摘要:

J O U R N A L OF THE CHEMICAL SOCIETY. PAPERS READ BEFORE THE CHEMICAL SOCIETY. I.-Some Derivatives of Pr 1%-Methylindole. By H. G. COLMAN Ph.D. M.Sc. Introduction. IN his classic researches on the compounds of the indigo-group, Baeyer obtained by the reduction of isatin successively-and Indole C6H4<NH>CH. CH Up to the present time the methyl-derivatives of these compounds have been but little studied and it seemed probable that they might be obtained from Pr In-methylindole (for nomenclature see E. Fischer, Annalen 236 l l S ) which thanks to the researches of E. Bischer and 0. Hess (Ber. 17 5591 can now be prepared in quantity without difficulty . Fisclier and Hess (ibid. p. 561) have shown that methylindole can be converted into methylpseudoisatin by a very remarkable reaction.They found that when methylindole or methylindolecarboxylic acid is treated with a solution of sodium hypochlorite a crystalline pre-cipitate is formed which on boiling with alcoholic potash yields methylpseudoisatin. The intermediate product was analysed by Fischer and Hess but the analysis was insufficient to decide whether the substance had the formula C9H9NBr20 or C9H,NBr20. At Professor Emil Fischer's VOL. LV. 2 COLMAN SOME DERIVATIVES suggestion I have made a detailed examination of the reaction the results of which are given in the following paper. The product of the action of sodium hypochlorite on methylindole or methylindolecarboxylic acid has the formula C9H7NBr20 and is most probably a dibromo-derivative of methyloxindole having the -C Br2- formula C ~ H ~ < N ( C ~ ~ ~ > CO since with phenylhydrazine it gives a , crystalline derivative which is identical with methylpseudoisatin-phenylhydrazone.The latter must have the constitution FN phenylhydrazine never reacts with a carbonyl-group which is directly combined with nitrogen (see Baeyer Ber. 16 2188). From this it follows that the two bromine-atoms must be in the Pr 3-position as given in the above formula. 1liis formula also easily explains the formation of methyl-pstudoisatin when the substance is boiled with alkali or even with water the two bromine-atoms being displaced by one of oxygen. By the action of sodium hypochlorite on methylindolecarboxylic acid the corresponding dichloromethyloxindole is obtained which corresponds in all its reactions to dibromomethyloxindole.This peculiar reaction with hypochlorites and hypobromites seems confined to those indoles in which the alkyl-group is attached to the nitrogen-atom. If indole is treated in the corresponding manner the products of the reaction are not nearly so simple. Methylpseudoisatinoxime C6H4<yi$gt1> CO can be obtained in two ways viz. by the action of hydroxylamine on methylpseudoisatin, or by passing nitrogen trioxide into a solution of methyloxindole. On reduction in acid solution dibromomethyloxindole loses first one atom of bromine forming monobromomethyloxindole, which by long-continued reduction loses the second atom of bromine, and is converted into methyloxindole C6H4<-cH2->C0. N*C H, By the reduction of methylpseudoisatin in either acid or alkaline CH(0H) solution methyldioxindole c6H4<~ (cH3>->C0 is obtained.Experimental Par f. The met,hylindolecarboxylic acid necessary for this work was pre-pared according to the directions of Fischer and Hess (Bsr. 17 561) OF PR ~WMETHYLINDOLE. 3 by warming methylphenylhydrazone-pyroracemic acid with dilute hydrochloric acid. The crude acid thus obtained is sufficiently pure for further experiments. The pyroracemic acid required was prepared by Dobner's method (AniLaZen 242 268) which gives a very satisfactory yield of the pure acid. Dibromomethy Zoxindole C6E4<- CBr2-> CO. N(CH3) The action of sodium hydrobromite on methylindolecarboxylic acid was found to proceed best under the following conditions :-5 grams of the crude acid are dissolved in dilute caustic soda solution and boiled with animal charcoal for a few minutes.The filtered liquid is gradually added to a well-cooled mixture of 22.5 grams of bromine in about 900 C.C. of water to which suficient caustic soda had been added to neutralise tthe bromine and the whole continually shaken during the addition. The substance separates a t once in fine needles the colour of which in the various experiments, varied from light brown to dark red. In order to purify the substance the crystals are collected well washed with water dissolved in alcohol and boiled with animal charcoal. The filtered solution is then partially evaporated and on cooling small yellow tables crystallise out.These are separated from the mother-liquor on the filter-pump twice recrystallised from alcohol, and finally dried over siilphuric acid in a vacuum. By this means the substance is obtained in almost white tables, which melt with decomposition a t 204". On analysis numbers were obtained,# which agree well with the formula C9H,NBr,0. A comparison of this formula with that of methylindole shows that it differs from the latter in that it contains two atoms of hydrogen less and the elements Br,O more. As it is easily con-verted into methylpseudoisatin the bromine substitution must have taken place in the pyrroline-ring. I n order to determine whether these bromine-atoms are attached to the same or to diferent carbon-atoms the substance waa subjected to the action of phenylhydrazine.For this purpose 4 grams of the crude product were dissolved in warm alcohol and added to ii solution of 5 grams of pheuylhydrazine hydrochloride and 7.5 grams of sodium acetate dissolved in as little water as possible. In a short time the liquid became dark brown, and on addition of water the product of the reaction was completely precipitated as a yellow oil which crystallised on standing. The crystals were collected washed and twice recrystallised from benzene. f For analytical numbers $c. in this and the remaining analyses see ArtnuZen, 248 114 &c. B 4 COLRIAN SOME DERIVATIVES It forms fascicular groups of small yellow needles which melt a t 144-945" (uncorr.) and gave on analysis numbers agreeing with those required for methylpseudoisatin-phenylhydrazone.A corn-parisan of its properties with the compound obtained from methyl-pseudoisatin and phenylhydrazine &owed conclusively that the two substances were identical. From this it follows $that the two bromine-atoms are attached to the same carbon-atom in the pyrroline-ring which condition is ful-filled only by the two following foi*mulae :-The first would be dibromomethyloxindole and the second dibromo-methylpseudoindoxyl. The hydrazones of the compound under discussion and of methyl-pseudoisatin being identical the two bromine-atoms in the one must correspond with that carbonyl-group in the otlher which is acted on by phenylhydrazine. Now it is well known that phenylhydrazine never acts on a carbonyl-group which is directly connected with nitrogen so that in methylpseudoisatin the carbonyl-group in the Pr 3-position must be the one attacked and the hydrazone formed must have the formula c6H4<-N(cH,) '(:N*NH'CsH5) __ >CO.It follows therefore, that in the brominated compound the two bromine-atoms must also occupy the Pr 3-position as given in the first of the above formula The substance consequently is dibromomethyloxindole. Its chief properties are as follows :-It crystallises from alcohol in yellowish-white tables which when quickly heated melt with decompositon a t 204". If heated slowly, however i t becomes brown a t 170" and melts a t 180". It is ~eadilg soluble in alcohol ether chloroform and benzene but only sparingly in light petroleum and insoluble in cold water.On boiling with water it is converted into methylpseudoisatin. It reacts very readily with alkalis ammonia amines hydrazines and reducing agents. If shaken with benzene containing thiophen and strong sulphuric acid, a brown coloration is produced which however after standing for several hours becomes changed to the same blue as that produced by m ethylpseudoisatin. The prepa,ration of this substance corresponds exactly with that o€ dibromomethyloxindole. The solution of methylindolecarboxylic acid in alkali ia purified by boiling with animal charcoal an OF P R 1?2-METHYLIKUOLE. 5 gradually added to a cold dilute solution oE sodium hypochlorite, care being taken that the latter is in excess. The substance separates first in small oily drops which soon solidify to small brownish-white needles.These are collected well washed and recrystallised several times from alcohol or acetone. Thus purified it forms white needles which melt a t 145-147". The numbers obtained on analysis agree well with those required by the formula C9H,NC1,0. Dichloromethyloxindole dissolves much more readily in alcohol than the corresponding bromine-compound and is also easily soluble in acetone and ether but insoluble in water. Towards reagents it behaves in exactly the same manner as dibromomethyloxindole but i t is not so easily decomposed by heat for whereas the former begins to decompose a t 170" the latter can be heated to 210" without any change taking place. -co-Methylpseudoisatin C,H,< N(CH3)>c0' This compound was obtained by Fischer and Hess (Zoc.cit.) from dibroxnomethyloxindole by boiling it with alcoholic potash. Instead of this it was found more advantageous to boil the bromine-compound with water. About 8 grams of crude dibromomethyloxindole are suspended in 300 grams water and the whole boiled for two or three hours using a reflux condenser. The solution becomes deep red and a considerable quzbnt,ity of resinous matter separates. This is filtered off' and the clear solut!ion concentrated on the water-bath, when beautiful red needles separate on cooling ; these after another crystallisation from water are quite pure. The properties of methyl pseudoisatin have already been given by Fischer and Hess (Ber. 17 561). C (:N*NH*C,H,)>Co. Jletlz ylpseudoisatbzphenytkydrazone C6H,<- N(CH3)-To prepare this substance 1 gram of methylpseudoisatin is dis-solved in hot water and to this an aqueous solution of 1 gram of phenylhydrazine hydrochloride and 1.5 grams of sodium acetate is added.The solution becomes turbid almost immediately and afher a short time oily drops separate which crystallise on cooliiig. The crystals are collect,ed washed recrystallised from alcohol or benzene, and dried a t 100". The results of its analysis are in full agreement with the above formnla. Meth ylpseudoisatinphenylhydrazone crystallises in fascicular groups of Emall yellow needles which melt without decomposition at 145-146". It is easily soluble in alcohol and benzene sparingly i n ether and insoluble in water and light petroleum. 6 COLMAN SOME DERIVATIVE3 As has already been stated the product obtained by the action of phenylhydrazine on dibromomethyloxindole is identical with this hydrazone.The preparation of this oxime is best carried out as follows :-Aqueous solutions of methylpseudoisatin and hrdroxylamine sulphate are mixed and allowed to stand. The liquid soon becomes turbid and in about 12 hours the reaction is complete part of the oxime separating as a bulky amorphous precipitate while part remains in solution. In order to iso1at.e the oxime the whole is shaken with ether 10 times successively the ethereal solution dried with calcium chloride the ether distilled off and the residue which is a yellow, crystalline mass purified by recrystallisation from hot water. In t'his manner the oxime is obtained as a light yellow substance crystallising i n small needles which on heating become plastic at 170" and melt at 180-183'.Even after repeated crystallisation from acetone the melting point does not become constant. The cor-responding ethylpseudoisatinoxime was found by Baeyer (Bey. 16, 2196) t o behave in a similar manner. Methylpseudoisatinoxime is fairly soluble in hot but much less in cold water easily in alcohol acetone ether and benzene. Reduction of Dibromomethy loxindole in Acid Solution. Dibromomethyloxindolc is very easily acted on by reducing agents, efipecially in acid solution. The reduction proceeds best as follows:-To a mixture of dibromomethyloxindole with an excess of zinc-dust suspended in alcohol concentrated hydrochloric acid is gradually added in small portions t,he whole being shaken after each addition.After a few minutes the dibromomethyloxindole dissolves forming a cleai- yellow solution which is warmed for a short time on the water-bath. After the solution has been filtered from the unaltered zinc-dust, it is largely diluted with water and heated on the water-bath till the alcohol is completely evaporated. The products of the reaction then separate for the most part as reddish-brown oily drops which collect a t the bottom of the dish. The clear colouriess mother-liquor is poured off and treated as shown later on. The oil is now boiled with a large quantity of water for some time, and thereupon partially dissolves. The liquid is filtered hot and from the colourless solution white needles separate on cooling.These ar OF PR ~-METHYLINDOLE 7 filtered off and the mother-liquor utilised for again extracting the residual oil. This process is repeated until the solution no longer yields crystals 0x1 cooling. To this solution the colourless mother-liquor above mentioned is added. Monobromomethy loxindole C6H4< N(CH3) CHRr->CO. The crystalline product was first examined with the following result :-After a single recrystallisation from acetone the substance was obtained in white lustrous plates melting at 132-134". It gave on analysis numbers which. agree well with the formula C9B8NBr0 and 18 therefore as one would expect monobromomethyloxindole. It dissolves easily in alcohol ether and acetone and crystalliaes best from the latter.On boiling with caustic potash solution i t dissolves but crystallises out unaltered on cooling. I t is soluble to some extent in hot water scarcely at all in cold, The bromine i n . this compound is very firmly combined. Methyloxindo le C,H,<-~*~- N(CH,) The mother-liquor was then examined being treated as follows :-The solution is extracted 10 times with ether the ethereal solution dried over calcium chloride and the ether evaporated. The residue is an oil which on standing for a short time solidifies to a beautiful, radiating cry st alline mass. If this mass be now crptalllised from water it is obtained in white, transparent needles some of which are 4-5 cm. long. These, however still eontain 2-3 per cent. of the monobromo-derivative.To completely eliminate the bromine the substance must be dissolved in hot water and boiled for half an hour with zinc-dust and hydro-chloric acid. This powerful reducing action has however also the effect of causing a considerable diminution in the yield. The solution after filtering off the zinc-dust is extracted with ether as before and the residual oil recrystallised from water. It is thus obtained in small white needles which for analysis were dried over sulphuric acid in a vacuum. The numbers obtained on analysis confirmed the supposition that the substance is methyloxindole. It melts a t 86-88' and volatilises slightly with steam. Heated by itself it distils with partial decomposition and formation of a reddish-brown substance. It is fairly soluble in hot water but mucli less so in cold water and in light petroleum easily in alcohol ether 8 COLMAN SOME DERIVATIVES acetone and benzene.It is precipitated from its ethereal solution by light petroleum in fine oily drops which solidify i n a short) time, forming beautiful transparent needles. It does not combine with phenylhydrazine even on long-continued warming. This fact bears out the supposition that in dibromomethyl-oxindole the bromine-atoms are in the Pr 3-position. When boiled with caustic potash solution it does not take up the elements of water so as to form the corresponding acid, It dissolves in the hot liquid but is precipitated unaltered on cooling. If bromine-water is added to an aqueous solution of methyloxindole, a crystalline precipitate is at once formed.This however is not identical either with dibromomethyloxindole or with monobromo-met.hyloxindole for it is quite insoluble in water and is not acted on by caustic potash solution. It seems probable therefore that the bromine is contaiued i n the aromatic nucleus. By the action of nitrogen trioxide on methyloxindole in dilute aqueous solution a compound is formed which was found to be identical with methylpseudoisatinoxime. When prepared by this method however it is much more difficult to purify. This compound is obtained by the reduction of methylpsendoisatin. The following method gives the best results :-4 grams of dibromorneth~loxindole are boiled with water for 2 to 3 hours. To the solution thus formed which cont,ains- methylpseudo-isat,in and hydrobromic acid zinc-dust is added and the whole boiled till the liquid is colourless more acid being added if necessary.The filtered and cooled solution is then extracted 20 times with ether. The residue left on evaporating the ether is always slightly yellow, part of the methyldioxindole being oxidised by the oxygen of the air to methylpseudoisatin. This is twice recrystallised from benzene and is thus obtained in the form of colourlesa needles or prisms. It must be dried over sul-phurin acid in a vacuum as it' becomes slightly brown when heated for any length of time a t 100'. I t s analysis agrees well with the formula CgHgN02. It melts at 149-151" and deconiposes on further heating. It is sparingly soluble in cold water alcohol ether and benzene but easily in the hot liquids.From water and alcohol th OF P R 1~-METHYLINDOLE. 9 crystals are always yellowish but it can as above stated be obtained white from its solut,ion in benzene. If the solution of methyldioxindole is allowed to stand in the air it, is gradually oxidised to methylpseudoisatin but if it be made alkaline oxidation will proceed very rapidly. One important difference is to be noted in the behaviour of isatin and methylpseudoisatin towards reducing agents. Isatin on reducticn in alkaline solution yields isatyd a compound containing a molecule twice as large as isatin whereas methylpseudoisatin yields the same product as in acid solution viz. methyldioxindole. The following table shows the derivatives of methylindole obtained up to the present time together with the corresponding indole-compounds. Iitdole m. p. 52" ; b. p. 245". Oxindole m. p. 120". Bromoxindole (co nstit n tion unknown) m. p. 176". -Dioxindole m. p. 180". Isatin in. p. 200-201". Isatinphenylhy drazone m. p. Isatinoxime 111. p. 202". 210". Methylindole b. p. 239". Methyloxindole m. p. 86-88". Bromomethyloxindole m. p, Dibromomethyloxindole m. p. Dichloromethyloxindole m. p. Methyldioxindole m. p. 149-Methylpseudoisatin m. p. 134". Methylpseudoisatinphenylhydr-Methylpseudoisatinoxime m. p. 132-134". 204". 145-147". 151". azone m. p. 145-146". 180-183'. The above research was carried out in Professor Emil Fischer's laboratory at Wurzburg and I take this opportunity of expressing my best thanks to Professor Fischer for the kind advice and assis-tance given me throughout the investigation

