitL. S Martins Lane.%< BIBASIC ACIDS AND THEIR DERIVATIVES.589 namely mnlonic and glutaric acids. to be sufficiently soluble. ethers :-Succinic acid was not considered The numbers obtained show the following relationships to the Ethyl malonate . 7.410 Malonic acid 3.474 Diff. for replacement of H? by ( CzK5jz. . 3.996 Ethyl glutarate. . 9.356 Glutaric acid 5.482 DifL €or replacement of H by (C2H5)2. . 3.874 I n the case of the fatty acids best comparable with these we get-Ethyl acetate . 4.462 Acetic acid. . 2.525 Dieerelice for replacement for replacement of H, of H by CZH,. . { by (C,H,) = 3,874. Ethyl propionate. 5.452 Propionic acid. . 3.462 Difference for replacement } 1.990 = for replacement of H, These comparisons show that the influence of etherification in the case of the bibasic acids is very similar to that of the monobasic acids.These results however are not quite so consi~t~ent as might be expected because the difference between the propionic and glutaric compounds and between the acetic and mslonic compounds should compare instead of which they are reversed ; this however, mag be caused by some small error due to examining ,the malonic and glutaric acids in solution. of H by C,H,. . { by (CzH5) = 3.980. P y rot art ar i c Anhydride . The primary object in examining this compound was to compare i t with the anhydrides of the unsaturzted acids as we11 as to study its rotation in reference t that of pyrotartaric acid itself. The latter relationship will be considered here the formel- further on. The rotat'ion of pyrotartaric (methylsuccinic) acid has not been determined but as its ether gives numbers nearly identical with those of ethyl glutarate there can be no doubt its rotation is practically the same as that of glutaric acid 590 PERKIN SATURATED AND UNSATURATED Pyrotartaric acid (estimated).. 5.482 , anhydride . 4.750 0-732 This number is about that which would be expected and shows t,hat this anhydride when uniting with water to form the acid gives a rotattion which is less t,han the sum of the rota,tion of the anhydride plus the rotation of water; this agrees with all previous observa-tions of saturated compounds when unifing with water to form new compounds. Acetyl and Xuccinyl Chlorides. Acetyl chloride was examined chiefly to get an idea of the value of chlorine in snch compounds as it was evident that by comparing it with aldehyde the value of this element when replacing hydrogen could be obtained thus :-Acetyl chloride 3.800 Aldehyde .2.385 Influence of C1 replacing la 1.415 Valueof H . 0.254 Value of C l . . . 1.669 -This is a little lower than the value of chlorine i n propy1 chloride, With respect to succinyl chloride the only compound it can a t which is 1.733. present be compared with is ethyl succinate. Ethyl succiuate. . 8.380 Succinyl chloride 7.242 Digerenee 1.138 -If a similar comparison be made with acetyl chloride and ethyl acetate thus-Ethyl acet'ate. . 4.463 Acetyl chloride 3.800 -Difference 0.662 x 2 = 1.324 we get a resuIt which is not very much more than half of that obtained with the succinic compound.At any rate it shows there must be a pretty close analogy between the rotation of the chlorides of acet(y1 and acetic compounds and the chlorides of succinyl and succini BIB9YIC ACIDS AND THEIR DERIVATIVES. 39 1 compounds. The above difference would at the same time indicate that the value of chlorine in succinyl chloride is slightly higher than in acetyl chloride. Mesityl Oxide. Methyl Isobutenyl Ketone. As no unsaturated ketone had been examined in reference to its magnetic rotation I was anxious to know whether this substance would bear to analogous sat,urated compounds the usual relationship. As this is an iso-compound it is necessary to compare it with a saturated isoketone or allow €or the influence of this group the latter will be the simplest method; methyl butyl ketone has not been examined but methyl propyl ketone has so that by adding the value of CH2 to this the desired rohtion will be found.Molecular rotation of mesityl oxide . 7.778 Methyl propyl ketone 5.499 + 1.023 6.522 1.256 0.111 Less influence of iso-group 1.145 This is a difference only slightly in excess of that found to exist between ethyl a-crotonate and ethyl butyrate. This ket,one therefore behaves in a manner similar to other unsaturated compounds as regards its magnetic rotation. Maleic Citraconic and Itaconic Acids. When considering the rotation of mesityl oxide reference was made to the difference of rotation between saturated and unsaturated com-pounds the latter having a larger rot.ation to the extent of a little more or less than 1.0 with the exception of ally1 compounds it has been found to be a little greater than 1.0 as in ethyl a-crotonate and ethyl oleate where it is 1.112.The following is a comparison of the ethereal salts of maleic citraconic and itaconic acids with saturated acids :-Ethyl maleate . 9.625 Ethyl succinate 8.380 1.245 Ethyl citraconate 10.517 Ethyl pyrotsrtarate . 9.347 1.17 592 PERKIN SATURATED AND UNSATURATED Ethyl itaconate 10.467 Ethyl pyrotartarate . 9.347 --1.120 In all these cases the difference is only a little higher than 1.0 and these acids may therefore be regarded as ordinary unsaturated com-pounds related to succinic and pyrotartaric (methylsuccinic) acids in the same way as a-crotonic and oleic acids are to butyric and stearic acids.The relationship of rnaleic and citraoenic acids to their ethers is also analogous to that existing between the saturated monobasic and bibasic acid and their ethers thus :-Ethyl maleate . 9.625 Maleic acid 5.633 Difference 3.992 Ethyl citraconate. . 10.51 7 Citraconic acid 6.567 Difference . 3.950 -It has been shown that in the case of malonic and glutaric acids and their ethers the differences are respectively 3.936 and 3.874 and with acetic and propionic acids 1937 and 1.990 respectively which multiplied by 2 give 3.874 and 3.980. These results go t o show that in the formation of the ethers of these unsatura’ted acids the same kind of chemical change takes place as with the saturated acids and therefore that they are of similar structura that is each acid contains two COOH groups.The relationship of ethyl and methyl citraconate to each other is also analogous to that of ethyl and methyl succinate :-Ethyl cit,raconate . 10.51’7 Methyl citraconate . . 8.364 Difference 2.153 Ethyl succinate . 8.380 Methyl succinate 6.232 Difference. . 2.158 E’umnk and Mesaconic Acids. From the magnetic rotation of the ethereal salts of these acids, they are evidently abnormal compounds the numbers they give being yemarkably high nearly as high as would be given by an unsaturated compound differing from a saturated oue by H, thus : BIBASIG ACIDS SND THEIR DERIVATIVES. 593 Ethyl fumarate 10.116 Ethyl sncciuate . 8.380 Differance . 1.736 Ethyl mesaconate 11.233 E thy1 pyrotartarate.. . . . . . . . . . . 9.347 1.886 --It may be as well to notice here that the relationship of et,hyl and methyl mesaconate is analogous to that of ethyl and methyl succinate -Ethyl mesaconate 11.233 Methyl mesaconate. . . . . . . . . . . . 9.U61 -2.172 As showu previously the difference in the case of the succimte is 2.158. As bearing upon the general structure of fumaric acid we may consider its chloride. The only comparison we have in this case is it,s relationship to its ether :-Ethyl fumarate . 10.116 Fumaryl chloride. . 8.747 -1-369 This is a little higher than the difference found between ethyl succinate and succinyl chloride which is 1.138 ; but it is nearly the Same as twice the difference found between ethyl acetate and acetyl chloride which comes to 1.324.SO that there it no reason to think that their structure so far as the existence of carboxyl-groups is concerned differs from that of ordinary acids. If then mxleic and fumaric acids contain these groups the cause of their isomerism must be related to the part of the acid they are attached to. From the high magnetic rotation of fumaric acid as well as its greater stability and smaller solubility than maleic acid it is natural to infer that in the case of the former there is some kind of con-densation or closer union between the molecules than in the latter, and I have previously brought this view forward (Trans. 1881 560). This idea coincides to some extent with the views advanced by KekulB in which an explanation of the isomerism is sought in the idea of saturated and free affinities.If this however holds good, probably all unsaturated compounds except fumaric and mesaconic acids and perhaps one or two others would have to be regarded as VOL. LIII. 2 594 PERKIN SATURATED ASD UNSATURATED having free affinities judging from the magnetic rotation of those already examined. But this idea of condensation or closer union of the molecules in fumaric and mesaconic acids is negatived by some of the physical properties of these substances. If it existed me shonld expect that the ethereal salts of these compounds would have higher boiling points and greaber densities than those of maleic and cit'raconic acids. The following comparison shows how they stand t o each other:-I Y O 15 Ethyl maleate b.p. . . . . . . 225.0" d A 5 1.0740 Etliyl fumarate , . . . . . . 218.5" , 1.0623 6-5' 0.0017 -15' 15 Etliyl citraconate b. p . . . 230.3" d- 1*04€8 Ethyl mesacona te , . . . . 228.0" , 1.0492 -2.3" + 0.0024 Ethyl ibaconate boils at; 227*8" and has a density of d E o 1.0504, 15" so that we find the boiling points of ethyl maleate citraconate and itaconnte are actually high el. than those of ethyl fumarate and mesaconate. The densities of ethyl maleate and itaeonate are also hiyhey than those of these ethers that of the citraconate being how-ever a trifle lower than that of the mesaconate. No doubt the most striking peculiarity of fumaric and mesaconic acids is their appwent inability to forrn anhydrides and in ibis respect they resemble terephthalic acid ; maleic citraconic and itaconic acids behave like phthalic acid which easily gives an anhydride.The isomerism between phthalic acid and terephthalic acid being due to difference of position can such an explanation be used in reference to the compounds under consideration ? Van't Hoff, I believe was the first to suggest this view. The difference of position in these compounds can be represented either by his fignre or on a plane by assuming the existence of a two-carbon chain. Taking malein and fuma,ric acids as instances we get-H-C-CO OH H-C-C 0 OH I1 COOH-(:-H II H-C-COOH Maieic acid. Furnaric acid. I n this vvay maleic citrazonic and itaconic acids would most resemble orthwcompounds and fumaric and mesaconic acids para BIBtiSIC ACIDS AND THEIR DERIVATIVES.595 compounds ; but if this be so are these differences of position likely to cause the ethers of the latter acids to give larger magnetic rotation than those of the former? This is difficult to answer at present. Difference of position in the aromatic series does affect the magnetic rotation of bodies very considerably and I may mention that I have examined the ethers of phthalic and isophthalic acids and find that the latter gives a slightly higher rotation than the former but the difference is very small. The more correct comparison however, would most probably be hetween phthalic and terephthalic acids. The latter I hope to measure before long. At the present moment tlie position theory appears to afford the best means of explaining the isomerism of these unsaturated acids.As t o the difference of constitution of citraconic and itaconic acids, the magnetic rotation does not give much light. If they be repre-sented thus-COOH COOH I I CH2 and C:CHz I C*CH, C H it I COOH I COOH the difference will be in reference t o displacements by CH,- and CH2= and we have no perfectly parallel cases examined as regards the influence such displacements would have on the magnetic rotation of substances. The only comparisons we have which are near to this are between the ethereal salts of succinic and methylmalonic acid aiid those of pyrotartaric and glutaric acids. In the former the rota-tion varies by 0.05 and in the latter by only 0.01 the lower rotations being for the methyl replacements.The rotation of ethyl itaconate is 0.05 lower than that of the citraconate so that if anything these com-parisons would be in favour o€ itaconic acid containing methyl. The boiling points of the ethereal salts of methylmalonic and pyrotartaric acids are a good deal lower than those of the ordinary snccinic and glutaric acids. The boiling point of ethyl itaconate is also lower than that of ethyl citraconate but only about 2.5". A number of experiments were made on the oxidation of citraconic, mesaconic and itaconic acids with chromic mixture and by fusion -\.vith alkali but they all gave acetic acid; in the case of citraconic acid, when fused with alkali the silrer salt prepared from the distilled acid gave numbers indicating the presence of propionic acid in small quantities.The oxidation of these acids with permanganate takes place with different degrees of rapidity. Thus when a small quantityis add& rC) 2 s 59 (i PERKIN SATURATED AND UNSATURATED a dilute solution of citraconic acid slightly acidified with sulphuric acid the colour disappears after about 15 seconds whilst with exactly similar solutions of mesaconic and itaconic acids the colour vanishes almost immediately. With alkaline permanganate moreover these acids do not behave in the same way; thus with dilute alkaline solutions of the three acids made exactly alike the alkaline per.-manganate does not become green with the citraconic solution until about 20 seconds have elapsed it then slowly becomes turbid ; the mesaconic solution becomes green a t once and then gradually opaque and greenish-yellow ; whilst the itaconic solution becomes green a t ouce and remains bright.These three acids when thoroughly oxidised with alkaline permanganate yield oxalic acid ; no acetic acid was found. iWdeic and Cityaconic Anhydrides. Thest? anhydrides were measured in different ways. Maleic anhydride being solid was examined in solut'ion only arid citraconic both in the pure state and dissolved. From the examination of the latter in the pure state there can be no doubt about its rstation but when dealing with solutions of t h e anhydrides in different solvents, i t is necessary to bear in mind that they are unsaturited compounds, and may combine more or less wit'h the solvents and produce saturated compounds therefore when doing those of maleic anhydride in acetic acid or acetic anhydride corresponding experiments were always made with citraconic anhydride and these solvents because the true value of this compound had been obtained with the pure substance.It was found that these solvents did slightly alter the rotation of citraconic anhydride and a t last citraconic anhydride itself was used as the solvent for maleic anhydride as these two compounds being of the same kind and so nearly related were not likely to influence each other. The following are the results obtained :-I. Rotation obtained for znaleic ar?hydride in acetic acid 4.448 4.417 4.545 Maleic anhydride in acetic anhydride . Maleic anhydride in citraconic anhydride Citraconic anhydride in acetic acid.. . . . . . . . . . . . . . Citraconic anhydride in acetic anhydride Citraconic anhydride alone 5.540 11. 5.148 5.488 SO that the solutions in Series I give numbers about 0*10-0*13 lo~~-er than do the mixture of maleil anhydride and citraconi BIBASlC ACIDS AND THEIR DERIVATIVES. 597 Mnleic acid . 5.633 Maleic anhydride 4.545 OH . 1.088 . anhydride. I n Series I1 they are from 0*058-0*092 lower than those given by pure citraconic anhydride. Density determinations were made with the solutions of maleic and citraconic anhydride in acetic anhydride from 10" to loo" thinking that they might throw some light on the cause of the small difference of rotation but they do not give any definite evidence on the subject.It was however thought best to give the determinations as they may be useful for future reference. There can be no reason to doubt however t,hat the magnet,ic rotation obtained for maleic anhydride when determined in its solution in citraconic anhydride is practically correct and this is borne out by the following comparisons of this subst,ance arid citraconic anhydride with their respective ethers with which they show practically the same difference :-Citraconic acid 6.567 Citraconic anhydride . 5.540 OH . 1.027 -Ethyl maleate 9.625 Ethyl citracouatc . 10.517 Male'ic anhydride 4.545 1 Citraconic anhydride 5.540 _-Difference 5.080 I -Difference . 5,077 I n previous papers I have drawn attention to the fact that when water unites with a substance so as to produce a new product the rotation of the latter is less than the sum of the rotations of water and the substance with which it has chemically united but in t,he case of maleic and cit,raconic anhydrides when they unite with water to form their respective acids we get the extraordinary result that the acids possess rotations actually greater than the sum of the rotation of the anhydrides and the water they have united with.Now if the water had been presmt even in an uncombined way its value would have been only 1.000 and yet there is 110 doubt that in this case its union with the anhydrides has resulted in t.he formation of new compounds. As no auhydrides of the bibasic acids had been examined the experiments on pyrotartaric anhydride already given were made (p.565) to see whether it behaved in a normal or abnormal mauner when hydrated. From the comparisons already given it is seen that the difference between the rotation of this anhydride andits acid is only 0.732 or considerably less than 1.000 a result consisteui; with all previous observations. Citraconic anhydride behaves as an unsaturat,ed compound givin 598 PERKIN SATURATED AND UNSATURATED a rotation which is considerably higher than the corresponding saturated anhydride thus :-Citraconic anhydride . . . . . . . Pyrotartaric anhydride. . . . . . 5.540 4.764 0.7 76 hut this difference is much smaller than that existing between most, unsaturated compounds especially those related to it which give from 1,120 to 1.245 as already shown.This peculiarity of the rotations of maleic and citraconic anhydrides leads to $he inference that there is something anomalous in their constitution or that when in the fluid condition they do not consist of siniple molecules o f the formule C4H203 and C5H403 but of those with more com-plex ones formed by one molecule saturating another and thus reducing the rotation (when in the state of vapour maleic anhydride has the ordinary formula Hubner and Schrieber Z. 1872 '7114). Some experiments were therefore made with citraconic anhxdride to see if such molecules existed whether they would break up on heating. The magnetic rotation determinations of this substance were made along with comparable ones of pyrotartaric anhydride because it is found that the molecular rotation of a substance is not quite constar,t for all temperatures falling off a little with rise of tempera-ture ; this matter is at present occupying my attention.The numbers obtained were-Citraconic anhydride a t 17.4" . . . . . . . Citraconic anhydride a t 65.7" . . . . . . . . 5.540 5.4i3 0.077 Pyrotartaric anhydride a t 11.6" . . . . 4.764 Pyrotartaric anhydride at 50". . . . . . . . 4.737 0.027 -~ The citraconic anhydride determinations a t high temperature show us difference slightly in excess of those of the pyrotartaric anhydride ; this would favour the idea of dissociation taking place to a very slight extent but the variation is almost within the errors of experi-ment and cannot be taken as any evidence of this.h large number of density determinations of citraconic anhydride were also made from 0-100" (p. 577) but i t was found that these change in a very regular manner with the temperature and within this raiige do not indicate dissociation. Endeavours were made to take the density OF this substance at its boiling point and also at the boiiing point of aniline BIBASIC ACIDS AND THEIR IlERlVhTlTES. 599 but in both cases decomposition with evolution of gas gradually took place arid rendered it impossible to do this. The method of determining molecular weights proposed by Raoult was brought under my notice and I have applied it to the determina-tion of the rnolecu1a.r weight of these anhydrides and most of the substances referred to in t h i s paper. The solvent used was glacial acetic acid and the proportions of the substance used varied from about 1.4 to 1% to 100 of acid.The following results were obtained :-Substarice. Citraconic acid Itaconic acid . Mesaconic acid. . Et,hyl citraconate. Ethyl mesaconate . Ethyl itaconate Ethyl succinate . Ethyl mtt1e:ttt Ethyl fuinarate . Succinic anhydride . Pyrotartaric anhydride Maleic an h y c I ride . Citraconic anhydride . Mol. wt. found. 134-4 134.8 13 4 - 2 189 -9 188.7 187 *7 180.6 179.1 177 *3 115 '4 131 *2 108 *9 149 *8 Mol. w t . calculated. 130 130 130 186 186 186 174 172 172 100 114 98 112 Difference. +4.4 4 -8 4'2 3 -9 2.1 1.1 6 -6 7 - 1 5 *3 15.4 17 -2 10 *9 18 *6 From the result's of this method of determining the molecular weight it appears that all the above acids and ethers have the mole-cular weight usually assigned to them the variation in the number being but small and probably due to experimental errors.In the case of the anhydrides however the variations are somewhat larger and moderately consistent and therefore probably not due to errors of experiment but as both saturated and unsaturated anhydrides behave in the same way their molecular conditions would appear to be the same so that these results afford no help in explaiiiing the peculiarities of the magnetic rotation of maleic and citraconic an-hydrides. So far the evidence of the magnetic rotation of citraconic a11 hydride at high tempera,tures the density determination through the range of temperature 0" to loo" and Raoult's method of deter-mining molecular weights all give evidence against the existence of complex molecules.It may be there is some peculiarity in the con-stitution of these bodies we are not acquainted with ; if so it is difficult to conceive what it can be. I have been struck however, with the peculiar behaviour of these anhydrides towards tertiary amine 600 PERKIN SATURATED AND UNSATURATED with which we should not expect them to react easily. For example, if citraconic anhydride be added to triethylamine action sets in with great energy the product becomes brown and strongly heated and a brown pitch result,s which is partially soluble in water and partially insoluble. Maleic anhydride acts similarly.Citraconic anhydride also reacts with picoline but not so freely as with triethylamine. Succinic anhydride does not behave in the same way with these bases; but whether the greater chemical activity of these unsaturated anhydrides is due to their being unsaturated compounds or t o difference in structure from ordinary anhydrides we have no means of proving at present ; any explanation of their peculiar magnetic rotations therefore mnst be allowed to stand until more compounds of this class have been obtained and examined. Our knowledge of unsaturated compounds and their physical characteristics is a t present very incomplete that they are very different from t'hose of saturated compounds the follow-ing instances in relation to boiling points will show :-Saturated Compounds.Ethyl succinate b. p. . . 216*5'} +34.5. Succinic anhydride 7 250.c 218*G } +294. Ethyl pyrotartarate , . . . . Pyrotartaxic anhydride , . . . . 847.0 Unsaturated Compounds. Ethyl maleate b.p . . 225" } -25. Maleic anhydride , . 290 Ethyl citraconate , . 230 } -17, Citraconic anhydride , . . . . . 213 The anhydrides in the case of the saturated compounds boil much higher than the ethers but in unsaturated anhydrides boil considerably lower than the ethers. The chief conclusions resulting from this inquiry may be briefly pummarised :-1. That glntaric acid appears to be the first true member of the homologous series of bibasic a,cids. 2. That the propyl ether of succinic acid has a lcwer series constant than the ethylic ether a result which is consistent with analogous observations on some of the compounds of the fatty acids, 3.That pyrotartaric anhydride has a rotation which shows that when it unites with water condensation takes place as with &her anhydriiles the rotation of the resulting acid being less than the sum of the rotation of the anhydride plus the rotation of water BIBASIC ACIDS AND THEIR DF RIVATIVES. 601 4. That the rotation of mesityl oxide shows that unsaturated ketones have rotations consistent with those of other unsaturated bodies. 5. That the ethereal salts of maleic citraconic and itaconic acids have rot’ations consistent with those of other unsaturated compounds differing from the saturated ones by H2 and that their general struc-ture appears to be analogous to that of ordinary bibwic acids.6. That the et,hereal salts of fumaric and mesaconic acids have much higher rotations than ordinary unsaturated compounds being nearly sufficiently high for those represented by saturated compounds less H4 and that their general struct,ure is apparently analogous to that of ordiuary bibasic acids and that this difference of character to their isomers is apparently best accounted for by difference of position i.e. by the Vant’ Hoff hypothesis. 7. That the rotations of maleic and citraconic anhydrides are ab-normally low and the reason for this cannot at present be satisfactorily explained. 8. That from the determinations by Raoult’s method of the mole-cular weights of most of the substances examined in this paper they seem to have the molecular weights usually ascribed to them-at any rate iione appear to be polymers. The following table gives a list of the substances which have been subjected to examination with their molecular rotations and the pages where they are referred to. Acids. Citraconic Glutaric Maleic Malonic. Ethers. Ethyl citraconate. Ethyl fumarate Etliyl gll-itarate Ethyl itaconate Ethyl maleate Ethyl eebate . Ethyl mesaconate . Met,hyl citraconate . Methyl mesaconate Propyl succinate . Anhy drzdes. Citraconic Maleic Pyrotartaric . Molecular rotation. 6 -567 5 *482 5 *633 3’474 10 -517 10.112 9 -356 10 -467 9 -625 14-459 11 *233 8’364 9 -061 10 -363 5 -540 4 -548 4 3’64 Page. 580 591 595 599. 566 589 600. 562 589. 572 591-593. 581 591 592 594 599 601. 567 587. 584 592 594 599 601. 572 591 594 599401. 568 587. 583 592 600. 586 593 599 601. 562 588 600. 574 593 591 599 601. 585 593 594 599-601. 576 596-601. 568 596-601. 564 589 598-600 602 WERNER OXIDATION OF OXALIC ACID Page. Molecular rotation. Chlorides. Acetyl Succinyl Fumaryl . Ketone. Mesityl oxide 3 -800 8 -747 7 *242 7.778 590 593. 575 593. 563 590. 587 591 601

