摘要:

OXZDISING PROPERTIES OF SULPHUR DIOXIDE. PART I. 1093 CXXIV.-The Oxidising Properties of Sulphur Dioxide. Part I. Iron Chlorides. By WILLIAM WARDLAW and FRANCIS HERBERT CLEWS. As this paper has tol deal with the reactions of sulphur dioxide and metallio chlorideti it may be well t a summarise our prewnt know-leldge relative to this subjeat. The olxidation of stannous chloride by sulphur dioxide in the presence of concentra,ted hydrochloria acid has been shown (Smythe and Wardlaw Prqo. Durham Phil. Soc. 1914 5 187) ta prowed quantitatively t o campletion according to the quatian 3SnC12 + SO + 6HC1= 3SnC1 + 2H20 + H2S. Sulphurous acid ie reduced by titmous chloride t a hypoaulphurous acid (Kneoht Ber. 1903 36 166) and its further reduction to sulphur was noltiwd by the same inve&gator.Smythe and Ward-law (Zoc. &t.) further proved that when sulphur dioxide is passed into a warm strongly aoid solution of titanous chloride hydrogen sulphide is freely evolved. Sulphur is formed by secondary relau-t4ion between the hydrogen sulphida and the sulphur dioxide and if the emaping hydrogen sulphide is led into an excess of sulphur dioxide in colnaentrateld hydrochloria acid the reaction whiuh goleis to compleltioa may be quantitatively summasised as follows : 350 + 12TiC1 + 12HC1= 12TiC1 + 6H20 + 3s. The &ma authors (201~. cit.) have shown that sulphur dioxide olxidises meruurous chloride in the praence olf conmntrahd hydroahloria aoid according to the equation SO + 4HC1+ 2Hg,Cl,= 4HgC1 + 2H20 + S. I n the same paper it was mentioned that in concentrafted hydra-chlorio acid ferrous chloride is oxidised by sulphur dioxide ta ferrio chloride with tlhe farmatlion off sulphur.No sulphuria aoid was debated in thei solution. This mactioln diffelred frm those alrelady quoted in that olxidatlion under the mmt favourable coaditions prolaeedeid olnly to a limited exteellltc the average yield od ferria iron in all the experiments being 7 per cent. of the total iron preselnt, the extremes being 4 and 11.6 per cent. I n these experiments, rigid aotntrol was not exercised olver the colnditioas of temperature, mnaentration eta. and it seemed desirable therefore that a systematic investigation of this reimtion should be carried out*. VOL. axm. T LO94 WARDLAW AND CLEWS THE OXIDISING EXPERIMENTAL.The general methold of procedure was as follolws. Pure ele,ct,ro+ lytdo iron was diwolveld in pure oonaentrafed hydrochloric acid contained in a flask madel entirely of glass and such that t,he react-ing gasea coiuld be passeld t,hrough the solution cont'aineld in it. This was connelcted with wash-b,ottlet+ contlaining wa,tes aad sodium hydrolxidel solution respeotively. Thew serveld t,o absorb the effluent sulphur dioxide! and hydrogen chloride and to1 exclude air, and so prevent atmospheric oxidation. The1 ternpelrature of the, flask was; controlled by immersion in a.n oiil-ba,th. A stream of aarbon dioxide was clontJnuoudy passed through the a,pparatus during t'hel sollutioln olf t'he rnet(a1. Whein the iron 1ia.d completely dissollved the flask was mnnecltad with a sulphur-diolxide syphon and t'hhe gas passeld for a.sta,ted pelriold. It was' nolticed that after the sulphur dioxide ha,d paissed folr at few minutes the so(lut,ion changeid to olivegree'n thea t'a relddish-brolwn a'nd beloamel dis-tinotly opa.lescent ofwing tlol the separation of sulphur. After t8hel rea,otioln ha.d proceledeld f olr the relquireld t'imel tlhe sulphur dioxide wa5 displaced by ca'rb'oln diolxidel the sollution ao1ole;d in a strelam 04 the sa;llle gas a.nd the iron titrabd aSt.er suit,a#b#le dilut8iolri witlh a,ir-free water with sta.nda,rd poltaasium dichroma'te accolrding ta Zimmernmnn a,nd Reinha,rdt's methoid. The sulphur was de,kmined by fi1t'ra)tion aad direlot weiighing . Quantitative Aspect of the Reactioln.Them are two possible reiaations involved colrresponding (a) with direlct reduotion of the sulphur dioxide to sulphur and ( b ) with initliad relduction of the sulphur dioxide to hydrogeln sulphide which react8 with ~ O ~ B S od sulphur dioxidel forming sulphur. Both retactions are represenhid finally by the equation SOz + 4HC1+ 4FeC1 = 4FeC1 + 2H,O + S, so thah it is impolssiblel t o l deicidel quantitativefly betlween the two. Morwvelr ming to the1 fact that the limit of reaction has been shown to be sooln reached the amurate estimatioln of the sma,ll quantity of sulphur is very diffioult. The following are examplee olf the results obt'ained by Smythe and Wardlaw (Zoc. cit.). TABLE I. Sulphur. Ferric iron & Experi - Concentration of produced. Found.Calc. ment. f crrous solution. Gram. Gram. Gram. 1 5.893 grams Fe per 100 C.C. 0.683 0.062 0.098 2 4.468 ,) )) 200 C . C . 0.392 0-040 0.056 5.450 y y y 200 C.C. 0-340 0.035 0.048 PROPERTIES OF SULPHUR DIOXIDE. FAltT I. 1096; The wnalusion to be drawn is that tlhe equa,tion melntioaeld above repreeents the reaction. From general considerations one is also led ta infer that i t undoubtedly fdlolws the course (a). Although hydrogen sulphide has never bem directly d e h t e d in the reaction, from the fact that sulphur is formeld in the neck of the flask and in the outlet tubes i t is pmsible that the reaction follows the course ( b ) to a vary limited extent. Znfluence of Cmcmtratiofi of Toltd Iron. A range of coincantrations of iron was invwtigated by dissolving varying quantities of iron (1-10 graxns) in 250 C.C.of concentrated hydrolohloric aoid. Sulphur dioxide was passed through the1 solu-tion for four hours a t 1 1 5 O a,nd the amount olf ferric salt subsequently determined by titration. TABLE 11. Experiment. 4. 5. 6 . 7. 8. Grams of iron dissolved in 250 C.C. of mid ........................ 1 3 5 7 10 Ferric iron per cent. ............ 5.3 4.2 3.4 3-3 3.6 These rault,s tend to show that the limit- of ocxidation is not influenced by the initial conaelntratioln of tahe iroa. The conmn-trafion of the hydrochlorio auid is not exactly constant in these elxperiments awing t o tghe varying loma o€ hydrogen chloride during the solutioln olf the diffsrelnt qua,ntitiss of metal and this undolub,tedly influenoes the degree of oxidation.TABLE 111. InfEu,ence of Temperature. Comentratiofi.-Two grams of iron in 100 O.C. of concentrated Dumtiom of Experiments.-Twa and a-half hours. hydrolchlorio acid. Experiment ............ 9. 10. 11. 12. 13. 14. 15. Temperature ......... 61" 70 79 93 115 125 gently boiling. Ferricironpercent .... 1.6 3.0 3.5 5.2 3.8 3.0 2.8 The existence of a.n optimum temperature (approlximatdy 950) is the rwdt of two or more oppwing fad.ors. The reaation-vetlocity will be favoured by an increaser in temperature whilst the higher temperature will lead to a mom rapid lms oif hydrochlorio a,cid, T T 1096 WARDLAW AND CLEWf3 THE OXIDISING espelcially in the early stages of the reaction. It is also highly progbable tha,t the sollubility of the sulphur dioxide decreases with rise in temperature.Zmflueirzce of the Comcentratiom of Hydrochlom'c Acid. The tlhreie following elxperiments are moldificatioas of those described in ta,ble I11 with a view t,o change the conmatration of hydrochloria aoid. Values from table I11 are a4dded for comp arism . TABLE IV. Coincmtmtiow.-Two grams olf iron dissolved in 100 0.0. of Dumtioln of Experimemt .-Two and a-half hours. concantr ahd' hydrolohloria acid. EX.-peri-ment. Description. From Table 111. x 100. Ferric iron. Per cent. Ferric iron Per&- -__ fure. Total iron 16 Sulphur dioxide passed through concentrated hydrochloric acid a t 95' before being led int.0 the ferrous chloride solution ......... 9Eie . 7.8 5.2 Mixture of hydrogen chloride and sulphur dioxide (60 per cent.of HC1 by weight)* passed into ferrous chloride solution ......... 115 4.7 3.8 18 Carbon dioxide passed through ferrous chloride solution at 115' for 30 minutes and then sulphur 17 dioxide for 2+ hours ............... 115 1.3 3.8 * In all cases the composition of gaseous mixtures of sulphur dioxide and hydrogen chloride will be expressed by the percentage of each constituent by weight. The increased yields in experiments 16 and 17 and diminished yield in axperimelnt 18 in which exaess of hydmohlotrio a'oid is removed from the sollution show thab the oixidising elffeict olf sulphur dioxide is only appreciable ast co,ncentra-tJons exceeding that of the mixtturel olf colnst'a,nt boiliklg polnt. Accoirdingly in the1 netxt experiments (table V) iroln was dis-solveld in hydrochlorio acid diluteld to1 the aonw'nt'ratioa of the, mixt8ure of oonsta.nt boiling point and a mixture olf hydrogein dhloside and sulphur dioxide in different proportions passeld into t'he ferrolus ohlotride solution.The ratio of sulphur diolxide to hydrogen chlocride wa.s olbserved by divelrtling a s,ma,ll prolportion od the gaMee by me1a.w od a T-piem, while tih.e experimentl wa.s in progress. The acid gasels were absolrbd in 50 a.a. od N-soldium hydrolxider thel chloride being sub PROPEIMIIBIS OF SULPHUR DIOXIDB. PART I. 1097 wquently titratad witch etmda,rd silvelr nitrate and ammonium thioIoyana,tel and the sulphib with standa*rd iodine and sodium $hiosulphak. TULE V. Gmcentratiom.-Two grams olf iron dissolved in 100 C.C.of Duration of Experimemt .-Four hours. hydrcwhlolrio acid (22 per cent. HCl). T e ~ ~ ~ ~ ~ ~ t ~ e . - 1 1 5 0 . Percentage composition of mixed gases. I c- I Ferric iron x 100. Experiment. so2. HCl. Total iron 19 81.7 18.3 20 56.7 43.3 21 22.5 77.5 23 10.1 89.9 22 15.8 84.2 2-3 2.2 4.2 8-6 3.9 The results shosw that for the colnditibns desmibsd in the above, experiments hhere is a cmnpamtlivelly na'rrow range of composition between 10 and 20 per cent. of sulphur dioxide which is most favourable for the olxidation of ferrous chloride a maximum beling maohed in the neighbourhood of 16 pelr cent. of sulphur dioxide. Limiting Concentration of Hydrochlovic Acid folr Oxidation uf Ferrous Chlwide b y Sulphur Dioxide.Since in dilute1 hydrochloria a8cid solutio8n sulphur dioxide com-pletdy reduaes ferric chloride to ferrous chloride there will be TA,BLE VI. Temperatwe .-95O. Duration of Experiment .-Four hours. SoZutiom.-Five grams of iron dissolveid in aoid speoified in columns 2 and 3. Concentrated Free HCl in hydrochlorio 1000 C.C. of Expcri- acid. Water. solution. ment. C.C. C.C. Gram. Remarks. 40 160 + 90 210.5 Little oxidation; about 0.6 41 140 + 110 179.3 Very little oxidation; not 42 130 + 120 165.8 Minute oxidation ae shown 43 126 + 126 165.1 No oxidation as shown by per cent. measured. by sulphur depmit. sulphur deposit 1098 WARDLAW AND CLEWS THE OXIDISTNG some' oonceatration of acid below whioh it is impossible to1 observe the midation of ferrous chlolride by sulphur dioxide.Iron was dissolved in acids olf different concentrations and bhe action oif sulphur dioxide f o r four hours a t 950 was observed. For the1 analysis a portion of the solution was withdrawn, weighed and afteir removal of the sulphur dioxide diluted t o a convenielnt volume. The iron and total chbride were1 deltermined, and from thel differemel the (( free1 " hydrochloric acid was caluu-lateld. The1 specific gravity of the1 remainder of the solution was determined in order to stlate the concentration in grams per litre (see1 table VI). It is concluded that oxidation by sulphur dioxide1 doe@ nolt occur in ferrous ohloride solutioas contlaining less than 165 grams pelr litre of (( free " hydrogen chloride.Limit of Odatioln of Fcrrows Chloride b?y S d p h w Dioride in Hydrolchlovic A cid Solutiorz. (a) Experiments at A tmospheric Pmssure.