ISSN:0368-1645    

DOI:10.1039/CT8895500001

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

10 11.-Action of Ethylenediamine on Succinic Acid. By ARTHUR T. MASON Ph.D. F.I.C. MANT years ago D'Arcet (Annalen 16 215) by the action of am-monia on succinic anby dride prepared succinimide and starting from this Ciamician and Silber have by means of phosphorus penta-chloride obtained tetrachloropprrol (Ber. 16 2398). Now although this compound cannot be reduced in the ordinary maliner to pyrrol, these investigators availing themselves of Hepp's discovery that tetrachloropyrrol and tetrabromopyrrol can be easily converted into tetra-iodpyrrol by treatment with potassium iodide in alcoholic solution found they had at their disposal a compound which by reduction with zinc-dust and potassium hydrate gave pyrrol with the greatest ease thus completing by stages the same synthesis which is effected directly by distilling succinimide with zinc-dusb containing hydroxide.The experiments about to be described were undertaken in the hope of arriving by similar reactions at an ethylenedipyrrol of the follow-i n g constitution :-C E C H . and although hitherto 1 have been unsuccessful in my object I take the liberty of laying the results already obtained before the Society i n order to secure this field of work as well as that with the aromatic diamines which I hare already begun. Succinic acid dissolves easily in an aqneous solution of ethylenediamine with evolution of heat and formation of the addition product (CH,*COOH),,(CH,*Nrr,) ; and as this has not to my knowledge been hitherto described I take t h i s opportunity of mentioning it.It is easily soluble in water aiid crjdallises therefrom i n thick white prisms. It melts at 181-182" t o a colourless liquid giviug up water and becoming semi-solid again. It is insoluble in alcohol and ether. An analysis of the subst,ance dried at; 100" gave the following numbem :-0.2175 gram gave 0.1593 gram H,O and 0.3235 gram COz. 0.1738 , 24.8 C.C. moist nitrogen at 18" and 718 mm. Calculated for C,HI,,N204. Found. C . . 40-45 40.56 H . 7-86 11.13 N. 15.73 15-55 0 . 35.95 ACTION OF ETHYLEX'EDIAMINE ON SUCCINIC ACID. 11 CH2-CO CO-CH, Etn ylenedisuccinimide I ) N ~ c H - c H ~ 1 , CHZ-CO 'CO-CH2 This compound is formed when the addition product just described is heated above its melting point water being eliminated it is however, by no means necessary to isolate the addition product in the pure state in order to obtain the best results.After preparing considerable quantities I have no hesitation in giving the following as the most advantageous method :-60 grams of succinic acid are mixed with 20 grams of ethylene-diamine hydrate and just sufficient water is added to bring the whole into solution on warming. The mixtl;zre is now heated in a flask over a small flame with a thermometer in the liquid. As the water evapo-rates the temperature gradually rises and the heating is continued until the thermometer indicates 195" when the whole has changed to a clear pale-brown syrup. After the temperature has reached 180', the thermometer rises rapidly and if not carefully watched over-heating may occur which curiously enough has an influence on the yield although the pure product can be distilled without decomposi-tion.On cooling the whole crystallises to a mass of prismatic needles, which is almost white; this is recrystallised from about 800 C.C. of water when 40 grams of a practically pure product are obtained in thick white prismatic needles which melt a t 250-251". It distils almost without decomposition at about 395") and sublimes in long, colourless prismatic needles-the sublimate being highly electrical. On distillation with zinc-dust containing hydroxide the pyrrol reaction with pinewood was easilx obtained but the compound conld not be isolated in quantity sufficient for an accurate investigation of its properties. The di-hide was dried a t 120" €or analysis; the following are the numbers obtained :-0.2215 gram gave 0.114 gram water and 0.429 gram carbon dioxide.0.1625 , 0.0816 , , 0.3192 , 9 7 0.1714 , 18.5 C.C. moist nitrogen at 14" C. and 726 mm. 0.1565 , 17.5 C.C. , , 15" C. , 719 ,, Found. 7 Calculated for r-"-C,O&2N,O,. I. 11. c . 33.57 52.82 53.57 H . . . 5-35 5.71 5.5i X . 12-50 12.10 1'2.41 0 . 28-57 - -It is soluble in hot water but only sparingly in cold ; boiling alcohol dissolves traces of the substance whilst in ether benzene acetone an 12 MASON ACTION OF ETHYLENEDIAMINE light petroleum it is altogether insoluble. The substance is not attacked by bromine and water at 120° but if heated in sealed tubes for three hours at 180" in the proportions of 1 mol.of substance to 4 mols. of bromine the whole of the bromine is absorbed and the tubes 011 cooling are filled with a pale-brown scaly product there being a t the same time a large pressure in the tubes due t80 carbon dioxide and monoxide. The brown scales on wa,shing with alcohol and ether became white and on analysis gave numbers closely agreeing with those required for ethylenediamiiie bromhydrate :-0,2974 gram gave 0,1251 gram water and 0.1231 gram cazbon dioxide. 0.2078 , 24 C.C. moist nitrogen a t 23" C. and 721 mm. 0,1925 , 0,3257 gram silver bromide. Calcdated for CJHl (NH,) 2,2HBr. Found. C . . . . . . . . . . . . . 10.81 11.22 H . . . . . . . . . . . . . 4.50 4.67 N . . . . . . . . . . . . . 12-61 12.20 Br . 72.07 72.00 Besides this a sample of pure ethylenediamine bromhydrate was prepared from the pure base and when compared the two prepara-tions agreed in all particulars.The formation of brominated succinic acids was not observed but as only two atoms of bromine are required by the bromhydrate and as a large pressure due principally t o oxides of carbon was found in the tubes we have probably to do with a more complete decomposition with formation of brominated ethanes. The action of the halogens on ethylenedisuccinimide as well as on aiialogous compounds belonging to the aromatic series in the absence of water will be treated of in a subsequent paper. In the preparation of this substance 22.4 grams of the di-imide are pulverised and dissolved in hot water and a solution of about 20 grams of pure barium hydroxide a,dded.The whole is then kept boiling for about 10 minutes and the excess of baryta precipitated by a stream of carbon dioxide. In the still warm filtrate the combined barium is carefully precipitated by the theoretical quantity of dilute hydrogen sulphate using a trace of Orange I11 (sodium salt of di-~netbyla.nilineazobenzenesulphonic acid) as indicator. When all the barium has been precipitated the mixture is allowed to stand on the water-bath for two or three hours filtered and evaporated to abou ON SUCCINIC ACID. 13 one quarter of its original volume. After standing several hours in a cold place the solution begins to deposit the new acid in the form of large colourless qnadratic plates having t,he constant melting point 1E4-185’.For analysis it was recrystallised from water and dried at 100”; the following are the results obtained :-0.1647 gram gave 0.099 gram HzO and 0.2768 gram CO,. 0.1735 , 0.1007 , , 0.2925 ,, 0,1415 , 14.1 C.C. moist nitrogen at 22” C. and 726 mm. Found. -3 Calculated for r--h-ClCIH16N2?06* I. IT. C . . . 46.15 45-83 45.97 H 6.15 6.67 6.41 N. 10.76 10.76 -0 . - . 36.94 The new acid is easily soluble in hot water with greatel. difficulty in cold. It dissolves in hot alcohol with tolerable ease but is only sparingly soluble in cold and is insoluble in ether benzene acetone, and light petroleum. In the presence of even very dilute mineral acids it gives up water on heating being converted into the di-imide described above. Neither hydrazone nor isonitroso-derivative could be prepared by the action of phenylhydradne and hydroxylamine and this was expected, as it has already been proved in many cases that compounds con-taining the ‘‘ carbonyl ” group CO between carbon and nitrogen do not react like true “ketones.” Silver S d t ClJ€,4N206Ag2.-The &her salt is prepared in the usual way by dissolving the acid i n aqueous ammonia evaporating till the excess of the latter has disappeared and precipitating the solution in water with silver nitrate.It falls as a wolumiuous white precipitate easily soluble in ammonia but insoluble in the general solvents. It darkens rapidly on drying at loo” but is stable in diffused sunlight. A silver estimation was made. 0.1647 gram gave 0.09886 gram silver chloride. Calculated for C10H14N206Ag2* Found. Ag 45.57 45.1 7 Calcium Salt ClOHl4N1O6Ca 4- SH,O.-I?repared from the di-imide by heating with the theoretical quantity of pure calcium hydrate suspended in water. The aolution is filtered evaporated on the water-bath and then allowed to stand over sulphuric acid; the sal 14 PICKERISG THE PRINCIPLES OF THERMOCHEMISTRY. separates in large prismatic crystals containing 3 mols. H,O. ca1ciu.m estimation gave the following result :-0.2280 gram gave 0.0362 gram calcium oxide. 0.1569 , 0.0245 , water. The Calculated for CloH,,N,O,Ca i 3H:O. Found. Ca 11:36 11.34 H,O . 15.34 15.61 Universify Lahorntory, ZiiYiCh