ISSN:0368-1645    

DOI:10.1039/CT8885300561

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

WERNER OXIDATION OF OXALIC ACID XLIV.-Oxidation of Oxalic Acid by Potassizcrn Dichromate. By EMIL A. WERNER F.I.C. Assistant in the Chemical Laboratory, Trinity College University of Dublin. IN a preliminary notlice on the above subject (Abstr. December 1887), I pointed out that t,he oxidation of oxalic acid by potassium dichro-mate was limited by the formation of a chromoxalate even in presence of sulphuric acid provided the latter was not presentl in a concen-trated form. In the present paper I propose to give the results of a study of the oxidation of oxalic acid by potassium dichromate per se and in vary-ing molecular proportions. A paper on the same subject has been quite recently communicated t o the Society by Mr. C. H. Bothamley (this vol. p. 159) but as the writer has overlooked the formation of a chromoxalate in t8he interactions I believe that he has been misled in t,he interpretation of his results.I n short for a complete and successful soliltion of the problems presented in the interactions of oxalic acid and potassium dichromate, a previous knowledge of the properties of the cliromoxalates is abso-lutely necessary more particularly of Croft’s red po tnssium compound, whose precise composition and relations I have recently studied (this Whether in the solid state or in aqueous solution 7 mols. of oxalic acid are required for the complete reduction of 1 mol. of potassium dichromate the sole products of the interaction being Croft’s salt car-bonic anhydride and water thus :-vol. p. 404). k’,Cr2O7 + 7(H2C20,2H,0) = KzH2C~*z( C,O,)d(OH) + 6C0, q- 19H20 BY POTASSIUM DICHROMATE.603 The experimental data proving the correctness of this equation are given under Experiment I further on. Bearing in mind this equation it seemed highly probable that d l cases of the interaction of potassium dichromate and oxalic acid, between 1 and 7 mols. might be represented by one general equation, and the outcome of the present investigation has been to give com-plete corroboration t,o this view and 10 prove that when dichromate on the one hand or oxalic acid on the other is used in excess beyond the proportions required by the foregoing equation that excess is found in the residue on completion of the reaction. The general method adopted in the experiments was the following : -An intimate mixture of the two substances both in fine powder was slowly heated in a dry weighed conical flask to the temperature of interaction after which the flask with its contents was heated in an air oven at 110-120° until the weight was constant and the loss determined.This does not represeut as Mr. Sothamley assumed, " the complete dehydration of the oxalic acid and its partial oxidation by the dichromate," but its partial oxidation together with its partial dehydration for the red potassium chromoxalate formed (not chromic oxalate) retains as I have shown (Trans. 1888 404) % mols. H,O, a t the temperature and under the conditions of the interaction. The residue was dissolved in water diluted to a definite volume and the chromium and oxalic acid determined in aliquot portions.The esti-mations of the carbonic anhydride by absorption in ammoniacal calcic chloridc solution were made in separate experiments carried out in presence of water ; the spontaneous nature of the reaction accompanied as it is by considerable development of heat when hhe substarices inter-act in the solid state rendering the correct estimation of the carbonic anhydride by any absorption method very difficult. The potassium dichromate and oxaiic acid used in these experiments were both purified by recrystallisation the latter carefully air-dried, whilst the former was heated to 150-160" and allowed to cool in a desiccator. A. Potassiuwb Dichromate (1 niol.) Hydrated Oxalic Acid (7 mols.) I n this case the dichromate is completely reduced and the inter-action takes place according to the equation already given.= 1.2973 gram K,Cr,Ol = 3.8922 , I€2C,04,2H20. h'xpt. 1.-5.1895 grams Temperature of interaction 28-30", A t 110-120°-Loss . . . . Theory . . 2.6791 , = 31.63 , 7) 2.6445 grams = 50.95 per cent. of tots1 weight 604 WERNER OXIDATION OF OSALIC ACID H,C204,2H20 (unoxidised as chromoxalate in residue)-Acid Acid taken. unoxidised. Found 2.2570 grams. Ratio 100 57.98 or Theory 2.2241 , Ratio 100 57.14 or 7 4.05. 7 4. The residue when dissolved in water yields a rich purple-red solu-tion perfectly free from any unaltered dichromate. A series of experiments had previously shown that water in what-ever proportion it may be present is entirely without influence on the nature of the interaction.13. Potassium Dichroma te and Hydrated Oxalic Acid equal Mol ecu 1 es. I n this case as the experimental results show only one-sevenbh of the dichromate is reduced six-sevenths remaining unaltered. = 16789 gram H2Cz04,2H20. = 3.9176 grams K2Cr207. Expt. II.-5*5965 grams Temperature of interaction 30-32". At 110-120"-Loss . . . . . . Theory . . 1.153 , = 80.61 , ,, 1.184 gram = 21.15 per cent. of total weight. Cr,O formed-K2Cr207 KoCr,0, taken. reduced. 100 14.66 or 7 1.02. Found Theory. 0.289 , = 0.339 , 100 14.26 or T 1. 0.297 gram = 0.5744 K,Cr207 H,C204,2Hz0 (unoxidised as chromoxalate) -Acid taken. Acid unoxidised. Found 0.9610 gram. Ra.tio 100 57.23 or 7 4.006. Theory 0.9593 , Ratio 100 57.14 or 7 4.Bxpt. HI.-In presence of water = 1.78 gram H2C204,2H20. GO evolved-5.9335 grams . . . . { = 4.1535 , K,Cr,07. Found . . 0.553 gram = 0.7917 gram H2C204,2H20. Theory 0.5327 , = 0.7628 , ,) Crz03 formed-K2Cr20i taken. K2Cr30; reduced. 7 1. Found 0.;-3110 gram Theory 0.3067 ? BT POTASSIUJI DICHROMATE. 605 H2C204,2H,0 (unoxidised)-Found . 1.032 gram. Theory 1.0171 ,, C. Potassium Dichromate (1 mol.) Hydrated Oxalic d c i d (2 mols.). I n this case -; of the dichromate are reduced + remaining un-altered. = 2.4833 grams H2C204 2H20. = 2.8372 , K2Cr207. Expt. IV.-5*3805 grams Temperature of interaction 51-52". At 110-120'- Loss 1.726 gram = 3247 per cent. Theory 1.706 , = 31.71 ,, Cr203 formed- Found . . 0.432 gram. H,C2O4,2H20 (unoxidised)-Theory 0.429 ,, Found 1-42] gram.Theory . 1.419 gram. Ezpt. V.-5%6 grams in presence of water. CO evolved-Found . . Theory 0.7819 , = 1.1195 , 7, 0.7933 gram = 1,1358 gram HzCz04,3H20. D. Potassium Diclwomafe (1 rnol.) Hydi-ated Oardie Acid (9 mols.), corresponding t o K2Cr207 + 7 + 2 mols. HzC20t,2H20. I n this case the interaction takes place as in A the excess of oxalic acid over the 7 mols. remaining unaltered." Expt. VI.-5.64 grams in pre-CO evolved- Found . . 1.1 10 gram. = 4.479 grams H2C2O4,2Hz0. sence of water . . { = 1.161. , K2Cr207. Theory 1.042 ,, Theory 0.600 ,, Cr20s formed- Found 0.621 gram. H2C204,2H20 (unoxidised)-Acid taken. Acid unoxidised. 9 6-03 Found Theory 3403 2.986 grams I 9 6.00 f In this particular case the excess of osalic acid combiries wit,h the red chrom-oxalate foming the feeble compound K2H4Cr2(C204)6 of the blue eeriea which, however is decomposed by much water 606 WERNER OXIDATION OF OSALIC ACID Solutions prepared directly from potassium dichromate and red potassium chromoxalate in the proper proportions were found in each case to be identical in every respect with the solut,ions of the products of the respective interactions.With anhydrous oxalic acid the interactions are the same as with the hydrated acid with the exception that a?d~ydt-ous chromoxalate is formed as the following experiments show. Expt. VII.-Potassium Dichromate and A1271 ydrous Oxalic Acid equal mols. 4.9645 grams. Temperature of interaction 40-42". Loss . . 0.7675 gram = 15.45 per cent, Theory for hydrated chromoxalate = 13-16 ,, , anhydrous , = 14.50 ,, Expt.VIII.-Potassium Dichrornate (1 rnol.) Adzydrous Ozalic Acid (2 nzols.). 5.28 grams. Temperature of interaction 54-56'. Loss . . 1.291 gram = 24.45 per cent. Theory for hydrated chromoxalate = 21.33 ,, , anhydrous , = 23.50 ,, The rather high r e d t obtained in each case is due to a loss of a small quantity of the oxalic acid by sublimation. The residue from the interaction presents the appearance of a light bulky porous, pale-brown mass which develops heat when moistened with water. From a study of t,he interaction of equal weights of potassium dichromate and hydrated oxalic acid Mr. Bothamley deduced the following equation as representing the change which takes place a t 110-120" viz.:-2K2Cr207 -!- 6H&z04 = Cr2(C20,)3 + 6C02 + 6H,O + 2K2CrO4. As I have already mentioned chromic oxalate is not formed in any of these decompositions and neutral potassium chromate is never present as a product! of the interaction of potassium dichromate and oxnlic acid below 200" under any conditions. The equation adopted by Mr. Bothamley agrees only approximately with his experimental results and moreover it does not represent, the molecular ratios with which he worked. Equal weights of potassium dichromate and hydrated oxalic acid, correspond exactly with the molecular ratios :-3K2Cr,07 . . 882 7(H,C,0,2H,O) . . . . 882, therefore 2 mols. of dichromate will be left unchanged according to the equation BY POTASSIUM DICHROJIBTE.C O i 3z(,cr20 + i(H,C204,2H,0) = K2H2Cr,(C204)4(OH) + 2KzCra0 + 6C02 + 19Hz0, and this is proved by the following experiments. E. Potassium Dichyomate and H!ydrated Oxalic Acid equuZ weights. E.apt. 1X.-5*73 grams (= 2.865 grams H,C,0,,2K20). Tempera-ture of interaction ;32-35". Loss . . . . . . . . . . Theory . . 1.9684 , = 34-25 ,, 1.9395 grams = 3i3.84 per cent. Cr203 formed-H2C204 2H20 (unoxi di sed) -Found . . 0.503 gram. Theory . . 0.4937 gram. Found 1.662 gram. Theory . . 1.63i gram. Expt. X-Same as above in presence of water. CO evolved-5.875 grams. Found 0.9022 gram. Theory 0.8792 gram. Mr. Bothamley's own results agree fairly well with the above equation thus he obtained in two experiments the numbers 100 54 and 100 53 for the ratios of oxalic acid taken to oxalic acid un-oxidised from which he concluded that half of the acid was oxidised, but the true ratio is 100 57 or simply 7 4.The absence of neutral potassium chromate in the products from any one of the preceding interactions is readily proTed by the absence of any immediate pre-cipitate on the addition of barium chloride o r nitrate solutions to the product. Mr. Bothamley states (referring to the solution of the product from the interaction of the dichromate and oxalic acid in equal weights) that when mixed with ammonia a brown precipitate of chromium chromate is formed ; in my experiments ammonia did n o t produce a trace of precipitate but simply a change in colour due to its action on the red potassium chromoxalate present.The interactions of potassium dichromate and oxalic acid at a low red heat vary considerably with the proportions of dichromate and red chromoxalate formiug the mixture and though the decompositions are very simple yet they require rather complex equations for their representation. The fact is that the changes which occur under this condition are the result of the ordinary decomposition of the pot,assiunl chromoxalate complicated by the exceptional oxidising action of the dichromate on the oxalic radicle of the latter. In the second part of my paper on the chromoxnlates (Trans. 1888 608 MTRNER OXIDATION OF OXALIC ACID 404) I have shown that the red potassium salt* decomposes at a red heat in accordance with the equation-2KzH,Crz(C204)4(0H) + 110 = 2K-Cr04 + Crz03 + In the presens cases the oxygen necesssry for the decomposition is wholly derived from the dichrorrinte (which is reduced correspond-ingly) when the latter is in excess whilst if the chromoxalate is in excess the whole of the dichromate is reduced (to Cr,O and K,Cr04), the remainder of the oxygen being derived from the air.A s this interaction is of secondary interest as compared with the more im-portant primary change I merely give the following two cases as examples :-16C0 + 4H,O. F. Product from Interaction qf R2Cr20 and Hydrated Oxalic Acid, equal mols. C 1K2H,Cr2(Cz0a)4(OH)z. 1 6KzCrz07. (See Ezpt. I& B). Ratio = Equation : 36KzCrz07 + 6KzHzCrz(CzO,),( 0H)z = 14Cr2O3 -!- 14KzCr20 + 28K2Cr04 + 48C0 + 12Ha0. Expt. XI.-0*944 gram.Hested to a low red heat. Deconiposi-Residue- Found . . 0,7900 gram = 83.68 per cent. Cr,03 formed-tion without violence. Theory 0.787 , = 83.37 ,, Found . . 0.1485 gram. Theory . . 0.1434 gram. G. Product from Interaction of KzCr207 and H,C,04,2H,0 equul weigh is. 1K,H,Cr2(C,04),(OH),. (See Ezpt. I X E) 2KzCra07. Ratio = Equation : 4KzCr207 + 2KzH&rz(C204)4(0H)2 + 5 0 = 3Crz0 + 6K2CrO* + 16C02 -t 4H,O. E q t . XII.-O.6175 gram. Heated t o low red heat. Decomposi-Residue- Found . . 0.4300 gram = 69.63 per cent. tion violent. Theory 0.4318 , = 69.94 ,, Omitting the water of crystallisation BY POTASSIUM DICHROMATE. 609 Cr203 formed-Found . . 0.1155 gram. Theory . . 0.1215 gram. Comparative experiments made with an intimate mixture pre-pared directly from finely-powdered dichromate and red potassium chromoxalate in the proper proportions led t o tbe same results.It is notewort,hy that the mixed solution of potassium dichromate and red chromoxalate which results from the preceding interactions, or a directly prepared solution of the two salts though exhibiting in every respect the properties of its constituents refuses to crystallise under the most favourable conditions. The absorption spectrum of the mixed solution was found from a preliminary examination to be the sum of the absorption-spectra of the solutions of the separate con-stituents. The two compounds appear t o exist in a feeble state of molecular combioation just sufficient t o prevent either one or the other from crystallising out.I hope to examine the solution further, later ou. The results of the present investigation may be summed up in the following conclusions :-1. The red potassium chromoxalate K2H2Cr2( C,O,),(OH) (Croft's salt) is in all cases without exceptiow a product of the inter-action of potassium dichromate and hydrated oxalic acid, below 200". 2. Neutral potassium chromate is never present as a product of the interaction of potassium dichromate and oxalic acid under any conditions below 200". 3. When hhe two substances interact in the solid state the initial temperature of the interaction which lies between 30" and 60 O varies with the molecular proportions employed. 4. The dehydration of the oxalic acid does not affect the nature of the interaction the anhydrous chromoxalate K,Cr2( C204),, being formed in this case. 5. Water by its solvent action facilitates the interaction that is, reduces the initial temperature but is otherwise without influence on the nature of the change. 6. Seven mols. oE oxalic acid is the minimum quantity necessary for the complete reduction of 1 mol. of potassium dichromate, and any excess of either above this ratio remains unchanged. 7. When the proportion of potassium dichromate to oxalic acid exceeds 1 to 7 mols. and the temperature of the mixture is raised t o low redness a secondary reaction occurs between the excess of dichromate and the red chromoxalate first formed. University Laboratory, Trinity College Dublin. VOL. LIII. 2