-With the1 purpose of determining the limitl ojf oxidation use1 was madel of a rather larger flask fitteld with a water-cooleld exit t u b and containing an amoluntl of solution sufficieat to1 profvide two1 samples for analysis. Five grams of iron dissolved in 250 C.C. of cioncreatrated hydro-chloric acid (33 per mnt.) were treateld with hydrogen chloride and sulphur dioxide at 1 1 5 O as describe'd in the following cnpeaimenh TABLE VII. Time of taking' sample from Expri-ment. 24 25 26 27 Description. Hydrogen chloride and sulphur dioxide (80 and 20 per cent,.) passed continuously into ferrous chloride solution.Rydrogen chloride and sulphur dioxide (50 per cent.) passed into ferrous chloride sohition. Sulphur dioxide alone passed for half an hour then hydrogen chloride and sulphur dioxide (50 per cent.) cont.inuoiisly. Sulphur dioxide alone passed for hnlf an hour then hydrogen chloride and sulphur dioxide (80 and 20 per cent. PROPERTIES OF SULPHUR DIOXIDE. PART I. 1099 TABLE VII (continued). Time of taking sample from commence-Experi- ment of Ferric iron msnt. Description. experiment. Total iron 'O0' 25 *The ferrous chloride solution was alternately cooled to 30' (1 hour) 3 hours 6.5 and then quickly raised to 115' (heated for 2 hours) hydrogen chloride and sulphur dioxide (50 6 , 7.0 per cent. of each) passed contin. uously ). 29 Experiment 28 repeated but cooled for 1 hour and heated to 115' for 6 , 8.8 1 hour.* This procedure enabled the solution to absorb a large amount of the gases at the lower temperrtturos. On rapidly raising the temperature to 115' the solubility values would not be attained immediately and during this interval tho temporarily increased concentration of hydrochloric acid and sulphur dioxide would be available for reaction with the ferrous salt. An oxidation od 8.8 pelr c a t . (in experimelnt 29) is the1 highest obtained by the action of sulphur dioxide on ferrous chloride opelrating undelr al pressure1 slightly in eixoelss olf the atmosphelrio. ' (b) Experiments with SeaEed Tubes.-A rather higher degree od oxidation u7as olbtaineld by the1 use of a seded tubs.Expt. 30.-Half a) gram of iron was dissolved in 10 a.0. of uon-celntrated hydrochloric aaid in a Carius tube in a current of carbon dioxide. The tube was i m e r w d in ice the solution saturated with sulphur dimide and the tube waled. It was then helated at looo f o r six hours and allowed to ooloil ovelrnight. Titration showed that olxidatioa had occurreld to the extent of 9.5 pelr cent. a value only slightly in exce8s of those obtained under normal pressures. L h t i t of Reduction of Ferric Ch1ori.de by Sulphur Dioxide in Concentrated HydTschlork Acid Solution. (a) Expen%nents wtder A tmospheric Pressure.-It is well known tchat exmss of hydrolchlorio acid prevent6 the comple!b reduation of feirrio ohloride by sulphur dioxide (Tresdwell and Hall '' Quanti-tative Analysis," 5th ed.p. 607 footnote). It was not known, hoiwewr t o what concentration of hydrochlocrio acid this referred or the extentl to which feirria chloride ww reduced. Since1 the reiduotioln od ferria chloride1 in ocmoentratd hydro-chloric aoid was found to proceed slowly mixtures s f felrrous and ferric ohlorid- were prepared and their compositions determined 1100 WARDLAW AND CLHW8 THH OXIDlST" bolth before and after passing sulphur dioxide and hydrogeln chloride (approlximatetly 50 per aent. od each gas) for a definib timei. By this means the value t'ol which the reduction would eventually att'airia was eatimacted. TABLE VIII. Cmcentmtiow.-Five p m s of iron in 250 U.C. of hydrochlolrio Ttmperature.-115°. Gas.-SO,+ HC1 (50 per cent.mixture). ataid (33 per cent.). Experi-ment. 31 32 33 34 36 36 37 Duration of experiment. Hours. 4.0 4.0 6.3 4.0 6.0 2.5 6.6 x 100. Ferric iron Total iron - value. 100.0 72.2 63.8 42.1 20.7 18.3 10.8 7z.2 value. 78.2 68-8 48.6 39.3 18.3 18.3 10.7 Reduction gradient (average reduction per hour). Remarks. 6.4 Sulphate formed. 0.98 ? Y 0.84 ? Y 0.70 ?? 0.40 YS I No sulphate. - -No sulphur wa8s folrmed in any of the above expelrimsnta, Apparently iroln aollutioas containing more than 18.3 per cent. 8f ferric iron are slowly relduwd by sulphur dioxide in the presenm of cancantrateid hydroahloria acid. There seems also to be a ranger of from 10 to 18-3 per cent. of felrria iron in which there is no evidetnm of reduction or oxidation by the sulphur dioxide during the time 04 the experiments.Evidently this reipremnte a zone in which the rate of rea;ctim otf the sulphur dioxide is very slolw. The solutioln in experiment 37 was analysd and it was shown tlo aontain in 1 libre 239 grams of '( frw " hydrmhloric a'uid and 0.314 gram ot sulphur dioxide. (b) Experiments in Sealed Tzcbes.-Five grams of ferrio chloride were dissollveld in 10 0.u. of hydrochloric acid (33 per cent.) and the solution was saturated with sulphur dioxide at 0". The tubs was selaled and hea,ted to l l O o for folur hours. Analysis showed a reduction od 20.6 per cent. and sulphuria acid w&s detected in the solution. A similar experimeint after twenty-five hours at l l O o gave only 22.3 pelr cent.of reduction. ApparenUy the high con-mntration olf hydrolchlmio aoid whioh exists in a c l d vessel inhibib the reduction by sulphur dioxide just as a high concen-tration of acid appears also to favour the oxidation of ferrous ahloride PROPERTIES OF SULPHUR DIOXIDE. PART I. 1101 Reductim of Ferric Ch1om.de b y Sdphur. Stokm (Bull. U.S. Geob. Survey Nor. 186 1901) has e x m i n d the &ion of pyrites and mwoasite on a hoh dilute solution of ferrio chloride and observed reduction la a considerable extent (65 per oent. of the sulphur) the sulphur being olxidid ta sulphurio acid. The premnt authors find t'hah the action of sulphur in conmntlrated hydrachlmia acid on ferrio chloride is slight. A solution of 5 grams ~f ferria chloride in 60 0.0.of conwntrafxd hydrwhlcria aaid was boiled in an atmmphera of aarbon dioxide for olne and a8-half hours. The reductioln oorrapondd with 0.66 per c a t . t a b sulpbur being oxidised to sulphurio add. A solution od 3 grams of feirrio ahloride in 50 0.0. of concentrated hydroshloilrio alcid to whioh 50 0.a. of colloidad sulphur solutdon were added on boliling for one and a-ha,lf hours raulted in 1.7 pelr cent. od retduc-tion. Sulphuric acid wars produced. Experiments on the linm of tho(% sholwn in ta,ble VIII in which a prolportioin of finelly divided sulphur was added showed that it exerted very little reducing aation in comparison with the sulphur dioxide. SUrn;mCM.y. (1) The axidamtion of ferrous ohloride by sulphur dioxide o m be reprwelnbd quantitahively by the eqpation 4FeCl + SO + 4HC1= 4FeCI3 + 2H,O + S.(2) The degree od oxidation is independent of the initial concmntration of total iron. (3) The most favoura,ble temperature for the oxidation by sulphur dioxide of a solution of ferrous chloride in 33 per oent. hydroohlaria acid is 95O. (4) Oxidatlion by sulphur dioxide at 95O doles not occur in solu-tions of ferrous chloride containing less than 165 grams per litre of " free " hydrogen ohloride. (5) A solution of ferrous chloride in hydrdlolria aaid of oonstant boiling point (22 per cent.) a t 115O gave it maximum. olxidation of 8-6 per u e n t . (felrric iroln) when treated with a mixture of sulphur dioxide and hydrogeln chloride containing 16 per cent. of sulphur dioxide. Mixtures containing 10 t a 20 per cent.of sulphur dioxide are mast favourable for oxidation under the above conditions. (6) The highest percentcage of ferric iron obtained in any of tlhe flask expm5mdis reoordeld in this paper was 8.8. This result was produced by trelatment of a ferrous chloride solution in 33 per cent. T T 1102 WARDLAW AND CLEWS THE OXIDISINO hydrwhloria mid a t 115O with a 50 per cent. mixture of sulphur dioxide and hydrogen ahloride under special colnditions. (7) Sealed-tube experiments gave a maximum oxidation of 9.5 per cent. of ferric iron. (8) Iron sollutioiis containing 10 to 18.3 pelr cent. of ferric iron in 33 per writ. hydrochloric acid a t 115O sholwed no evideince of oxidation o r reduction when a 50 per cent. mixture of sulphur dioxide and hydrogen chlolridel wasI passed into them for varying periods.(9) Under the same experimeatd aonditions a's in (8) iroa solutions contlaining more than 1S.3 per oelnt. of ferric iroln weire slowly r e d u d . (10) Ferric chloride in aonaentrated hydroahloric aoid was reduced to a smadl extank by sulphur. Th e o ~ e t i c d . The oxidation of a felrrous chloride solution by slulphur dioxide has been shown to be quaatitative~ly reprewnted by the equation 4BeC1 + SO + 4HC1= 4FelC13 + 2H,O + S . . . (1) Moreoveir since sulphur is able t o relduce ferric chloride to some extent it seems justifiable to assume that the above equation is reive~rsible. 4FeC1 + SO + 4HC1 4FelCl,+ S + 2H,O . . . (2) This fact is generally obsaured however by the motre gelneral q u a ti on 2FeC13 + SO + 2H,O = 2FeC1 + 2HC1+ R,SO .. . (3) Since no sulphuric acid is detelcted when a pure felrrous chloride sollutdon is oxidised by sulphur diolxidel in the1 preselnce oS minoen-trated hydrochlorio acid it oan be1 assumed that under these con-ditions the reaction Lhat oloours is sollely reprelsentled by equation (2). Molrelover seeing that sulphurio acid is only detteoted when sulphur dioxide in the prsence of concentrat.ed hydrochlorio acid reads with iron sollutdoas containing motre than 18.3 per cent. of felrria iroln it appears that reaotioa (3) is only olperative i n such solutiolns. The idela tha't a reversible reactiota takes place when pure ferrous chlolride soflutioln is oxidised by sulphur dioxide recelivesl added sup-port fmm the faat that only a limited yield od ferria salt is possible,, and thak the reactlioln is not greatly influelneed by the initial con-centratioln of totall iroln.Applying the lalw of mass action to1 equation (Z) it appears that for a given concentration of sulphur dioxide and hydrogen chloride the equilibrium position would b PROPERTIES OF SULPHUR DIOXIDE. PART I. 1103 determined solely by tlhe raltio of ferrous to ferria iron assluming that the active masw of the sulphur alnd water are aonstant. The importance of a high colncentratioln of hydrogen chloride ta bring about the oxida,tion also follows logically from the idea of a ballaaaeid relaction. The dependence of sulphur dioxide as an oxidising agent on a high concentration olf hydrochloric aoid has led to tha suggelstion that hydroohloria acid and sulphur dioxide interact f oming thionyl chloride la a small extentl (Smythe and Wasdlaw Zoc.c i t . ) . This idea receives support from the following reaotions with the marcaptans : SOC1 + 4R*SH = %S2 + R2S3 + H20 + 2HC1 (Holmberg AnmaZen 1908 359 Sl), (Smythe and Forster T. 1910 97 1195). SO,[ + HCl] + 4R*SH=&S2 + RZS + 2H,O[ + HCl] 011 this assumption the reaction SOC1 + H20 SO + 2HC1 must be reversible. Although this has not been proved direotly, them is some indirest evidence in that when thionyl chloride reacts with memaptans at law temperatures (Oo to -70°) hydrogem chloride and sulphur dioxide are evolved and water is fmnd among the residual prolduats (Taskelr and Jones T. 1909 96, 1904 1910). I n addition the reactions of the sulphoxidw and the halaid adds are to some extent analogous. (Zincke and Frohneberg Ber. 1910 43 837), (CH,Ph),SO + 2HBr (CH,Ph),SBr,+ H,O ( F r o m and Raiziss A d e n 1910 374 90; Fromrn ibid., 1913 396 75). From this idea the question arises as tIo whehher the oxidising properties af sulphur dioxide ara only opemtive in the preselnoe of concentraked hydrochlorio acid. Experiments have been in progrws to determine this point and the results will be cmmunioahed in a further paper. CH,-SO*C,H,*CH + 2HBr CH,*SBr,*C,H4*CH3 + H20 THE UNIVERSITY, BIRMINGHAM. [Received August 12th 1920.1 T T*