ISSN:0368-1645    

DOI:10.1039/CT8895500010

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

14 PICKERISG THE PRINCIPLES OF THERMOCHEMISTRY. 111.-The Principles of Thermochemistry. By SPENCER UkIFREVlLLE PICKEMNG M.A. THE connection between a chemical action and the heat evolved therein is a question of vital importance to all chemists and physicists yet the fundamental principles on which it depends are at present in an eminently unstable and unsatisfactory condition. On the one hand it is acknowledged that the atoms possess a certain amount of potential energy or affinity which becomes partially or entirely saturated when they combine together and which in its saturation must according to the principles of physical science, evolve an exactly equivalent amount of kinetic energy or in the calorimeter heat,* while on the other hand the heat evolved in a reaction is not yet recognised as a measure of the affinities saturated, and there are thousands of instances known in which the saturation of these affinities apparently results in a paradoxical absorption of heat.I n 1853 Thomsen (Pogg. Ann. 92 34 and Ber. 6 425) stated that “ every simple or complex action of a purely chemical character is associated with a production of heat.” Naumann in 1869 (Lieb. Ann. 151 158) stated that “with few exceptions capable of being otherwise explained those chemical changes which must take place with an absorption of heat are so to speak indirect changes. That is t o say they occur simultaneously and are dependent upon other changes which are themselves accompanied by a production of heat.” f Unless we assume the existence of some form of kinetic or potential energy which has hitherto escaped our observation an aseumption which we are scarcely justified in making even when all other possible explanations fail PICKERIKG THE PRINCIPLES OF THERMOCHEMISTRY.15 While Berthelot in 1879 (Me‘c. Chim. 2 421) thus enunciated his more emphatic and comprehensive Principe de travail maximum : “ Every chemical change which is completed without the intervention of external energy will always tend towards the production of that body or that system of bodies developing the maximum quantity of heat,” adding a.s a corollary that “ every chemical reaction capable of occurring without the previous expenditure of work and without the intervention of external energy necessarily occurs if it develop heat.” No one can study the mass of thermochemical data which exist without concluding that such statements cannot be very far from the truth a t the same time we must agree with L.Meyer (Modern, Theories 429) in considering that Berthelot’s explanation of many endothermic reactions is decidedly forced ; for to explain reactions occui~ing in solution he has to refer them to the heat of formation of the anhydrous molecules thus ignoring the chemical nature of solu-tion of which however he is a firm supporter ; nor does he attempt my explanation of the heat absorbed when many strong solutions are diluted a chemical action again according to his views.* But when we examine the wording of Berthelot’s principle more closely we see that the expression “ tends towards ” destroys the whole value of the statement and affords R loophole for explaining (?) away any discordant facts whereas if “ produces ” be substituted for “ tends towards the production of” the statement must be met with an absolute denial hydrogen and oxygen do not combine a t O”, though they would develop heat in so doing; water decomposes at 2000“ absorbing heat ; and endothermic compounds are often when formed quite stable.On still wider grounds however we must reject any principles, such as those of Rerthelot and Thomsen the gist of which lies in a distinction between physical and “ purely chemical ” action a distinc-tion which never has been possible and which is every day becoming less possible. The whole of the thermal results in any action must be explained on one and the same principle.* Meyer’s objection to Berthelot’s principle on the ground that it is applicable to bodies at the absolute zero only is based I think on an unfair interpretation of what Berthelot meant by heat being an external energy ; similarly his objection on the score of the heat of neutralisation bearing evidence opposed to that of the “ nvidity ” of acids is entirely due to his misconception of the quantities measured in neutralisation ; the heat of neutralisation affords as a matter of fact stronger evidence than any yet obtained of the direct proportionality of tho heat evolved to the affiity saturated (Trans. 1887,593). For a criticism of some of the explana-tions of endothermic actions given by Berthelot see Rathke Ueber die Prinripien der Thermochemie Halle 1881 1 6 PICKE RING THE PRINCIPLES OF THERMOCHEMISTRY.In seeking for such a principle we must start with obtaining it clear conception of the facts to which this principle must apply. On the one hand it is a fact that substances will not combine until a certain temperature be reached even though their combination at lower temperatures would be accompanied by an evolution of heat ; while on the other hand it is also a fact that when the temperature of any body is raised to a certain point i t decomposes whether its decomposition be attended with an absorption or an evolution of heat, this being probably true even of the elementary molecules themselves, Thus the conversion of the potential energy of affinity into kinetic energy (heat) occurs only above a certain definite temperature, different for each different body and this kinetic energy becomes converted back again into affinity at some higher temperature ; but we know far too little about atomic motions to attempt my explana-tion of how these temperatures are conditional in each special case.We must content ourselves with the fact that combination occurs between certain limits of temperature only. The phenomena which we have to explain are therefore confined to those accompanying actions which do actually occur and the only principles which we can attempt to enumerate are those which deter-mine whether a certain reaction will occur provided the temperature be between the limits at which i t is possible and to determining which out of several possible reactions will occur.The accepted principles of dissociation the chemical nature of solution and the teaching of the thermal results of neutralisation, will I believe afford grounds sufficient for the foundation of such a principle. Inasmuch as combination is the result of the saturation of affinity, and the saturation of this affinity must always liberate a correspond-ing amount of heat it is evident that every act of contbinadion must cause a n evolution of heat and that in any reaction where heat is absorbed this absorption must be due to some accompanying decomposition. But as decomposition cannot be the direct result of affinity it must be due to the fact that some of the substances present are at the temperature of +he reaction above that temperature at which they begin to dissociate.This dissociation moreover cannot be that of any of the products for even if the products were entirely dissociated back again into the reagents this would be tantamount to no com-bination of the reagents having occurred and hence the minimum value of the heat evolved would be nil and not a negative quantity.* * Heat would be absorbed if the compound dissociated into substances simpler than the reagents themselves ; if for instance KC1 combines with water to form a hydrate which when formed dissociates partially into K and C1 &c. ; but such a caae is I think impossible. If the more saturated hydrate dissociated into K an PICEERING THE PRINCIPLES OF THERMOCHEMISTRY. l’i Any dissociation occurring must therefore be that of the reagents.Hence ‘‘ in every endothermic reaction one or more of the reagents must be in a partially dissociated condition.” Moreover when combination occurs it will occur independently o j whether it involves subsequent absorption of heat through the removal of the products qf dissociation and the consequent necessity for the occurrence of further dissociation. It is obvious that the affinity of the reacting substances and not the subsequent consequences of their reaction can alone determine whether they shall react or not. It also follows as a matter of necessity I think that in any compl~x system of atoms where two or more arrangements are possible and where the various products remain within the sphere of action capable of further interaction where such inieraction is possible (that is where the tem-perature is within the limits above mentioned) those products the formation of which is attended with the greatest evolution of heat wit1 be formed to the ezclusion of the others.Thus in illustration of my meaning if potassium be brought into the presence of excess of hydrochloric and hydrobromic acids in aqueous solution the two actions-K + HC1 = KC1 + H and K + HBr = KBr + H, are both known to be possible and it is also known that the KCl and KBr formed remain in the solution capable of reacting with any excess of HBr and HCl respectively ; in such a case my proposition states the potassium will be converted entirely into chloride or bromide according as the gross heat of formabion of one or other of these salts is the greater.* Before enquiring as to how far the principles are supported by known facts and how endot,hermic reactions may be explained in accordance with them we must point out that those endothermic reactions which are brought about by the so-called concurrence of an0 ther exothermic reaction require in reality no special explanation, the endo- and exo-thermic reactions forming in reality but one action.Thus copper will not dissolve in weak sulphnric acid the action being endothermic but zinc does dissolve the action being exothermic ; yet when alloyed with zinc copper dissolves in the acid the action being C1 &fortiori the less saturated anhydrous salt would do so also and the dissocia-tion products of the hydrate would therefore not be simpler than the reagent.* Some of both salts would no doubt be formed in the first instance but the one which was formed with the least evolution of heat would be eventually entirely converted into the other this reaction being ex hyp. one of those which does occur, and which having once taken place could not be reversed without an absorption of heat. VOL. LV. 18 PTCKERINO THE PRINCIPLES OF THERMOCHEMISTRY. accompanied with an evolution of heat. But this is not really a case of the copper dissolving but of a compound of copper-brass-dis-solving and ,since brass is capable of dissolving with an evolution of heat it is but in accordance with general observation to find that it does so. As true solids do not react with each other the cases to be examined are those in which gases or liquids figure.The reactions indicated below are the chief reactions in which gases are concerned and which are endothermic at 18". HZO 0,aq. c12,o. X O . N,O. N,02. Nz0,O. N20,2H20( = (NH,NO,). N2,2H20 = (NHdNO,). C2,% C,N,H. S 02aq S. H,I. I co27c* This list affords a striking argument in favour of the above prin-ciples for not one of these reactions is capable of taking phce at ordinary temperatures. One or two of them occur directly at higher temperatures (C,& ; C2,H2j but at these temperatures they are probably exothermic at any rate our imperfect knowledge of the heat capacity of the bodies concerned is not sufficient to enable us to affirm that they are not so. In the case of GO + C = 2C0 the reaction which takes place at 600" is no doubt endothermic at that tempera,ture and affords one of the simplest illustrations of the satisfaction of affinity producing endothermic results indirectly owing to the dissociation of the reagent.Thus at 600" carbon dioxide is partially dissociated that is the stable condition of a mass of that gas is oC02 + (1 - x)CO + (1 - x ) + 0 2 and if either of these three siibstances be removed the amount of dissociation will be increased or diminished till this stable condition be reproduced. Carbon being capable of combining with the free oxygen at this temperature, evolving 28,000 cal. in so doing removes this oxygen and necessi-tates the liberation of a fresh supply by the further dissociation of the dioxide and so on till this latter has been entirely decomposed a decomposition which absorbs 68,000 cal.leaving the algebraic sum of the actions at -40,000 cal.* * Referring to this action Rathke states that he considers it possible that th PICRERING THE PRINCIPLES OF THERMOCHENISTRY. 19 No real difficulties arise till we come to consider cases in which liquids are chiefly concerned and the three most difficult classes of such cases are the following :-(1.) The endothermic results on dissolving solids in liquids. (2.) The endothermic results on diluting strong solutions. (3.) The endothermic results attending double decomposition between substances in solution. Neither the immediate nor the mediate source of the absorption of heat which occurs when many salts are dissolved in water (to take a concrete instance of a solid and solvent) have ever been elucidated.It is j u s t as insufficient to say that it is due to the fusion of the solid as to say that this is a physical action and therefore requires no explanation. As a matter of fact the heat absorbed cannot possibly be accounted for by the fusion of the solid. The absorption amounts in many cases to some ~0,000 cal. per equivalent of salt.,* and this represents bnt a portion possibly but st half o€ the total value of the endothermic action for it is always counterbalanced t o a greater or less extent by the heat evolved in the formation o€ the hydrates of which the solution is composed. The heat of fusion of very few salts has been determined and to calculate its heat of fusion at the ordinary temperatures at which it is dissolved it is neces.mry to know not only its heat of fusion at the temperature at which fusion naturally occurs but also its heat capacity (specific heat) in the liquid and solid state.Potassium and sodium nitrates are the only anhydrous salts for which we have these data but judging by a comparison of these salts with ot'her bodies, their heat of fusion is not abnormally small yet it amounts to only-- (5300 + 3849 =) -1451 cal. for NRNO at 18", -(4800 + 2678 =) -2122 , for KNO ,, quantities wholly insufficient t o explain the heat absorbed in the dissolu-tion of the salts at 18" which is -5000 and -8M3 cal. respectively. Moreover we have a still more fatal objection in the fact that the heat absorbed i n dissolving a salt increases rapidly as the temperature is lowered,+ whereas the heat absorbed in.its fusion diminishes with a fall of temperature.presence of the second reagent may of itself inducedissociation of the first one. This amounts to the inadmissible conception of the satisfaction of a6nity producing directly a further supply of affinity that ie an endothermic reaction occurring in which affinity is the only agent. The whole virtue of dissociation in producing ei&khermic results consists in the presence of a third body (the product of the dissociation) capable of reacting with the other reagent ; till some of this third body is present no such reaction can take place. * I refer for the sake of simplicity to anhydrous salts only. t This increase cannot be due to a diminution of heat evolved in the formation of 0 20 PICKERING THE PRINCIPLES OF THERMOCHEXISTRY.But when a salt is dissolved in excess of water it becomes far more disintegrated than when it is merely fused. When fused the mole-cules are within the sphere of each other's attraction and are indeed, I believe combined to form molecular aggregates but this cannot be the case when they are separated from each other by several hundred molecules of the solvent ; they are then as much beyond the sphere of each other's attraction as if they were in the gaseous condition ; indeed insisting as I think we munt do on the continuity of the liquid and gaseous conditions,-a continuity which has so often been urged against the hydrate theory of solution but which as a matter of fact is of vital importance to that theory,-we must acknowledge that the condition of La substance dissolved in excess of water is identical with that of its vapour at the same temperature and to separate the molecules from each ohher to the same extent whether the condition be the dissolved or the ordinary gaseous condition must absorb the same amount of heat.Thus we have not only the heat of fusion of the solid but also its heat of volatilisation as a source of absorption of heat and the sum of these two quantities would cer-tainly be amply sufficient to account for the absorption noticed on dissolution," being in those cases where data are known ten or twenty times greater than the heat of fusion alone; and moreover it is a quantity which increases as the tempemture falls precisely what is noticed in the heat absorbed in dissolution.Thus the heat of fusion of Br2 is -388 cal. at 18" and diminishes by 4.8 cal. for every fall of 1" ; tlhe heat of volatilisation is - 7562 cal. increasing 11.3 cal. for a fall of 1". The sum of these two is -8032 cal. increasing by 6.5 cal. for a fall of 1". In the case of water-Heat of fusion at 18" = -(1580 +8*64(t - 18)). Heat of volat. a t 18" = -(lo798 - 12.05(t - 18)). Sum a t 18" . . . . . . . . = -(12378 -3*41(t - 18)). Having thus traced to its source the absorption of heat which occurs during dissolution the next question is what forces exist sufficient to bring about such endothermic results ? As previously stated they must be due to the dissociation of the reagents,-the salt the hydrates these hydrates are lesa dissociated at lower than a t higher tempera-tures and the heat of complete formation of any particular hydrate is probably influenced but very little by temperature a t any rate this is so with the formation of solid hydrates as I have shown ('l'rans.1887 335). * The heat of volatilisation in such a case mould be 580 cal. less than it is when the substance is vaporised in the usual way since this amount of heat is absorbed in the external work of expansion in the latter case PICKERISG THE PRINCIPLES OF THERMOCIBGMISTRY. 