ISSN:0368-1645    

DOI:10.1039/CT8885300602

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

S L V . - T h e Dete!rmination of the. Molecular Weights of the Carbo-hydrates. By HORACE T. BROWN and G. HARRTS MORRIS Ph.D. BUT very little is known with certainty at the present time about the true molecular composition of the majority of the carbohydrates. The vaponr-density method is obviously inapplicable to them and chemists have had for the most part to be satisfied with a determi-nation of the niizzimum size of their molecules from a study of their somewhat indefinite metallic derivatives and of their acetyl-compounds. Musculus and Meyer (BUZZ. Soc. Chim. [2] 35 370) have attempted to determine the relative size of the molecules by observing the rate of diffusion of the different members of the group but, although the results are of inierest they do not go far in deter-mining the particular point we have before us.In the case of dextrose and levdose there is a considerable amount of positive evidence that their molecular composition is expressed by the formula C6H120s. This is shown by their intimate relation to the hexahydric alcohol mawnitok and by the recent researches of Kiliani on their cyanhydrins which yield hydroxy-acids containing seven atoms of carbon. With regard to the higher carbohydrates the knowledge we possess as to their molecular weight is entirely indirect. In the case of starch and the dextrim we are quite sure from the way in which they break up under the action of diastase and dilute acid that their molecular structure must be very complex and we are able to learn something about the relative size of the molecules but that is all.Within the last few weeks Victor Meyer (Ber. 1888 556) and Auwers (Ber. 1888 860) hare directed attention to a new method for determining molecular weights which is applicable to all organic substances and is of special value where a determination of vapour-density is impossible. This method was devised by Raoult (Ann. 4 401 1885; id. [6] 8 289 and 317 1886; Cornpi. reizd. 94,1517, 1882; 101 1056 1885; 102 1307 1886) and is the outcome of his elahorate investigation into the laws governing the freezing point of dilute solutions and it is certainly a remarkable fact that these important researches should up to recently have received so small a share of attention from chemists. Cl'im. Phys. [ 5 ] 28 133 1883 ; id.1161 2 66-124 1884; id. [6] MOLECULAR WEIGHTS OF THE CARBOHYDRATES. 611 Blagden as early as 1788 (Phil. Trans. 78 277) established the fact with regard to inorganic salts that the lowering of the freezing point of their aqueous solutions is proportional to the weight of substance dissolved in a constant weight of water. De Coppet ( A n n . Chirn. Plzys. [4] 23 25-26) in 1871-72 clearly pointed out that when this lowering of the freezing point is worked out for a deter. minate quantity of the substance dissolved in 100 grams of water, the result which he terms the “ coeficient of depression,” is constant for the same substance and that the coefficients for different sub-stances bear a simple relation to their molecular weights. It was left for Raoult to show clearly what those relatioils are and to extend the investigation to organic substances and to other solvents besides water.Briefly stated Raoult’s generalisations are as follow :-When certain quantities of the same substance are successively dissolved in a solvent on which it has no chemical action there is a progressive lowering of the point of congelation of the solution and this lowering is proportional to the weight of t h e substance dissolved in a constant weight of the soZvent ; in other words ihe lowering of congelation is dependent solely on the respective masses of the substance and solvent and is in dependent of the temperature. If the observed depression of the point of congelation of a solution be taken as C and the weight in grams of the anhydrous substance in 100 grams of the solvent as P then when the substance exists in solution in the anhydrous state the quotient - which we will repre-sent by A and which Raoult terms “ gross coefficient of depression ’’ (coeficient d’abnissement b r u t ) is the lowering of congelation produced by 1 gram of substance in 100 grams of solvent.If we multiply this C coefficient - = A by the molecular weight of the body dissolved, P we obtain the depression which would be produced if 1 mo1.s of the substance were dissolved in 100 grams of the solvent. This is the “ true molecular depression ” (abaissement rnole’culaire vrai) which is represented by T. We have then-C P f l L T = x M. P This formula Raoult finds to be sensibly correct even for substances which do not exist in solction in the anhydrous form provided we take solutions so dilute that the observed lowering of congelation C is about 1” C.* By “ 1 mol. of substance ” dissolved in 100 grams of water Raoult means of course a weight of the substance in grams equal to its molecular weight. 2 T 612 BROWN AND MORRIS THE DETERMINATION OF T is a quantity varying with the nature of the solvent but with the same solvent remaining constant f o r numerous groups of compounds, and it may consequently be considered as a known quantity. On the other hand the coejicient of depression - or A can be obtained ex-perimentally so that if the molecular weight M of the substance is unknown it can be calculated by the formula-C I? and from amongst the possible molecular weights of the substance T under experiment we take that which approaches nearest to - A' In carrying out this method any liquid may be used as a solvent, provided it is capable of solidifying a t a definite temperatme.It suffices merely to know the value of T for that particular solvent and for certain groups of bodies analogous to the one under experiment. The solvents which Raoult recommends in his latest paper ( A n n . Chim. Phys. [6] 8 317 1886) are water acetic acid and benzene. For inorganic saZts the values of T for water have been found by Raoult to be six in number corresponding to certain well-defined groups of salts with benzene the values of T are reduced to two, and for acetic acid T has a constant value for all inorganic compounds.With oi-ganic compounds with but very few exceptions the respective values of T for the solvents mentioned above remain constant ; they are as follows :-T . Water 19 Acetic acid 39 Benzene . 49 Raoult has examined a large number of organic substances the molecular weights of which have been put beyond doubt by determi-nations of their vapour-densities and the results illustrate in a remarkable manner the accuracy and general application of his method. I n determining the value of T €or water Raoult has recorded in his tables numbers which he obtained f o r cane-sugar, invert-sugar milk-sugar and mannitol and which indicate that the commonly received forrnuh for these substances express their molecular composition but he does not call any special attention to these experiments nor does he appear to have examined any other of the carbohydrates.It seemed therefore a matter of interest in the present state of our knowledge of this important group of substances, to submit its various members to a method which promises in th THE MOLECULAR WEIGHTS OF THE CARBOHYDRATES. 613 near future to throw much light on the molecular size of non-volatile organic compounds. Owing to the comparative ease with which most of the carbo-hydrates with the exception of dextrose and levulose are hydro-lised the employment of acetic acid as a solvent was impracticable, and our choice was necessarily limited to that of water. With the exception of oxalic acid and the amines all the bodies examined by Kaoult in aqueous solution give normal results.The method of experiment we have adopted is extremely simple and is essentially tbe same as that described by Auwers (Ber. 1888 712), with the exception that when working with aqueous solutions it is not necessary t o take any precautions to exclude the air. A solution of the carbohydrate is prepared containing a known weight of the substance in 100 C.C. of the liquid. About 120 C.C. of this are introduced into a thin beaker of about 400 C.C. capacity closed with an india-rubber plug with three perforations through one of which a small glass stirrer passes and through the second a thermometer graduated to .l,th of a degree C. This is viewed through a tele-scope and since the scale is an open one there is no difficulty in taking readings to &th of a degree The beaker is immersed in a, mixture of ice and brine a t a temperature from 2" to 3" below the freezing point of the solution which is allowed to fall in temperature from 0.5" to 1" below its point of congelation; this i t will readily do without the formation of ice.Freezing is now brought about by dropping into the beaker through the third aperture in the plug, a very small fragment of ice from a little of the same solution which has been previously frozen in a test-tube. The liquid is stirred briskly and as freezing commences the thermometer rises very rapidily and in a few second8 becomes stationary at the true freezing point of the solution the concentration being always so arranged that the observed depression is never more than 1" to 2" below zero.I f we take C = observed depression of freezing point, x = grams of substance in 100 C.C. of solution, y = grams of water in 100 C.C. of solution, then the " coefficient of depression " is expressed by the equation and the molecular weight M of the substance by 19 &I = -A 614 BROWN AND MORRIS THE DETERIiIINATION OF As the molecular composition of dextrose may be looked upon as fairly well established it will be well in the first place to show how far Raoult's method when applied to this substance bears out the generally accepted formula C6H1206. In all the experiments which follow, Column E gives the observed temperature. , C , the depression of freezing point corrected.* , A , the " coefficient of depression." , M , the molecular weight deduced from experiment.Dextrose C6H,,06. M = 180. Freezing point of water used O"-OOO. Strength of solution 12.616 grams dextrose in 92.25 grams water. E. C. A. M. - 1.450" 1.450" 0.106 179 - 1.450 1.450 0.106 179 - 1.450 1.450 0.106 179 St'rength of solution 8.3704 grams dextrose in 94.86 grams water. E. C. A. M. - 0.945" 0.945" 0.107 177 - 0.940 0.940 0-106 179 - 0.940 0.940 0.106 179 Strength of solution 4.1140 grams dextrose in 97-47 grams water. E. C. A. M. - 0.445" 0.445" 0.103 184 - 0.445 0.445 0-103 184 - 0.440 0.440 0.104 182 Calculated for C S H 2 0 6. Found (Mean). A = 0.106 A = 0.1052 M = 180.0 M = 180.2 These experiments with dextrose show very clearly the concordant nature of the results obtained by this method even when the solutions vary considerably in density.If dextrose had been a previously unknown substance whose relations and derivatives had not been studied and f o r which only * The correction here applied is the difference between the observed freezing point of the solution and the freezing point of water determined in the same apparatus and under exactly similar conditions THE MOLECULAR WEIGHTS OF THE CARBOHYDRATES. 615 the empirical formula CH,O had been determined by combustion, we should have had no hesitation in selecting from among the possible molecular weights 30 60,90 120 150 180 210 &c. the one which corresponds most nearly with the observed value of M = 180, and with the formula CsHlZO6. Dextrose exhibits in a pre-eminent degree the phenomenon of birotation ; the action on polarised light of a freshly-prepared solution of crystallised dextrose being double that of the same solution after standing for some hours.The phenomenon of birotation has never received any physical explanation and as it seemed to us possible that it might be in some way intimately connected with the size or" the molecule in solution we submitted t o Raoult's method freshly prepared solutions in which the amount of birotary carbohydrate was concurrently estimated by the polariscope. Freezing point of water used + 0.025". Strength of solution 10.013 grams dextrose in 93.85 grams water. x. C. A. M. -1.115" 1.1 40" 0.106 180 [ a ] j at time of experiment 105.6" = 72.6 per cent. birotary dextrose. E. C. A. M. -1.115" 1.140" 0.106 180 [ a ] j at time of second experiment 97.2" = 58.6 per cent.birotary .dextrose. Calculated for C6H1206* Found. A = 0.106 A = 0.106 M = 180.0 M = 180.0 It is clear from the above that whatever may be the cause of birotation it is certainly not to be attributed to a condensation of the molecule. Cane-sugar. ClzHz2011. 31 = 342. Freezing point of water used O*OOO. Strength of solution 13.052 grams in 91.98 grams water. E. C. A. M. - 0.825" 0.825" 0.059 322 -0.835 0.835 0.058 328 - 0.835 0.835 0-058 32 616 BROWN AND MORRIS THE DETERMlNhTION OF Strength of solution 10.1410 grams sugar in 93.77 grams water. E. C. A. M. - 0*600" 0.600" 0.055 345 - 0.600 0.600 0.055 345 - 0.600 0.600 0.055 345 Strength of solution 8.2580 grams sugar in 94.93 grams water.E. C. A. M. -0.500" 0.500" 0.05 7 333 - 0.490 0.490 0.056 340 - 0.490 0.490 0.056 340 Strength of solution 6.064 grams sugar in 96.28 grams water. E. C. A. M. -0.355" 0.355" 0.056 340 -0.355 0.355 0.056 340 -0.350 0-350 0.055 345 Calculated for C12H22011- Found. A = 0.0555 A = 0.0562 M = 342.0 M = 337.5 The lowest possible empirical formula C12H22011 evidently repre-sents the molecule of cane-sugar in solution and our results con-sequently do not bear out a suggestion which Winter appears to make in his recent paper on levulose (AnnuZen 244 1888 308) that the molecule of cane-sugar is more complex than this. Ihv er t e d Cane- sugar. Since the molecular weight of cane-sugar is 342 and that of dextrose 180 it seemed almost certain that Raoult's method applied to invert-sugar would yield a value for M of 180 and that the value of A would consequently be approximately doubled during the process of inversion.The experiment was made by determining the depression of the freezing point of the same soZutiorc of cane-sugar both before and after inversion which was brought about by the addition of a little invertase.* f Invert,ase is readily prepared by triturating fresh solid yeast with fine sand, digesting the pasty mass with water a t the ordinary temperature for a few hours, filtering and precipitating the filtrate with alcohol of about 80 per cent. The pre-cipitate is well washed with alcohol dehydrated with absolute alcohol and dried over sulphuric acid in a vacuum. As thus prepared invertnse is a white friable substance completely soluble ;n water and readily inverting several hundred times its own weight of cane-sugar THE MOLECULAR WEIGHTS OF THE CARBOHYDRATES.617 The results were as follows :-Cane-sugar Xolution before Inversion. Freezing point of water +0.025". Strength oE solution 4.9818 grams sugar in 96.94 grams water, E. C. A. M. - 0.27O" 0.295" 0.058 328 -0.270 0.295 0.058 328 - 0.2 75 0.300 0.058 328 Calculated for C,zHz,O 1' Found (mean). A = 0.0555 A = 0.058 M = 342.0 M = 328.0 The above solution was completely inverted with 0.030 gram of invertase the volume being maintained constant ; it gave After Inversiom. Freezing point of water +0.025". Strength of solution 5.344 grams sugars in 96.72 grams water.E. C. A. M. -0.585O 0*6?0" 0.110 173 -0,580 0.605 0.109 175 - 0.580 0.605 0.109 1'75 Calculated for CBHlZOIS. Found (mean). A = 0,106 A = 0.1093 M = 180.0 M = 174.3 This experiment may be taken as a proof that the value of M f o r levulose like that for dextrose is 180. MaZtose. C12H2,011. M = 342. That this is a saccharose having the same elementary percentage composition as cane-sugar there can be but little doubt but whether these two compounds are mebameric or polymeric is still open to question. The metallic derivatives and acelyl compounds oE maltose tend t o show that the simplesb possible foiamula C12H22011 also expresses its molecular composition but Herzfeld has recently questioned this (Annalen 220 1883 220) and is inclined from hi 61s BROWN AND XORRIS THE DETERXINATION O F experiments on the behaviour of maltose towards Fehling's solution, to assign to it a molecular formula a t least three times as large.To put this matter to the test of direct experiment the following deter-minations were made by Raoult's method :-Freezing point of water +0.030. Strength of solution 15.785 grams maltose in 90.40 grams water. E. C. A. M. - 1.010" 1.040" 0-059 322 - 1.000 1.030 0.059 322 - 1.005 1.035 0.059 322 Strength of solution 10.499 grams maltose in 93.68 grams water. E. C. A. M. - 0.635" 0.665" 0.059 322 - O.635 0.665 0.059 322 -0.635 0.665 0.059 322 Strength of solution 5.124 grams maltose in 96.89 grams water. E. C. A. M. -Q2S5" 0.315" 0.059 322 - 0.28.3 0.315 0.059 32.2 -0.285 0.315 0.059 322 Calculated for C12H,,Oll* Found (mean).A = 0.0555 A = 0.059 111 = 342.0 M = 322.0 These experiments prove beyond doubt that the molecules of cane-sugar and maltose when in solution are of equal size and that these substances are therefore metameric not polymeric. We must con-sequently attribute the difference in their properties to the different arrangement of atoms in the molecule. Milk-sugar C,2H,,0,,. M = 342. Freezing point of water + 0.030". Strength of solution 10.263 grams in 93.59 grams water. E. C. A. M. - 0.580" 0-610" 0.055 345 -0,585 0.615 0.055 345 - 0.585 0.615 0.035 345 Calculated for C,,HZ,Oll. Found. A = 0.0555 A = 0.055 14 = 342.0 X = 345. THE MOLECULAR WEIGHTS O F THE CARBOHYDRATES. 619 These results indicate that the usually accepted formula for milk-sugar expresses its molecular composition and that the suggestion made by Herzfeld (AnnuZen 220,1883,222) that the true formula is a multiple of C12H22011 is not correct but that the three sugars of the saccharose group cane-sugar maltose and milk-sugar have the same molecular weight.Arabinose C,H,,05. M = 150. This sugar a product of the action of dilute acid on gum-arabic, was formerly considered t o have the formula c,H:,,06. Receat researches of Kiliani ( B e r . 20 1887 343 and 2710) have however, established the fact that it is a compound with only 5 atoms of carbon, and that it is represented by the formula C5Hlo05. We have submitted this substance t o Raoult's method with the following results having first convinced ourselves of its purity by a determination of its optical activity :-Freezing point of water +0*030".Strength of solution 4.1355 grams in 97.45 grams water. E. C. A. M. -0.510" 0.540" 0.127 149% -0.505 0.535 0.126 150-7 - 0.505 0.535 0.126 150.7 Calculated for C5H1005. Found (mean). A = 0.126 A = 0.1263 M = 150.0 M = 150.3 These results fully confirm Kiliani's conclusions. Raflnose. This sugar which occurs in the molasses of beet-sugar and in the seeds of various plants has been the subject of considerable investi-gation. It crystallises in well-defined needles or prisms and from analyses tlie formula C18H32016,5H20 or a multiple of this has been deduced preference being given to a molecule represented by double this formula.We are indebted to Dr. Griess for a specimen of pure crystalline raffinose as well as that of the pure arabinose mentioned above. The substance had an optical activity of [a]j 116.6' or [a]= 104.6, which agrees exactly with the numbers given by Tollens for hydrated raffinose. Preezing point of water + 0.030" (5.30 THE MOLECULAR WEIGHTS O F THE CAABORYDRATES. Strength of solution 8,2225 grams hydrated substance in 94.51 grams water. E. C. A. M. - 0.280" 0.310" 0.0356 533 - 0.880 0.310 0.0356 533 - 0.290 0.320 0.0367 518 Calculated for C,,H320,6,5H,O. Found (mean). A = 0,032 A = 0.036 M = 594.0 M = 528.0 Our results indicate that the molecule of raffinose approximates to the above formula and that it is not a multiple of this. Manizitol C6HBla06.M = 182. Although this substance is not strictly included in the ordinarily accepted definition of a carbohydrate yet its relations to the group are of so intimate a nature and the size and constitution of its mole-cule have been so accurately determined by its i*eactions that we have considered it well as a further proof of the accuracy of Raoult's method when applied to compounds of this class to include the results of its examination. Freezing point of water + 0*030". Strength of solution 7.5382 grams in 95.09 grams water. E. C. A. M. - 0.8O5" 0.835" 0.105 181 -0*803 0-835 0.105 181 - 0.805 0.835 0.105 181 Calculated for C6H1406. Found. A = 0.104 A = 0-105 M = 182.0 M = 181.0 The application of this new method to starch and t o the non-crystallisable products of its transformation soluble starch the dextrins and malto-dextrin seemed full of promise since chemists are still divided in their opinions as t o the true nature of these compounds, and as to whether the differences in the properties of the dextrins are such as to justify the view that they are polymeric or on the other hand compounds ha,ving the same molecular weight but differing in constitution RAMSAY NITROGEN TRIOXIDE AND NITRIC PEROXIDE. 621 Certain difficulties have however arisen at this stage of our inquiry owing to the very high molecular weight which these sub-stances evidently possess. As a result of this the freezing point of even very strong solutions is depressed t o such a small extent as to render it necessary before we can assign any approximately accurate numerical value to our resultr to determine the limits of error of the method which manifestly increase with the molecular weight of the substance. We have however convinced ourselves that the mole-cular complexity of these compounds is very great indeed and me hope to lay certain results before. the Society at an early date