ISSN:0368-1645    

DOI:10.1039/CT9201701093

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

1104 BRUSTBAIJ) THEl HYRROLYSIS OF CXXV.-The Hydrolysis of Platinum Salts Part I. Pot assiuni PI u tinichloride. By EBEN HENRY ARCHIBALD. WHILE aarrying o u t a seriea of elxperirnentg on the sollubility of potassium plstinichloride (Archibald Wiloox and Buckley, J . Amer. Chem. SOC. 1908 30 747) it waa ndiaed thart this salt undelrgoes hydrolysis. in aqueous so;lutJons at the ordinary tempera, ture. Some time latter while1 studying the conductivity of solme pla8tinum colmpounds (Archiba,ld and Patrick ibid. 1912 34, 369) it was found that this hydrollytic dwoimpwibion proceeded much mars rapidly when the solutions were exposed to1 the act'ion of light. As the extelnt ta which this reaction has tlakeln placw is any giveln time1 oould be measureid velry accurately whilst the rate ajt whioh it prolaeiedeld was suffiaiently slotw to1 allolw off a number of meaaurement8s being made with any olnel solution-a coadition thah ia satisfied by velry few inorganic salts-it was thoiught worth while to make a sonmwhat extended study obf the hydrolysis of this salt under diffelrent aolnditiolns as tol (1) dilutioln; (2) the presence of other chlarida and neutral salts; (3) the reversibility of t h e reaction.Prmiow Obssrwatim cegading thk Hydrolysis. The adion otf light oln poltassium platinichloride appears to have been first nolteld by 8onsta,dt (P. 1898 14 25). Hei states that light has the same elffect on very dilute solutions of the salt as he1a.t. A sollutiw containing 1 past of salb in 10,000 pasts olf water beloame turb,id whelii helat8eld folr a.n holur oc two.He abseirved no effect i n the ca,w olf more conmntmra,tced sollutions and seems to have judged the extant of the rea,ctio,n from t,he appearance of the solution and the formation of a seldimeiit, considelreld ta be pla'tinum motnoahloride. It is of i n t e r s t heIra t,o reifelr to a letter of Sir John Herschel to Dr. Daahay writIten in 1832 (Phi$. Mag. 1832 [iii] 1 58). This letter st.ak that if a solution oif pla,tinum in nitromuriahio a.oid in which t.he exoess o'f a,&d has bmeen nelutralised by the addi-tion of lime t.his being folllolwwed by filtration is mixed with water in the dark no prelcipita,tion takes pla,m folr a vary loag while, but if t<he mixt<ure is exposed to sunlight it instlantly beoomes milky a,nd a copious preloipitafs forms.The writer of the letteir further shotwed that this elffeot Wafs confined to t,hs vioilet end of the spe&rum no1 aation t(aking place when t u b e cont4aining th PLATMUM BALTS. PART I. 1105 platinum solutions were immersed in reid- or yellow-oolourd solutions and tlhen expomd t o the sunlight. Thab light greatly acceIerates the hydrdytlia decmposition of platinum tetrachlolride seems to have been genelrztlly remgnised. Kolhlrausch found that the conductivity oif aquelolusi solutions of this compound increiaseid muoh more rapidly wheln undeir the influence of light than when kept in the dark. The presence of the platinum eleictroldes also inurelased the veloicity olf tlhe reaction. Solutions od chlorolpla8tinic acid motre croaoentrateid than N / 10 were apparently not affected by light.EX P E R I M E N TAL. Pwpamtiom of Mat erkls. Hydrochloric A&d.-The hydrmhlosia acid used was prepared by heating concentrated Izydroluhlolria acid and passing the libera8kd gas into distilled water the first and last parts olf the distillate being rejedxd. Potassium ChZo.ride.-Coxnmercial potassium chloride was re-cryst allised selveraal times from water saturalteld with hydrogen chloride finally from pure wa,tm. Pdrtions so obtained were washed free of mother liquor and dried a t al high tempemtme. Potassium P%c&nichlm.de.-Tn preparing the chlolroplatiniu acid from which the platiniohlocride wag obt'ained platinum scrap was frmd of surfam impurities theln bolileld for some tJme in conoen-trabld hydroichloricl acid.The platinum wa,s thela dissollved in aqua regia land the solutioa evaporated almost tol dryneaq after adding colnceintrated hydroohlolricl acid. After again adding hydcro-ohlaria acid and evalpporating a second time the residue was dis-solvsd in water containing hydrolchloric add and the! platinum preicipita;t;eld from this by adding a solutioln olf ammolnium ohlaride. The resulting ammolnium platinichloride was colllsated in a Goloch filter washeid with aluohol and watlelr and dried in an air-ba,th a% a low termpera(tlure. The dry salt was then reduced by heating in a current of hydrogen and the platinum-black folrmed was well washed in watm. In mder to ensure the absenue of any nitrio aoid from the final prepara,tion the platinum-black was dissolved acaording ta the melthod suggehd by Webelr ( J .Amer. Chem. SOC. 1908 30 29) and modified by the author (Zeitsch. amwg. Chem. 1910 66, 169). Aumrding to this method the plat.inum-blaok is ma8de the anode in the lower past of a glass tube aboutl 2 m. in diamelter, containing conoenttrated hydrachloriu acid as edeotrolyte. At the a ' n d e the uhlorine ailtacks the platinum forming platinum chloride, and the remlting ohloroplatinio acrid falls to the bottom and oa 1106 ARCRIBALD TRE HYDROLYSIS OF be drawn off through a siphon sealed to the bottom of the main tube. The sollution prepared in this way is somewhat diluted and the platinum then precipitated by adding slowly a solution of a polrtion of the purifieid pokassium chloride.The precipitated plaltiniohloride a f h r being washed and dried is ready folr usel. A p a r a t us. The graduatiolns on the pipettes and buret,tes were tested by welighing the1 watelr delivered allowanoe beling made for air-dis-placement and the temperature! od the1 water. I n the case of the flasks a graduation mark was made a t thatj point on the stern a t which the flask coat8aineld waiter sufficient to balanoel brass welight8 equal to1 the apparent weight of a kilolgram or 100 grams as tlhe oase might be of water weighed in air a t 20°. The weights welre correlctad by the melthod suggested by Richards ( J . Amer. Chem. Soc. 1900 22 144). M e t h d of Meamring the Extent of the Hydroltytic Actims. As hydrochlorio aoid is formed as the hydrolysis proceelds the rate at which the reaction takm place and the extent to which it has prooeeded a t any given time can be measure!d by titrating a known volume of the solution with a standard solution of an alkali such a5 barium hydroxide.Among selveral indicators tried, such as methyl-red methyl-mangel coohineal and phenodphthalein, none appeared superior tlo phenolphtbarein. The mlour relaktion with this subsitanoe was distinct and delicatel. With the b u r e t h employed in this work the error in reading the volume delivmed did not exceed 0.02 c.a. and this with the stlrength of solution employed as standard corresponded with 0*0000078 gram of hydrogen chloride. K,P t C1, - ~ = 4 - 8 6 4 grams The solutions first studied contained K,PtCl K2PtCI K PtCl ____- 4oo 1.216 grams and -2d - 800 - 2oo - 2.432 grams ~ -0.6080 gram of pottasium platinichloride in a litm of solution.In terms of e'quivalent gram-molleculee od platinum chloride they were rapeotively N / 2 5 N / 5 0 AT/lOO and N/200. These solu-tions were prepared by weighing the required amount of salt in eaah case; the nesessary wahr was added in the dark and the solution caredully protleoteld frotm the light until everything was in readiness to begin EL seriw of measurements. The velocity olf the hydrolytic readion was so lolw eveln fm the most concentratad solution studied that the1 time rsquired tol dissolve the platinum salt need not be considered in any of the measurments. Th PLATINUM SALTS. PART I. 1107 initial audity was now measurd-this was seldom equivalent to more than 0.05 0.0.of the standa'rd for a 10.0 0.0. portion of the phtinum solution. The velsrYeils containing the soluttions welre then immersed in wate,r-b,a,ths conta8ineld in glaw t,anks and here exposed, ah a certain disttanael to1 $he radiations frolm a 300-wa8t;t laamp. The tempelra,tizre of t'he bath was ma.intlained const,ant. witihin 0*5O by means off a system of tubee through which water circulated. An ammetelr reading tol 0.001 ampere was placed in series with tBei lamp and by means off a volltimelter tbei elnergy bedng used was measureid a,t frequent intervals. Frolm time t o tdme 10 C.U. por-tions of the plattinurn solutions were withdrawn by means of a pipet.ts and the acidity was tltrated against the stlandard dka81i. The results olbt,aine:d for the abolve fonr solutions are givein bellow.The figura in the first wlumn indicab she time in minutes, during whioh the solution has been exposed to1 the light. The seoond column sholws the number of C.O. of alkali necessary to neutlralisei a 10 0.0. portion of the platinum solution. The third column cointaJns the weight. in grams of hydrogen chloride formed in 100 0.0. of saluticm. TABLE I. N/200-K2PtC1 SoTzition. I N / 100-K2PtC1 Solutiom. Time, minutes. 5 20 40 65 125 215 265 400 580 945 1736 2200 2900 B4OH), solution C.C. 0.04 0.10 0-14 0.20 0.32 0.54 0-64 1.08 1-72 2-34 3-06 3.30 3-35 HCl. Gram. 0~00015 0.00039 0-00054 0.00073 0.00125 0~00210 0.00249 0.00421 0.0067 1 0.009 13 0.01193 0.01287 0.01365 Time, minutes.40 60 125 240 430 1035 1630 1910 2050 2400 2700 Ba(OH), solution C.C. 0.27 0.32 0.51 0-84 1-53 4-04 5.24 5.68 5.86 6-36 6-46 HCl. Gram. 0.00105 0.00125 0.00199 0.00328 0.00597 0.0158 0.0204 0.0222 0.0229 0-0248 0.0252 Time, minutes. 40 125 265 410 580 955 1455 1810 1900 2150 2750 Ba( OH 12 solution C.C. 0.20 0.40 0.74 1.34 1-92 3.00 3-96 4.14 4.20 4-24 4.29 HCl. Gram. 0.00078 0.00156 0.00288 0.00495 0.00749 0.01174 0.01644 0-0161 5 0.01638 0-01653 0.01 673 Time, minutes. 40 60 125 240 430 1035 1630 1910 2280 2600 Ba(OH)2. solution C.C.0-32 0.42 0-68 1.10 1-88 6-46 7.24 8.12 8-56 8-70 HC1. Gram. 0.00125 0.001 64 0-00265 0.00429 0,00733 0.0213 0.0282 0.031 7 0.0334 0.033 1108 ARUHIBAJiD THE HYDROLYSIS OF These resultsl show thab the different solutions read a condition olf elquilibrium. in almolst the same time. The N/200-solutioln attlaine a condition of maximum acidity some two or thrm hours after the modt colncentratmd one. I f we calculahe the percentage of clhlorine that has been set f r w from the pla,tinwn salt wheln equilibrium has hien reached we find t'hat for the four solutions tlhe values are beginning with the mmt FIG. 1. 9.00 8.00 7.00 x N 3 6.00 3 6-00 $ .$ ,.$ 4.00 5 + 3.00 CJ 2.00 1.00 d % T h e in minutes.dilute solution 74.7 45.8 35.2 and 23.2 pelr cent. of the chlorine present as platinic chloride. The relamtiomhip between the time and the progrew of t'he reae tioln is belt,telr sholwn by the curves bcf Pig. 1 where1 times are plot-ted as absaissze againstl vollumes of ba.rium hydroxide solution used for the tlitratioa. The first pa,rt of the aume sholws nearly a stttsaight line tha.tl is, during the gelriold that t'he first thre'el-fifths od the reaction is t'aking pla'm indioating tha,t the hydrolys'is goes on a,t a,n almost oonstlant rats fofr a oonsiderab,le period of time. A velolcity-constant for this part olf the reatdim may tlhen be adoulated by dividing th PLATINUM SALTS. PART I. 1109 Time of expbbtll'e for solution N/iO0, minutes. BNCH) - solution C.C.At 20 cm. At 40 cm. I 0.16 35 125 0.24 50 265 0.40 126 410 0.64 205 580 0.94 315 955 1.68 515 1455 2.12 640 1810 2-92 925 2370 3-48 175 3165 4.00 500 4105 4.16 860 6686 m o a n t of hydrogeln chlotide fotrmed by the time and multiplying by t8he dilution. There is an indicatioln in the oaxe 04 the two weaker sollutioas of wha8tl Gooldwin (Zeitsch. physikal. Chem. 1896 21 1) has tomeld an induction period during whiclh the reaotioin prmemds very slofwly. This would suggest that solme substmce may be f oming-a produot of the reaction-that ca,balysea the remtioln during its later stag-. This point can be discussed tol better advantage when considering the reaction that takes place in the dark. I n order to show that the rate of tlhe reaction is proportional t o the intensity of the light folr a given source of light the folllorwing melasurments were! made for N / 100- and N/200-solutione placed at a distance of 40 an.from the source. The temperahure and otthelr fa.doas we're maintained the same as in the previous me8asureime8nts. N/200-So~Zutiort at 40 cm. I N/lOO-Solution at 40 cm. Time, minutes. 220 405 585 950 1741 2472 3195 4010 5135 Ba(OH), solution C.C. 0.14 0.28 0-48 0.76 1-44 2.24 2-56 2.70 2.84 Time, minutes. 125 265 410 580 955 1455 1810 2370 3165 B4OH), solution C.C. 0.16 0.24 0.40 0.64 0.94 1.68 2.12 2.92 3.48 Folr the sake1 of comparison we1 niay selt dotwn opposite the vollume of hydroxide solution nelcessary for the1 titration the time! during whiah the solution was elxpolsed; the correispolnding time for the sollutioas elxposetd a t 20 m.dist8aiioe is a3so sholwn in the t'able, these valuea being t a h n from the curves of Fig. 1. TABLE 111. Ba(OH), solutioh c 0.14 0-28 0.48 0.76 1.44 2-24 2-56 2.70 2-84 2.92 Time of exposure for solution N/200, minutes. F 40 220 loo 405 188 585 300 950 510 1741 870 2472 125 3195 280 4010 460 5135 555 5665 .c. At20cm. At40cm 1110 ARCHIBALD THE HYDROLYSIS OF These resulb show that at the beginning of the hydrolysis the rate of the reactioln is approximately proportional to the intensity od the light. However after the reaction has promeded a aertain distmaetwheln about one-tenth of the toltal amount of hydrogeln chloride has bean formed-the rate od tho reaction for the solution at the greater distance is more rapid t*han the1 intensity law would predict.This is perhaps to be expectled if the l a t m stages of the reaation are influelnced by a prolduct formeld during the hydrolysis. It is worth noking thatl this change in rate occurs when practically the same amolunt od hydrogen chloride has befen folrmed in eiach solution. The final equilibrium point is apparelntly not affected by a change in the intensity of the light as the1 titration is almost ide1ntiaa.l in the two oases. It will be of i n b r a t to recolrd a t this point tlhe behaviolur of mlutims of 'the platinichloride wheln made! up and kept in the dark. The solutions were protected from the1 light by wrapping the container in black paper and then enclosing it in a thick wooden box blackened within and without.The following tables will show the1 r e d t s of them obselrvatiolns. I n the preparation. of the N/25-solution the water had belen very oarefully distilled and bailed again just before using. The salt1 had been kept in the dark for several days bedorel making up the solutions and every precaution was taken ta exclude light both while preparing the solutions and after. The volumes of solution and weights of hydrogen chlolride are expremed in the1 units used before. TABLE IV. N/ 25-K2PtC1 in Darknew 1 N / 50-K,PtC16 in Barknew. Time, hours. 68-3 162.0 354-0 546.0 937.0 1120.0 1440.0 1775.0 2177.0 2515.0 2735-0 3090.0 WOH), solution C.C.0.06 0.12 0.28 0.60 1-52 2.04 3.04 4-94 7.14 8-13 8.46 8.65 HCl. Grams. 0.00023 0-00047 0~00110 0.00236 0.00592 0.00796 0.01185 0.0 192 7 0.02785 0.0317 0.0330 0.0337 Time, hours. 68-3 162.0 354.0 546.0 1625.0 2455-0 2755.0 3662.0 4850.0 BWH), solution C.C. 0.04 0.04 0.04 0.04 0-28 0.44 0.84 1.64 6.04 Ha. Gram. 0.00016 0.00016 0.00016 0-00016 0.001 10 0.00173 0.00330 0.01177 0.02355 In the cams@ of the N/100- and N/200-solutio;ns the're was no indiaa.tion that hydrolysis had even stlarteld after t$hey had been in the dark for six months. For the N/25- and N/50-solutions th PLATINUM SALTS. PART r.1111 results were as indicated. I n the la4tltm case the hydrolysis had not proceeded fair enolugh to bme. measured until approxima,tely thirty days had elapsed. For the N/25-s,olutJon the rea,atioa had proceeded t,o such a,n extelnt that itl could be detected a,t t'he end od five days. The ourves of Fig. 2 obtained by plotting the results of table IV sholw much more dist?inctly the cha,ra.ct.er oif tthe " induction " period. This period become6 motre' elxte8ndeld and exaggera,bd as t<hel solution beloo,mes mom dilute until f o r a sollu-tioln as dilute as N / 100 na hydrolytic decomposition wha,tever t,a,kes place over as ext'endeld a peiriod as six mont'hs. It appears 8-00 7.00 3 3-00 0: CJ 2.00 1-00 FIG. 2. 0 0 0 0 0 0 0 0 0 0 d G . I e 4 c * I c c ) m * 0 0 0 0 0 0 W W e a ~ O P .l ~ Z ~ 8 h u 4.00 3 3.50 .