2 I or the water. Dissociation of the salt may occur to a certain extent in the case of hydrated salts but it is scarcely worth enquiring further into its influence since it will not help us to explain other cases; it must therefore be the dissociation of the water which acts as the primary cause.On views which I and others have for some years been pressing all liquids and solids must be regarded as consisting of compounds or aggregates of t4he fundamental molecules these aggregates just like the hydrates in a solution being more or less dissociated and being reduced t o less complex ones as the temperature rises ; and the recog-nition of these aggregates can alone give a satisfactory explanation of the physical properties of matter in its three conditions. Thus in true gases such aggregates as the vapoitr-density tells us, do not exist and from gases we learn that the heat capacity of each atom is a constant quantity.* With solids as with imperfect gases, the heat capacity though very nearly the sum of the atomic heats is not exactly so and with solids increases slightly with the tempera-ture ; this is exactly what would occur if the solids consisted of dis-sociating aggregates tlie heat absorbed by the dissociation renders the apparent heat capacity greater than it is with gases and as the aggregates dissociating become less complex and theleefore more firmly united as the temperature is higher more heat mill be absorbed in their decomposition and hence the apparent heat capacity of the solid will increase.Rut this variation in the heat capacity of solids will not be very great since the stability of solid particles is unfavourable to dissociation ; when however we come to liquids, where the particles are less restrained in their motions dissociation will take place to a much greater extent and we find as a consequence, that the heat absorbed in this dissociation is so great that it not only renders the apparent heat capacity of a liquid much greater than that of the corresponding solid or gas but that it makes it increase so rapidly with a rise of temperature and produces such irregularities in the increase that no approach to any so-called law can be observed here.As the boiling point is appruached the absorption of heat generally becomes much greater and under ordinary atmospheric conditions an almost sudden absorption (heat of vaporisation) occurs at this point when the simplest possible aggregates are resolved into their fundamental molecules.The irregularities observed in the expansion and other physical properties of many liquids can also be explained only on the supposition of a #discontinuous action which is wholly inconsistent with the idea of the fundamental molecule being * But not the same in the two ca8es. Wit,h gases 2.4 and with solids 6'4 is the heat capacity of each atom 22 PICKERINO THE PRINCIPLES OF THERMOCHEMISTRT. the acting unit of a liquid.* The continuity of the liquid and gaseous conditions is strictly adhered to according t o this view and the heat of volatilisation of a liquid a t any temperature (less the heat absorbed in producing the expansion) is simply the heat of decomposition of the liquid aggregates existing a t that temperature into the funda-mental molecules.Every physical fact relative to water tends to show that its compo-sition in the liquid condition is pre-eminently complex atnd its heat of volatilisation tells us that a t 18" (for instance) the heat of formation of the water aggregates is as much as 10,000 cal. approximately.+ It is argued that the so-called determinations of the molecular weights of solids and liquids by measuring the extent to which they lower the freezing point of some solvent (Rxoul t's method) proves that these molecular weights are of a very simple character. But these results which are inconsistent with so many other facts receive an easy explanation on my views as to the nature of dissolved substances. Raoult's method applies only to dilute solutions and in these dilute solutions the substance is really in the gaseous condition and we are determining the molecular weight not of the solid or liquid but of the gas.$ Now according to the kinetic theory of gases which in this respect applies equally to all fluids a mass of water consisting of' agqregstes having the average composition of zH,O at a temperature of 18" is made in reality of aggregxtes some a t a temperature above lS" some a t a temperature below 18" those aggregates which are at the higher temperature will be dissociated into less complex aggregates than * All that is said of the heat capacity may indeed be said of the expansion of substances.Perfect gases where no dissociation occurs expand regularly ; in dis-sociating gasps the expansion increases rapidly ; iu solids where but little dissocia-tion is possible the expansion is comparatively constant whereas in liquids where dissociation may occur to a large extent the expansion increases rapidly and often irregularly.I t may be suggested that the peculiarities in the expansiou are the causes of those in the heat capacity but this still leaves us with the equally d i 5 ~ u l t problem of explaining the former. I t is far more probable that they are both con-sequences of dissociation. t Taking the iiienn heat capacity of 18 grams of water between 18' and 100" as 18.1 and that of steam at constant volume as 6'65 and the heat of volatilisation of 18 grams of water at 100" as 9650 cal. we get. [9650 + 82(18*1 - C.65)=] 10,589 cal. as the heat of volatilisation at 18" of which 580 cal.are absorbed in producing the accompanying expansion. The correctness of this value hou ever is doubtful as the heat capacity of steam below 130"has not been determined ; but an error of even several thousand caioiqies would not affect the present argument. $ Ramsay (Trans. 1888,623) found the method applicable to nitrogen tetroxide when dissolved in only 18 mols. of acetic acid ; but in this case the vaporisation of the tetroxide due to its dilution would be materially increased by the tern-perature of the determination being only 10' below its normal boiling point PICKERING THE PRINCIPLES OF THERRIOCHEMISTRY. 23 sH20 say mH,O mlH,O &c. whereas those at the lower temperature will be more complex say zH,O zlH20 ; at this particular temperature, therefore the stable condition of a mass of water is such that there is a certain number of x m and zHzO aggregates presenh and if any of these be removed from the sphere of action more dissociation or com-bination will take place till this stable conditioii be restored, I n fact the water at this temperature is continually giving off fundamental molecules (that is has a vapour-tension) a certain number of these fundamental molecules must be present in the mass of the water and these molecules possess a potential energy equivalent to 10,000 cal.greater than that of the average particles constituting this mass and these particles will be able to effect a combination with evolution of heat which in the case of the average particles would involve the absorption of some 10,000 C R ~ .and therefore be impossible. One fundamental water molecule coming in contact with a salt molecule would thus be capable of combining with it if the heat of volatilisation of the salt molecules was liot greater than 10,000 cal. : the simultaneous arrival of two such water molecules would combine with the salt if its heat of volatilisatiou were double this quantity; but it is not necessary even to have recourse t o this simultaneous arrival even in such cases €or the combination of the salt molecule with one molecule of water only would not remove the former entirely from the sphere of attraction of its fellows it would not be completely volatilised and would not require to be supplied with as much as its full heat of volatilisation.The free water molecules being thus removed by their combination with the salt from the sphere of action other water aggregates must, according to the laws of dissociation split up to supply the vacancies, and this action is arccompanied by an absorption of - 10,000 for every 18 grams thus dissociated. But if this absorption of heat were not subsequently counterbalanced we should have proved far too much. I n the cases which have been investigated it has been found that each salt molecule combines ultimately with over 100H20; the heat absorbed in liberating this 100HzO would be 1,000,000 cal. not t o mention the heat absorbed i n the volatilisation of the salt, and it is quite impossible to imagine that the heat of combination of the water and salt molecules is so great as to nearly and often indeed more than counterbalance such an absorption." But here the teaching of the heat of neutralisation comes to our aid ; we learn from it as I have shown (Trans.1888 872) that the affinity which binds the dis-solved molecules to those of the solvent does not affect that by which * The heat developed in the mere combination of each water molecule with a salt molecule is probably between 200 and 5000 cal 24 PIOKIIRINO THE PRINCIPLES OF TIIERDIOCHEMISTRT. the solvent molecules are united with each other ; in dilute solutions, the water molecules are just as much combined with each other as they are in a mass of pure water the hydrates present are compounds of the salt with the aggregates or polymers of H,O ; and thus when a solid is dissolving as the proportion of the water molecules in the hydrate increases these then recombine with each other and in doing so will of course evolve the same amount of heat that their produc-tion from the water aggregates absorbed.The net results obtained, therefore when dissolution is complete will simply be the algebraic sum of two quantities (1) the heat evolved in the combination of the salt and water molecules (2) the heat absorbed in volatilising the salt molecule; and according as the former or latter of these is the greater so will the heat of dissolution be positive or negative ; but the motive power if I may use such a term which produces these results is the energy contained in the free water molecules. When a salt is dissolved by admixture with ice the heat absorbed is greater by the heat of fusion of the ice than in the case of water, but the same explanation will be sufficient in this case also.Ice near its melting point is certainly in a state of incipient fusion ; and some of the particles of liquid water present in it are certainly dissociated, even as far as the fundamental molecules as is proved by the con-siderable vapour-pressure of ice at this temperature. We therefore, have the same motive power as in the case of water. It may be predicted however that no such action would occur if the ice were perfectly dry as it is at a temperature some degrees below zero and it is certain that no such action could take place if the temperature were below that of the formation of the so-called cryohydrate.The endothermic results noticed in marly cases when strong solutions are diluted are but the extension of the action primarily occurring when the salt is dissolved. As the dilution is increased the hydrates become higher and less dissociated evolving heat while the salt becomes more entirely volatilised absorbing heat and the sign of the thermal change depends on the relative value of these two actions. Some years ago (Chem. News 64 217) I was led to believe in the existence of t w o such opposite actions from the mere study of the curves representing the heat of dilution as given by Thomsen. h o t h e r endothermio reaction also undoubtedly occurs in many cases-the dissociation of a salt into its free acid and base. This I think is a purely mechanioal action operating in the following manner.The salt in question when liquid is somewhat unstable and partially dissociated at the existing temperature even when no water at all is present and the extent of this is limited by the chances which oocur of the dissociated components meeting each other when in a suitable condition and recombining and these chances o PICRERING THE PRINCIPLES OF THERMOCHEMISTRY. 25 meeting are diminished a hundredfold when we increase a hundred times the space over which the substance extends by diluting it. The amount of dissociation occurring would thus be directly pro-portional t o the volume of the liquid and Thomsen’s results with acid sulphates (Thermochem. 3 Platte VI) tend to support t h i s view.* On such a view dilution could never start but only increase disso-ciation and we have no grounds for supposing i t to be otherwise.The third important class of enthodermic reactions to be explained is that in which double decomposition occurs between two dissolved substances. Double decomposition between two salts presents us with an instance of most frequent occurrence and to investipte this we may go to the root of the matter by ascertaining how and on what principles a base divides itself between excess of two different acids. According to the deduction drawn above from theoretical considera-tions the acid which evolves the most heat on neutralisation will take the whole of the base and consequently if both acids have the same heat of neutralisation as is generally the case when excess of water is present they will each take the same amount of the base this re-ferring only to cases where the salts formed are stable and remain in solution and it being assumed of course that the acids are present in equivalent proportions.When the acids are not present in equivalent proportions the base will divide itself between tbem in proportion to the number of equivalents of each present ; the division being regulated simply by the chances of impact. This is nothing but the law enunciated by Berthollet in 1803 and discarded at the present time as being altogether insufficient. B u t I think that it will yet be found sufficient while the more elaborate theories of recent days will fail. In cases where one of the salts formed is partially dissociated, the stable salt will be formed to the exclusion of the dissociated one when the solvent water is very large; but if the water is not in large excess there will be st limit to the dissociation and some of the less stable salt will be formed.For the salt being dissociated means that a t the given temperature its condition of stability is xAB + (1-%)(A + B) (A and B being the acid and base which form it) ; the free base B coming in contact with and com-bining with the stronger acid A ie thus removed from the sphere of action and more of the salt AB dissociates to give a further supply * There are of course other actions oocurring besides the dissociation of the salt the dilution proceeds ; we should not therefore expect the action to be repre-sented by a straight line but by lines which more nearly approach straightness than they do in cases where these other actions are the only ones occurring as in the case of diluting stable salts.Such are the characters of the curves in the two cases 26 PICKERING THE PRINCIPLES OF TEERXOCHEMISTRY. of free base and this action must continue as long as any dissociation at all takes place. But the proportion of the free weak acid present increasing apoint will be reached when every molecule of AB will find itself within the sphere of action of so many moleciiles of this acid that there would always be one of these present in a suitable condition to recombine with the base B the instant it dissociates from its former acid molecule. Practically there would be no longer any dissociation under these circumstances.By separating the salt AB farther from the free acid an increase in the proportion of water present would increase the limits of dissociation and therefore also the proportion of stable salt formed. It is obvious also that this latter would be increased by adding more of the stronger acid and diminished by more of the weaker one. All the determinations which have been made of the division of base between two acids by thermal methods depend on the comparison of the action of an acid on the base with that of snlphuric acid on the same base. Supposing in the first place that the heat of neutralisation of H2SOa per H displaced is the same as that of HCl and HNO,(a supposition which I shall shortly justify) then when 4NaOH is mixed with 4HCl and 2H2SOr the system formed according to the princi-ples of division of the base which I have laid down would be 2NaC1 and 2HC1 NazSOc and H,S04,-an equal division.But as a matter of fact whatever the explanation of the fact may be (and the explana-tion will be given below) Na2S04 and H,SO react on each other and form the acid salt 2NaHS04 thus leaving no free sulphuric acid, and an alteration in the division of the base would therefore become necessary in order to supply the place of the free sulphuric acid thus removed. In fact sulphuric acid acts as a monobasic acid only in this reaction and consequently we should compare 4HC1 with 4H,S04 in which case the base would divide itself equally between the two acids whereas when we compare 4HC1 with 2 H z S 0 4 the base would divide itself in the proportion of two equivalents to the former ai;d one to the latter.Now these theoretical deductions are entirely supported by the ascertained facts of the case. HN03 HC1 HBr and HI acids of which the heat of neutralisation is the same and which form stable salts divide the base between them equally the relative numbers obtained by Thomsen being 100 100 89 and 79 a@ these numbers are certainly as nearly equal as could be expected seeing t,hat Thorn-sen’s method contains many obvious sources of inaccuracy for he regards certain small quantities as being negligible he assumes certain actions to be represented by true hyperbolae which (judging from my results on the heat of dilution) they are not and the water which he The latter action is therefore of paramount importance PICKERIXG THE PRINCIPLES OF THERMOCHENISTRY.27 used was only 100H20 per each equivalent a quantity far too small to admit of t’he thermal results of dissolution being complete.