ISSN:0368-1645    

DOI:10.1039/CT8885300610

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

RAMSAY NITROGEN TRIOXIDE AND NITRIC PEROXIDE. 621 XLV I.-The Molecular Weights of Nitrogen Tyioxide and Nitric Peroxide. By W. RAMSAY Ph.D. IT was shown by Dr. Sydney Young and myself in a paper read before the Physical Society (Proc. Phys. 806. Lond. 1887 9 45) that the Messrs. Natanson’s experiments on the relations be tween the pressure, temperature and volume of nitric peroxide interpreted by the light of the equation p = bt - a (see previous communications t o the Physical Society) lead to the probable conclusion that at low temperatures the formula of the peroxide is N204 and that no more complex molecular groupings are formed than those corresponding to 2N0,. But owing to experimental difficulties it appears to be impossible to prove this statement with absolute certainty from experiments on the density of the substance in the gaseous state.A means of determining the molecular weight of liquid and solid substances has however recently bem placed at the disposal of chemists by the brilliant researches of M. Raoult. In a series of memoirs published in the Annales de C h i d e et de Physique [ 5 ] 20, 217; 28 133 ; [6] 2 66 93 99,115; 4,401 ; 8 289 317) he has proved that the depression of the freezing point of a liquid caused by the presence of dissolved liquid or solid is proportional to the absolute amount of substance dissolved and inversely proportional t o its molecular weight. This law holds for the great majority of substances with which he has experimented and the exceptions are so few in number and so striking as t o call for further research to explain their anomalous behaviour.With glacial acetic acid as solvent however among nearly 150 substances with which he experimented there are barely half-a-dozen whose behaviour proved abnormal ti22 RAMSAY THE MOLECULAR WEIGHTS OF This method makeg it possible t o determine the molecular weight of liquid nitric peroxide; and it also throws light on the question whether nitric peroxide undergoes f nrther dissociation at low tempera-tures by dilution which may be regarded as equivalent to reduction of pressure if the liquid and gaseous states be compared with one another. Experiments (an account of which follows) tend to show that not merely is the formula of nitric peroxide N,Oa a t teniperatures in the neighbourhood of 16" but also that no appreciable alteration in molecular weight is produced by considerably increasing the relat,ive number of molecules of the peroxide in a given volume.The accompanying diagram shows a convenient form of the appa-ratus required for such experiments. A wide test-tube is closed by an india-rubber cork A perforated with two holes. Through one of these a piece of wide glass tubing B passes in which a stirrer CC moves freely up and down. The thermometer D serves to show the temperature of the liquid while by surrounding the tube by a beaker E with hot or cold water as required the temperature may be raised a few degrees above or depressed a few degrees below the Ereezing point of the solvent NITROGEN TRIOXIDE AND MTRIC PEROXIDE. 623 A quantity of acetic acid fractionated from water amounting to 41.02 grams was weighed out.A small bulb containing 0.378 gram of nitric peroxide was added and broken in the acetic acid by crushing it with the stirrer. The melting point of the acid was lowered by t,his addition to 16.300". The depression is therefore 0*380°. Had one part of peroxide been added to 100 parts of acetic acid the depression would have been according to this measurement 0.4214". And 0.4214 x 94.6 = 39 (Raoult's constant for acetic acid) ; hence the molecular weight of the peroxide appears from this experiment to be 94.6. Without disturbing the apparatus, a second bulb of peroxide weighing 0.5085 gram was crushed in the acid and the melting point was now 15.825" ; the total depression amounting t o 0.855".Calculating as before the depression for 1 gram per 100 is 0.3956 and the molecular weightt 98.58. Subsequent additions were made as follows :-It melted a t 16.680". 1.5405 gram lowered the melting point 1.590" ; mol. wt. = 92-11. 2.2080 2.280 7 7 = 92-07. 3.679 3.865 ,) = 90.29. 7 7 7 7 7 7 3.1510 7 7 7 7 3.215 ,) = 93.18. 7 7 7 9 ) A second determination gave the following result :-Acetic acid taken 40.05 grams melting at 16.675" ; the addition of 0.893 gram of the peroxide lowered the melting point to 15.768"; depression = 0.907". Depression produced by 1 gram per 100 would therefore amount to 0.4068" ; and the molecular weight is therefore 95.87. It must therefore be concluded that the molecular weight of nitric peroxide in the liquid state at about 16" is 92 and its formula conse-quently is N,04. It is also manifest that the relative number of molecules of the peroxide in a given volume of acetic acid may be decreased from 8.97 t o 0.92 without materially altering the molecular weight; no dissociation therefore would appear to take place on dilution. Similar experiments were tried with nitrogen trioxide prepared by dissolving N204 in acetic acid and passing NO through the cooled mixture ; but they gave no reliable results owing to the dissociation of the trioxide whichis rapid a t 16"