$ 3'00 h N v 3 0) s 2 50 * 2 Time in minutes for reaction in light in hours for reaction in dark. strange perhaps that the more dilute solutions are1 the more stable. The aonmntlratioin of the hydrogen a,nd hydroxyl ions has evidently little to do with the progrws of tlhe reaction although it might be argued that these factors are1 practically mnstant for the different sollutions the propoirtJon of water tol salt being so large for all concentrations studied. The time required for the N/25-solution t o reach an equilibrium point in da,rkness is approximately on0 hundred timB as long as when exposed to the radiatioas of the 300-watt lamp. F o r the N/50-sollutions the difference in time is somewhat greater.It weans possible that for the molre oolnmntratmd sollutiolns 1112 ARCHIBALD THEl HYDROLYSIS OF suffioient although perhaps an exwedingly small amountl of some substance-perhaps an hydroixy-salt-is protdumd whein t,he salt is first dissollved to clatalysel the hydrolyticl relaction and in the case of the N / 25-solution tlol give the1 reactiotn an appreiciable vellooity almoet a t the beginning. The shape1 of the curve8 oif Fig. 2 is thea more easily undeirstootd. The steep parts shosw tlhe acoeler-ating elffelct of the oatalyst in the absence of any effective radia-tJoins in al very stsiking way. For the morel dilute solutiolns this oaltalyst is noti prolduceld in colnaelntratiolns high elnough to affect the proigras of the reaotion.The Reve,rse Reaction. On teeeting the soilutJons tor deltermine whether the relaction could be drivein in the opposite direction it was folund that whein poltlassium chloride soldium chloride or hydroahloric acid was added tol a hydrolysad solution the reaction prolueedeld in the opposite direction either in the da,rk olr in the light the extent to which the reverse rewtion tolok plaaei delpending in thei oase oif any olne sollutlicm on the amount of chloride that had beieln addeid. The rate a t which the reverse reactioa prolwelded was very muoh slower in the dark than in the light? as melasurements given bellow will show. The efffect of platinum-blaok on the rciaotioa wa's also studied as s e t forth in the tablee. For this purpose a stlrip of phtinum foil was covered elect~rolytically with platinum-black and this strip afte'r beling thoroughly washed was immerseid in the solution to bcr studied.TABLE V. Relvelrse Reiacltliolns in Light N / 100LK2,PtlC1 Solution. Time, minutes. Initial 65 95 255 430 620 775 1305 2070 2660 N / 10-KCl. Ba(OH), solution C.C. 4.2 9 3-40 3.08 2.28 1.50 1-16 1-04 0.82 0.60 0.56 HCl. Gram. 0.0167 0.0133 0.0120 0.0089 0.0059 0-00452 0.00436 0.00320 0.00234 0.00218 Time, minute. Initial 20 245 385 700 1175 1775 2665 NI20-KC1. WOH), solution C.C. 4.29 3-90 2-56 2.06 1.62 1-26 1.16 1.10 HCl. Gram. 0.0167 0.0152 0.00998 0-0080 0.0063 0.0049 0.0045 0-004 PLATINUM SALTS.PART I. 1113 TABLE V. (comtinued). N / 200-Ii2PtC1 Solution. Time, minutes . Initial 65 95 255 430 620 775 1305 2070 4850 6600 N/lO-KCl. Ba(OH), solution C.C. 3.35 2-86 2-74 2-06 1.70 1-48 1-34 1.04 0.92 0.59 0.52 The reverse rea.ction HCl. Gram. 0.0131 0.01 12 0.0107 0.0080 0.0066 0.0058 0.0052 0.00405 0.00359 0.00230 0.00203 Time, minutes. Initial 35 185 385 810 1205 1775 2323 4850 5600 N / 20-KCl. WOH), solution C.C. 3-35 3.00 2.54 1-98 1.46 1-24 1-12 1-06 0-86 0-70 HCl. Gram. 0.0131 0.0117 0.0099 0.0077 0.0057 0.0052 04044 0.004 1 0.00335 0.00278 is ma t o tta.ke pla.ce at a compa!ratively rapid ram& a't the beginning the amount of change beling grela,t,er hem i n a given time t.han for the direlot reiaotion.This; is na doubt beca'use the added salt has so greatly increased the conmn-tra.tlioin of the chloirine ion. Towards the elnd holwever tGhe pro-g r a s b,eiooma very slow with the result that the time relquired for the reverse action to go to complelt'ion is muoh greabr thaa the time nelcessq for the hydrolysis t,ol t,ake p1a.w. I n the cams@ of the N / 200-pla8tinum solutions t'he time relquired for the reverse relactioa. is much greaher t'han for the N / 100-solutlions. The latter st,a.ge od the relaotioln for the N / 100-potassium platini-chlolrideN / lO-pot,assium chloride solutioln is complicated by the f a,ct thatti 8,s the potassium platinichloride is rsgenelrated the solu-tdon h o m e s supersaturakd wit$ reapeot to t-his compound and it orystdIises otut to a slight extlelnt.This probab,ly explains the croissing o f t[he curvels for the N / 10-potassium chlolride solutiolns as shown in Fig. 2. This also goes to show tha.t the hydrollysed salt is slightly more soluble in polt,assium chlolride solutioas than the normal oompound. If the r a b od the! revelme rea,ctioa is expreissed a,ocolrding to the usual formula using t,he relsults of the mela.suremeats say for the N / 200-potassium pla,tinichlorideN / 10-potassium. chlolride solution, a colnstlant is not obtaineld. The expression for a unimohular resotioa give6 a vadue which continua,lly diminishes whilst the bimoilecula,r formula yields ZL continually increasing number.The rels;ults of me,a,suremetnts made on solutioas reacting in the reverse direlatioln in the da,rk a,re &own below in table VI. The && of the addition of sodium chloride to the bydrollysed solution is also shown 1114 ARCHIBALD THE HYDROLYSIS OF TABLE VI. Re,verse Reactions zcrt Darkness. Potassium Chloride Added. N/50-K,PttCl,. NI20-KCl. I N/ZOO-K,PtCl,. N / 10-KCI. Time , hours. Initial 1.50 19-58 73.50 260.50 601.50 1101.5 1657.0 2540-0 3096.0 B 4 OH 12 solution C.C. 6.60 5.32 4.98 4.32 3.34 2-80 2.38 2.10 1-84 1.80 HC1. Gram. 0.0257 0.0208 0.0 194 0.01 69 0.0130 0.0109 0.0093 0.0082 0.0072 0-0070 ' Time Ba(OH), hours. solution C.C. 4-25 3.22 49.25 2-60 317-0 1.98 1973.0 1.10 3797.0 0.90 5957.0 0.72 8693.0 0.52 ~ Initial 3.35 HC1.Gram. 0.0131 0.0126 0.0102 0.0077 0.0043 0.0035 1. 0.00281 0-00203 Time, hours. Initial 317-0 1973-0 3797.0 5957-0 8693.0 49-25 Ba(OH)* solution C.C. 3.35 2.78 2.22 1-32 1.12 0.92 0.74 HC1. Gram. 0.0131 0~0108 0.0087 0-006 15 0.00437 0.00359 0.00289 S0diu.m Chloride; Added. N/200-K2PtC1,. N / 10-Na8C1. I N / 200-K2PtC1,. N/ZO-NaCl. Time , hours. Initial 48 75 1732 3556 5716 8452 12300 Ba(OH), solution C.C. 3-35 2.62 2.42 1.34 1.10 0.86 0.50 0.29 HCl. Gram. 0-0131 0.0102 0.0094 0.0052 0.00429 0.00335 0.001 95 0*00109 ' Time, hours. Initial 48 76 3556 5716 8452 16828 20476 -Ba(OH), solution C.C.3-35 2.94 2-82 2.1 6 1.80 1.72 1-50 1.20 -N / 100-K2Pt.C1,. N / 10-NaC1. Time, hours. Initial 29 219 1296 2376 4488 Ba(OH), solution C.C. 4-29 3.98 3-42 2.52 2-16 1.68 HCl. Gram. 0.0167 0.0165 0.0133 0.0098 0.0084 0-00655 HC1. Gram. 0-0131 0*0115 0.01 10 0.0084 0.0070 0.0067 0.0059 0.0047 PLATINUM SALTS. PAB.T I. 1115 Thel% reaulte show that the reverse maation brought about by the addition of a soluble chloride to the hydrolyd solution o m -t i n u a in the absence of light until folr the more colnmntrated sohtfions much the same equilibrium point is maohad as in the oase of the same retaotion taking place in the light.F o r the more dilute solutions the la,tter equilibrium point is pa& the reaction continuing for approximately two yela'rs by which time the hydrolysis has. almoist disappeared. The aatalytia effelcrt of platinum-bla'ck on tlhe reverse reaction is shown by ths results set forth below. In tlhe first oaw the sollu-tions were exposed to the radiations from the 300-watt lamp whilst the second series of resultcr refers to1 the realchion taking place in the absenae of light. In each cam theae reactions were studied simult7anelously with solutions kept under exactly the same conditions except that no platihum-blwk was present. TABLE VII. Reverse Reacti,om with and withowt Platiwmblack. I n Light. N / 100-KzPtC1,. N / 20-KCl. With Platinum-black.I Wit.hcmt Platinum-black. Time, minutes . Initial 20 245 385 7 00 1175 1775 2665 Ba(OH), solution C.C. 4-29 3-90 2.66 2.06 1-62 1.26 1-16 1.10 HC1. Gram. 0-0167 0.0152 0~0100 0.0080 0.0062 0.0049 0.0045 0.0043 BNOH), solution C.C. 4-29 3.90 2.56 2.06 1-62 1.26 1.16 1.10 HCl. Gram. 0.0167 0.01 52 0~0100 0.0080 0.0063 0.0049 0-0045 0.0043 In Darkness. N/lOO-KZPtCl,. NI20-KCl. With Platinum-black. 1 Wit,hout Pla8tinum-blaak. Time, hours. Initial 2 19.7 1296.0 2376.0 4488.0 8376.0 28-75 BNOH), solution C.C. 4.29 3-72 2-84 1-80 1.36 1-14 1.02 HC1. Gram. 0-0167 0.0145 0.01 11 0.0070 0.0063 0.0045 0*0040 B@Hh solution C.C. 4.29 3-88 3.52 2.36 2.02 1.54 1.30 HCI.Gram. 0-0167 0.0151 0.0137 0.0092 0.0079 0.0060 0.005 1116 ARCHIBALD THE HYDROLYSIS OF It is apparent that the effect of the platinum-black is no4 great enough to show wheln the reladion is taking place at a redatively rapid r a I k before tlhe lamp but it is quite noticeable when the reasation is proomding slotwly in the dark. A few relsults will show the effect of the prewnw of a neutral salt such as poltmium nitlrate in the solution undergoing hydrolysis. The values from measurements of two so'lutioas are given. TAELE VIII. Direct Reactiom with Potassium Nitrate:. Time, minutes. Initial 100 175 350 465 665 850 1380 1775 2020 2650 3000 Be(OH)* solution C.C.0.00 0.20 0.40 0.78 1.00 1.44 1-86 2-66 2.92 3.04 3.28 3.44 HCl. Gram. 0.00078 0*00156 0.00304 0.00390 0.00562 0.00723 0-0104 0.0114 0.0119 0.0128 0.0134 -Time, minutes. Initial 100 190 225 315 605 800 1215 1776 2020 2650 3000 Ba(OH)!a solution o.c, 0.00 0.22 0.46 0-58 0.84 1-52 1.91 2.40 2-90 3.08 3.26 3.40 HCl. Gram. 0~0000 0.00086 0.001 79 0.00226 0.00328 0.00592 0.00745 0.00936 0.0113 0.0120 0-0127 0.0133 These raults show thah whilst the potassium nitrate has a, retlarding effelct a t tlhe beginning of the reaction the acidity of thei solution finally reaches just as high a value as in the a;bsmce of the neutral salt. The total time required for the ractioln to reach an equilibrium point is but slightly greater when the potassium nitrate is preaent.In agrement with the retarding effedl of the nitrate is the f a d tlhat the solution whioh contains the grsa4telr amount od neutral salt lags slightly behind the other. As stated above it appears from the results in table I that a substance may be formed from the hydrolysis which acts as a oatalyst of the reacbioln inoreasing the speed very perceptibly during tlhe first half of the decomposition. This polint was further tested 51s follows. Two so1ut.ions were prepared in the same manner of equal concentration as regards platinum salt whilst one contained 1 C.C. of dilute hydrochlolrio acid. They were then exposed at the same temperature and at the same t h e to the radiations from the lamp at equal dishanax frolm the source.Measurements of the aoidity of $he solutions were then made at frequent intervals. The results failed to show a,ny acm1era;ting influence whatever on the part of the hydrochloria acid. Th PLATINTJM SALTS. PART I. 1117 reactioa ne:cewarily did not proceed so far in the solution co,ntaining the; added chlolrine ions but t'his was the olnly eiff elct noltimd. Anoher axperimeat with the same object in view was madel as follows. Two1 sosluttion od t'he pla.tinum salt were prepared one N/100 the other N / 4 0 0 . These1 welre exposed to the light until p d l y hydrolysed then pla,cejd in t'he da'rk. The acidity of the molre mnce8ntIrakld sodut.iojn wa,s melaaured af t'elr twenty days and the me'asurement sholwwed that the hydrollytic reaction had a n -t,inueld until the usual equilib,rium polint hamd been readhd.In the aase of the N/400-solution a measuremeat was made after thirty days b,ut the rise1 in acidity i f any wa,s so small thab it could not be detected with certainty. After thirtyeight days more the result of another measuretment indicated that the hydrolysis was promled-ing b,ut very slowly. A 10 C.O. port.ioln which neut,raliseld 0.88 0.0. of aJka1ina sollutioln when first plaroe.d in the dark now required 0.98 0.0. The nelxt tlwa months b,roaght no pelrcepltible change in this so;Iution and sixteen niolnths aft.elr it ha'd beeln placed in the dark a 10 0.0. porkion relquiretd olnly 1.10 C.C. of hydrolxide sollutioln. Ano,t,helr N/$OO-solution made up at the same time as this me' but nevelr exposed to the light showed no1 indication of any hydrolytic atation after sixteen molntlis.It would selelm as if a certain con-ae.nt8ra.tion of the catqalytlic relageinti was necessary before the hydrolysis will promeld. In the caw of tlhe N/4OO-solutlon that had been exposed to the lightl t'his coaaentration had apparently just b e m ma.ched befo'rei the d u t i o n was placed in th.e dark. It wa.s not elxpeotefd t'hah the acceleirating influence of p1a.tinum-black woluld be suffic:ieiit'ly grelat t'o bje noticed in a soIlution undelr-going hydrollysis b3edoIre the1 light. It wa8s tlhought wojrth while, however to memure this elffect on sollutIolns rea,oting in the dark. Accolrdingly two solut8ions were ca,rrsfully prepared ela$ch N / 25.In one was placed 0.05 gram od pla,tinum-black. B d h solutions were placed in the dark and me'asureld from day to day. After three days 10 C.C. of one solution neutrahed 0.06 off dkali solu-tion whilstl the1 same1 volume1 of t.he one cmhining the platinum-blauk required 0.25 C.C. After five days the oorresponding voluma o,f a.lkali solutlion were 0.06 0.0. ahd 0.45 a.0. The effelat of the platinum-black was very evi delnt bolth in stasting the hydrollysis and in acmlelra,ting the reactioin. Anot'her expelrimelnt almost idelnticaJ wit'h bhis one wits made by a,dding 5 C.U. of an N/25-solution conipleltelly hydrolysed tlo a nelwly prepre'd N/lOO-solution and pla<oing this in the dark. The relading for a 10 a.a.portion of t.his sodution wm now 0.98 0.0. 09 alkali; after two months tqhe vollume of a1ka;li required for a 10 0.0. pmtion was 2.32 ox. showing that a sufficient ammnt o 1118 ARCHTBALD THE HYDROLYSIS OF the a8cmlelrat8ing sub,stame had bwn added to cause the hydrolysis to take place. The efielct of the1 tmpelrature oln the rake of tlhe rsaotim and t,hel extelnt of t,he hydrolysis rsceiiveld some attention. It was first asmrt8aineld wheltlhelr a sollutim which would not undetrgo hydrolysis in t'hhe da'rk a(t t'he olrdina,ry tempera.tnrel woald hydroilyse if kept a t 80°. An N/lOO-solutioa was te#st'eld in this way. The titratioa for a 10 0.0. portion of this sollut8ion was 0.04 0.0. at ZOO. After being kept in the dark a t 80' for three hofurs the aorresponding tit.ra,tion was 0.16 C.C.On cololling to 20° still in the1 da.rk the titra8tion fell to1 0.08 C.C. After being kept in tlhe dark a t 80° fo'r a,nother periold of thr'ee holurs a 10.0 C.U. polrtion aga,in requireld 0.16 U.C. of a(lka1i. I n the1 a4bs.elnce of light the t,e,mpera8ture has little i f a.ny influeam o a the! hydrolysis. The1 same1 conclusion is drawn from a' colniparison of t.he rate od the1 retactlion taking place a& 25O with that1 a t 35'. The1 va8riatloln here is only manifest towasd the elnd of tlhel relafotion wheili the diffelrelncel in the1 elquil-ib'rium point-a grelatelr degre'e od hydrolysis a,t the higher ternpelratnre-is sufficieatl t'ol shomw in tho fina,l reatdingsf. For the purpose of ascelrtaining to wha$ extelnt the1 hydrollysis would be inmease'd by al rim in tempelra,tare t'hreel solutioas welre elxpowd to t'he radiatdons of the 300-waftt la.mp at a.dist.anae1 of 20 an. the wafelr-ba.th beling maSntained a t the temperature shown bellow. From time to timel 10 C.U. portiom of t,he platinum s o h -tlions were withdrawn aad tJtra,te,d t'he light being continued a.t a,ny one temperature until equilibrium ha'd beefn a,tt&eld. TABLE IX. EfJect of Temperaituse om the Hydrobysz's. N / 100-K,PtCl,. I iV/50-K2PtCl,. 1 N/25-K2PtC1,. Tem- Ba(OH) HC1 pera- solution (100 c.c.). ture. C.C. Gram. 20° 4.29 +0-0167 50 5-24 +0*0204 80 5-90 +0.0230 Ba(OH) HCl solution (100 c.c.). C.C. Gram. 6.45 +0*0262 7-45 +0*0291 8.20 +0*0319 Be(OH) HCl solution (100 c.c.). C.C.Gram. 8.70 +0*0339 10.16 +0-0396 11-06 +0-0431 If we express the inorelase in the acidity of these solutions as percentages of the va,lues a t 20° we obtain the1 following coefficients for temperatures between 20° and 80° N/100 0.62 N/50 0-45, N / 2 5 0.45 per cent. These cmfficienta are notl very diffelrent for the1 several cIonmn-trations studied. From the amount of hydrogen ahloride formed a t 80° we find tha& for the iV/lOO-solution 63 per mt. of th PLATINUM SALTS. PART I. 1119 chlorine preaent as platinic chloride has bem used to f m hydrogea chloride. If we! represent by ohemiaal elquatioas the several stage@ of t h e hydrolyticr de~mposition of the platinum salt we find that for the N / 25 -solution the equakioa K2PtC1 + R,O = 2K’ + PtC&(OH) ‘I + H’ + c1‘ indiaaIkl pretty clotselly t,he eixtelnt t’ol which the1 hydrolysis hati taken pla’ce; whilst for the1 N / 50-so3ution t>he elxpreesim would represent morel marly the conditIion of the solution.When the solutions are as dilute1 aa N/100 olr N / 2 0 0 the rspelotive equa)tions would be and 2K$?tc16 + 3820 =4K’ + Pt,CI,(OH)” + PtGl,(OH)” + 3H’ -+ 3C1 K2Ptc16 + 2H20 = 2K’ + Pt~C14(OH),” + 2H’ + 2C1’ + 3HzO = 2K’ + Pt,C&(OH),” + 3H’ + 3C1’. The a h 0 equat.ions c’orrelspoad with a temperafure of 20°. At highelr tmnpera,tures t,he deoompolsitdon of the1 sa,lt is more ne:arly colmpleitq which is in a4gre80metntl wit’h the factl that when aI dilute solut.ion off thei pla,tlnichloside is boile’d in the light an insoluble substance is deposited. Obviously the possibilities of this hydrolytic a.ctim should be kept in mind when making a delterminatioa od poltassium by melamns of this salt; if a solutioln of the pla,tinichlo’ridel is b,eing elvaporahed, a suffioient amount of hydrochlorio a.cid must be preseatl to prevent the hydrolysis taking plaw whilst i f the salt is beling precipitated, hydrolohlolric acid must’ amgain be present to ensure1 the formation of the nolrmal compound. Pohassium plat8inibrolmide shows solme inhrest’ing felaturels not nolt,icelable in the oase of the platinichloride and it is holpeld to submit soon a oommuniaakition dealing with this colmpound. Summary. It has been sholwn tha8t solutions of potlassium platinichloride undergo hydrolysis when exposed t,o the action of light. I f the solution is as concelntrated as N/50 this hydrolysis will begin and will be completed in the dark; for a N/lOO-solution or one more dilute no decompoaitioa takes place when light is excluded. A subatIanm is formed by the1 hydrolysis which catalysee the reaction and will initiate1 the decompmition in a newly prepa6red solution. The addition of a soluble chloride tol the hydrolysed solutio 1120 JONES AND LEWIS: Oilusesl a oomplejte revelrsad of the relaction showing that the substances formed during the dired reaction are sohble. The reverse rewtioa is influelneed by light1 in muoh the same way a8 the dire&. The complelte reversal od a saluticm as dilute as N / 200 mquirels nearly tIwa ye8a8rrs. A neutrd salt has 8 slight reltarding effect on the dire& readion, bmut doee not influence the equilibrium polint. The accelelrating influenw sf platinum-bhuk on both the direct and reverse relaotions is quite noticelable when t7hew relactiam am takifig-place in the da,rk bat is not melasurable when light is atding on the sol ' u t' 10ms. CHEMICAL LABORATORY, VANCOUVER CANADA. UNIVERSITY OF BRITISH COLUMBIA, [Received July 23rd 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701104