* With iH2S04 and iH2S04 in accordance with my deductions we find that one-third only of the base is taken the numbers found being 49 and 45 respectively,? while with the other acids investigated the numbers were as follows :-Trichloracetic acid 36 Orthophosphoric acid . 25 + Oxalic acid 24 Monocbloracetic acid 9 Hydrofluoric acid 5 & Tartaric acid 5 + Citric acid 5 Acetic acid 3 4 Boracic acid (,B,Os) 1 + Silicic acid 0 Hydrocyanic acid 0 Of these all except phosphoric and oxalic acid form salts dissociated by water.and hence in accordance again with my deductions we find that they take either none of the base or but a small proportion of i t ; the dissociation of the trichloracetates is very small comparatively, and hence the acid gives an exceptionally high value. With oxalic acid, the quadrantoxalate is probably formed and hence 2C2H204 instead of QC2H204 should be compared with HN03 in which case the value for the avidity would be 96 that is nearly 100 as with other strong acids. With phosphoric acid only the results seem rather anomalous, but it must be reuiembered that in addition to other sources of uncer-tainty these numbers were not obtained by direct comparison with nitric acid but with sulphuric acid where the results may be compli-cated by the formation of acid and double salts.Ostwald (J. pr. Chenz. [ 2],19,473) made some determinations of the so-called “avidity” of acids when used in normal and decinormal solutions which showed that with the weaker acids the avidity was * For objections raised on other grounds Bee Hagemann Eilaige kritische Bermerkzcngen zur Aviditatsf ormell. t I.e. when HNO and +H2SO4 is mixed with zNaOH for every 100NaOH taken by the former acid the latter takes only 49 or one-third of the whole. $ The fluorides are certainly dissociated in solution as is shown by their alkaline reaction and their action on glass. The abnormally large heat of neutralisation of hydrofluoric acid is probably due to the 8ame causes as those which I have suggested (Trans. 1885 598) to meet the case of sulphuric acid this would involve the recognition of the acid having a more complicated constitution t,han HE” many facts inchding its thermal reactioiis render this very probable.Berlin 1887 28 PICRERING THE PRINCIPLES OF THEHMOCHEMISTRY. far greater when dilute than when strong. These results apparently in opposition to my deductions above are easily explained. The comparison was made by determining their relative action on calcium oxalate and the more the calcium salt formed was dissociated the more acid would there be left to continue the action on the oxalate. Directly opposite results would certainly be obtained by other methods. We assumed in the above that the heatt of neutralisation of srilphuric acid was the same per H atom displaced as that of the other acids, namely 13,800 cal.As a matter of fact, the experimental value is 2 x 15,690 cal." for the displacement of the two atoms of hydrogen ; but as we have seen i n this case the two atoms of hydrogen are not displaced but only the first one and the displacement of this evolves only 14,754 ; but even this number is greater than i t should be under perfect conditions for on the one hand it would be reduced by several hundred cal. if the dilution were infinite while on the other the acid salt formed is partially decomposed into the normal salt and free acid, a clecomposition which evolves heat and the removal of these two sources of evolution of heat would no doubt reduce the heat of neutralisation to the normal 13,800 cal.One more difficulty which lies at the root of the matter remains to be explained namely why is the acid sulphate formed in preference to the normal sulphste since the formation of the latter corresponds to the greater evolution of heat? Or in other words why does the normal salt combine with free acid to produce the acid sulphate with absorption of heat ? The explanation given by Berthelot (11 642) is not I believe, far from the truth. He points out that although the reaction between the sulphate and acid in weak solutions is endothermic yet between the anhydrous substances it would be accompanied by an evolution of heat. But it is not necessary to go back so far as the anhydrous substances to find an exothermic reaction and as these anhydrous substances do not exist in the solutions by so doing we do not in my opinion obtain any real explanation.The reaction how-ever will be exot,hermic when it takes place between the sulphate and any of the lower hydrates of the acid some molecules of which must certainly be present owing to dissociation even in comparatively dilute solutions. Thus although the reaction-NaqSO,2OOHZO + HzSOa200H,O = 2(NaHS04200HzO) gives -1870 cal. yet NazS04200H20 + H2S049H20 = 2 (NaHSOa104.5H20) * The number refers to H2SO4,200Hz0 with 400H20 it would be about 300 -1. smaller PICRERING THE PRINCIPLES OF THERMOCHEMISTRT. 29 gives (- 1870 + 2150 - 150 =) +130 cal. and with still lower hydrates of the acid and of the normal sulphate the reaction would become rapidly more exothermic. This reaction being known to occur when the substances are taken in this degree of hydration, would necessarily occur here and the removal of these lower hydrates of sulphuric acid from the sphere of action would necessitate a fresh dissociation of the higher ones to supply their places; hence the absorption of heat observed.The action is but an illustration of the principles here enunciated,-% possible action must always take place if it develops heat whatever absorption of heat its occurrence subse-quently involves owing t o the partial dissociation of the reagents. It is scarcely necessary however to point out that this reaction is never complete at any rate in weak solutions for it is limited by the reverse action the acid sulphate formed being dissociated back into free acid and neutral salt by the action of excess of water.” And an increase in the amount of water present will not only increase this reverse action but will also diminish the chances of the combination of the acid and normal salt by diminishing the proportion of the lower hydrates of the former in the liquid.It will thus be seen that the whole notion of the distribution of a base between two acids being det.ermined by certain constants peculiar to the acids termed their “ affinity,” or “ avidity,” becomes unnecessary and incorrect. And the manner in which this distribution occurs, instead of being irreconcilable with the results of the heat of neutralisation as L. Meyer maintains is determined solely by it and the known laws of dissociation. It is indeed incomprehensible how these ideas of “ avidity ” could have been accepted almost without question as has been the case, unless it be that the interesting mathematical exercise relating to affinity indulged in by Guldberg and Waage (ztudes mr Zes afinite’s Chimique Christiania 1867) was sufficient (as is generally the case when x and y is introduced into chemistry) to ensure the blind acceptance of t h a t which common sense would reject.What can be the meaning of an acid having a property which is a “ constant,” and which yet varies continuously with a variation in the proportion of the solvent present. In every cage which has been investigated the water bas a most marked influence on the division of the base. Thus Thomsen’s results (I 131) which he interpretad as showing that the water has no in-fluence on the avidity give-# This reaction would be exothermic with any hydrate of the acid aulphate which contains sufficient water to form on disso&tion a hydrate of the acid higher than about H,S04,9H,0 30 PICKERINCI THE PRINCIPLES OF THERMOCHEMISTRY, Avidity of H2S04 when 150 H20 for each double equivalent is present When 200 H,O is present 7 300 7 = 52* = 46 - 49 -while Berthelot who combats the idea of this “avidity,” gives the following values for the reaction of-i$K2SOa on HNOy in total of 2 litres of water -1810 cal.7 99 9 4 9 -1780 ,, 77 7 9 9 9 8 97 -1600 ,, 7 9 9 9 20 9 7 -1500 ,, And Ostwald (Zoc. sup. cit.) gives amongst others the following numbers :-In I n Relatire avidity of N solution.N/10 solution. Formic acid 2-33 12.9 Acetic acid. . 1.05 7-35 Monochloracetic acid . 4.6 21.3 Citric acid. . 2.75 14.4 Yet these numbers have been accepted as being constants in each case.? It must even be doubted whether the concordance between the vdues obtained by different methods is sufficient to warrant us in con-cluding that the numbers obtained really represent the division of the base which has taken place in the particular solutions investigated ; thus the values for-Sulphuric acid vary between nearly 100.0 and 46.0 Formic acid vary between 12.9 , 2.6 Acetic acid vary between 7.4 , 1.2 Monochloracetic acid vary between 22.0 , 5.1 Trichloracetic acid vary between 89.9 , 36.0 Oxrtlic acid vary between 43.0 , 22.6 Isobutyric acid vary between .5.8 , 0.9 Citric acid vary between . 14.4 , 3.1 and so on; numbers which no one who was not bent on proving a pet theory, If the proportion of water was sufficient to dissociate all the acid sulphate formed the +H,SO would either take all the base or exactly half of it according as its heat of neutralisation (to form the normal salt) in this state of dilution still remained greater than that of the nitric acid 13,800 cal. or which ie quite possible, was reduced so as to be equal to it. t Perhaps I am somewhat unfair in my criticism of Ostwald’s opinions he cer-tainly admits that the water present as well as the temperature influence the values for the affinity to a very great extent ; but on the other hand the whole ides of the existence of such a thing aa a conutant of atfinity is dependent on ite non-variation PICKERINO THE PRINCIPLES OF THERMOCHEMISTRY.3 1 irrespective of fact would ever have regarded as being identical in the respective cases.* When a base (NaOH) is mixed with two acids (HCl and HBr) of which the heat of neutralisation is the mme the enormous number of molecules actually taken in any experiment is sufficient reason for practically equivalent amounts of the two salts (NaC1 and NaBr) being formed but it is not so apparent why these same salts should be formed in equivalent proportions as we know they are when we mix one of them with the other acid NaCl with HBr for instance, unless dissociation occurs to such an extent that the fundamental molecules themselves are broken up into their constituent atoms, which would then combine with the other atoms of opposite character according to the frequency of collision that is in equivalent propor.tions. This resolution into atoms cannot I think be maintained but the necessity for it is obviated if more than two hydrates of each substance saturated to different extents be present. For the lower and less saturated hydrates of the one salt might react with the higher hydrates of the opposite acid so as to produce an evolution of heat while the same would occur with the lower hydrates of the other salt acting on the first acid and thus we should get ever-occurring opposite reactions admitting of the known interchange of radicles and soon rekulting in a condition of equilibrium.From the principle that the sum of the kinetic and potential energy of any system is an unalterable quantity and that affinity is energy it follows that the heat evolved in any reaction is the difference between the total energy of the system before and after the reaction and hence it seems at first sight that we should be able t o calculate the total energy in any substance and consequently the heat evolved in any reaction from a knowledge of the heat necessary to raise the reagents and compound from the absolute zero t o the temperature of the reaction. The principle of this method is indeed applicable with absolute certainty to the determination of the diference in the heat evolved in any reaction at two different known temperatures (Person’s principle the non-application of which would mean that energy could be created and destroyed see Trans.1887, 329) but it fails when we attempt to apply it to any determination of the actual amounts measured by extending our arguments as far as the absolute zero for the following reasons. * The most reliable thermal method (though even this would not be absolutely certain) would be t,o make a series of determinations with acids neutralised to different extents previously with the base and to plot out the results in a diagram and thus find the proportional neutralisation requisite to form solutions which on being mixed would develop no heat. Thomsen’s results quoted above were deduced from some determinations of this kind made by him 32 PICKERISG THE PRINCIPLES OF THERMOCHEMISTRY.(1.) The heat capacity of substances at ordinary temperatures affords no clue as to what their heat capacity would be at such low temperatures indeed we have good reason to suppose that great and comparatively sudden changes would be experienced in this heat capacity before the absolute zero were reached (see L. Meyer 87). (2.) Because we do not know where this absolute zero may be situated the generally accepted temperature of -273" is simply what the zero would be if a gas remained a gas and contracted regu-larly when cooled to this point; both of which suppositions we know to be incorrect in questions on thermodynamics -273" gives correct results simply because it is applied only to cases where perfect gases are in question and its use is simply equivalent to the shatement that gases expand 2+3 of the volume at 0" C.for each degree." Person's attempt (Awn. Chim. Phys. 21 295 ; 27 250) to find the absolute zero from other data treated in a precisely similar manner, led to discordant results. Assuming that ice and water could remain as such at the absolute zero and that they had then the same heat capacity as at known temperatures he found that the absolute zero should be -160" instead of -273" and if he had applied his principle (as it should be applicable if true) to the case of water and steam he would have found the still less acceptable result +850" C.f for his absolute zero. It is useless to base any theory on the supposition of facts being otherwise than we know them to be. (3.) Because it by no means follows that at the absolute zero of temperature potential energy of affinity as well as kinetic energy would be non-existent.Facts indeed favour the contrary view. Affinity can cease to exist as such that is become converted into heat only by being saturated by the combination of the sub-stances endowed with it. No such saturation can take place on cooling a perfect gas since a perfect gas is a substance in which the fundamental molecules never come within the sphere of each others i t The confirmation of -273" by Joule's evolution of Carnot's function (Scientifi Papers ii 290) is not independent as it is based on the coefficient of expansion of gases. Raoul Pictet's (Compt. rend. 88,855) calculation of the melting points of the elements based on -273" being the absolute zero gives more acceptable confir-mation but it depends on an hypothesis to start with and the variation of the constant obtained between the somewhat wide limits of 4 and 5 would allow of considerable latitude in the zero point taken.t The absolute zero is according to Person's argument the temperature at which the heat of fusion of ice is tail and similarly it should be that a t which the heat of volatilisation of wat,er is also nil. It appears to me that this latter tem-perature must be identical with the critical temperature of the liquid in question, but to calculate it properly we should have to take the actual (unknown) heat capacities a t these temperatures and not those a t other lower temperatures as ie the case abore ISOMERIC SULPHONIC ACIDS OF P-NAPHTHTLAMINE.33 attraction (in proof of which we find that when perfect gases combine to foPm a perfectly gaseous compound the heat of their combination a t constant volume is the same at all temperatures) with solids, the constancy in the heat given out in cooling a t most 6.4cal. per atom shows that the greater part of this is in all probability due to the fall of temperature only and that very little of it is due to combination ; this leaves but the heat evdved in the passage of the substance from the perfectly gaseous to the solid condition less that evolved by the mere fall of temperature to account for t'he total affinity possessed by the perfect gas an& this would I think fall far short of the amount of affinity known to. be possessed by many gases, for it could rarely if ever amount to. 10,000 cal. per moleede." The heat of neutralisation gives us again much information on Chis point for it shows that the agnity which serves to unite the similar molecules of a solvent with each other and which could aloiie become saturated by a fall of temperature is not the only €ree afiinity possessed by tbe molecixles fop it is independent of bhnt affinity owing to which these molecules combine with those of a salt and effect its dissolution; in other words there is other affinity besides that which could become satisfied by cooling the liqmid. For these reasons the so-called absolnte zero can give us no aid in calculating the heat evolved in a chemical reaction and we must be content to wait f o r the present till some other meana of doing so be discovered