ISSN:0368-1645    

DOI:10.1039/CT8885300621

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

624 XLVII.-The Action of Heat on the Halts of Tetramethylammoniurn. By A. T. LAWSON and NORMAN COLLIE PhD. F.R.S.E. THE following experiments on the action of heat on the tetramethyl-ammonium salts were undertaken in order t o ascertain in what respects the compound ammonium salts when subjected to the action of heat resembled and also in what points they differed from the corresponding phosphorus and sulphur salts. The action of heat on a considerable number of the trimethyl-sulphine salts (chiefly the salts of sulphur acids) has been investi-gated by Crum-Brown and Blaikie (J. pr. Chern. [a] 23 395); whilst the action of heat on the tetramethylphosphonium salts is the subject of a separate paper by one of us (p. 636) but the decomposition that the tetramethylammonium salts suffer when heated has only been studied in a very few cases.Hofmann (Ber. 14 494) has noticed that the hydroxide is easily decomposed by heat-(CH,)aN*OH = (CH,),N + CH,*OH, whilst Thompson (Bey. 16,2339) has found that the cyanide volatilises unchanged. The salts that tetramethylammonium hydroxides form with the more common acids have not received much attention since Hofmann discovered these interesting compounds nearly 40 years ago. Duvillier and Buisine (Ann. Clzi9n. Phys. [ S ] 23 331) have shown that methyl nitrate and also methyl bromide when heated with metbylamine or with dime thylamine yield te trame t h ylammonium Compounds but they did not prepare many of the salts Hofmann mentions that crystalline salts can be prepared by neutralising the base with sulphuric oxalic or nitric acids and he also prepared the chloride but he gives no details as t o the solubility crystalline form, or other properties of these compounds.The bromide and cyanide have been prepared by other workers and also a number of double salts ; but the chief work on the tetramethylammonium compounds Seems to have been directed towards the preparation of a number of addition products obtained by the action of chlorine bromine or iodine on the halogen salts (Waltzien Annahz 99 1 ; Stahlschmidt, Jahresber. 1863 403 ; Dobbin J. Chem. Soc. Trans. 1886 846). The starting point from which we prepared all our saltis was the iodide of tetramethylammonium. It was made according t o the method suggested by Hofmann. Methyl alcohol saturated with ammonia gas was digested with methjl iodide in sealed tubes at a temperature of 1.00-120".It was found better to put the methy ACTION OF HEAT ON SALTS OF TETRAMETHYLAMXONIUM. 625 iodide in a separate tube (open at one end) and not to mix it with the ammoniacal methyl alcohol till after the tube which contained both had been sealed. The yield varied considerably in different tubes several tubes after heating for only a few hours being filled with crystals while the yield in other tubes even on prolonged heat-ing a t a temperature of 140" did not seem to be materially increased. We believe this was due possibly to the presence of small quantities of water in the methyl alcohol. The iodide of tetramethylammonium can be easily separated from the iodide of ammonium and from the hydriodides of mono- di- and tri-methylamine by crystallisation from water in which it is not very soluble.The mean of several analyses of the salt gave 63.1 per cent. of iodine the theoretical amount required by (CH,),NI being 63-2 per cent. iodine. When this salt is heated i t decomposes a t a temperature not much fihort of a low red heat without melting giving trimethylamine free iodine and other products. It probably first splits up into trimethyl-amine and iodide of methyl-and at the high temperature both the trimethylamine and the iodide of methyl are partially decomposed (the latter almost completely), (CH,),NI = (CH3)SN + CHJ, Action of Heat on Bromide of Tetramethylanzmonium. This salt was prepared by neutralising hydroxide of tetra-methylammonium with hydrobromic acid and evaporating the solution over the water-bath.On allowing the salt to remain over sulphuric acid in a vacuum it soon crystallised. An analysis of the salt gave tha following results 0.430 salt took 27.7 C.C. decinormal AgN03 solution = 51.5 per cent. bromine ; theory for (CH,),NBr = 51.9 per cent. bromine. It forms needle-shaped crystals which are deliquescent and their solubility in water is considerably greater than %hat of the iodide; 100 C.C. of water a t 15" dissolve 55.26 grams of the salt. The salt on heating to 300" in a vacuum gave off no gas b u t on raising the temperature above 360" the salt sublimed and condensed again on the walls of the tube (which was used as a condenser and was surrounded by a f'reezing mixture) in the form of a white powder.This solid was analysed and from a bromine determination proved to be pure bromide of tetramethylammonium. (It contained 51.6 per cent. bromine.) At the end of the experiment the whole of the salt had sublimed and scarcely a trace of permanent gas had been evolved. (CH3)JY"r = (CH,),N + CH,Br, Evidently the bromide on beating dissociates-and the two gases a t once recombine on cooling. VOL. LlII. 2 626 LAWSON AND COLLIE THE ACTION OF HEAT Action of Heat on Chloride of Tetramethylarnmonium. The chloride was prepared by treating the iodide with hydroxide of silver and neutralising the base thus obtained with hydrochloric acid. The solution was evaporated over the water-bath to the consistency of a syrup and allowed to stand in a vacuum over sulphuric acid when it soon crystaIlised.Attempts made to determine its solubility in water were unsuccessful on account of its great solubility ; it is also deliquescent. The salt was heated in a vacuum a t 150" till perfectly dry when a chlorine determination gave 32.4 per cent. of chlorine : (CH,),NCl contains 32.4 per cent. C1. When the salt is heated to above 360° it decomposes completely without the slightest charring yielding trimethylamine and a gas which burnt with a greenish flame and behaved in every way like chloride of methyl. I n one experiment 3.52 grams of salt yielded 750 C.C. of gas. The theoretical yield of methyl chloride would be about 800 C.C. The trimethylamine was converted into the chloropbtinate and gave the following numbers on analysis.Theory 0.144 gram salt gave 0.0527 gram Pt = 36.60 per cent. Pt. The gas was also analysed :-for (Me,HNC1),PtC14 = 36.93 per cent. Pt. Gas taken 8.0 C.C. Gas arid oxygen . 31.0 ,, After explosion and the addition of a few drops of water 19.8 ,, After addition of caustic soda. . 12.0 ,, This shows that one volume of the gas on explosion with excess of oxygen yields nearly its own volume of carbon dioxide which is the amount required by methyl chloride. The decomposition of the chloride is nearly quantitative and can be expressed by the following equation :-(CHS)4NC1 = (CH3)SN + CH3C1. Action of Heat on Fluoride of Tetramethy kammortium. After the extremely neat manner in which the chloride decom-posed when heated we had every reason to expect that the fluoride would decompose in an analogous manner yielding trimethylamine and methyl fluoride and the decomposition besides being of interest in illustrating the general method of decomposition of the tetra-methylammonium salts would also be useful in the preparation of organic fluorine compounds ON THE SALTS OF TETRA4METHYLAMMONIUM.627 Although fluorine itself has recently been isolated still on account of the great difficulty of uniting fluorine with carbon the number of organic compounds where fluorine is combined with hydrocarbon radicles of the paraffin series is small and their properties have not been much studied. The salt was prepared in a manner similar to that employed in the manufacture of the chloride The base was neutralised with hydro-fluoric acid and evaporated over the water-bath to a syrup.This solidified on cooling to a solid mass of radiating crystals. They were, however by no means dry for on heating at 100" in a vacuum a considerable amount of water was lost. Great difficulty was experienced in drying the-salt completely and it could only be accomplished by prolonged heating in a vacuum at 160". A deter-mination was made of the amount of water contained in the salt which had been dried over sulphuric acid. 0.900 gram salt heated at 160" in a vacuum lost 0.150 gram H20 = 16.6 per cent. H,O. Theory for Me4 N F H,O . Found. B,O . . . . 16.2 per cent. 16.6 per cent. The tube in which the salt was heated waq not etched showing Some of the dried salt that no hydrofluoric acid had been liberated.was analysed :-I. 0-500 gram salt gave 0.19'75 gra,m CaF2 = 19.2 per cent. 11. 0.2727 gram salt gave 0.1186 gram CaF = 21.1 per cent. fluorine. fluorine. Found. Calculated for rA-7 Me,NF. I. 11. 3'. . . . . . . . 20.4 per cent. 19.2 21.1 per cent. The great difference in the percentage of fluorine found is pos-sibly due to the great difficulty in obtaining the salt pure and dry at the aame time for if the salt be heated even as high as 160" in a vacuum it is not perfectly anhydrous and if the temperature be raised above that point it begins to slowly decompose. When the salt is heated to 180" in a vacuum it be,gins to decom-pose and yields trimethylamine and a gaseous substance. During the first experiments made on the action of heat on this salt the tri-methylamine was condensed by passing the products of the decompo-sition through a U-tube surrounded by a freezing mixture.Sub-sequently it was found better to absorb the trimethylarnine by p=rmice-2 u 628 LAWSON AND COLLIE THE ACTION OF HEAT stone moistened with sulphuric acid (which absorbed only the tri-methylamine). The trirnethylamine obtained was converted into the chloroplatinate and analysed (0.362 gram salt gave 0.132 gram P t = 36.6 per cent. ; theory for (Me3€€NC1),PtCI = 36.9 per cent. The amount of tetramethylammonium fluoride which was decom-posed was also noticed as well as the amount of gas evolved. 2.614 grams of the fluoride gave 400 C.C. of gas which proved to be fluoride of methyl.This gas was first prepared by Dumas and Peligot (Anmaleiz 15 59) by heating together potassium fluoride and potassium methyl sulphate. The gas prepared by heating the fluoride of tetramethylammonium was slightly soluble in water but more so in alcohol ; it burnt with a blue flame yielding hydrofluoric acid and it had a pleasant odour. On analysis it yielded its own volume of carbon dioxide :-Pt). Taken of gas After explosion. . 39.0 ,, After addition of caustic soda. 31.0 ,, 8.0 C.C. Gas and oxygen 51.0 ,, thus showing that 8.0 C.C. of gas yielded 8.0 C.C. of carbon dioxide. The fluoride of tetramethylammonium therefore decomposes in a manner similar t o the chloride :-Action of Heat on Nitrate of Tetramethylammonium. The salt was prepared by the action of silver nitrate on the iodide.Evaporated over the wate~bath to a small bulk the solution crystal-lises in long needles ; when pure it does not seem t o be perceptibly deliquescent. Several grams of the salt were heated. No decompo-sition occurred till the temperature had risen t o above 300". Slight blackening then took place but it was found that if the temperature was kept just at the melting point of the salt nearly the whole of it decomposed without much charring. A yellow liquid was found in the condensing apparatus and a small quantity of gas was produced, consisting chiefly of nitric oxide but on treatment with oxygen and water there remained a small amount, which from its properties seemed t o be methyl nitrate ; the quantity however was too small for identification.The yellow distillate was alkaline and smelt strongly of trimethylamine it was therefore warmed with water in order t o free it from the base and then treated with a small quantity of pure caustic soda j on warming a further quantity of trimethylamin ON THE SALTS OF TETRAMETHYLAMMONIURI. 629 was evolved which gave the characteristic chloroplatinate. The remaining caustic soda solution was treated with carbon dioxide and evaporated to dryness it was then extracted with absolute alcohol and the alcoholic solution of the sodium salt evaporated to dryness. Thiis treated a smd1 quantity of a soluble sodium salt was obtained. An attempt to prepare the silver salt wa,s unsuccessful owing to the reduction of the salt to metallic silver ; with mercurous salts a similar reduction took place and the sodium salt itself gave carbon mon-oxide when heated with strong sulphuric acid ; the salt in questtion was, therefore probably sodium formate.From this it will be seen that the decomposition of the nitrate is complex trimethylamine alone being formed in any quantity. I f methyl nitrate is also formed it is decomposed yielding as oxidation prodncts formic acid &c. and as reduction products methyl nitrite and nitric oxide. Action of Heat on Nitrite of Tetmmethylamrnonium. This salt was prepared by treating a solution of iodide of tetra-methylammonium with nitrite of silver. It is deliquescent and much more soluble in water than the nitrate When subjected to the action of heat it decomposed at a temperature above 300" with great rapidity ; trimethylamine was produced and at the same time a small quantity of an orange-coloured oxide of nitrogen mixed with a considerable amount of some other gas was given off.On treat-ment with caustic soda there was little diminution in volume but on adding oxygen the orange peroxide of nitrogen was produced which dissolved in the caustic soda solution. About half of the gas collected consisted of nitric oxide and the remainder was inflam-mable. This residual gas was mixed with an equal volume of oxygen (under the supposition that it was methyl nitrite) and exploded in a eudiometer. The result was unexpected for the two volumes oi mixed gases became nearly five volumes and the remaining gas was inflammable ; evidently the oxygen used was not nearly sufficient for its combustion and another experiment was therefore made with the following quantities :-Gas used .5.0 C.C. Gas and oxygen 37.0 ,, After explosion. . 24.0 , After treatment with caustic soda . 