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

1120 JONES AND LEWIS: CXXV1.-Studies in Catalysis. Part XIV. The Mechanism of the Inversion of Sucrose. By CATHERINE MARGARET JONES a.nd WILLIAM CUDMORE MCCULLAGH LEWIS. IN comexion with the investigations caxried out in this l a h a t t o r y on the oheanioal reactivity of mollelcular and iolnia species from the point of view ot the radiation hypothe& it was found necessary, in one selatioln of the work t o make a series of determinations of vedooitly-coinstant,s in the case od a felw familiar reiactioas suoh as the inversioln olf SUCTOBB with the object of studying molre particu-larly the influence olf change od elnvironment on the rate of the reaction. The principle olf mass actioln in it8 usual formulation, affords no1 information of an a prio1.i kina regarding the effectt of efiviromnentr.It is helped that tlhe radidion hypolthesis may be of assistanm in this colnnexioln (oompare Lewis Sc?;emth 1919, 25). As B preliminary it is nenemary tol p"sess as o l a r a view IM pwsible of the acttaal material mechanism of the selected reac-tion ifi olrder to! be able t o proceed with solmei degree of oonfidenm to the furthelr problems invollved in altelrations oif material aad tapretture eliivironment. The inversion of sucrolse is a readion particularly suitlabla for the purpose in vielw in so far as preoision of measuremeat is coacerned. Furt(her this reiactdon has been frequently illveatigated but ih spite of this the inversion proces STUDIES IN CL4TALYSIS. PART XIV. 1121 obvio;usly requires further inv&iga.tioln more particularly as regards ths way in which the hydrogen ion entelrs into the proms.The p r a i n t mssarch was underta'lcen prima'rily for this purpw. As will be seen the expeIrhnent~a,l melasurelmelnts co'nsist oa the olne ha,nd of deteirminatioas od relaction velocitiee and on the olther of determinations olr" the a#verage (geomeltric mva.n) activities of the hydrogen iojns olbst'ained by the ele,c.t,ro~met~ric melthold. In agree ment with t'he ooncllusion a;lrela3dy relacheid by Ha*rned ( J . Amer. Chem. Soc. 1918 40 1461) in c80anexion with othe'r reactions cahalysed by ions it has been found that tlhe a,ctivitly od the hydrogen ioa as defineid by G. N. Leiwis is the detelrmining fa.ct.or for the rake of the reaotion. This colnclusioa is of p a t importanm, as it not only includes t o a certain exte'nt the phenomenon known aa the sollvmt displa,oement effect b'ut adsol a.s polinbd o u t by Harned appea4rs t,o exclude the neatmity of ascribing any catalytio influence t o tlhe undisso,ciated molleloule olf the acid.In order to obta'in data which could be mplolyed for various kinds of oaJcula-tion care has been t,akeln t.0 deltexmine the amounts of all aon-stituents watees included in knolwn volumes od the va'riorus sollu tions. AS will be sholwn later the most probable material mechanism of the inversion rea,&ioln is that expresseld by RH'+H,O + dextrose + lmdow. Thah is t'he rea.ation is a true bimollecular onel bNet,wean a moleoule of wafer aad a complelx ion formeld by tfhe a,ddition of hydrogen ion to the sucrose moleloule.E x P E R I M E N T A L. Rtmctiom Velocity Measurements. The rat& of inversion olf sucrolse was oarried out in the ordinalry mannelr with the usual pretcantiolns a t 20° 30° 40° and 50° in the presence of N / 10-sulphurio acid the initJa1 concnent8ration oif SUCTOSCY being va8riield over a wide range namely from 10 to 70 per cent. in order to b,ring into prominence1 any elffelct produced by the displacement of t'he soclvent,, water the volume of the va.rious d u -tdons being ma,inta.ined const,a;nt,. All de!telrminatqiolns were carried o u t in duplica,tei and satiaf act80ry mimolecular velocity-constiants weire obt,aineId t,hronghoiut the entire1 ra,nge examined. To! save space the meran valuels only olf tIhe olbselrveld vedwity-coastants, relfelrred to bhe ba,w e and in seconds -1 as well1 a.s tbel initia'l ooncentrations of sucrolse aad watelr are1 given in the following t*a blel 1122 JONES AND LEWIS: TABLE I.CataJyst 0.1 AT-H,SO,. Grams of sucrose in 100 C.C. of solution. 10 20 30 40 60 60 70 Gram-molecules of water ( M = 18) per litre. 51.95 44.99 41.62 38.09 34.69 30.94 48-45 Unimolecular velocity -constant. at 20". at 30". at 40". at 50". 4-43 1-83 6-73 2.29 4-79 1.97 7.37 2-56 6.2 1 2.12 8.04 2.81 5.64 2.29 8.80 3.08 5.95 2-45 9.53 -6.22 2.58 10.22 -6-29 2-66 10.92 3.94 A - x 106 x 105 x 106 x 104 It will b obsesveld that in all cases displacement of the1 water by the sucrose1 causes a definito increlase in the velocity-constant a further illustration of the anti-catalytic elff ect of water already observed in other reaotiolns for example hydrolysis of esters.If the reaction is a true1 birnolecular one it is necessary to divide the velocity-constants by the oolrresponding ooncentration of water in olrdelr to obtain comparable quantitieies in so far as this stoicheiol-metric colrrelctioii is concerned. Whether the obselrved velocity-constants require to be thus divideld or not it is possible to obtain values for the critical inurementl 3 by means of the equation d log k/dT=E/RT2 from the velocity-constank a t diffelrent temperatures. It was thus found that with an increasing initial colnmntratJon of sucrose the value1 of B rises shadily over all three ranges of temperature invatJgated namely 20° to 30° 30° to 40°, and 40° to 50°.That is the critical inarment (or tlhe temperature coefficient) apparently risee whilst the velolcity-constant itself also inoreases. As this is in direclt contradiction t O the conclusion already drawn namely that the gre'ater the1 oritical increment the smaller ceteris parribus the1 velocity-constant it was concluded that the catalytio oonditions were nolt cotmparabk a t m y pair of temperatures as the contentl of sucrose was varied. The behaviour, in fact coald be accounteld folr on the1 assumptiolns that ( a ) the catalytic influence od the acid a t any given temperature! increlases with increasing concentration of sucrosel and ( b ) tlhat this inorease in aatalytio act4ivity is greater the higher the temperature.This conclusioln did not appear to1 be1 a very probable one on the basis of tbe degree of detctrolytic dissooiatioa of t3he acid f o r in the oase of sulphurio acid the1 catalytio effelct ascribed to the undis-sociated molecule is approximately the same as that of the hydrogen ion and in general the1 ratio1 otf the1 catalytic effect ascribed to the molecule1 to that o€ the ion decreases as the temperature increases. Owing to tlhel large viscosity effects producleld by a variation in th STUDIES IN CATALYSIS. PART XIV. 1123 clonaeintratioln of suorow eleotrical conductivity measuraents could not give direct information even assuming that the original q u a -t'ion olf Arrheiiius wa,s valid an assumpt,ion which ha.s recently beeln called in question.On this account it was decideld to delt,elrmine the a>ctivity or thermodynamic cornaentra.tJoa of the hydrogeln ions (striatly speaking the geomet'ria mean of the activity of hydrion and HSO,') by xmans of dwtromotivel-folrce medsurments. Activity of Hydrogem I o n ilt Apzce~ows Solutims of Sucrose. The cdl employed was of the following type: I H,SO + sucrose i saturated i normal calomel :!:::% I 0.1 N J KC1 electrode The use of a saturated solution of potassium chlolride w a middle liquid t o eliminate colntact potential differelnces has been fre-quently recommended (compare Falee and Vosburgh J. Amer. C'hem. Solc. 1918 40 1291). The absolute value of the normal calomel electrode wits taken to be +0*56 volt at 18'. Using T. W. Richards' value for the temperaturecmfficienb of this electrode, namely 0*0006 vollt per degree the polbntial difference of the calomel electrode at 20° was taken to be 0.5612 volt a t 40° 0.5732 vollt.The value of rH the potential of the hydrogen ellectrode in the sulphuria acid-sucrose solutions was obtained by means of the folllowing eiquations : rH = 0.277 + 0.058 log, H' a t 20° rH = 0.296 + 0.062 log, H' at 40°, where the eleotrdytio potential of hydrogen has bwn assumed to vary directly its the absolute temperature. The absolute value may not be correct on this basis but the quantity involved is a constant at any given temperature the relative valuea of rII at two different temperaturee are comparable. Table I1 contains the E.M.F. data obtained a t 20° the last column giving the average aotivity of the hydrogen ioln expressed in gram-molleaulm per litre.Table I11 contains similar data for 40°. In all oases diwolved oxygeln was removed from the sumose solutions t o prevent any ohange in the suarme in contact with the platiniwd platinum eledrder. an 1124 JONES AND LEWIS: TABLE 11. Temperaltus.e 20°. 0*1N-H+30,. Grams of sucrose in 100 c.c of solution. 0 10 20 30 40 50 60 70 Gram-molecGes of sucrose per litre. 0 0.292 0.585 0.877 1.169 1.460 1.755 2.047 Gram-molecules of water per litre. 55.55 51.95 45-45 44.99 41-62 38.09 34.59 30.94 (M = 18) E.M.P. of cell observed, in volts. 0-3555 0.3520 0.3485 0-3450 0.3410 0.3380 0-3345 0.33 13 P.d.of hydrogen electrode, 0-2057 0.2092 0.2127 0.2170 0.2202 0,2282 0.2267 0.2299 r n . Activity of hyfk.ogen ion in gram-molecules per litre. 0-060 0.068 0.078 0.0895 0.105 0.118 0.139 0.1 62 TABLE 111. Tempera;turq 40Q. O.lN-H,SO, Grams Of sucrose in 100 C.C. of solution. 0 10 20 30 40 50 60 70 E.M.P. of cell in volts. 0.3580 0.3545 0.3522 0.3460 0.3370 0.3280 I -P.d. of hydrogen electrode. 0.2 152 0-2 187 0.2210 0.2272 0.2362 0.2452 --Activity of H' in gram-molecules per litre. 0.050 0.056 0.062 0.078 0.09 1 * 0.109 0-130* 0.152 (Values marked with an asterisk are interpolated from the curve.) It will be observeld that the aotivity od the hydrolgen ion is 1-s atr 40° than it is a t 20°.This would be elxpsated for the cmcen-tratiom of the ion since the dissauiation of the aoid is amlmpanied by a n evolution of helat. The first conclusion to be drawn from the1 above datla is that the aativity of the hydrogen ion inareasee apprecbbly at both tempera-turels with an inoream in the aoncentration of the sucrose and furthw as shown latelr in the figure the rate of increlase in aotivity is greater a t 40° than it is a t 20°. The belaring of these rwults on the velocity-constants wiIl bs considered in the next sedioln. The wlclolnd oondusion is that the aativity of an ion is related to its colncent8ratlion in a very secondary manner. This has already been sholwlz to1 be the case by several Anmrican investigators.The &ect is weill marked in the prewnt instance. Thus when the suc1"olse colntelnt is 70 per cent. tIhe thermodynamio colncentration of the hydrogen ion is 0,162 at 20° and 0.152 at 40° although the STUDIES IN CATALYSIS. PART XIV. 1125 maximum aattaal conoatration 09 hydrogen ioin oannot exmeld 0.10. The third conclusioin is that the displacement of the solvent by a noin-ellelctrolyte sucrom producm effects entirely analogous t o those! prolduoeld by addition of nelutral salts the1 addition olf the sucrose and cionselquent eilimination of water causing an increlase in the activity of hydrolgen ion from two- to three-fold. It is p m polsed t o investigate this asp& olf the displacememtl e$fect (compare Griffith and Lewis T. 1916 109 67) in furthelr researches in this laboratory.The1 activity oif ions in presenae of a noin-eleictrollyta appears tlol have bem investigatetd in a single instance only namely, by Harned ( J . Amer. Chem. Soc. 1915 37 2467)) who deter-mined the activity of the hydrogea ioln from hydrochloric add in the presence of mannitol witholut olbselrving ho.uelvelr any marked effect over the concentsation range employed. THE PROBABLE MECHANISM OF THE INVERSION PROCESS. It was found that the direotly obseirved velocity-oonsbanb (table I) a t 20° when divided by the concentration of the water and also^ by /tthe corresponding activity of the1 hydrogen ioin gave a quantity which was a constlant within tihe limit of the expan-mental error. Similarly the data atl 40° gave a colnstant independent of the sucrose or water content tqhe numerical value beling od cosrse grelater than that a t 20°.These coastants repre-sent bimoleioular velocity-oolnstantt3 relduced to unit activity of hydrogen ions. The va,lues are given in tables IV and V. TABLE I V . Temperature; 20°. O*liV-H,SO,. Grams of sucrose in 100 C.C. of solution. 0 10 20 30 40 60 60 70 Gram-molecules of water (M=18) per litre. 55.55 51.95 48.45 44.99 4 1.62 38-09 34-59 30.94 Uniniolecular velocity-constant observed. x 108. 4*14* 4.43 4.79 5.21 5.54 5.95 6-22 6-29 Unimolecular velocity-constant divided by water c oncen t.ra ti on. x 108. 7.46* 8.53 9-85 1 I -58 13.31 15.61 17.97 20.33 Unimolecular velocity-constant x lo6 divided by water and also by activity of H ions.1.24 1-25 1.27 1.29 1.27 1.32 1.29 1-25 (Values marked with VOL. CXVII. Mean = 1 . 2 7 ~ lo-'. an asterisk are obtained by extrttpolation.) u'i 1126 JONES AND LJEWlS: TABLE V. Tempemture 40°. O.lN-H,SO,. Grams of sucrose in 100 C.C. of solution. 0 10 20 30 40 50 60 70 Grain-molecules of water per litre. 55-55 51.95 48.45 44.99 41.62 38.09 34.59 30.94 Unimolecular velocity-c on.. t ant observed. 5*98* 6-73 7.37 8.04 8.80 9.53 10.22 10.92 x 105. Unimolecular Unimolecular velocity- velocity-constant constant divided by dividcd by concontration. by H' activity. 1*08* 2.16 1-30 2.31 1.52 2*46? 