ISSN:0368-1645    

DOI:10.1039/CT8895500014

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

ISOMERIC SULPHONIC ACIDS OF P-NAPHTHTLAMINE. 33 IV.-The Isomeric Sulp phonic Acids of P-Naphthylanaine. By ARTHUR G. GREEN. BY the sulphonation of 6-mphthylamirre under different conditions, four isomeric monosulphonic acids have been obtained [a (Badische), /? (Bronner’s) y (Dahl’s) and d (Bayer’s)] but our knowledge con-cerning them is still very incomplete. It therefore seemed of interest t o communicate a few results which I have obtained in their investi-gat ion. By heating P-naphthylamine with 3 to 114 times its weight of ordinary sulphuric acid at 100-105” a mixture is obtained which * With Br it is for instance less than 8000 cal. and supposing i t were as much as this with H, this would give the afinity of H + Br2 as 16,000 only whereas we know they combine to form 2HBr with an evolution of 17,000 cal.and that this compound so f0md is far from being saturated as is shown by its heat of dissolution. T’OL. LV. 34 GREEN THE ISOMERIC SCLPHONIC ACIDS consists according to Dahl (Germ. Pat. No. 29084 32271 32276),of the a- @- and y-acidsin the proportion of about 50 per cent. of a 10 per cent. of /I and 40 per cent. of y. These can be separat'ed by means of the difference in the solubilities or" the sodium salts in spirit and of the barium salts in water. The proportion of the several isomerides varies greatly with the temperature at which the reaction takes place ; thus by heating the above melt for some time at 120' the quantity of a-acid is greatly diminished whilst that of the p-acid is increased. On the other hand by sulphonation with three parts of fuming aulphuric acid (20 per cent.anhydride) a t 70-80" for a short time about 70 per cent. of the y- and 30 per cent. of the a-acid is formed but scarcely any of the @-acid. A similar mixture is obtained (Dahl Germ. Pat., No. 32276) by agitating P-naphthylamine sulphate with ordinary sulphuric acid for two or three days at a temperature of 15-20'. 13s heating p-naphthylamine hydric sulphate at 200-210" EL product is obtained which oonsists chiefly of the @-acid (Liebmann Monit. Sci., 1885 1043). By heating /I-naphthylamine snlphate (1 part) with 3 parts of ordinary sulphuric acid at 160-170" for one hour a mixture of about equal quantities of the P- and &acids is formed (Bayer and Dnisberg Rer. 20 1426 ; C . Schultz Ber.20 1358). The &acid is also obtaiued from a-naphthalenedisulphonic acid by heating it under pressure a t 250" with aqueous sodium hydrate and then with tmmonium chloride (A. Weinberg Ber. 20 2906 3353). The 6-naphthylamine-P-snlphonic acid is obtained from @-naphthol-P-sulphonic acid (Schaeff er's acid) by heating with ammonia under pressure (Farbfabrik vorm. Bronner Germ. Pat. No. 22547). The constitution of these four acids is probably represented by the formuh-a B Y 6 In these formuls it will be seen that the a- and y-acids contain the HSO group in an a-position whilst in the p- and &acids the HSOJ gronp is in the P-position. This explains the influence of temperature on the formation of the several acids for like the a- and P-sulphonic acids of naphthalene, the acids with the HSO gronp in the a-position (the a- and y-acids) are formed at low temperatures whilst those with the HSO group in the P-position (the p- and &-acids) are formed at higher temperatures, Also just as a-naphthalenesulphonic acid is converted into P-naph-thalenesulphonic acid by heating with HzSOa to a higher temperature OF 6-NAPHTHYLAMINE.35 so each of the a-acids of p-naphthylamine (the m- or ./-acid) is converted into a mixture of the two @acids (the p- and &-acids) by the same treatment. Products of the Sulphonation of /3-Naphthylamirte at 100-105". P-Naphthylamine was heated for five or six hours with 3-34 times its weight of ordinary concentrated sulphiiric acid at a tem-perature of 100-105" ; the melt was poured into water and the pre-cipitate washed pressed and dried.For the separation of the isomeric acids the method given in Dahl and Co's. patent was employed and found to serve very satisfactorily. The acids were converted into the sodium salts and boiled for an hour with six or seven times their weight of 90 per cent. spirit. The insoluble residue after pressing and a final extraction is the pure sodium salt of the or-acid. From the sodium salt the pure a-acid was obtained well crystallised in the form of prismatic tables. For this purpose i t was dissolved in boiling water some ammonia added and then acetic acid just short of pre-cipitation ; on cooling the acid crystallises out. Precipitation with acetic acid from an ammoniacal solution was found to be a very con-venient way of obtaining all these isomeric acids in a well-crystallised form.From the alcoholic filtrate containing the p- and 7-acids the spirit was distilled off the residue dissolved in water and precipitated with hydrochloric acid. The precipitated sulphonic acids were neutralised with barium hydrate and left to crystallise. A sparingly soluble barium salt crpta,llised out whilst the mother-liquor contained the easily soluble barium salt of the y-acid. From this the y-acid wm set free by hydrochloric acid and obtained pure in the form of small plates by precipitation with acetic acid. The sparingly soluble barium salt was purified by recrystallisation from water. According to Dahl id consists of the salt of the P-acid only but my experiments prove that it is a mixture of about equal parts of the p- and 8-acids.By repeated fractional crystallisations from hot water the two acids were separated. The more soluble one was found to be identical in appearance properties and in its sodium and ammonium salts with the &acid obtained by Bayer's method of sulphonating at 170". The &-acid was also obtained from the Yodium last which crystallised out on cooling the hot alcoholic solution of the mixed sodium salts (see above). This according to Dahl is the sodium salt of the P-acid but from my experiments it appears tb consist almost entirely of the salt of the &acid. The presence of the &acid as well as the p-acid amongst the products of the sulphonation at 100" might certainly be expected since as bas already been men-tioned both the a- and y-acids which are probably the primar 36 GREEN THE ISOMERIC SULPHONIC ACIDS products are converted into mixtures of p- and &acids on further heating with snlphuric acid.The proportion in which the four isomerides are formed a t 100" may be roughly estimated as about 50 per cent. of s,40 per cent. of 7, 5 per cenlt. .of @ and 5 per cent. of 6. Properties of the four Isomeric Acids. I n the formulae given above it will be seen that the a-acid differs greatly from the p- y- and &acids in being a homonucleal compound, whilst the other three are heteronucleal. This is fully borne out in their properties. Thus the a-acid is the only one whose sodium salt is insoluble in spirit. The azo-compounds also show characteristic differences.For instance the scarlets obtained by combining the diiizotised acids with p-naphthol are very similar in shade and readily soluble in water whether the 13- y or &acid is employed but that from the a-acid is almost insoluble. Again by combining diazotised primuline or benzidine with either the (3- y- or &acids scarlets of almost the same shade are obtained but the a-acid gives an orange. By diazotising and boiling with dilute sulphuric acid the a-acid was converted i.nto the corresponding a-sulphonic acid of @naphthol (Bayer's) whose sodium salt was soluble in alcohol and crystallised from it in silky plates exceedingly soluble in water. It is to be observed that the aaphkhylaminesulphonic acid insoluble in spirit, correspon\ds to the naphtholsnlp honic acid soluble in spirit.The ammonium salt of the a-acid forms very soluble large solid prisms; that of the y-acid exceedingly soluble tables; the &salt tolerably soluble small plates ; whilst the ,@salt which is the least soluble of ali crystallises in beautiful large thin plates often 1 or 2 inches long and having a violet fluorvscence. The ammonium salt of the p-acid serves very conveniently for its identification and separation from the 6-acid. The sodium salt of the @-acid crystallises in flat needles which when air-dried contain 2H20 (as given by Forsling Ber. 20 77). The sodium salt of the &acid crystallises in plates (according Bayer in needles). In regard to the crystalline forms of the free acids it has already been mentioned that the a-acid crystallises in large tables the ./-acid in plates.The &acid from whatever source it was obtained always formed very fiue voluminous needles (as stated by Bayer and others). When quite free from acid it is tolerably soluble in water. Since the occur-rence of the &acid together with the @-acid (whether obtained by sulphonation a t 100" or from the sulphonic acid of @naphthol) has hitherto not been suspected it appears probable that the @acid has scarcely ever been obtained quite pure. That this is indeed the case The ammonium salts of the four acids are very characteristic OF P-KAPHTHTLAMINE. 37 seems to be shown by the fact that the p-acid is always described as crgstallising in lustrous plates (which are even regarded as very characteristic) whereas I found that when obtained from the pure ammonium salt it invariably crystallises in compact prismatic needles.In order to prove that this difference of crystalline form is due t o a trace of &acid a small quantity of &acid was added to an alkaline solution of pure P-acid (needles) on precipitating from the hot solution with an acid the whole then came out in silky plates. S-Na~hthylaminesu~honic Acids from P-Na~lLtholsulpl2onic Acids. It is usually considered thatl two monosulphonic acids only are formed by salphonating P-naphthol under varying conditions viz., Bayer's acid and Schaffer's acid ; the former being the chief product at a low temperature the latter at a high temperature. Considering the analogous reactions of hydroxy- and amido-compounds it seemed t o me probable that corresponding t o the behaviour of P-naphthyl-amine p-naphthol should give on sulphonation at a low tempewture, a mixture of two a-sulphonic acids ( a and 7 ) which by heating to a higher temperature would be converted into two P-sulphonic acids ( p and 8).The different behaviour of Schaffer's acid so called when obtained under different conditions strengthened this assumption, and led me to attempt to prove the presence of another acid associ-ated with the P-acid. The product taken f o r invzstigation was the p-naplltholsulphonic acid obtained according to Armstrong's method, by heating molecular proportions of p-naphthol and 100 per cent. sulphuric acid a t 100". The sulphonic acid so obtained is usually assumed to be identical with Schaffer's acid.As the separation of the p-naphtholsulphonic acids is very difficult whereas that of bhe P-naph-thylaminesulphonic acids is comparatively easy the method which was employed consisted in converting the naphtholsulphonic acids into naph thylaminesulphonic acids by treatment with ammonia and separating these. 100 grams of ,%naphthol was heated with 70 grams of 100 per cent. HzSOa for 2 or 3 hours at 100-105" till the reaction was complete when the melt solidified t o a hard mass of the sulphonic acids. This was dissolved in water neutralised with sodium carbonate (filtering from a little tar which remains insoluble) and the sodium s d t precipitated with sodium chloride. Or else the hot solution was neutralised with ammonia when the sparingly solu-ble salt ci-ystallised out on cooling The yield of the ammonium salt is about 110 grams.The conversion into p-naphthylaminesulphon ic acid was performed by heat'ing with aqueous ammonia under pressure at 250-280" or by passing dry gaseous ammonia over the dry sodinnr salt heated to about 280-290". The product was precipitated wit 38 MATTHEWS ON ETHTLIC CINNAMTLDlETHACETATE. sulphuric acid and submitted to a careful series of fractional preci-pitations and crystallisations of the ammonium salt. By this means pure /?- and 8-sulphonic acids were isolated from it and had all the properties pyeviously described. The P-acid crystallised in prismatic needles its ammonium salt in large thin plates and its sodium salt in flat needles. The &acid crystallised in very fine matted needles its ammonium salt in small plates and its sodium salt in small plates. It is thus proved that the P-naphtholsulphonic acid obtained by Armstrong’s method is a mixture of the 6- and 8-sulphonic acids, whose constitution is probably represented by the formula-Whether the yacid occurs along with the a-acid amongst the pro-ducts of the sulphonation of @naphthol a t a low temperature I have not yet been able t o determine but hope to be able t o do so before long. In conclusion I desire to express my thanks to Messrs. Brooke, Simpson and Spiller in whose laboratory the above research was carried out

ISSN:0368-1645    

DOI:10.1039/CT8895500033

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

38 MATTHEWS ON ETHTLIC CINNAMTLDlETHACETATE. V.- On Et hylic Cinnam y ldiethacetate. By F. E. MATTHEWS Ph.D. SOME time since I showed (Chem. SOC. Trans. 1883,200) that a conden-sation product of ethylic diethacetoacetate with benzaldehyde could be obtained by the action of hydrochloric acid gas upon the mixture of the two substances. The product was proved to have the constitution CsH,-CH C H. C 0.C ( C2H5) 2* C 0 0 C2H5 or e t h y lic cinnamyldiethace tat e, but on account of the very poor yield of substance obtained and the difficulty of purification I was unable to do more with it than make analyses and obtain a bromine addition product. Since that time I have found a method by which the yield of the substance may be very considerably increased and as a t the same time it is much simpler and more convenient I have been able to prepare the substance in much larger quantities.In the previous process the mixture of substances after saturation with hydrogen chloride was allowed to stand for a few days ; it was then poured into ice-water the separated oil washed with sodic hydrate dried with calcium chloride and fractioned in a vacuum. After some time th MATTHEWS ON ETHYLIC CINNARIT'LDIETHACETATE. 39 portion boiling at 200-205" a t a pressure of 3 mm. solidified. It was then reci*ystallised from light petroleum and thus obtained pure. I have since found that if instead of allowing the mixture satu-rated with gaseous hydrochloric acid to stand for four days only it was allowed to remain for about a month and that during this period t,he mixture was two or three times more treated with hydrochloric acid gas at a temperature of 0" after this time crystals began to form in the mixture and continued growing till the whole became a solid mass but containing a large amount of the mother-liquor.The crystals were collected in a funnel fitted with a platinum cone, and by means of a filter-pump the mother-liquor was removed as far as possible the latter was then again saturated with hydrochloric acid, when in a few days a further crop of crystals was produced. This process was repeated until no more benzaldehyde remained in the mixture. The various crops of the crystals were first drained on porous plates and then dried by pressure between filter-paper and exposure to warm air. They were found to be free from chlorine and they all melted between 100" and 102".A portion was recrystallised from ether for analysis; after recrystallisation it resembled in every way the ethylic cinnamyldieth-acetate previously prepared ; i t melted at 101-102" and gave the following remlt on combustion :-I 0.2023 gram of the substance gave 0.5469 gram C02 and 0.1477 gram OH,. 11. 0.2027 gram of the substance gave 0.5504 gram GO2 and 0.1463 gram OH,. Found. Calculated for r-7 C,;H2,03. I. IT. c . 74.45 73.73 74.05 H 8.03 8.11 8-02 Analysis I was made with the crude substance I1 upon a portion that had been recrystallised. The substance is therefore even without recrystallisation almost pure ethylic cinnnmyldiethacetate. An attempt was made to saponify some of the substance with canstic potash but although a reaction took place it was not found easy to isolate the products.A small quantity of a potash salt was however, obtained and this yielded an acid which from its melting point appeared to be cinnamic acid but the quantity was insufficient for an analysis. On substituting baryta for potash saponification took place much more readily. Some of the substance was placed in a flask connected with a Liebig's condenser an excess of baryta-water was added an 40 MATTHEWS ON ETHYLIC CINNAMYLDIETHACETATE. the mixture raised to the boiling point. The ether melted under the solution and a gradual deposition of barium carbonate was noticed, a t the same time an oil somewhat resembling peppermint in odour, distilled over in small quantity; it was separated from the water by means of ether the ethereal solution dried the ether distilled off and the residue allowed to stand for some time when i t partly solidified.The crystals were separated from the liquid and were found to melt a t 100"; the oil on analysis gave figures approximating to those required by the original substance. The distillate appears therefore to consist chiefly of the original substance probably mixed with a small percentage of cinnamyl diethylmethyl ketone. The residue in the flask after saponification was acidified with hydrochloric acid when a dense white precipitate was produced which after purification by dissolving in sodium carbonate repre-cipitating with hydrochloric acid and subsequent cry stallisation from dilute alcohol melted a t 138-133" and possessed all the properties of cinnamic acid.0.1403 gram of the substance gave 0.3748 gram CO and 0.0740 Theory for It gave the following figures on analysis :-gram OHz. Cg HqOz. Found. c . 72*!47 72.86 H . 5-41 5.86 The diethacetic acid remaining in solution was not isolated. The saponification of ethylic cinnamyldiethacetate by baric hydrate takes place chiefly according to the following equation :-B[C,H,-CH:CE€-CO.C( C2H5)z~COOC,H5] + 2BaH202 = (C6H5*CH:CH.COO)2Ba + [CH(C,H5)z*C00]2Ba + 2CzH5*OH. I have also tried t o prepare the corresponding mon-ethyl compound in a similar manner but after the mixture of ethylic ethacetoacetate and benzaldehyde saturated with hydrochloric acid had been standing for three months no crystallisation was observable. This fact appears to confirm my previous observation that ethylic cinnamyl-monoethylacetate is not crystalline at ordinary temperatures. The corresponding reactions with ethylic dimethyl- and mono-methyl-acetoacetates have also been investigated but in every case I have failed in obtaining any definite product. The reaction appears to be much more complicated than that wiih the corresponding ethyl compounds the complication being probably caused by the sub-stituted methyl-groups in the substance also being capable of taking part in the condensation. Royal Indian Civil Enginee&rrg College, Coopers Hill