14.4 ,, Thus 5.0 C.C. of the gas yielded 9.6 C.C. of carbon dioxide or nearly twice the volume and the remaining gas in the eudiometer was nearly pure oxygen. This proved that the gas under examinatio 630 LARSON AND COLLIE THE ACTION OF HEAT did not contain nitrogen and also that two atoms of carbon were present in the molecule; in all probability the substance was methyl ether. For when mixed with its own volume of oxygen and exploded two volumes would give five volumes of mixed and inflam-mable gases :-CZHeO + 0 2 = co + co + 3H, Lpv-2 L-,___J whilst if it were exploded with excess of oxygen it should yield twice its volume of carbon dioxide :-2C2H60 + 602 = 4c02 + 6H20.Evidently then when the nitrite is heated it is decomposed into trimethylamine and nitrite of methyl the latter being further decom-posed into methyl alcohol iiitric oxide and oxygen :-2 vols. 5 vols. (CH,),N.NOZ = (CH3)3N + CHJTOZ. 4CH3N02 = 2(CH,),O + 4NO + 0 2 . The nitric oxide and oxygen on cooling combined forming some of the higher oxides of nitrogen which probably united with the tri-met h ylamine. Action of Heat on Acetate of Tetramethylamrnonii~m. The hydroxide of te tramethylammonium was neutralised with acet8ic acid in order to produce this salt ; the sclution was evaporated, and solidified to a mass of aeedle-shaped crystals when allowed to stand in a vacuum over sulphuric acid.The salt was highly deli-quescent. When heated it melted a t about 70° and a small quantity of water distilled ; a t 190-200" complete decomposition took place. The condenser which was surrounded by a freezing mixture con-tained a liquid which on the addition of water separated into two layers one of' which proved to be an aqueous solution of trimethyl-amine whilst the other was acetate of methyl. This was proved beyond doubt by the boiling point 57-58' (methyl acetate b. p. 56") and by its conversion into methyl alcohol and sodium acetate On treatment with caustic soda. The sodium acetate was converted illto the corresponding silver salt and then analysed.0.5395 gram salt gave 0.348 Ag = 64.5 per cent. ; theory f o r AgC2H3O2 = 64.6 per cent. Ag. Some of the liquid b. p. 57*8" was shaken with a con-centrated solution of acid sulphite of sodium but no crystalline double salt was formed. The decomposition of the acetate is there-fore quite simple :-(CH,),N*C2H302 = (CH3)sN + CH3.C2H302 ON THE SALTS OF TETRAMETHYLAMMONIUM. 631 Action of Heat on Benzoate of Tetramethylammonium. This salt was prepared in the same way as the acetate. It is a deliquescent salt but could be obtained in the form of long needles by allowing the salt to remain over sulphuric acid in a vacuum. When it was heated it melted a t 220-230" and at once decom-posed. There was no charring and the whole of the salt distilled by the time the temperature had risen to 250'.No gas was produced by the action of heat. The distillate was completely liquid and sepa-rated into two layers when water was added the one an aqueous solution of trimethylamine the other a liquid which when dried over calcium chloride and distilled boiled at 198" (methyl benzoate, b. p. 199"). It did not contain nitrogen and in order to be szre that it was methyl benzoate it was boiled with caustic soda. The distillate contained methyl alcohol and from the residue contailiing the sodium benzoate the silver salt was prepared. 0.230 gram salt gave 0.110 gram Ag = 4'7.1 per cent. Ag; theory for AgC,H50 = 47.1 per cent. Ag. An analysis was also made of the chloroplatinate of trimethylamine. 36.5 per cent. Pt was found while the theory for (Me3HNC1)2PtC14 = 36.7 per cent.Pt. The benzoate decomposes in exactly similar manner to the acetate :-Action of Heat on Xulphate of Tetrarnethylammoniu?n. This salt was obtained by neutralising the base with sulphuric acid. It is crystalline and very deliquescent and before the last traces of water could be removed it had to be heated t o about 160" in a vacuum. An analysis of some of the salt thus dried gave the following num-bers :-0.4342 grsm salt gave BaS04 0.417 gram = 39.57 per cent. SO,. Theory for (Me4N)2S04 . . . . . . . . . . . . . . = 39.34 ,) 7 7 The remainder of the salt was carefully heated (5.72 grams). It melted at 280" and at once began to decompose. The temperature was kept its near as possible to 290° till all effervescence had ceased and the loss that the 5.72 grams had suffered was 1.42 grams.The whole of this was found to be due to the trimethylamine no other sub-stance passing over into the condenser. The salt on cooling solidified t o a mass of deliquescent crystals which were broken up and analped. They were found to contain sulphur but their solution in water was not precipitated by a barium salt. The sulphur therefore had to be determined by it combustion of the substance (which Dr. Plimpto 632 LAWSON AND COLLIE THE ACTION OF HEAT kindly undertook using his new method f o r analysing such com-pounds). 0.196 gram salt gave 0.2517 gram BaS04 = 1'7.63 per cent. S. A determination of carbon and hydrogen was also made. 0.497 gram salt gave 0.590 GOz and 0.3765 HzO = 32.38 per cent.C and 8.41 per cent. H. Found. Calculated for -1 (CHd4N. (CHdSO4. I. 11. C . . 32.47 - 32.38 H . 8.11 - 8.41 S . . 17.29 17.63 N - '7.56 0 34-60 -- -The first decomposition which the sulphate of tetramethylam-monium suffers is the loss of trimethylamine whereby it is converted into the methyl sulphate of tetramethylammonium. (Me4N)2S04 = (Me4)N*MeSOd + Me,N. The 5-72 grams which were used should lose on heating 1.38 grams of trimethylamine and the amount found was 1.42 gram. The further action of heat on the methyl sulphate of tetramethylammonium was complex ; under these circumstances part of the salt passed over into the condenser unchanged while compounds possessing a very strong smell recalling that of sulphide of methyl were formed.There was also produced in small quantities a highly crystalline substance which resembled dimethylsulphone and much charred matter remained behind in the distilling flask. Action of Heat on Oxalate of Tetramethylramm,onizLm. Two methods were employed for the preparation of this salt-one by the action of oxalic acid on the base the other by the action of silver oxalate on the iodide. A deliquescent salt was obtained by both methods and was most difficult to obtain anhydrous. When allowed to remain in avacuum civer sulphuric acid a crust formed on the surface of the salt while the underlayer remained in a liquid state for weeks. The only method which gave at all a. dry product was heating the salt in a vacuum at 160". An analysis of some of the dry salt was made.0.590 gram salt gave 0.1355 CaO = 36.35 per cent. ($04. Theory for (Me4N),Cz04 = 37.28 9 2 The rest of the salt was subjected to the action of heat. Scarcely any decomposition occurred below 360" whilst above that temperatur ON THE SALTS OF TETRAMETHYLAMMONIUM. 633 the salt seemed to slowly sublime without melting ; decomposition occurred at the same time for trimethylamine and a gas were evolved. When the salt was more strongly heated however the evolution of gas became more rapid. The gas seemed to be composed of carbon dioxide mixed with nearly its own volume of carbon monoxide; a small quantity of an inflammable gas was also present. I n two experi-ments made with weighed quantities of the oxalate the following amounts of gas were obtained :-I.2.5 grams salt gave 500 C.C. of gas composed of 225 C.C. of carbon dioxide 225 C.C. of carbon monoxide and 50 C.C. of in-flanimable gas. 11. 2.4 grams salt gave 450 C.C. gas composed of 205 C.C. carbon dioxide and 205 C.C. of carbon monoxide and 40 C.C. of inflam-mable gas. As far as could be ascertained no methyl oxalate was formed ; this was obviously due t o the extremely high temperature a t which the oxalate decomposed. Trimethylamine was formed in considerable quantity and was converted in to the chloroplatinate aiid analysed. The decomposition of this salt is therefore not a simple one owing to the high temperature at which i t occurs. Probably methyl oxalate and trimethylamine are first formed and the former a t once decom-poses into carbon dioxide carbon monoxide and other substances, perhaps methyl ether.(Me4N),C,04 = 2Me3N + Me2C204, Me2C204 = Me,O + CO + GOz. The amount of carbon dioxide and carbon monoxide evolved by the 2.4 grams and 2.5 grams respectively agrees fairly well with the amount required by theory ; 2.4 grams should yield about 230 c.c., whilst 2.5 grams should yield about 245 C.C. of mixed gases. Action of Heat on the Acid Carbonate of Tetramethy lammonium. A solution of the base saturated with carbon dioxide was evapo-rated first over the water-bath and finally over sulphuric acid in a vacuum. The salt was crystalline but highly deliquescent and could only be obtained anhydrous by prolonged heating in a vacuum. When subjected to the action of heat it began to decompose a t 180" with effervescence but more rapidly a t a temperature of 210-2220".Tri-methylamine methyl alcohol and carbon dioxide were the only sub-stances produced. This decomposition, (CH,)JT*HCO = (CH3)3N + CH,*OH + COZ 634 LAWSON AND COLLIE THE ACTION OF HEAT seemed to be nearly quantitative 3 grams of the salt yielded 280 C.C. of carbon dioxide the theoretical yield according to the above equation being about 500 C.C. Attempts were made t o prepare the normal carbonate by dividing a solution of the base into two equal parts saturating one with carbon dioxide and then adding the other half to it. On evaporating and leaving the salt for two months in a, desiccator a white friable crystalline deliquescent salt was obtained. This salt when heated gave exactly the same resiilts as the acid carbonate and was probably a mixture of the acid carbonate with hydroxide of tetramethylammonium.Not a trace of carbonate of ethyl was produced. Possibly therefore the normal carbonate does not exist. A few other salts were examined the hydrosulphide the acid sulphite and the phosphate. The hydrosulphide is a very deliquescent salt and when heated to about 200" easily decomposes into trimethyl-amine and methyl mercaptan. The acid sulphite crystallises fairly easily from concentrated solutions and is not very deliquescent ; on heating this salt it melted at 180" and gave off some water of crys-tallisation leaving a white salt behind ; this did not melt or decom-pose till the temperature had risen above 300° it then split up in a complicated manner yielding trimethylamine methyl alcohol sulphur dioxide and small quantities of a volatile crystalline substance with a high boiling point but it was not obtained in amount sufficient for purification.The phosphate of tretramethylammonium is also a deliquescent salt. It was prepared by shaking a solution of the iodide with phosphate of silver ; the solution thns obtained was strongly alkaline. With am-monium nitromolybdate it gave a ligh t-yellow precipitate which con-tained tetramethylammonium phosphate and molybdic acid. When the phosphate was heated at a very high temperature it decomposed, giving trimethylamine and methyl alcohol which distilled while meta-phosphoric acid remained in the flask. Traces also of sulphide of methyl were apparent.Conclusion. It appears therefore that the action of heat on the salts of tetra-met hylammonium is usually of a simple nature and trimethplamine is always produced. If the salt heated be one which decomposes at a low temperature trimethylamine and a salt of methyl are the only substances produced. This is seen in the case of the fluoride, iicetate &c., (CH3)iNF = (CH3)2N + CH3F ON THE SALTS OF TETRAMETHYLAMMONIUK 635 but if the salt decomposes only at a high temperature it is often the case that the salt of methyl (which is no doubt at first produced) is decomposed ; for instance the nitrite oxalate &c. (CH3),"0 = (CH3)3N + (CHs)N02, 4(CH3)N02 = 2(CH3)@ + 4N0 + 0,. One salt aloiie decomposed in an unexpected manner namely the normal sulphate but Crum-Brown and Blaikie (Zoc.cit.) have noticed that when the hyposulphite and sulphite of trimethylsulphine are heated a similar splitting up of the molecule takes place-(Me3S),S03 = (Me,S)MeS03 + Me2S, (Me4N),S04 = (Me4N)MeSO4 + Me3N. It will be seen that the salts experimented with may be divided into two groups firstly those which are easily acted on by heat and which decompose at a temperature of about 200"; secondly those which are more stable and are only decomposed at temperatures above 300". Those belonging to the first class are the hydroxide, carbonate acetate benzoate fluoride and hydrosulphide ; whilst those which belong to the second class are the iodide bromide, chloride oxalate nitrate &c. Another point of interest is the solubility iu water of the salts of tetramethylammonium which seems to be in many cases exactly the reverse of the solubility of the ammonium salts for the iodide of tetramethylammonium is the least soluble of the tetramethyl-ammonium compounds with the halogens the fluoride and chloride the most soluble.Amongst the other salts the oxalate and sulphate are highly deliquescent whilst the nitrate is scarcely even hygro-scopic. When tlhe action of heat on the tetramethylammonium salts is compared with the action of that agent on the corresponding phosphorus and sulphur compounds it is seen that the decomposition which they undergo is similar. This is shown in the case of the acetate-(CH,)4N*CzH30 = (CH3)3N + C'H3*C2H302, (CH3)3S*CzH,O = (CH,),S + CH3.CzH302, (CH,),P*C2H302 = (CHs),PO + (CH,),CO.The apparent difference in decomposition which the phosphorus salt suffers is at once explained when we remember the intense affinity of that element for oxygen. Phosphorus sulphur and nitrogen are a group of elements which show a regular gradation in their affinity for oxygen and electronegative elements. When once phosphorus i 636 COLLIE ACTION OF BEAT combined with oxygen it is usuitlly no easy matter to separate these two elements consequently we find the method of decomposi-tion of the tetramethylphosphonium salts containing oxygen differ-ing in this respect from the corresponding ammonium compounds. The decomposition of the tetramethylphosphonium and the tetra-methylammonium chlorides by heat also illustrates this difference-2(CH,),PCl = 2(CH,),PHCl + CzH4, (CH,),NCl = (CH,),N + CH,Cl. As sulphur does not possess such a strong attraction f o r oxygen a8 phosphorus yet still possessing more than nitrogen for that element, we find that the sulphine salts resemble both the compound ammonium and phosphoniurn salts in their behaviour when heated