1.79 2-30 2.1 1 2.31 2.50 2-30 2-96 2.27 3.53 2.33 water water and also x 106.x 105. -Mean = 2.305 x 10-6. (Values marked with an asterisk are obtained by extrapolation.) The two1 mean values 1-27 x 10-6 at 20° and 2.305 x at. of the 40° repre,sent t.he true bimo1eoula.r velolcJty-cons.t8ant k rea,cltioln whelm Icbi is de,fined by where uni is tlis olbserveid unimo1e.cula.r ve!locity-const,ant, [I-%,O] t,he oonoelntration of the water (M= IS) and [H'] is the act.ivit,y o!f t'he hydrogen ion. The vaduee of kbi as t.hus defineid a,rel in-dependelnt olf t'he colnoelntlration of sucrolse. or water and also of the activity olf the aoid ca.ta.lystl. Thei valuels od kbi depend o'nly on the temperature. Sinaa t,he change in the olbserved velocity-coastantl with t'hhe com-position of the solutioln is elntirelly acrcojunted f olr after t,he int.ro8-ductioln od the ne8mssary stoicheiornet,ria colrrelotion f olr wa,telr by t,he aotivity of tlhel hydrogen ioln it f 01lo~wwe that t$he undissociated molecule od the aoid possesses8 no1 ca8talytio effelct in this oasel.This osndusion has alre'ady bem drawn by Harned (Zoic. c i t . ) in olther easels in the prelmnoe. o'f neubral salts. It is hopeld that furthe'r invwt.igatbon with othes acids will se.tt.le the1 que'stioln a.s t'ol wheltheir tlhis csndusioa is a ge,neral one folr aque'olus sollut'io.ns. I n the case of gaseous syst,ems catadysis b,y means of acid is sca.rcedy knofx-n. Del Hemptinne. (Zeitsch. physiknl. Chem. 1892 13 561) stmates that a positive uata.lyt,io eEelc t' is producleid by liydrogeln ohlo'rids gas in the hydroslysis of gaselous ee.teirs.I n t'hheisel ciroumst.anoels, a.nd probably hhere9 olre in nom-ionising sollvent.s thel undissociated molelculel of the acid is the ca,ta,lysing individual. Th0 fadl that const,ant values for kbi as definsd abovel a,re k i = kuni /[H,O] [H'] STUDIES IN CATALYSIS. PART XIV. 1127 obt&ed a t a given temperature re'movw the diffiaultly already ment~ioineid in connexio,n with t'hhe apparent varia,tio.n o:€ t,he critica,l increment with compositJon of the1 syst.em. When the catalytlo condit'ions are1 re'ally made the] same a.t two difielre,nt temperatures, a single value for E thel critical increment per gram-molecule od sucrolse invelrted is ob,t'a.ined this value being indetpenclent od t,he cofnce,ntrafiomn oif sucrose olr water in the system.The vadue oif E doulat'ed from kbi ah Zoo a,nd 40° is 26,390 calories. The accuracy od this value depe'nds on the reht'ive a,ccura,cy with which t,he a.ct,ivities of the hydrogeln ions atl 20° a,nd 40° ha,vvei be,ea deter-mined. This numetrical value represents the sum of t,hel orittical increments of the reactmanta which will bma shown later t,o be t,he complelx ion (sucrose R') and wa,ter. The! constanoy olf kbi may be' employeld as a orit8e1rioa in ahtempt-ing to dete;rminel t,he meohaaism o,f t8h0 inversion pro'wss by m.ea,ns of stoicheiomet'rio equations f osr t'hesel elqua.t4iosiis must be such as t.01 lela,d fina,lly to1 an elxpression of t,lw folrm kbi= k,i /[HZ01 [H'].Apart from this consideraiion many adtermtive moldes oif expressing the inve.rsioi-1 pro'oess suggest themsellves. We shall considelr five oif the moistl probable of t'hese and sholw tlha.t olnly olne of them is in agrelelmeint with the critlerion. The lat,itade od choice a,risee from the doub,t as to whether (a') the hydrolgea ion which re.a,at's is hydrated oc not (6) whethetr the suoro~e whioh rea.cts is hydrated olr noh. The pro'b81em of hydrahioln is olnei od the least sat.isfact,ory a,speds of the thelory of solutdons the widetncei in most ca,sers beJng conflioting. Possibility l.-Assumel tha,t practically a31 t8he suctrose is hydrakd and tha.tl the! same1 is t,ruel for the' hydrogea ions butl thajt it is t'he non-hydra,t'ed sucrose which.reacts with a hydra,te,d hydrogein ion (H,O,H'). Applying t'het law of mass action t,ol the hydration of the sucrose R + H2Q = (R,H,O) we ham X = [R,H,Q] / [R] [H2Q], whe're X is t,he elquilibrium oonstant 09 hydratdoa and R stlands for non-hydra,ted sucrowl. The inversion process assumed to be correlot ia R + (H20,H*) -+ dextrose + lzevulose. Hence ra'te; of invers'ion = kbi [R] [M20,H']. Butl ra.te of inversioln = kuni &serv&[(R,H@)], since pra,cticc,zlly all t,he sucrose has beeln assumeid t,o bs hydratad. Hence, kbi = kuni [(R,W,O)]/[R] [f120,H'] =Auui . K . [H20]/[H20,1-3[']. This me,chanis;m requires thelref o're t,hat4 the product of the olbseirveld vdooity-oonstant by the wa8ter colnaentra4tlon divided by the activity of the hydrogen ions sholuld be it colnstlant indelpendelnt of t,he initial concent,rat.ion 04 sucrose.This diffelrs from t,he true n u 1128 JONES AND LEWIS: oriterbn and in fa.& the right-hand side of the quation is not a colnstaat. Possibility 2 .-Assume( t,ha5t pra.atica811y all the sucrme is hydrateid butl tha,t the hydrolgea ioln is practically all unhydra,M, and that t'he inversion prooees is (R,H,,O)+H' + dextroBe + lavuloee. The right-hand side of this ecxpression is not oonst,aat. Henm, pmsibility 2 is incolrrect. PossibiZity 3 .-Assume) tlha8t praotiaadly all the suaroae is hydrated and tha.t t,he hydrogeln i o a is also1 practlically all hydrated but t$at it is the noln-hydrated hydrogen i o a which relaots with hydratad suc!rolsle as in possibility 2.We have nolw to allow for Ki t.he equilibrium colnsta,nnt of hydra(t.io1n off the ioas, This assumpt,ioa leads finally t o kbi = k,I,i .&[RzO] . Ki . /[H,O,R'], which is indis,binguishab,le frolm possibilitly 1 and is thelref ore i ncolrr ect. Po~si~biJity 4 .-Assume thatl the] sucrose1 a.nd the1 hydrogeln ions amre practdca,lly all hydratsd a.nd that it is tshel hydra(ted folrm of ea.ch which relact8s a(oco1rding t,oi the e;qua,tian (R,P-I,Q) + (H,O,H') -+ delxt'rose + lawuloael. Then kbi = kmi /[H,O,H'] which beling equivalentl to pmsibility 2, is incomelot. Po.ssibiZity 5.-Assume t'hat t'be sucrose as well as the1 hydrogen iolns is pra,ctioally all noa-hydra.te:d and thamtl the first stage is a,dditioa t801 form a co!mplsx ion t,hus R -+ 33' =RHO which is f ollloweld by the true inversion reactioa, RHO + H,O 4 dext'rmel + lzvulmei.Wo then have, ra.tel of inversion =kUAi [R] alsoI ratel olf invelrsion= k . [RH'] [H20] wheaoe kbi = kuni [R]/[RH'] [HzO]. Nolw R,, the elquilib,rium colnstantl olf the complex-ion foirmation is given by H,=[RIR']/[R] [H'] whelnce khi= kuni / K c . [€I,Q] [H']. This is in agrejelmelnt with t,hel critelrion the1 right-ha,nd side being a. coinsta,ntl, since it only diffe,rrs frolm the! criterion in conntaining the colnst'ant, X,. It ma,y be1 sholwn furtheir ttha,t if the above1 mechanism is assumetd with. the1 modifioatioa tha;t t'hei sucrose is marly all hydrate,d an expression is obtained which is not in agrmmelnt with the experime,nt,al re8sult,. Also( if polssibility 5 is eunploqye,d with the mofdifica.tioa thatl t'he ions arel pra#ctically all hydrateid an equally incorrelcb expreasioln is obtained.Finally if possibsility 5 is etmplolyeld with tjhei moIdifi&ion that bolth suorose aad the ions a#re practic3a.lly all hydrated an incorrect expreaion is obtIaineld. Helnnael possibility 1 is incolrred. This leads fina811y t.0 the conclusion tha,t kbi = kuni / [H '1. Ri= [R~O,H']/[H'] [HZQ] STUDIES IN CATALYSTS. PART XIV. 1129 It is reasolnable ta coIndude therefore that polssibility 5 as i t stands is the only satisfactolry meahanism. The two stloicheiometric equations which exprem t'hei inversion prolcess are thelref ore : and Itl is obviolus tlhat this melohanism accolunts for the1 faat thatl the hydrogeln ion is neIcmsary in olrdsr that inversion may proceeld with measurable speed.There1 is also some evidence od a prelliminary nature f o r the existleinm of an addition complex of sucrose and hydrogen ion which itl is hopeid may be communicated in detail later. The mechanism of the1 inversion process to which we have been leld involves etquatiolns (1) and (Z) and also! the assumptioln that the hydrogen ions and thel sucrose molwules are not appreciably hydrated in aqueous solution. This relpresents the simpled set of conditions but the r e u l t is somelwhat surprising. Sucrose is usually regarded as being helavily hydrated in sollution. As already pointed out howeiVelr such an assumptioln would no6 lead to the obselrved constanoy of the quantity elxprelssed in the final clollumns of ta$blels IV and V.R + H' = RH' (practically instantaneloas) . . (1) RH' + H,O = dextrolsel+ lzvulowi (measurable) . . (2) Hydvoigem-ioa Activity as a Fwnctiom of the Compositiom of the1 S0~2~tiOYnl. Rosanoff ( J . Amer. Chem. SO:^. 1913 35 173) has suggested that the cat'alytia elffect of a solvemt may be1 eocpressed as an expo,neatia,l funct'ion 04 the1 concentration of the solvent. A similar rehtdon has bean etmployecd by Wilsoln (ibid. 1920 42 715) to a,ocoant folr t.hel effeat of nelutral sa.lts on the1 hydrogen ioln as delter-mined by eleot,rometlric me.asurements. Wilso'n appears tlo relgard t,he increase in macenttra,tion of t'hei hydroge'n ion in the prelselnce of ne>utra,l salts as rela,l. The e,ffect howevelr involvee the a,ctivity, and nolt nemsarily the c,oncentlratdon of the ion.The ana'logy of the1 e,ffed produced by the1 displaoemelnt od water by a'ddition oif suorose to thah prolduced by a> neutral sa'lt has already been inent.icmed. I n the aondit,ioas olbtaining in the1 present' investliga;fmion we deal with t<hs aimultaneloius influeince of sucrose and wa'ter since by a,ddition od one mlnstitne.nt a cert,ain amoant of tihe1 other is elliminateld. Let us suppow thab the activity of the hydrogen ion can be expressed by [H'] = A . e(bR+b'W) . . . . . . . (3 1130 JONES AND LEWIS: whelre R and Jlr are the concentratiolns of suclrme and watelr respectivelly in gram-molelcules per litre b and b' are the1 oatalytia environmental constants characteristic olf suorose and wabr b is a positivel whilst bl is a negative[ quantity.When there1 is no sucrose present W becomes IV, (namely 55.55 gram-molecules per litrel) and H* belcomels TI*(). We can thus repwrite equation (3) in the1 form : Hence, (34 H' = H',e4 ~ R - ~ ' ( W O - W \ . . . . . . loge N' =loge H.0 + bR - b'(W9- W). . . . (4) In the present case itl happens thatl a straight line is obtained when the aoncentration of sucroae is plotteld against the1 oonmn-tration of the water. Hence we can write TV=W,+pR where1 p is a negative constant having the value -12.1 the sucrose and water being expressed in gram-moleculee per litre. Equation (4) can thereforel be writtetn in the present case in the form or alternatively, l ~ ~ ~ E € ' = ~ o g ~ H ' ~ + (b+b'~3)R .. . . (5) logeH' = 10geH.O + (b/p + b')( W - Wo) . . . (6) Equatioas (5) and (6) are both linear thatl is they represent the1 obseirveld belhaviour of the1 activity of the hydrogen ion as a function of the composition of the mixture as is shown in the figure (graphs C and 0). Heam eiquatlioln (3) is justified in so far a t lelast as it satisfies the above condition in the present case. From the1 experimental data the follolwing mean vadues are1 obtained: b - 12.lb' = 0.47 a t ZOO, b - 1 2 W = 0 * 5 6 , 40'. Itl will be olbselrved that equations (5) and (6) being elquivaleint do noh permit of a calclulation of b and bl separately. Furthelr experi-melntal da,ta invollving a diEerent functional relationship beltween the aonoeintration of the sucrose and the water are required.I n equations (3) to (6) we have employed the most general type of folrmula in which a possible catalytic elf€ect has even been ascribed to1 the reactant solute sucrose. In this connexion there is an important coinsidelration which has t o be taken into1 amount. T he1 obselrved unim ole cula r v el ocit y-con st an ts obtained at various temperatures are1 found tot remain constant within tlhe limit; of expeirianental error throughout the entire course of the reactioln. This is the case1 even when the initial concentration of sucrose is as high as 70 per wnt. as is shown by the following results of duplicate expelrimeuzts which give the observeid velody-aonstant ST(JD1ES IN CATALYSlS. PART XN. 1131 obtaineid with 70 per cent. suerow at 40° in the presenoei of N / l O -sulphuric acid.The vellociity-coust'aiit is calculated to1 the base e . -.-I 3 5 4 0 4- 5 5 0 5 5 B O 5 5 5 0 4 5 4 - 0 3 3 3 3 Water concentration moles per litre. (k = okerved veloci% constant) \ water concentration 1 TABLE VI. Experiment 2. I Experiment 1. Time in seconds. 0 780 1600 2100 3060 3900 5160 6420 7500 Unimolecular velocity constant x lo6. 10.82 11-03 10.98 11-00 11.03 11-07 11.11 10.98 (55 per cent. of the sucrose decomposed.) -Time in seconds. 0 1200 1950 2460 3060 3960 4440 6360 6900 Unimolecular velocity constant x 106. 10-81 10.81 10.83 10.77 10.89 10.86 10.96 10.97 (53 per cent. of tho sucrose decomposed.) 1132 STUDIES IN CATALYSIS.PART XIV. The facb tha.t the velocity-coastant does noit alter indioates tha,t the a,ctivity od the hydropn ion is likelwise sensibly constant. As, howelver the conoent,ration olf the sucrose ha.s diminished b,y more than onel ha81f it follo8ws tlhat the eaviroamental influenca of tlhe sucroBel if any ass melasurelcl bsy the1 quant,ity b must blel t,he same! as that of t'hel de'xtrosei a,nd lzvuloleel formeld a's a relsult od t'he invelrsioln. If these sub~st8ance8s a,rel inelrt it woiuld foillow that b = 0 and tha.tl thetreifolre the1 elnvironmelntad mtadytia teirm b', cha,raotelrisbic of wa,t,eIr is -0.039 ab 20' aad - 0.046 a't 40'. The nega<t,ivel value indica,t,ea of colursel t'ha4t the wa.ter is al negative cata,lyst for t'he procelss.The question ot t,ha albsoilutle value olf b will be deIdt with. in a la,te.r clommunica.tion. Rehurning t'ot thei graphs shown in the1 figurel it1 will b'e olbserveld that witb diminution in tshel co8ncent,ra'tioIn of wat'er the aurvels folr the hydrogeln-ion a&ivity art8 20' a,nd 40' a.re1 noit paradlel but coavorgent. The same relation is exhibiteid by the mrvea for the velocity-aolnstantl shown in tbe same diagram graphs A a.nd B. When t'he two1 wfta of curvea adel oombineld coastant va'lues folr k,, as dehed in the prejcelding sectioa are1 olbt8a8ineld. The relahive pmitioas8 olf t,he two sets of ourves a,fford the most direct emidenm yet obhaineld fo'r the1 colnclusion that the activity of t'he ion ooImplet,elly delterminels thel velocity of the relaction.8ummury. (1) The1 vellolciity od inswrsioln od sucrolsa in the1 presence of N/10-slulphuria amaid has bteen dete'rmineld a8t 20° 30° 40° and 50° the compoeitioa od the sollut>ion beling altetreld by gra,dual displa4cmelnt of t'he wa,ter bmy the sucrose. The ~e~lolcity-constanta vary with the initial colmpolsit8ion olf the mixtare. (2) Thei a4velrage activitks of t,he hydrogen ion ha4ve beein deltelr-mineld e~lec1t~rome~trica.lly in tbs varioas mixtures referred t,oi in (1) at 20° and 40°. It is sholwn tha,tl the1 a,ltera,tioln in the vellodty-const'ant ca,n be a,ccountad for completely by (a) allowing folr the st,ob&eiornet,ririo colrreiction f oc t,he wa.tes preseat and ( b ) by allow-ing for the cha*nge in the act'ivity of the hydrogen ions. (3) I n a,greeimetnt with (2) the inversion process is shown t o be bimollecula,r. Iti consists osf tswo proaes6els (i) union olf the non-hydra,teld hydrolgeln iojn with an noIn-hydratd molleiauls of sucrwel, thus R + IP' =RHO this proiceas being pmctioally inst8antaneoas, and (ii) the actual inversion reIachion RH' + H,O = delxtroset hvulme. It is a,lsol concluded that. tlhei hydrogen iolns a,nd the sucrose moleIcule8 a,re not sensibly hydrate'd in a.quwus so1ut.ion. (4) I n agrememt wit'h Roeanoff's suggestion regarding the mod THE PREPARATION OF GUANID'ENE ETC. 1133 of eixpressing the influence of solvent cdalysts the aotivity of the hydrogen i o n is folund to be an eixponential functioln of the coaaentration of sumose and water praeat. (5) It is shown thatl the e'nvironmeatal cahalytio influence of a molleculel of SUCTO~S~ refelrreld tlol in (4) is idetntical in magnitude with that exerted by one molleculej of dextrose tolgether with one molwule of laevuloae. MUSPRATT LABORATORY OF PHYSICAL AND ELECTRO-CHEMISTRY, UNIVERSITY OF LIVERPOOL. [Received August 4th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701120