ISSN:0368-1645    

DOI:10.1039/CT8895500038

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

41 VI.-The Action of Ammonia o n some Tungsten Compounds. By SAMUEL RIDEAL D.Sc. Lond. Fellow of University College, London. W~HLER in a paper " Ueber Amidverbindungen des Wolframs '' (Annalen '73 190) described the results of the action of ammonia on tungstic anhydride and tungsten chloride. I n the former case he found thaA when tungstic anhydride was heated to dull redness in a stream of dry ammonia i t was converted into a black compound, whilst water condensed in the cool part of the tube. The compound at a higher temperature yielded metallic tungsten. The analysis gave results which varied between the numbers 87.65 and 88.47 for the percentage of tungsten present and a nitrogen determination gave 7-15 per cent. The compound also contained a small quantity of hydrogen 0.2 per cent.From these data he concluded that the compound might be regarded as a mixture of nitride amide and oxide of tungsten and he named the compound tungsten nitretamid-oxide. The formula with the modern atomic weight for tungsten is The action of ammonia on tungsten chloride however gave a nitrogen compound containing no oxygen. The percentage of tungsten in this varied between 86.76 and 90.80 and a determination of the percentage of nitrogen in the specimen containing the highest percentage of' tungsten was found to be 8.24. From these results he concluded that two compounds were formed represented by the for-mula 2WN2 + W(NH,) (W per cent. 86.58) and 2WN + W(NH,), (W per cent. 90.44). The latter it will be seen is produced from the compaund 2WN,,W(NH,) by the removal of one molecule of nitro-gen.It could also be obtained by heating the former compound in a current of hydrogen when ammonia was formed. It is to be noted that the theoretical percentage of nitrogen in the latter compound should be 8-92 and that Wohler obtained only 8.24 per cent. No determination of the amount of nitrogen or of hydrogen present in the former compound appears to have been made. I n a later communi-cation (Annulen 105 258) he records the fact that when the chlorides of tungsten are heated with ammonium chloride similar black com-pounds are produced which may be either the above-mentioned compounds or a nitride of the metal. No analyses of the compound prepared by this reaction are given. It seemed of interest to compare these results with the action of VOL.LV. E 4 WNz,Wz( NHz),,2 WOZ = W,N,,H,O, 42 RIDEAL THE ACTION OF AMMOXIA ammonia on the oxychlorides and also to endeavour to obtain the compounds in a purer state. Roscoe's work on the tungsten-derivatives has given to chemists a means of preparing the oxychlorides of tungsten and the present note is to record the results which were obtained by substituting these for the hexachloride and also a re-examination of some of the compounds obtained by Wohler. Action of Ammonia o n Ignited Tungstic Anhydride. A current of dry ammonia was passed over a layer of tungstic anhydride heated to dull redness. Water condensed a t the further end of the tube and the pale yellow tungstic anhydride was converted into a black amorphous product.After allowing the tube to cool a current of dry air was drawn through it to ensure the removal of any residual ammonia. The compound was analysed by ignition in air until the black colour was entirely destroyed and the weight became constant. The addition of a few drops of nitric acid helped the final oxidation of the tungsten which was then strongly heated in order Lo destroy any compound with nitric acid which might be formed. The resu1t.s obtaining by noticing the decrease of weight in the tungstic anhydride after treatment with ammonia gave also a set of results which agreed with the determination of the percentage of tungsten obtained by the analysis of the compound. The mean of several experiments gave 85.26 for the percentage of tungsten in the compound a determination o€ the nitrogen by Dumas' method showed that 0.3845 gram yielded 24.5 C.C.a t 12.5" and 747 mm. = 7.4 per cent. N. Theory. Found. Tungsten 84.6 85-26 Nitrogen 7.6 7.4 Hydrogen 0.27 0.27 Oxygen. 7.3 7.07 The formula with which these numbers best agree is WbN6H3OJ, which indicates that the removal of the oxygen had not been so complete as in the experiments described by Wohler. The Action of Ammonium Chloride o n Tungstic Anhydride. When tungstic anhydride is mixed with ammonium chloride and the mixture heated in a hard glass tube or small crucible a black product is formed. After repeatedly reheating with fresh ammonium chloride the weight becomes constant. Different preparations how ON SOME TUNQSTEN COMPOUNDS.43 ever vary in the amount of tungsten they contain between the limits 83.9 and 81.0 the average of several experiments being 82.4 per cent. The amount of nitrogen in these products i R much smaller than in the compound formed by the action of the ammonia. A compound con-taining 83.9 per cent. of tungsten having 6.7 per cent. of nitrogen and that with 81.0 per cent. only 5.7 per cent. of nitrogen. Theory for Highest. Lowest. Mean. WN, W03. Tungsten . . 83.9 81.0 82.4 82.8 Nitrogen. . . 6.7 5.7 6.2 6.4 It will be noticed that an increase in the percentage of tungsten is accompanied by a riRe in the amount of nitrogen as if the tungstic anhydride WOs (W per cent. 79*3) wa8 being converted into a nitride, say WN2 whose percentage composition is W = 86.8 N = 13.2.The Action of Ammonia o n Tungsten Oxychloride WO,Cl,. The oxychloride was prepared by Roscoe’s method and the ammonia carefully dried was passed into the tube in which the oxychloride was condensed so as to prevent decomposition by contact with the moisture in the air. The reaction takes place withont the application of heat and white fumes of ammonium chloride are formed in the further part of the tube. The product which is scmi-crystalline and of a dull dark brown colour was purified from ammonium chloride by gently heating the tube in a current of dry hydrogen. The analysis of several specimens prepared in this way yielded a percentage of tungsten varying between 84.5 and 85.6 with an average of 85.09. The product differed from the foregoing in not evolving ammonia on heating with soda-lime and two det.erminations of the amount of nitrogen present only yielded a few cubic centi-metres of gas.It seems therefore that in this case the ammonia removes chlorine from the molecule and leaves the dioxide (W per cent. = 85.18) in a semicrystalline form. This result was partially confirmed by observing that a permanent gas was formed during the reaction. It is interesting to note that the action of ammonia on this oxy-chloride of tungsten WO,CI, is similar to that which I have previously shown to take place when dry ammonia is allowed to act upon chromyl dichloride Cr02C1 (Trans. 1886 49 367). Action of Ammonia on the Red Oxychloride WOC1,. This compound which on account of its unstable character was only prepared in small quantity is also rapidly attacked by dry E 44 ACTION OF AMMONIA ON SOME TUNGSTEN COMPOUNDS.ammonia in the cold. A small quantity (0.2318 gram) of the black compound formed gave 0.2066 gram tungstic anhydride from which it is seen that 88.9 per cent. of tungsten is present i n the product. This was the highest percentage of tungsten in any oE the products examined. The quantity formed did not permit of a nitrogen deter-mination being made. If the remainder is chiefly nitrogen it approaches in composition to a nitride of the formula W,N, in which the percentage of tungsten is 89.5. The Action of Ammonia o n Tungsten Hexachloride. Dry ammonia rapidly attacks the hexachloride in the cold yielding white fumes of ammonium chloride and a black powder having a semi-metallic lustre.The latter can be freed from ammonium chloride by washing with water. It is insoluble in nitric acid dilute sulphuric acid and soda. When fused with soda it gave off ammonia and was converted into sodium tungstate. It is oxidised by aqua regia t o tungstic acid. Strong hot sulphuric acid converts it ipto ammonia and tungstic acid. When heated in the air it glows and is converted into yellow tungstic anhydride. The oxidation to tungstic anhydride in the air was sometimes accompanied by a slight smell of ammonia but when the substance had been well washed with water, or heated in a current of dry hydrogen until all the ammonium chloride had been volatilised it did not give off ammonia when heated in this way. The percentage of tungsten as determined by the ignition of the black compound to turigstic anhydride in the air, gave results varying between 87.3 and 92.8 per cent.The average of all the determinations gave 90.05 for the percentage of tungsten. It will be noticed that the lowest result obtained was slightly higher than the lowest determinatioii by Wohler. The decomposition of the compound by hot and strong sulphuric acid suggested Kjeldahl’s method for estimating the nitrogen in this substance. Two deter-minations with different samples gave 10.57 for the amount of nitrogen present. These results agree with those required by the formula WzN3. Found. Calculated for W2N3. Tungsten. . 90.05 89.8 Nitrogen. . 10.57 10.2 The somewhat high result for the nitrogen constant may be due to the fact that the compound seems to have the property of condensing ammonia upon its surface.Wohler determined the percentage of nitrogen in a specimen containing 90.8 per cent. of tungsten to be 8.24 and by assuming that hydrogen was also present arrived at th THE ACTION OF CHROMIUM OXYCHLORIDE ON PINENE. 45 formula 2WN,W(NH2),. The amount of tungsten in other specimens was less than this the minimum obtained by him being 86.76. To account for this low result he assumed that the difference was due to an increase in the nitrogen t o 12.8 per cent. and that a second com-pound of the composition 2WN2,W(NH2) was therefore produced when the conditions were slightly modified. Finely divided metallic tungsten after heating to redness in st current of dry hydrogen underwent no alteration in weight when heated in a current of dry ammonia. No action was observed when dry ammonia gas was passed over the heated blue oxide. A black compound is produced when a solution of tungstic acid in aqueous ammonia is evaporated to dryness and the product gently heated in a covered crucible ; water is given off. and the black crystalline pro-duct on heating in the air is converted into yellow cryetaJline tungstic anhydride. The acid salt is said to form the blue oxide on ignition in a closed vessel but the compound does not appear to have been very carefully examined

ISSN:0368-1645    

DOI:10.1039/CT8895500041

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

THE ACTION OF CHROMIUM OXYCHLORIDE ON PINENE. 45 VII.-The Action of C7tromium Oxychloride o n Pinene. By G. G. HENDERSON B-Sc. M.A. Assistant to the Professor of Chemistry University of Glasgow and R. W. SMITH. RTARD in studying the action of chromium oxychloride as an oxidis-ing agent (Ann. Chemz. Phys. [S] 22 SlS) found that some of the terpenes yield compounds with this substance which when treated with water give corresponding camphoaldehydes but he merely mentions the fact and gives no description of the camphoaldehydes obtained. It seemed to us of interesh to examine these compounds more fully and for a commencement we took pinene the terpene boiling at 159-161" which we obtained in a state of great purity. Chromium oxychloride attacks pinene with almost explosive violence and therefore in order to moderate the action we employed 10 per cent.solutions of each substance in dry carbon bisulphide. The pinene solution was put into a flask connected with a reflux condenser, and kept cool by a stream of water and the solution of chromium oxychloride was added in small portions by means of a dropping funnel. After each addition of the chromium oxychloride a voluminous dark-brown precipitate was formed and quickly settled to the bottom of the flask. When all of the reagent had been added 46 HENDERSON AND SMITH THE ACTION OF the flask WM allowed to remain for some time until the precipitate had settled; the carbon bisulphide was then filtered off as rapidly 8s possible by aid of the pump the precipitate washed with dry carbon bisulphide dried at a gentle heat and put into dry well-stoppered bottles.The solid compound thus obtained is almost black when moist but when dry it is of a light greyish-brown. When exposed to the air it rapidly absorbs water and decomposes and when heated to between 80" and 90" it loses 1 mol. of hydrogen chloride with slight explosion. Analysis of the compound gave the following results :-I. 0.3710 gram substance gave 0.5594 gram carbon dioxide = 0.0980 gram carbon and 0.1302 gram water = 0.0145 gram hydrogen. 11. 0.530 gram substance gave 0.1780 gram Cr,O = 0.1222 gram chromium. 111. 0.485 gram substance gave 0-6128 gram silver chloride = 0.1516 gram chlorine. Found. 7 Calculated for /->--CloHl6,2CrO2CI,. I. 11. 111. Clo 120 26.84 P.C.26-42 p. C. - -B 1 6 . e . 16 3.58 3-90 ,, 2Cr . 105 25.49 , -202 . 64 14.32 , - - -- -25.05 p. C. -2C1,. . . 142 31.76 , - - 31.25 p. c. I _ -447 100.00 Pinene therefore like the other substances investigated by €hard, forms with chromium oxychloride a solid compound which has the formula ClJX1,,2CrO2Cl2. When thrown into cold water this is immediately decomposed with evolution of a considerable amount of heat and a heavy oil of a brown colour separates while the chromium sctlte go into solution. This oil was extracted by shaking up the solution with ether and the ethereal solution thoroughly washed, fir& with dilute caustic soda and finally with water dried with potassic carbonate and the ether then distilled off. In this way a transparent brown oil was obtained with a strong but pleasant aromatic odour.In order to purify it a portion of it was first shaken with a saturated solution of sodium bisulphite but no crystalline cornpound was formed. We then attempted to distil a part of it but found that it was entirely decomposed by heat ; heal y white fumes, with a suffocating and most disagreeable odour were given off and a black resinous mass was left in the flask. Another portion of the oil wa8 distilled with steam and although a considerable residue o CHROMIUM OXYCHLORIDE ON PINESE. 47 resinous matter was left in the retort a fair quantity of the oil was obtained now apparently pure. (In preparing a second supply of the oil after decomposing the solid chromium oxychloride compound with water we did not extract with ether &c.but simply passed sulphur dioxide through the solrition in order to reduce any chromic acid that might be present and then distilled off the oil with steam and dried it over potassic carbonate.) The oil was now golden-yellow in colour and perfectly transparent with the same pleasant odaur as. it had before distillation with steam. Its sp. gr. at 15' is 1.01366. Analysis of the oil gave the following results :-1. 0.1720 gram oil gave 0.4640 gram carbon dioxide = 0.1265 gram carbon and 0.1602 gram water = 0.0178 gram hydrogen. 11. 0.3075 gram oil gave 0.8298 gram carbon dioxide = 0.2263 gram carbon and 0.2830 gram water = 0.0315 gram hydrogen. 111. 0.2826 gram oil gave 0.0958 gram silver chloride = 0.0307 gram chlorine. Found.Calculated for --h- 7 C2oHuOC1. I. 11. 111. Cz0 . . 240 73.95 p. c. 7351 p. c. 75-59 p. c. -H 3 3 . . . 33 10.16 , 10.34 , 10.22 , -0 16 496 ,, C l . . . . 35.5 10.93 , - -- - -10.86 p. c . -424-5 100.00 The simplest formula that cau be given to the oil is therefore, C,H,,OCl. We were surprised to find chlorine in it having expected to obtain an oxy-compound possibly an aldehyde and we therefore heated the oil for fiome time with alcoholic potash but without alter-ing its composition to any appreciable extent. Several analyses of the oil were made both before and after distilling it with steam but the results were in each case very close to those given above. It seems possible that! the oil may be a mixture in equal proportions of CloHIaO and CloH,,CI but if this be so we were unable to separate i t into two fractions.As stated above it does not combine with sodic hydric sulphite. When heated with acetic chloride for some time its colour becomes slightly darker but i t is otherwise unchanged and it does not give any reaction either with hydroxylamine or phenyl-hydrazine ; it does not alter on exposure to the air. On attempting to distil the oil under ordinary atmospheric pressure, it is completely decomposed but this is not the case when it is distilled under diminished pressure ; the decomposition is then only partial. A smdl quantity OF resinous matter is left in the flask and an oil mixed with a little water comes over. The oil was dried and agai 48 MCMURTRY ON THTONYL THIOCYANATE. distilled under diminished pressure when it all came over between 180" and 185".In appearance this oil is very similar to the one pre-viously described ; its odour is almost the same and it behaves in the same way with alcoholic potash sodium hydrogen sulphite acetic chloride and phenylhydrazine ; its sp. gr. however is rather less being 0.97407 at 15" and its composition is quite different as is seen by the following analyses :-I. 0.2110 gram oil gave 0.6405 gram CO = 0.1648 gram C and 11. 0.2525 gram- oil gave 0.7225 gram CO = 0.1970 gram C and 0.1970 gram H20 = 0.0219 gram R. 0-2340 gram 320 = 0.0260 gram H. 111. 0.3705 gram oil gave 0.1697 gram AgC1 = 0.0420 gram C1. Found. Calculated for f- -7 C2oH31C1. I. 11. 111. C2". . . . 240.0 78.55 p. c. 78.13 p. c. 78.04 p.c. -HB . . . 51.0 10.11 , 10.37 , 10.29 , -C i . . . . 35.5 11-56 , - - 11-38 p. c. - -306.5 100.00 The simplest formula of this second oil is therefore C,oH,lCl and i t is formed from the first on distillation by loss of 1 mol. H20. C,oH,sOCl = C,oH,,Cl + HZO. This oil may also be a mixture of Cl0Hl6 and CloHl,C1 in equal pro-portions but we again failed to split it up into any fractions. We intend to prepare larger quantities of these oils in order to examine them more closely the results of our work being so different from what we expected