ISSN:0368-1645    

DOI:10.1039/CT8885300624

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

636 COLLIE ACTION OF BEAT XLVIIL-Action of Heat on the Salts of Tetramethylphosphonium. By NORMAN COLLIE Ph.D. F.R.S.E. THE action of heat on the salts of tetramethylphosphonium was under-taken partly to complete a series of experiments which had been made on the general method of decomposition of phosphonium salts when heated (Phil. Mag. Ang. 1886 p. 183; ibid. June 1887 p. 27) and partly to compare their decomposition with that of the tetramethyl-ammonium salts when similarly treated. The iodide of tetramethylphosphonium was the starting point for the preparation of the other salts. It was prepared according to the method recommended by Hofmann (Ber. 4 208) ; phosphoniuni iodide being heated with purified wood-spirit in sealed tubes at 180". The iodide thus obtained was recrystallised from alcohol and ether.It gave no free phosphine when boiled with caustic soda and a determination of iodine was made (58.9 per cent. and 58.7 per cent. iodine ; theory for (CH,),NI = 58-21. The iodide when heated does not decompose easily but at a temperature above 300" complicated decomposition occurs free iodine and other products being formed. Hofmann has already tried the action of heat on the hydroxide ; he found that it split up into t'rimethylphosphine oxide and marsh-gas-On repeating his experiment the same result was obtained ; 7 grams of the iodide were converted into hydroxide and on heating this sub-(CH,),POH = (CH,)J?O + CHI ON THE SALTS OF TETRAMETHYLPHOSPHONIUM. 637 stance to a temperature of 115" complete decomposition occurred, 690 C.C.of gas were evolved and a crystalline substance (trimethyl-phosphine oxide) remained in the flask. The gas proved t o be pure methane (5.3 C.C. gave 5.2 C.C. of carbon dioxide) and the theoretical yield according to the above equation should be about 720 C.C. The trimethylphosphine oxide which remained in the flask was distilled. On redistillation it was obtained as a highly crystalline and deli-quescent substance ; boiling point (corr.) 214-215" ; melting point (corr.) 137-138". Hofmann gives no analysis or melting or boiling point of this substance. 0.310 gram gave 0.440 CO and 0.275 H,O = 38.71 per cent. C and 9.85 per cent. H. Theory for (CH,),PO = 39.1.3 per cent. C and 9.78 per cent. X. When mixed with chloride of platinum and hydrochloric acid a chloroplatinate was obtained which crystallised from concentrated solutions sometimes in magnificent orange plates at other times in needle-shaped crystals.I. 1.0945 gram heated at 90" lost 0.030 gram = 2.74 per cent. HZO. 11. 0.583 gram gave 0.1635 Pt = 28.04 per cent. Pf. 111. 0.748 gram gave 0.204 P t + 63.0 C.C. AgNO (decinormal) IV. 0.352 gram gave 0.196 PO2 t 0.141 H,O = 15.18 per cent. = 27.27 Pt + 29.90 C1. C + 4.45 per cent. HzO. Found. Theory for +-7 3Me3P0,2 H C1 Pt Cl, H,O. I. 11. C 15.34 15.18 H 4.45 - 4.40 Pt 27.89 27.27 28.04 C1 30-20 29.90 H,O 2.54 2-74! ---These results were unexpected for the oxide of triethylphosphine and tribenzylphosphine give with platinic chloride chloroplatinates containing 4(C2H5)3P0,H,PtCl and 4( C7H,),P0 HzPtC16.Action of Heat o n Chloride of Teti.amethylphos~honi.um. This salt was prepared by adding hydrochloric acid to a solution of the hydroxide till it was neutral. On evaporation a very deli-quescent crystalline salt was obtained which gave with chloride of platinum a n insoluble chloroplatinate crystallising in glittering yellow octahedra. 8 grams of the chloride were heated the salt did no 638 COLLIE ACTION OF HEAT melt till the temperature was above 300° and i t did not decompose till the bottom of the flask was hot enough to colour the Bunsen flame yellow. Eventually 800 C.C. of gas were collected and a solid crystalline subst,ance had distilled. The gas consisted almost entirely of ethylene ; an analysis of it was made when 8.5 C.C.gave 16.5 C.C. of carbon dioxide and the remainder was nearly all absorbed by bromine, giving a liquid b. p. 132.4 and which WAS therefore dibromethylene. The crystalline solid was soluble in water and had an acid reaction It contained chlorine and when treated with caustic soda trimethyl-phosphine was liberated as an oily liquid which rapidly volatilised on warming and caught 6re at the mouth of the tube. The chloride therefore decomposes as follows :-probably methylene is first produced during the decomposition of the chloride but at once polymerises and becomes ethylene. Action of Heat on Sulphate of Tetramethylphosphonium. The sulphate was prepared by the action of sulphate of silver on iodide of tetramethylphosphonium. The excess of sulphate of silver which had dissolved was precipitated by the careful addition of sul-phuretted hydrogen and the solution was then made neutral with a small quantity of the hydroxide.On evaporation a very deliques-cent salt was obtained which crystallised in thick needles. When mixed with a concentrated solution of aluminium sulphate and allowed t o stand no octahedral crystals could be obtained or any double salt which seemed at all like an alum. When heated the solid sulphate decomposed at a temperature above 300° only just melting and much charring occurred. The dis-tillate was crystalline and when treated with a little water did not entirely dissolve. The aqueous solution was separated from the crystals, and when redistilled gave pure oxide of trimethylphosphine b.p. 214.5" and m. p. 137.8". The crystals which had been separated from the trimethylphosphine oxide proved to be the sulphide of tri-methylphosphine. They melted at 105" and when boiled with water rapidly volatilised ; when warmed with a solution of a silver salt they gave a black metallic mirror of silver sulphide. Action of Heat on Benzoate of ~etramP,thyT23hosphonium. This was made by neutralising a solution of the base with benzoic This salt was also very soluble in water and when obtained in acid ON THE SALTS OF TETRAMETHYLPHOSPHONIUM. 639 the crystaJline condition it rapidly deliquesced if left in contact with the air. 20 grams of this salt were heated but no decomposition occurred below 250° and between that temperature and 300' the whole of the contents of the flask distilled over.During the decom-position a little gas was formed which was chiefly carbon dioxide. In the receiver a highly crystalline substance collected which when treated with water dissolved and formed two layers which were separated. The lower layer proved to be an aqueous solution of trimethylphosphine oxide which on redistillation gave 8 grams of nearly pure oxide of tzimethylphosphine (b. p. 214*5") whilst the upper layer contained traces of trimethylphosphine and toluene but when distilled the thermometer rose almost a t once to 190" and the whole of the substance passed over between that temperature and 210'. On redistillation most of it passed over at a temperature near 200" and seemed to consist of methyl phenyl ketone (b.p. 200"). Methyl phenyl ketone however is a solid which melts at 20". The fraction 199-202" could not be made to solidify till it was cooled below O" and the crystals so formed melted again below 10". The substance was unchanged when boiled with caustic soda solution, (and therefore was not methyl benzoate) when oxidised with chromic acid solution it yielded formic and benzoic acids. From the above results the benzoate decomposes almost completely as follows :-while a small portion decomposes-Several other salts were experimented with but as their method of decomposition is similar to that of the same salts of tetrethylphos-phonium only a short account of them is necessary. The acetate when heated decomposed i n a manner similar to the benzoate chiefly into trimethylphosphine oxide and acetone ; traces of ethyl acetate and trirnethylphosphine were also observed.The acid carbonate decomposed at a temperature a little above 100" into trimethylphosphine oxide carbon dioxide and methane. When the salts of tetramethylphosphonium are compared with the salts of tetrethylphosphoriiim they show great similarity in their method of decomposition by heat but owing to the greater stability of the methyl-group the changes effected by the heating are not so complicated. The chief decomposition is always (in the case of oxy-sal ts) into the oxide of trimethylphosphine sometimes accom-panied by a ketone sometimes as in the case of the sulphate, by other products. This change was first pointed out as occur 640 ACTION OF HEAT ON SALTS OF TETRAMETHYLPHOSPHONIUM. riug in the paper by Professor Letts and the author (Zoc. cit.), on the tetrethylphosphonium salts. But i t is more clearly seen and the decomposition occurs more neatly when the tetramethylphos-phonium salts are heated. The decomposition of tetramethylphos-phonium chloride resembles that of the tetrethylphosphonium salt, whilst the decomposition of the sulphate into the sulphide and oxide of trimethylphosphine exactly resembles the decomposition of the sulphate of tetrethylphosphonium. The comparison with the tetra-methylammonium salts has already been made in the paper by Dr. h,WSOn and the author in the preceding paper

ISSN:0368-1645    

DOI:10.1039/CT8885300636

出版商:RSC    

年代:1888

数据来源: RSC

摘要:

XL1X.-Researches on the Relation between the Molecular Xtructure of Carbon Cornpounds and their Abso ytion-spectra. (Part IX.) O n Isomeric Cresols Dihydroxybenzenes and Hydroxybenzoic Acids. By W. N. HAKTLEY F.R.S. Professor of Chemistry Royal College of Science Dublin. SAMPLES of the ortho- meta- and para-cresols and of hydroquinone (qninol) pyrocatechol and resorcinol were obtained from Mr. Kahlbaum’s agents. Although they were found to be satisfactory after a single purification nevertheless these specimens were redis-tilled and rendered free from any slight colour which they might have acquired by keeping the final distillation being performed just previous to their examination. The distillates from the para- and ortho-cresols appeared quite colourless just at the moment of conden-sation but a t the lower end of the condensing tube they were observed to be pale yellow in colour in other words though colour-less when hot these substances were colonreil when cold.The meta-cresol became slightly coloured after keeping for some time. The three bodies stand in the following order as to colour :-Metacresol colourless. Paracresol yellow. Orthocresol darker yellow. The specimens of salicylic acid metahydroxyhenzoic acid and pnrahydroxybenzoic acid the spect’ra of which were described in the Philosophical Transactions Part I 1879 were also examined by the method which I have more recently described. It was deemed advisable to recrystallise the two latter substances. They were accord-ingly dissolved by boiling in water ; both formed somewhat brown solutions.Crystals from the solutions were carefully selected washed free from mother-liquor and recrystallised a.s often as it appeared that they gave a slight tinge of colour to the liquid i n which they were dissolved. Finally they were obtained quite free from admixture with other crystals or uncrystallisable matter and appeared as nearly as possible of perfect whiteness yielding solutions quite free from any perceptible colour. The strength of the solutions photo-graphed as in cases latterly described were molecular proportions in milligrams dissolved in 20 C.C. of alcohol. The descriptions of spectra and the molecnlar absorption curves are presented with this note. SO far the law of absorption of rays which it was expected would guide us in the orientation of the substituted hydrogens in the benzene nucleus does not appear to be the same for the hydrocarbons as for the cresols and dihydroxybenzenes.VOL. LlTI. 2 64 2 HARTLEY THE MOLECULAR STRUCTURE OF I n the hydroxybenzoic acids the order of maximum absorption is the reverse of what it is in t8he xylenes. Thus the oscillation frequencies of the most extreme rays trans-mitted by a milligram-molecule of the four classes of isomeric sub-stances are the following :-Oscillatiom Frequencies of the most Refrangible Rays transmitted by a Nilbigram-molecule. Dihpdroxy- Hydroxyben -Xylenes. Cresols. benzenes. zoic acids. Ortho 3611 Meta . . 34433 Mete 3466 Para 3359 Meta . . 3580 Ortho 3413 Ortho 3399 Meta 3080 Para ,. 3537 Para .. 3359 Para 3151 Ortho. 2986 I n the case of the hydrocarbons cresols and dihydroxybenzenes, the 1 4 derivatives exercise the greatest absorption Though they differ from the xglenes the cresols and dihydroxybenzenes follow the same order of transparency ; but the hydroxybenzoic acids altogether reverse the order of the xylenes and differ from the cresols and dihydroxybenzenes. We may assume that the absorption of rays manifested by one of any three isomerides is a measure of its rate of vibration and conse-quently of the dissipation of energy resulting in the formation of the molecule. Hence the following classification is deduced :-Dissipation of Euergy during Fornzcition. Least. Greatest . Xylenes . Para meta ortho Dihydroxybenzeiies . . . . . . Para ortho meta .. . . . . . . . . . . . . . . Cresols Para ortho meta Hydroxybenzoic acids Ortho meta para In the J. pr. Chem. 22 1-45 V. Rcchenberg has given an account of the heat of combustion of the three hydroxybenzoic acids. The substance which erolves the largest amount of heat on combustion must be that by which the least amount of energy was dissipated during its formation and it is worthy of remark that according to v. Rechenberg the hydroxybenzoic acids follow the order of classifica-tion given above namely ortho meta para the heat units evolved beingX 759,000 754,000 and 752,000 respectively. For the curves and measurenients of the three xylenes see Trans., 1885 48 702-749. For explanations of the plates see Trans, 1887, 51 201. * These numbers are taken from Pattison-Muir’s Elements of Thevmal Chemistry p.65. Macmillan 1885 OURVES OF MOLECULAR VIBRATIONS. SALIQYLIU AOIO (NATURAL) .-.-.-.-.-METOXYBENZOIC AOlO *-PAROXYBEHZOIC AGIO *** -- _____c_ IL 0 Scale of Oscillation - Ihquencies Harmon & Sons Lith. S Martins > axe.% C OURVES OF MOLECULAR VIBRATIONS. . . -.-.-I --.- 1.4. QU I N 0 L a . . PYROCATECHOL * .-------- 1.2. RESORCINOL * a * .- 1.3. TIM GUWCI of Pytmattclwl and Rcrorcinol run me into the other al tAe point8 marked thur ORTHOCRESOL C6H4(CH3)*OH 1 2. 0.108 gram in 2890 *3 3480 2364 - 2890.3 to 2444 3480 to 4016 - 4253 ~ ~~~ Thickness of layer of liquid 2875 Description of spectrum, ----Continuous spectrum to. Absorption band from Two very feeble lines at., ,) . Feeble spectrum to . Thickness of layer of liquid,. Continiious spectrum to . Absorption band from Feeble spectrum to . Faint spectrum to w 5 mm. Oscillation frequencies. --3413 3413 to 4125 4125 4136 -Wave-lengths. 2930 2930 to 2424.3 2424.3 2418 -2 mm. 3460 3460 to 4093 4232 -4 mm. 3439 3439 to 4125 12906.5 I I 4G5 1 1 mm ~~ ~ ~~~~ Thickness of layer of liquid Continuous spectrum to . Faint spectrum to Weak spectrum to . Absorption band from 5 mm. 3493 3493 to 4016 4253 -Description of spectrum. 3493 3493 to 3890 4253 Oscillation frequencies. 2863 Continuous spectrum to . Absorption band from Wave-lengt,hs. 3525 2836 *5 3525 to 3832 2836'5 to 2609 2863 2863 to 2490 2352 -Thickness of layer of liquid 2 mm.Very feeble spectrum to -Weak spectrum to . 1 4331 - 1 2310 4 mm. 3531 1 (Absorption band but rays are very feebly between lengths 2831 and 3768 4331 1 ORTHOCRESOL-continued. 0.108 gram in 500 ~ontinuoua spectrum to. I 8531 3768 4331 Very feeble spectrum to . I Weak apectrum to 1 i - But feeble t o . . Thickness of layer of liquid 2831 *5 2653 2310 -5 mm. Continuous spectrum to. Spectrum extends to But faint to 4 mm. 4426 9 2259 3768 2653 L I I -I-l- I-~-I Same aa last. I I I Thickness of layer of liquid. . 2 mm. 1 mm. I 4426 * 7 466 METACRESOC C6H4(CH3)*OH 1 3. 0.108 gram in 20 C.C. alcohol. Oscillation frequencies. ~~ Thickness of layer of liquid,.Wave-lengtbs Description of spectrum. ---3433 3433 to 4125 4125 4136 -Continuous spectrum to . Two very feeble lines at . Two weak lines a t . . Absorption band from,. . . 9) . . . . . . . . . . . . . . . . . 1 ) 2912 -5 2912.5 to 2424: 2424 -3 2418 -I Thickness of layer of liquid Thickness of layer of liquid . , Continuous spectrum to,. . Absorption band from Spectrum extends feebly to 5 mm. 5 mm. 2 mm. 3460 I 2890 -3 4190 1 2387 3460 to 4125 2890.3 t,o 2424.: 4 mm. Oscillation frequencies. 3460 3460 to 4125 --4125 4136 Vave- :::::;, -2890.3 1 mm. 4190 METACRESOL-continued. 0.108 gram in 100 4 mm. Continuous spectrum to . 3493 2863 3493 Absorption band from 3493 to 3890 863 to 2568 3493 to 3890 2863 Spectrumextends to I 4190 1 2387 I 4253 ~ Thickness of lager of liquid Continuous spectrum to .. . . . . . . . . . Feeble spectrum t o . . . . . . . . . . . . . . . . . Spectruni extends to 2 mni. 3531 3768 4331 1 mm. Spectrum extends to. Continuous spectrum to. . . . . . . . . . . . . 1 3525 2836 - 5 3531 . - - 3768 Spectrum extends to . . . . . . . . . . . . . . 4253 2352 4331 Feeble spectrum t o . - Absorption band from . . . . . . . . . . . . . . ~ 3525 to 3768 2836 -5 to 2653 I 4426 *7 I 2259 &fETACREsoL-co?ttinzted. 0.108 gram in 500 Thickness of layer of liquid,. . 5 mm. 2836 -5 2653 2310 Thickness of layer of liquid 2 mm. 4 mm. 1 mm. 4660 PARACHES~L C,H,(CH,).OH 1 4.0.108 gram in 5 min. Oscillation frequencies. Wave-lengths* --3359 2976 * 5 4125 2424 '3 4136 2418 - -3359 to 4125 2976'5 to 2424'3 Thickness of layer of liquid . 4 mm. Oscillation frequencies. Wave--Same as last. Description of spectrum. 3392 3392 to 3890 4163 Continuous spectrum to. . Absorption band from . Two very feeble lines at . Spectrum extends to )) 3 9 . 2948 Thickness of layer of liquid Continuous spectrum to. Absorption band from Spectrum extends to Thickness of layer of liquid 5 mm. 4 mm. I 1 mm. I 2 mm. Same as last. Continuous spectrum t o . . . Absorption band from . Q,.-L -- - - L - - d - 4 3392 1 2948 I A 1 QZ Oion 3392 to 3890 2948 to 2658 Same as last. UUGVUI~UILI GAWUUJ L U .. I XLUU I YUilU I I I 2 mm. Thickness of layer of liquid ! Thickness of layer of liquid. 1 mm. 5 mm. Oscillation Description of spectrum. frequencies. Wave-l%ths. Continuous spectrum to . Very feeble spectrum to . Spectrum extends to. Continuous spectrum to. 3392 2948 Absorption band from 3392 to 3832 2948 to 2609 Very feeble spectrum to . - -Spectrum extends to 4232 2364 3426 3768 4253 I Spectrum extends to 3426 -3’768 4253 4331 1 2310 2018 * 5 2653 1 2352 4 mm. Same as last. I Thickness of layer of liquid. 2 mm. 1 mm. 4660 PYROCATECHOL C,Il,(OH) 1 2. 0.110 gram in 20 3460 3460 t o 3890 4253 Thickness of layer of liquid 5 mm. 2890.3 4 mm. Continuous spectrum to . 3460 Absorption band from 3460 to 4016 Weak spectrum to 4136 -~- -Continuous spectrum t 0.. . . . . . . . . . . . I 3399 1 2942 I 3413 2890 '3 2890.3 to 2490. 2418 Thickness of layer of liquid. . Continuous spectrum to. . . . . . . . . . . . . Absorption band from Two weak lines a t . . . Weak spectrum to . . . . . . . . . . . . . . . . . 9 ) )) 2 mm. 1 mm. 3439 2906 -5 4125 2424.3 4136 2418 3439 to 4125 2906'5 to 2424, 3460 3460 to 4016 2890.3 - -4136 P Y R o c A T E c H o L - c o ~ t i e ~ . 0.110 gram in 100 4 mm Thickness of layer of liquid Thickness of layer of liquid 2 mm. 4 mm. 5 mm. 1 mm. Continuous spectrum to. ~ 3531 2831 *5 Absorption band from ~ 3531 to 3768 2831.5 to 2653 Weak spectrum to 1 4331 2310 . Paint spectrum to,. - - Description of spectrum.3’768 3531 -4374$ -4 I Oscillation 1 Wave- frequencies, . Thickness of layer of liquid Continuous spectrum to Very faint to Continuous spectrum to. ~ 350’7 2852 *3 Absorption band from 3507 to 3832 2852 3 to 2609 Weak spectrum to 1 4331 1 2310 4426 #? Same as last but stronger. I 4660 I 1 mm. I 2 mm. -I- I 3531 3531 to 3’768 2831.5 I 4331 I I 1 RESORCINOL C,H,(OH) 1 3. 0.110 gram in 20 3507 3507 to 4125 4125 4136 -Thickness of layer of liquid 2852 -3 2852'3 to 2424.: 2424 -3 2418 -Description of spectrum. ' Continuous spectrum to. Two faint lines at . Absorption band from ¶ > ,) Thickness of layer of liquid Continuous spectrum to. Two weak lines at Absorption band from .Weak spectrum to )> )) . ~ 5 mm. I 2 mm. 4 mm. 1 mm. 350'7 to 4016 2852.3 - 3507 1 -4163 RESORCINoL-con~~nz~ed. 0.110 gram in 100 I 1 4 mm. I Thickness of layer of liquid 5 mm. I I I I I I Continuous spectrum to. 350'7 2852 -3 3531 Absorption band from. 3507 to 4016 2852'3 to 2490.5 3531 to 3890 2831.5 Weak spectrum to,. 1 4163 1 2402 I 4253 1 I Thickness of layer of liquid,. . Continuous spectrum to. Absorption band from . Very faint to Weak spectrum to,. 2 mm. 3537 1 2826.5 - I 3537 to 3832 2826’5 to 2609 4253 1 2352 1 mm. 3580 3768 --4374 -4 Description of spectrum. , Oscillation Continuous spectrum to . 3537 3647 Faint spectrum t o . . I Absorption band from I 364’7 to 3’768 Weak spectrum to .. . . . . . . . . . . . . . . 4331 Very faint to . 1 -I I- -___-2826 5 274Q -2’740 to 2653 2310 Thickness of layer of liquid Oscillation frequencies. 2 mm. 3537 3647 364’7 to 3’768 4331 Continuous spect,rum to . Faint spectrum to 3’768 3 580 Weak spectrum to . . . . . . . . . . . . . . . . . . 4374.4 Wave-2’793 2653 2286 2740 REsoRcINoL-contilzzced. 0.110 gram in 500 Thickness of layer of liquid . 5 mm. 4426.7 4660 QUINOL C6H4(OH) 1 4. 0.110 gram in 20 C.C. Alcohol. Continuous spectrum to . Very feeble discontinuous to Absorption band fi-om Faint discontinuous to Thickness of layer of liquid ~ - ~~ . I 5mm* I Thickness of layer of liquid. 3151 1 3171 - -I - I - -I 2 mm. Description of spectrum.Cont,inuous spectrum to. 3151 3171 Absorption band from 3151 to 3890 Weak discontinuous to. . 4050 Continuous spectrum to . ~~~~ 4 mm. I 3171 to 3568 2469 ‘5 -1 mm. 318’7 3187 to 3832 4125 -QUINOL. 0.110 gram in 100 C.C. Thickness of layer of liquid 5 mm. Continuoils spectrum to 318’7 3 140 Absorphon band from 3187 to 3832 3140 to 2690 Continuous spect,runi t o . 1 4125 I 2424’3 318’7 3187 to 3832 4136 314 Thickness of layer of liquid, . . 2 mm. Thickness of layer of liquid, . 1 mm. 5 mm. Description of spectrum. 3320 3320 to 3500 4190 Continuous spectrum to 3194 3130 Absorption band from 3194 to 3701 3130 to 2701 Continuous spectrum to I 4136 1 2418 3014 3221 to 3647 3104 41 36 3221 I Thickness of layer of liquid QUINOL.0.110 gram in 500 C.C. 2 mm. --4660 I I Cont,inuous spectrum to 3297 3033. Absorption band from 3297 to 3531 3033 to 2831 -5 Continuous spectrum to I 4190 1 2387 Continuous spectrum to 3359 2976.5 Absorption band . 3359 to 3493 2976.5 to 2863 Spectrum extends to . . . . . . . . . . . . . . I 4331 1 2310 4 mm m W cn Q) 03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E : ,o .o,o In P Thickness of layer of liquid 2 n -I I 2 mm. I Description of spectrum. Thickness of IaFer of liquid Spectrum ext,ends to 3066 3261 Absorption band from 3066 to 3641 3261 to 2’744 -5 Rays transmitted t o . . 1 3970 I 2518 4 mm. I 5 mm. 1 mm. Spectrum extends to .Absorption band from Rays transmitted to . 3080 3245 -5 4028 2482.5 3080 to 3525 3245.5 to 2836 3151 3151 to 3494 31’ 4033 I Oscillation frequencies. I- -4130 4415 4130 to 4326 2421 3080 3080 to 3525 3245.5 4028 I I tQ 4 Spectrum extefids to Absorption band from Rays transmitted to SALICYLIC AcID-continued. 0.138 gram i n 500 4033 24’79 * 5 - -- -Thickness of layer of liquid 2 mm. I 1 mm. SAIJCPLIC Acm-continued. 0.138 gram in 2500 C. Oscillation frequencies. Thickness of layer of liquid. . . . . Ware-5 mm. Thickness of layer of liquid . . . . Oscillation frequencies* Wave-lengths. I i Description of spectrum. 2 mm. Spectrum extends to . . . . . . . . . 242 1 Absorption band from . .. . ,. . . . . . . 2421 to 2313 Rays transmitted to ,. . . 1 4415 I 2265 4130 4130 to 4326 Thickness of layer of liquid . . . . 5 mm. 4 mm. Spectrum extends to. . . . . . . . I. . . . 3080 I 3245 *5 3080 I ~~~~~ ~ ~~ Spectrum extends to. . . . . . . . . . . .I 4658 1 2148 -5 41 mm. I- --4i30 4550 1 4130 to 4243 2421 I 1 mm. 4658 1 The solution 0.138 gram in 20 C.C. gave a brilliant blue fluorescence decreasing diluted Thickness of layer of liquid 3115 3115 to 3641 3885 2 mm. 3208 1 mm. oscilla'tion Wave-lengths. frequencies. 1 i Description of spectrum. Spectrum extends to 3245 *5 Rays transmitted to Absorption band from Thickness of layer of liquid fi Spectrum extends to Absorpt,ion band from w + Rays transmitted to .I I 2 mm. Same as 3 mm. METAHYDROXYBENZOIC ACID-continued. Thickness of layer of liquid. . . I 5 mm. Spectrum extends to 3080 3245 *5 Absorption band from Rays transmitted to I 3885 1 2572 3080 to 3826 3245 . 5 to 2613 I I i Oscillation frequencies. wave-3080 to 3826 3245 1 3885 3885 0.138 gram in 100 318'1 1 3187 to 3568 3914 3140 &IETAHYDROXPBENZOIC ACID-continued. Thickness of layer of liquid. 0.138 gram in 500 5 mm. -Spectrum extends to Rays transiuitted to Absorption band from I I - I ---318’7 3140 3914 2553 318’7 to 3568 3140 to 2802 *5 Description of spectrum. 3221 3221 to 3494 39’70 3104.5 I I I -4055 4055 to 4311 4420 Thickness of layer of liquid 2 mm. 2466 1 I I Thickness of layer of liquid Spectrum extends to 4028 2488 -5 Absorption band from I Rays transmitted to 5 mm.Spectrum extends to 1 4055 4055 to 4311 Rays transmitted to 4420 Absorption band from 2466 2466 to 2321 2263 4 mm. 4055 4055 to 4311 4420 2466 4 mm. 0.138 gram in 250 Thickness of layer of liquid . . , , Description of spectrum. Thickness of layer of liquid . . -Spect.rum extends t o . . . . . . . . . . . . . Absorption band from . . . . . . . . . . . . . . Rays transmitted to . . ,. . . . . . , 1 mm. 2 mm. 2 mm. I 1 mm. 2450 4658 -4555 2195 -Slight blue fluorescence. PARAHYDROXYRENZOIC ACID C,H,(OH).COOH 1 4. 0.138 gram Thickness of layer of liquid. . . PARAHYDROXYBENZOIC Acm-contiiizced.Thickness of layer of liquid Thickness of layer of liquid. 2 mm. 5 mm. Thickness of layer of liquid J -I I 5 mm. 4 mm. Description of spectrum. Spectrum extends to . 3525 Absorption band from 3525 to 4415 Rays transmitted to - 2836 *5 2836.5 to 2265 -Spectrum extends to 3500 2857 -5 - Absorption band from 0.138 gram in 100 4 mm. I ---3500 I 1 mm. 3525 4415 1 3525 to 4326 2836. 1 I Description of spectrum. Thickness of layer of liquid. Spectrum extends to Absorption band from Rays transmitted to 2 mm. 2744 -5 3641 to 4306 2744.5 to 2323.; 4415 3fi41 1 2265 --1 mm. l-l--3641 to 4297 2744.6 45 3641 50 1 3641 3641 to 4291 4550 2744 * 5 2744 -5 to 2329 2197 3885 3885 1 o 4179 4658 ~ 2572 2572 to 2393 2148 *5 Thickness of layer of liquid.. Spectrum extends to Absorption band from Rays transmitted to Thickness of layer of liquid Spectrum extends to. Absorption band from Rays transmitted to 5 mm. 4 mm. Same as 5 1 mm

ISSN:0368-1645    

DOI:10.1039/CT8885300641

出版商:RSC    

年代:1888

数据来源: RSC