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

THE PREPARATION OF GUANID'ENE ETC. 1133 CXXVIL-The Preparation of Gua.nidine by the Interaction of Dicyanodiarnide and Ammonium Thioc yanat e. By EMIL ALPHONSE WERNER and JAMES BELL. BY heating a mixture of dicyaaodiamide and ammonium chloride a t 195O folr ten minutes Bamberger and Dieckmann (Ber. 1892, 25 545) obtained diguanidei C,H,N,. The yieild wa,s pooh and Ostrogovich (Bul. Soc. qtainfe Bucaregti 1910 19 641) using ammonium iodidei in plaae oif the ohloride under similar wnditiolns, obtained it much btter resulti. The reactioin has been represented thus: HN:c(NH,)*NH.CN + NR,*HX= HN:C(NH,)~NH*C(NH,):NH,HX. The dicyanodiamide complelx is supposed to remain intact whilst the! cyazmgen group unites with ammolnia. On this assumption the relaation is considelred to uphoild the cyanoguanidine formula for dicyanoldiamide propoeeld by Bambeirger (Ber.1883 16 1459). I n the statia oonditiotn dicyanoidiamide is stable up ta 2 0 5 O , when i b melb and is simultaneously depolymelrised t o cyanamide* and largely re~pollymelrised ta melamine (oompa(re Werner T. 1915, 107 715). Several experiments have sholwn that dicyanoldiamide is reladily depolymetrised to cyanamide at' comparatively low temperatures in the premnce of certain relagentis and it6 behavicrur in the presence * This fact is not referred to in the literature if a gram or two of dioyano-diamide i8 heated to the melting point in a porcelain crucible and quickly covered with a glass bell-jar standing over a layer of water the latter after a few momentswill be found to give quite a copious yellow precipitate of silver cytmamide on addition of ammonio-silver nitrate solution.u u 1134 WERNER AND BELL THE PREPARATTON OF CUANIDINE od ammonium thiolcyanah folr example( furnishels a case in point whiah is olf pradiaad value. P'urei guanidine t,hiocyanato has been easily prepared in amord-mm with the squatlion C2H4N4 + 2NH4*SCN = ZCH,N,*HSCN . . . (1) Whilstl the main change is equa81 to 90 pelr c,entl. od tlhei theoretical, it. is aocrompa,nied by a seloonda,ry rea,cltion whereby thi~amme~line is formed in small quant'ity. This does not. interfe're with the sucaelss of t,he prelpa8ra.tioln as its sepa,ra,tio(n from t,he chief proiduct is a simple rnaf'br. Pure diayanodiamide wa8s useld in preliminary sxpelrimelntis tIo detefnninei the b.elstj conditioas but' from an eloonoimia point of view the commercia,l ma,terial may be .conveniently employeld.The1 sample use'd in the following prepasat,ion contained dicyano-dia,mide = 95*5,* oa,lcium casb(o1nat.e = 3.25 mellamine = 1.25 per cent. An intima.b mixture of 43.5 grams oQ dicyanoidiamide (=42 grams pure) aad 76 grams olf dry ammonium t,hiocya,nafei in coarse polwder wa,s hela8iad in a tall na'rroIw beakelr past,ly immelrseld in a glymlroll-bath. A 10,ose cIa,rdb,oa,rd oovelr ca$rrie8d a the:rmolmelter, which served at the same1 tlimel as a stlrres. At' about' 80° tlhel mixture began to1 mellt,; the i;ernpelra.tare wa.3 gradually raJsed to1 120° about selventy minutm being required for t,he purpose and this tempe8ra,t.ure was maintaineld for t-hree and a,-ha,lf hours.As the resct8im prolceode,d the product which in the earlielr s t a p was an almorjt clela,r liquid graduadly betmms very visoous. It was notw t'reahd witholut previous coo,ling with a,bout 250 C.C. o,f wates aad a,llowed t,ol digest unt'il cold. After filtrat'ion and wa.shing, 7.4 grams of amolrFhosus relsidue welrei separa<teld (residue A ) . The filtlra,te was colnclentlrated a8 far a,s possible by eva,polra8t8ion a.t loo", aad the ciystladlinel mass which formed on cooling weigheld wheln dry 110 grams (Folund SCN = 47.76 ; guanidine thiocyanat'e relquiresl 8CN=49.15 per oent.). The product wa.s redissolved in aboat 200 0.0. of warm wafer and 1-02 grams of amorphous solid (residue B ) welrel separateld by filtra.tion.The filt8ra4tej wa,s e:va,porateld t'ol a' syrupy oolnsistency a t 10Qo and a,fter " seelding " thei cold solut.io,n with a minute cryst,al of guanidinel thiocyanat'e itt quiokly set to a. crystlallinel mass of thO pure1 salt (Found SCN=48.96 pe.r cent,.). The yield of pure A single recrystallisstion of commercial crude dicyenodiamide is The material generally sufficient to obtain a product of this degree of purity. should be free from calcium hydroxide which is occasionally present BY THE XNTERACTION OF DICYANODIAMIDE ETC. 1135 guanidinel tihiocyanatel was 107.1 grams equal to 90.8 per cent. of the theoretical. The oharacteristlic picrate was prepared a.s a means of idelntifi-oation. Whilst residue A colntained the impurities originally present in the1 dioyanodiaanide 5.4 grams of pure thioammeline, C,TT,N,S weire separated from it1 by trelatmetnt with sodium hydr-oxide sollutioln and precipitation after filtratioa by carbon dioxide.It was identified by its properties as deswibeld by Elason (1. pr. Chem. 1886 [ii] 33 290). The picrate melted ak 215O and as it separated from solution in peculiar crystalline formations which, under the) microscotpel resembled a highly divided palmatifid lelaf, this colmpound may be used for the idelntification of the substance. Since thioammeline results from the interaction olf dicyanoi diamide and thiocyanic acid. according t o the equation i t is not! possible to supprms it's formattion a8s dissolciation of ammolniurn tlhiocya,nalte to a smasll extsnt ca.nnolt.b~e avoided under the conditions' of the1 elxperiment. Residue1 B was pure thioammellinel geaerabed as above from small quaa t,it,im of dioy anod iamidel a,nd amin olni um thiocy an a,te which ha.d escaped change. This warns proveld by eivapora.ting to dryness a t looo al so3utlion od 2 grams of dicyaaoldimide and 3-6 grams of almmonium tlhiocyanate in 50 C.O. of water wheln 0.29 gram of thio-amemline was obkined. For this relasoa e.vapora#tion of the solu-tion t,o dryness in the first inst,a.noe wa,s found t40 be1 the most. efficient melt4hod for pmpasing a pure prolduct and the1 a,ddition of ab,out a gram of ammo,nium thiocyana,te t'ol t'hs fusion when the1 remtiotn haa been in progretss €or t'wol hours is a8dvisa8ble. When a.n 0xw1ss of the salt was used at' the outlset of the experiment the yielld of thioammeline was increased.Shoald the cryst,als of guanidine thio,cya,na.ts sho'w opalescence after arystdlisatlon from and while strill in hhe mo,ther liquor a, second sotlutim and filtra,tion is necessary t'o remove the la.& traces of t,hioammelinel. On a.ccoIunt. olf the grelat solubility of guanidins thiooyanate in water its complete separatlion in crysta,lline form is tedious; it may be remvered as carbonate by mixing the visoous mo,theIr liquor with ab,out four volumes of alcohol and afte'r the a,ddit,ion of the requisite amount of potassium hydrox.ide t.he guanidine is precipit'ate.d by a current od casbon dioxide,. Apa,rt from itls pract'ioal va.luel the re,a80tion is of t.heore,t,ical interest since i t is obvious that delpo,lymerisat,ion of dicyanodiamide u u* 1136 THE PREPARATION OF OUANIDINE ETC.must be the first! pha\se of the ohange in order ta yield guanidine in such quantity as relquireid by elquation (l) whilst the foirma,t,ioln olf t,hiolammeline the1 mastlitutioln off which has been cle8arly dmoln-stsateld by Klasoln (Zoic. cit.) acoolrding tho equahioln (2) woald be difficult t o elxplain on t'hhe basis of the '' clyanoguanidina " structu rc of diuyamdiamide. Considering t~ha.t Bamberger and Dieakmann (Zoc. cit.) obt'ained digumide by heIat,ing guanidine hydrochlolride a.t 1 8 5 O thelre can be no doubtt tlhat the lattler was first formed in their prepa,rtrt.ioln of diguanide from dicyanoldiamide. This has been verified from qualit,amtivel egxperiment~ which h.owever welre olf no1 praoticd interestl; on the1 other ha,nd very encouraging rwults have been abtaine'd in the prepasation of methyl- aad ethyl-guanidine an a,ccolunt od whioh i5 reiselrveid far a future communica4tion.Sol far a5 the a.uthors a<re a,wa,re nolne olf the methods hitherto demribed for the1 preparation of guanidine can colmpare with tyhO process now sat forkh either in mspe& od cost, simplioitly or yield oif pure produot,. I n this colnnexioln it may be useful t'o relcoiUllt the autholrs' experience of Ulpiani's method (1909 D.R.-P. 209431) foir the prelparatioln s f guanidine nitrate by the acljioln of amqua regia at 60-65O on dicyanodiamida. A quarntit8ative yield is daimed. Since the change (indireot oaxidation) is accompanied by the e;vollut.ion of muah ca,rbon dioxide and nitmgela from dicyanodia-midine simult,aneolusly produced the maximum yield of guanidins is represented by the ratio C,H,N -+ CR,N3,HN03; from three casefully conducted experiments the beat yield was 26 grams of guanidine nitrah from 42 grams olf pure dicryanoc diamide equal ta 42-7 per mint.of thO theoreitiaad calculated on the folregoing ra,t,it.ia. It is evide,nt from this result t,hat not less than two1 mollelmla od diayanodiaznide asre invoilveld in t.he production of olnne of gua.nidine bsy t,his method. The assa,y of dioya'noldiaxnide was colnveniently cronduoted by hydrolysis aa follows 2 grams of &he powdereld sample were mixed with 25 O.C. of water N-hydrochloric a,aid was addeld until the alkaline impurities ware neukalised using melthyl-orange as indica,tor after whioh the pro,duat was heated for fort.y-five minutes a,t looo with 25 O.C. of N-add. The residual acidity was deter-mined by titaa,tion wit,h N-sodium hydroxide. Earoh 0.0. of N-acid neutradised is equal to 0.084 gram of diayanodiamide. UNCVERSITY CHEMICAL LABORATORY, TRMlm COLLEUB, DUBLIN. [Received A q w t 24th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701133