ISSN:0368-1645    

DOI:10.1039/CT8895500045

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

48 MCMURTRY ON THTONYL THIOCYANATE. VII1.-On Thiony 1 Thiocyande. By G. C. MCMURTRY Student in the Normal Schools of Science, South Ken sington. THIONYL CHLORiDE acts with great violence on mercuric thiocyaiiate. When the two substances are brought together the rise of temperature is sufficient to bring about the total decomposition of the mercuric salt. By mixing the thionyl chloride with carbon bisulphide the reaction becomes more manageable and results in the formation o MCMURTRY OK THIONYL THIOCYANATE. 49 thiony Z thiocyanate and mercuric chloride. Lead and silver thio-cyanates are similarly acted upon by thionyl chloride although with much less violence. The best method of preparing the new compound is to allow the mixture of thionyl chloride and carbon bisulphide to act on excess of mercuric thiocyanate in a closed flask at the ordinary temperature.After standing for a few days the liquid is decanted from the partially altered mercury salt and allowed to evaporate in a vacuum. On washing the residue with hot benzene and afterwards with ether, t.hiony1 thiocyanate is left as an orange-coloured amorphous powder. It was analysed with the following results :-I. 0.2394 gram treated by Carins's method yielded 1.0154 gram barium snlphate. 11. 0.0958 gram mixed with copper oxide and heated in a vacuum gave 22.32 C.C. nitrogen a t 481 mm. pressure and at 16.5" C. No nitric oxide was present. 111. 0,2002 gram heated with copper oxide and lead chromate gave 0*1110 carbon dioxide. These results me in sufficiently close accordance with the numbers demanded by the formula SO(SCN),. Found. Calculated. S . 58.26 58.53 K . 17.46 17.07 C . 15.11 14-63 Thionyl thiocyanate is an extremely stable substance It is prac-tically insoluble i u cold water and but slightly soluble in hot water. Hydrochloric acid even on boiling has no action on it ; sulphuric acid in the cold does not attack i t ; it is however completely decomposed by hot oil of vitriol with the evolution of sulphur dioxide and the precipitation of sulphur. It is but slightly soluble in ammonia; i t is dissolved by hot benzene and by carbon bisulphide but is quite insoluble in alcohol ether petroleum phenol chloroform amyl alcohol and acetic acid

ISSN:0368-1645    

DOI:10.1039/CT8895500048

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

50 1X.-On Mercuric Chlorothiocyana fe. By G. C. MCMURTRY Student in the Normal Schools of Science, South Kensington. ON treating the residue of mercurial salts obtained by the action of thionyl chloride on rnerciiric thiocyrtnate (see preceding paper) with hot water the dear solution deposited crystals of a compound which analysis showed to be mercuric chlorothiocyanate. This salt which does not appear t o have been pre.riously prepared may be readily obtained by treating a mixture of 5 parts of mercuric thiocyanate and 7 parts of mercuric chloride with boiling water and allowing the clear solution t o stand. The substance was analysed with the following results :-I. 0.4066 gram dissolved in dilute alcohol mixed with hydro-chloric acid and treated with sulphurebted hydrogen gave 0.3209 gram mercuric sulphide.11. 0.3786 gram heated with copper oxide in a vacuum gave 22.32 O.C. of a mixture of nitrogen and nitric oxide measured dry at 14.5" and 534 mm. pressure. After absorption of the nitric oxide there remained 22.32 C.C. of nitrogen at 14.5" afid 485 mm. pressure. 111. 0.2272 gram heated with copper oxide and lead chromate gave 0.0332 gram carbon dioxide. IV. 0.3731 gram treated by Carius's method gave 0.3010 gram barium sulphate. These numbers lead to results which accord with the formula c1 Hg<Cs or HgC1,*Hg(CSN)2. Found. Calculated. Mercury 67.99 68.12 Nitrogen . 4.7 1 4-77 Carbon . 4.46 4-09 Sulphur 11.08 10.90 Mercuric chlorothiocyanate is only sparingly soluble in cold water, but readily in hot water and in alcohol ; it is also slightly soluble in ether.When heated on platinum foil it intumesces in much the same way as mercuric thiocyanate. Its crystalline characters were kindly examined by Mr. Miers who reports as follows :-" Slender prisms having a prism angle of 71;" ; one fairly perfect cleavage (c) equally inclined to two prism faces which form the acute edge of the prism and at an angle of 42:' to that edge; an imperfec UERIVATIVES OBTAINED FROM a-PYROCRESOLE. 51 cleavage (73 equally inclined to the same two prism faces and inclined a t a smaller angle to that edge in the opposite direction. System probably monosymmetric. m1m2 = 71" 10'. cm1 = 64" 30'. If c is the basal plane OP = (OOl), and m is the prism OOP = (110). Then a b = 2.076 1. '' One optic axis is visible through a cleavage plate and is not very A cross section at right angles to the Plane of the optic axes is parallel to the far from perpendicular to c. prism shows only one axis. plane of symmetry (OlO).

ISSN:0368-1645    

DOI:10.1039/CT8895500050

出版商:RSC    

年代:1889

数据来源: RSC

摘要:

UERIVATIVES OBTAINED FROM #-PYROCRESOLE. 51 X.-Some Derivatives and New Colouring Matters obtained from a-Pyrocresole. By WILLIAN BOTT Ph.D. Berkeley Fellow of Owens College and J BRUCE MILLER A.I.C. Owens College. THE authors have been investigating the reactions of a-pyrocresole and its derivatives with a view of definitely ascertaining its consti-tution and expect shortly to be able to publish their results. I n t'he meantime it seemed worth while to describe a number of new derivatives which have been obtained and whose preparation is not directly connected with the main reaearch as yet uncompleted 52 BOTT AND MILLER SOME DERIVATIVES AND Trichlol.-a-PyrocresoZe C15H,,Cls0. This compound was obtained by the protracted action of chlorine on solutions of a-pyrocresole in chloroform or carbon tetrachloride, and repeatedly recrystallising the product from boiling benzene.It forms a white bulky mass consisting of slender silky needles which under the microscope are resolved into characteristic aggregates of thin transparent flat prisms or bars. The compound is insoluble in water alcohol ether and acetic acid but soluble in chloroform and still more SO in boiling benzene. Its melting point is very high but cannot be determined with precision as the substa,nce although quite pure melts only gradually first showing signs of melting about 225". The following numbers were obtained on analysis :-Oombustion. I. 0.198 gram substance gave 0.418 gram I T . 0.268 gram substance gave 0561 gram H20. HZO . Chlorine Determination.CO and 0.0625 gram CO and 0.0'775 gram I. 0.1995 gram substance gave 0.2796 gram AgCl. Pound. Calculated for r-&-T C1,H,iCl,O. I. 11. C 57.41 p. c. 57.30 57-83 p. c. H . . 3-50 , 3-43 321 ,, CI 33.98 , 34.62 - . 7 7 0 (by difference). 5.11 , 5.11 5.11 ,, It will be seen that in both analyses the carbon found is too high and the hydrogen too low this discrepancy being accounted for by traces of chlorine that is of hydrogen chloride having found their way into the potash bulbs during combustion. The chlorine in the sub-stance cannot be readily determined by Carius' method as the compound is not always completely decomposed by nitric acid ; the chlorine therefore was estimated by heating with pure lime. Dinitro-a-Pyrocresole Oxide C1bHIO(NO,),O,.In a former paper the three tetranitro-derivatives of the pyrocresoles have been described no other nitro-compounds being known. We have lately obtained the first intermediate nitro-derivative namely, dinitro-a-pyrocresole oxide and are now trying to obtain the corre-sponding compounds from p- and ypyrocresole. The a-derivativ NEW GOLOURING MATTERS FROM a-PYROCRESOLE. 53 was prepared by adding a-pyrocresole oxide to cold concentrated nitric acid in small portions at a time until a dark reddish-brown solution was obtained. Upon the addition of water a yehowish precipitate was thrown down consisting of a mixture of the dinitro-product with unaltered oxide. The latter was removed by extraction with boiling alcohol and the residue recrystallised from glacial acetic acid or nitrobenzene.The pure substance forms yellowish-white crystals which are very slightly soluble in hot water slightly soluble in alcohol a little more so in glacial acetic acid and freely in hot nitrobenzene. They melt at about 235" with very slight decomposi-tion and when heated more strongly decompose but do not burn with a flash like the tetra-nitro-compound. On annlysis the corn-pound gave the following numbers :-0.192 gram substance gave 0.4075 gram CO and 0.063 gram H20. 0.195 , , 15.6 C.C. moist N at 15" and 748.5 mm. Calculated for Ci5H10(N02) 2O2. Found. C 57.32 p. c. 57.88 p. c. H 3-18 , 3.64 ,, 0 30.51 , (calc.) 30.57 ,, N 8.92 , 9-22 ,, Reduction of the Nitro- compounds. The formation of amido- and other reduction-products has already been observed by W.Bott a considerable time ago but we have only recently begun a closer study of the action of alkaline and acid reducing agents on the nitro-derivatives of the pyrocresoles. The results so. far obtained open out a wide field of investigation and comprise the beginnings of a new series of colouring matters which probably differ essentially in composition and structure from the azo-colours already known. The compounds of a-pyrocresole only have thus far been examined. Tetramido-a-Pyrocresole Oxide CI5H,( NH,) &O,. This compound has been obtained by the reducing action of tin on the corresponding nitro-derivative suspended in a mixture of strong hydrochloric and glacial acetic acid. The reaction is hastened by working under pressure.The amido-derivative is also formed by means of zinc-dust and acetic acid hydriodic acid and similar reduc-ing agents in acid solution but tin answers the purpose best. After complete reduction the brownish-yellow solution is evaporated to expel excess of acid the tin removed by sulphuretted hydrogen aa 54 BOTT AND MlLLER SOME DERIVATIVES AND the filtrate made slightly alkaline with caustic soda or ammonia, which precipitates the amido-compound as a greenish-yellow mass. This is well washed with water and niay be further puri6ed by redis-solving it in dilute hydrochloric acid passing sulphuretted hydrogen to remove traces of tin which obstinately adhere to it and reprecipi-tating the base with alkalis. I t is not necessary to recrystallise the compound from alcohol in which moreover it is not readily soluble.Tetramido-a-pyrocresole oxide thus prepared forms a greenish-yellow powder sparingly soluble in alcohol and ether and almost insoluble in benzene. It is soluble in acids and the solutions give a dark red-dish-brown coloration with sodium hypochlorite. The melting point appears to lie considerably above 300° but has not yet been accurately ascertained. 0.140 gram substance gave 23.5 C.C. moist N at 12" and 756 mm. bar. Calculated for C15Ht3 (N H2) 4O2. N 1 9 . 7 1 ~ . c. Found. 19.55 p. c. Diamido-a- Pyrocresole Oxide C,H, (NHJ 202. This substance is obtained from the new dinitro-compound in the same manner as the previous derivative. Its properties have not yet been closely examined but in appearance and solubility it greatly resembles the tetramido-compound.0.161 substance gave 16 C.C. moist N at 16" and 761 mm. bar. Calculated for C15H10(NH2) 2O2. N 11.02 p. c. Found. 11.40 p. c. Azo-dei-ivatives of a-Pyrocresole Oxide. Both the tetra- and di-amido-derivatives of a-pyrocresole oxide cau be diazotised in dilute acid solutions in the ordinary manner. It will, in all probability be impossible t o isolate the diazo-salts from these solutions on account of the unstable character peculiar to these sub-stances but from the examination of some more stable derivatives, their composition that is the number of diazo-groups present may, we hope be deduced. The solutions of these diazo-salts react in the well-known manner with phenols giving rise to the formation of oxyazo-compounds.This reaction takes place most readily with alkaline solutions of /I-naphthol and the compounds thus formed represent the first colouring matters obtained from pyrocresoles. I f a diazotised solution of tetramido-a-pyrocresole oxide is adde NEW COLOURING MATTERS FROM a-PTROCRESOLE. 55 to an alkaline solution of (3-naphthol a bright-red precipitate is immediately thrown down consisting of the oxyazo-compound. After washing with cold water and drying on a water-bath it foi-nis a dark-red powder insoluble in water but soluble in alcohol ether, chloroform and benzene. With concentrated sulphuric acid it gives a beautiful and characteristic reaction dissolving in the strong acid with st dark-green colour which on gradual dilution with water changes to red the colouring matter being reprecipitated in red flakes.This reaction somewhat resembles the test given by safranine, which also dissolves in concentrated sulphuric. acid with a green colour. With safranine the green colour is however readily dis-charged by a drop of strong nitric acid which i n the case of the new colouring matter changes the colour from green t o purple but does not discharge it. By means of fuming acid containing 30 to 60 per cent. of SO, the colonring matter can be sulphonated and obtained in solution It dyes silk and wool a fine maroon shade. By the action of diazotised solutions of diamido-a-pyrocresole oxide on alkaline solutions of &naphthol a red colouring matter is formed resembling the previous compound in all respects but pos-sessing a brighter and finer shade.Like the preceding compound it gives a highly characteristic test with strong sulphuric acid and yields soluble sulphonic acids suited for dyeing purposes. It imparts to silk and wool a bright salmon colour. By the action of the diazo-salts on an alkaline solution of a-naphthol a brownish colouring matter is formed which dissolves in strong sulphuric acid with a beautiful dark-blue colour and is repre-cipitated by water. The closer examination of the above colours is being proceeded with and we shall extend the reaction to other mono-phenols and to the meta-series of the diphenols and arnidophenols. Regarding the composition of these new colouring matters we can at present only conclude from their mode of formation that they nre oxyazo.compounds or trapzeolins but the number of azo-groups con-tained in their molecules remains to be ascertained by a careful esti-mation of the nitrogen in the purified products. We shall then also be able to deduce the formuh of the diazo-compounds originally present in solution. The action of reducing agents in alkaline solution on the nitro-derivatives of a-pyrocresole oxide gives rise to the formation of azo-compounds and also of small quantities of amido-products. The reaction with ammonium sulphide is particularly interesting. If a small quantity of tetranitro-a-pyrocresole oxide is heated with alcohol and a few drops of ammonium sulphide the supernatant liquid assumes a reddish-brown colour and on the addition of hydrochloric acid and warming a red precipitate is thrown down insoluble in wate 56 LING SOME METALLIC DERIVATIVES but soluble in chloroform ether benzene and acetone with a reddish-violet colour.It is practically insoluble i n carbon bisulphide and may thus be separated from any admixture of sulphur. It dissolves in concentrated sulphuric acid yielding a yellow solution and is re-precipitated by water in dark-red flakes. If in the above experiments the action of the ammonium sulphide is allowed to continue €or some time the solution with hydrochloric acid no longer yields a red colour ; on diluting with water a yellow precipitate is formed soluble in alcohol ether and chloroform but almost insoluble in benzene. It is very sparingly soluble in cold water a little more so in hot water, the solution dyeing silk a bright-yellow shade. As the red and yellow substances have only been prepared quite recently we have not had time to study them more closely. From the manner in which they are produced it appears probable however, that the red substance is an azoxy- or oxyazo-derivative whilst the yellow substance is derived from it by reduction. The probable constitution of the derivatives described in this com-mimication will be discussed in our next paper on the structure of a-pyrocresole

ISSN:0368-1645    

DOI:10.1039/CT8895500051

出版商:RSC    

年代:1889

数据来源: RSC