出版商:RSC    

年代:1920

数据来源: RSC

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SYNTHESIS OF SOME NITRO-DERIVATIVES OF TOLUENE. 11 37 CXXVIIL-The Synthesis of some Nztro-derivatives of Toluene. By OSCAR LISLE BRADY and PERCY NOEL WILLIAMS. IN the course of an investigation it was found nemsary tol pre-pa(re a considerable quant<ity of pure 3 4-dinitrolt,oluene. This compound is formed with the 2:3- and 2:5-ismerides by the nit'ratioln of m-nit8roto;luelne and can be readily selparaiteld from the mixtare by freelzing (Beilstelin and Kuhlberg Annalen 1870 155, 25; Haaiuswrmann and Grelll Ber. 1894 27 2209; Holleman and Sirks Prolc. R. A7cad. Wetensch. Amsterdam 1906 9 280). This melthod is satisf aatory althoagh the yieilds are not lasga. Eaeusser-mann and Grelll ( h c . c i t . ) mentlion the preparation from 3-nitro-p-toluidinel by the Sandrnelyer rea,dion but do not give det'ails.As a tfrial of Ha,eusselrmann and Gredl's melthod did not give golod remlts and as m-nitrotoluene was unobtainable ab the time and it4 preparation o a a labolratory scale was very tedious other melthods of prelparation of 3 4-dinitrotdueme weire considered. The premnt p a p r deta'ls with one of thew methods. The starting material was o4duidine and the reactions involved may be summarisad M follolws : Me Me The nit?ration od ol-t801uidine to 4-nit8ro-o-t~olluidine desaribsld by Noelltling and Colllin (Ber. 1884 17 265) but by a, moldificatJon of t'heir prwelss the seipasation of t,he isomerio nitrm t'oluidines formed has been grelatly simplifield. The yiejlds obt'ained to the stage of the dinitroitloluidines were satisfasotmy but t h 1138 BRADY AND WILLIAMS THE SYNTHESIS OF remolva.1 od tlhe amincFgroap f r m these1 cojmpounds did not prove as easy as expearielnce witch similas compo'unds ha.d led the aut,hors to expect and the yield of 3 4-dinitrot.oluenei wa,s' disappoint-ing.On t,he ofbher ha,nd the oxidation of the amino!-group in the dinit,ro!-tolluidimls tlol the1 nitroigroup by mea<ns of Caro:s acid proceeds very smo801t;hly and prolvidels a oonveinisnt meitho,d of synt,he&s of 2 3 4-and 2 4 5-ttrinit,rot.olue:ne8s ivhic'n hit,he,rto ha've beeln obt,ained only by 'che nit,ra.t'ion of m-nit~roltlduelne a.nd sepasatioln of the t,wcu isommerides by fra&iolna,l crystmallisatdon (Wepp An(na+len 1882 21 5, 366) or by nitratioin off the rare 2 3- and 2 5-dinit'rotoluenes (Will, Bey.1914 47 704). E X P E R I M E N TAL. 4-Nitroux;ceto-o-toZ~~~~~de .-Onel hundred grams of o-hluidins were dissolved in 1087 O.C. ojf sulphuric acid (D 1-8) care being taken Lo avoid rise of temperature. The mixture was cooled bellow Oo in a freezing mixture and al mixture off 163 0.0. of sulphuric? acid (D 1.8) and 50.8 O.C. of nitria acid (D 1.42) coioleid to! Oo slolwly run in so that the bmperahure did not risei above Oo. When all the acid had belen added the mixture was allowed to1 remain for one hour. At this stage Noelting and Colllin (loc. cit.) neutralised all the1 acid with sodium hydroxide. A morel economical methold which avolids a great increase in the bulk od the liquid and the, formation oaf tarry products consists in adding to! the1 nitration mixture1 onehalf its bulk of watelr with thorough cololiiig and stirring.On keeping the sulphatel of 4-nitro-o~toluidine separated, and was removed by filtration and washeld with alcohol. The yield of sulpha,tte was about 60 per cent$. of the theoretical. The 6-nitro-o-toluidine formed during the nitration (Gram and Lawson T., 1891 68 1014 say 20 per cent.) remaineld in the filtrate. The sulphate was ground in a morhar with a slight excelss of 10 per cent. sodium hydroxidei and the free1 base collecteld wa,shed thoroughly with water dried a8nd acetylated with acetia anhydride. Nitration of 4-Nitro~cetol-o.toluidi~e.-A solntlion of 20 grams oif 4-nitroaw~tol-ol-toIuidide in 60 C.O. of concenl-rated sulphuria acid was added slowly with stirring tot EQ C .C . of nitric acid (D 1.5) cooled in ice. When d l the solution had been added the mixture was allowed to! remain in ice for thirty minutes and then poured into 4 litres of ice-water. The solid separating was collected at onw and thoroiughly washeld by grinding three1 or four times in a, mortas with watelr and filtering. A 70 to! 80 per aent. yielld of the mixed dinit rolscet o - o 4 oluidides was obtained . Sepuaatioa of the Dinitro-oi-tolu~~~es.-Fifty grams of the mix SOME NITRO-DERIVATIVES OF TOLUENE. 1139 turel of dinitrolamtol-o-hluidides were hydrolysed by heating for four o r five hours on the! water-bath with a mixture of 200 C.O. of oonceintratecl sulphuric acid and 400 C.O. of water. On coolling t.he mixture[ filtering and washing the precipitate first with 50 per cent.suiphuric acid and then with water a 45 pelr cent. yield of a substance mslting at 1 2 2 O was ofbtaineld. On diluting the filtrate, a 25 per cent. yielld of a ma(teria;l melting at 150-170° was p r e cipitated. The1 compound melting a t 1 2 2 O was recrystalliseld several times from alcohol1 until the product was of constant melting point, and oriented by conversion into 2 3 4-trinitrotoluene (see belolw). 3 4-Dinitro-o-tolluidine cry stallism in lustrous yellowish-brown needleis mellting at 131-131.5" (Found N = 21.5. C7H70,N, requires N=21-3 per cent.). The substance1 mellting a t 150-170° was recrystallised twice from alcohol and orienteld by conversion into 2 4 5-trinitrotoluene (see below). 4 5-Dinitro-o~toluidine orystallises in yellow needles melt-ing a t 191-191.5° (Found N=21*6.C7H70,N requires N=21.3 peir sent.). Prepration of 3 4-DinitrotoZzcene.-For this purpose it is not necessary to1 setparate! tho mixture of dinitro-o+duidine as bolth give 3 4-dinitrotoluene on removal of the aminobgroup. Nine. grams of the mixture welro dried and dissolveid in a mixture of 180 O.C. of freshly distilled absolute alcohol and 45 O.C. of faming sulphuric acid (containing 20 per ceat. of sulphur trioxide). The, solution was heated on the water-bath and 27 grams of finely powdered dry sodium nitrite were added in small portions with vigorous shaking. When all the nitrite had beea added the mix-ture was heated for five minute& oooled and diluted with water.The oily solid whioh separated was crystallised first from hot nitrio acid (D 1.4) to destroy tarry matter and then from alcohol with tohe additioa of animal charcoal when pure 3 4-dinitrotoluens was obtained. The yield was not good 2 grams only being obtained from 9 grams of the mixture of dinitrotoluidinea. Prepamtiom of 2 4 5-Trz.nitroto~luene.-Toi Carol's a d prepared from 10 g r m s of ammonium persulphatei and 7 C.O. of conceln-trated sulphuria acid poured on 20 grams of crusheld icel a solution od 2 grams of 4 :5-dinitro o tduidine (m. p. 191O) in 10 C.C. of 80 per cent. sulphuric acid was added. A clear solution was obtained which on keeping overnight deposited dinitronitrosol-toluene!; it was then diluted with water and the precipitlateld nitroaoccompound added to ten times it6 weight of nitrio acid (D 1.5) and warmed uiitil reld fumes weire not longeir evolved.On cooling and diluting the1 solution a crystalline precipitlate of 2 4 5-trinitrotoluene was obtained whioh after onel recrystallisa 1140 FERRISS AND TCTRNER: tion frolm ahholl wa8s pure. The yield was about 80 per cent. of the theoretical. Pre,paItim of 2 3 4Trinitrcrtolwen,e.-A sollution of 3 4-dinitro-o-t'csluidinel in 80 per cent. sulphurio acid was added to Ca,ro's a,cid a's acbroive; in this case holweiver the amina was pre&pit&ed by t,he dilution oif t,he sulphurio acid so the mixture1 waa tra'nsfermd to a stoppe#re,d bottllei and leift fo'r folur days wit<h freiquelnt shaking. At the end of tha.t time thei precipit'atle was collectreld and treatsd with nitric a.cid as in the previous cam when 2 3 4-t;rinit,ro~t801uene was olbt8a,ineid in goold yield. The 'authors wish ta express their thanks to the Director of RESEARCH DEPARTMENT, ROYAL ARSENAC, ArtJllelry for permission t,oi publish t'his work. WOOLWICH. [Received August 27th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701137

出版商:RSC    

年代:1920

数据来源: RSC

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1140 FERRISS AND TCTRNER: CXXIX-Studies in Ring Formation. Part IIL The Condensation of Aromatie Amines with a- and &Diketones and with 4 &-Diacetyldiphenyl. By CLARENCE VICTOR FERRISS and EUSTACE EBENE~ZER TURNER. The Comle?zmtion of Bemzidime a d Toli&na with BerzziJ a d CONDENSATIO: products off loenzidinel and tdidine with belnzil or glyolxal were deeoribed by Cain and Mioklelthwait (T, 1914 105, 1437) but the prelselnt a-utlhors after clarefully repeating their eixperiment8 are unable1 to confirm the formulz assigned by them. to the protducts obtained from benzidiim aiid these1 two diketoncs. Whilst the oolndsnsation product from b e n d and belnzidina has now been obtained in a statel of purity its cornplelte analysis and a determinatlion of its molleloular weight by the oryoscopic; method have not leid to1 any definite colncllusions as to1 its stmature.Con-delnsation seelms to1 take place1 in a more aomplelx mannelr than is assmeld by bhe above autholrs. Hydrollysis of the1 profduck with rninelral acid showed tha,t more mollelculee of benzil t<han of benzidinel elnter intlol the reladioin. Again although such a con-deineatioln might be elxpelcted to1 prolceeld quantlitativdy we1 have ;not sucweded in obtaining more than 70 pelr wnt. of the aaloulated G l y o ~ x d STUDIES IN RING FORMATION. PART III. 1141 yield nolr is an appreoia,brle quantitly o:f aaeltylb8enzidine formeid as might be supposed. Of t,hel prolducta ob,taineId from glyoxal t,hat formed with bemidinel is a highly insoilubls norn-crystlallina mass of unknown rno1e:cula)r comple,xity.The oo8ndensaf8ion olf glyolxad aad tolidine ga,vei a substqa4nce of tlhel e,mpiricad folrmula folund bly Cain and Miaklet8hwait b'ut its insolubility relnders a mollelcular-welight det8elrmination impossib3ei so tlha,t4 itl ma,y possibly be f ormeld by the colndelnsation not olf ojiiel molelmle oC glyolxad with one of t401idinel, b,ut by tlhe condelnsa.tion od two! molleiculelsi od each together. The Codenmtion of A mines and Dimnines with Ac1e'tylaCe:tome a,& Benzoy lac e t on,e. Condensation prolductsi o F acetyla.celt onel a,nd benzoylamt~olns with bemidinel and othelr b,a,sea ha,vve previoasly been dmcrib,ed by one of us (T. 1915 107 1495; 1917 1111 1). Further examples have now b'ee'n studieid.h o ' n g olthelr reeults it hae been found thab monolaicet?/liso~rrol;olyl~e,netoil~~nei is a liquid ah the ordinary teimpeira~turei and dz;acetyli.,o~olrylzdenetoli~~e a so;lid melting a.t 1 0 8 O (uncolrr.) whe'ress t'hhe c'olrresponding colmpolunds froem beazidine mellt res8pect8ivetly a.t 137O and 198O' (cornparre benzylide'ne-o-t.oluidine1 a liquid a'nd benzylidelnelaniline m. p. 48-49O). Combes (BuLl. Soc. c h k . 1888 [ii] 49 89) wha first studied tIhe a,ctioln of aminea on a&,ylacetone stla,teld thati the prolduclt of aondensa,tion of p4olluidinel a.nd a,cetyla,ce~t~oae melted ah 39-40°, a8pparelntlly reterring t*o the trimelthylquinoiline f olmed by its furthelr colndelnsa.tioln in the preeelnm of sulphuria soid. Pfitzinger ( J . pr. Chem. 1888 [ii] 38 40) givea t'he melting polint of the trimeithylquinolinel in question as 63-64'.The present aut,hoas ha,ve found t,ha,t pLttoluidinel and a,mkIylamt~one colndense undelr the influeaae of helast aJone t,ol give1 tsh el tkriinetchylquinoline the melting polintl o€ which is 64O a fa.ct which renders p-toluidine an ab~no~rma81 compound as regards its aation on amtylacet80ae. Ketones of the DZphenyl Series. Attempts to1 Condense 4 4f-Dicnce t y ldiph eny 1 with o-Ph eny 1 ertediamhe. Hitherto our knowledge of ketones derived from diphenyl has bwn r estriche d t o p hen y 1 a celt op hen one 4 -p hem y lbenzo phenoas, 4 4/-dibeazoyldiphenyl diphenylyl benzyl ketone and diphenylyl a-naphthyl ketone. Satisfsctolry proof olf the constitution of these keitlonee has only beeln giveln in the uasel of 4 4/-dibenzoyldiphenyl.This substance originally obtained by Wolf (Bey. 1881 14 2031 1142 FERRISS AND TURNER: by the adion of benzolyl chloride on diphenyl in the presence of aluminium chloride was pretpa.reld by Ullma,nn (Annulen' 1904, 332 79) from 4-iodobe8nzo~phelnolne~ and colpper brolnm and thus shown t,o be1 the 4 4/-delriva,tive. Froam thip it follows thatl Wolf's phelnylb,enzophenone is a 4-deriva.tive . Va.rious e'rrolrs harm been noltimld in the1 liteIra,tnrel t>racreable t,o the work of Adam (Anln. Chim. Phys. 1886 [vi] 15 224). This aut<holr as a relsult od a' more or less sjstematic study od the Friedel and Crafts readioln in t'he diphenyl serie,s concludeld t'hat in all suoh relactiom saw olnel 3-suh~stlitlutied diphelnyls were prolduced a aonolusion based on the1 fa,ct that these' compounds ga8vei on olxida8-tion a,n acid mellting at 160-161° which adam t,oolk t,o be diphen y l- S-ca,rb,oxylic acid .His ,ofne' e,xcelp tio,n diphetny lb elnzOc phenolne obt8a.ineld from oarb,onyl chlolride a,nd diphenyl proved to be identica,l witlh the prolduot obta,insd by Weilelr (Ber. 1873 6, 1181) from methylal and diphelnyl and gave on oxidation an acid (diphe'nyl-3-aarboxylic) me~lting a8t 21 7-21 8O. Adam's phenyla,cdolphenoae was state,d by Volrlandes (Bey., 1907 40 4535) to! be the 4-delrivamtJve~ since deriveid oompoands formeid a,nisotropio liquids a prolpesty which would not be p o e s e 8 d by 3-derivat'ives. The aation 09 a.ceityl cIiloiride1 on diphenyl in the prese'nce of aluminium chloride has now beleln sho,-wn t,o relsult in t,he formatioln olf 4-pheinylaceitophenoae (m.p. 121') and 4 4/-dia:cetyldiphenyl (m. p. 19O-19lo). The fomelr (idelntica,l with Adam's phelnyl-acetophenonel) gives oa oxidaDion diphenyl-4- and nolt. 8,s st.atod by Adam diphenyl-3-carbolxylio acid. The constitlutlio8n of these ketlonee has been set beyoad doubt b,y tlheir synthesis respectively, from 4-oyanob a.nd 4 4'-dicya.no~-diphe~nyl b,y melam of magne8sium methyl iodide. Since Adam's phenylam4tophe8nonel is the 4-de.riva8tive and since his supposed S-et,hyldiphe,nyl ga,vel t,his keltonec o,n partial oixidation, this elthyl deirivat'ive must be 4-ethyldiphenyl. It is evidentl, simila,rly tha.t his supposed 3 -methyldipheayl is actua'lly 4-methyl-diphenyl .A.gain the diphenylyl henzyl ketone ob,ta.ined by Papeke! (Ber., 188'8 2 I 1339) by t,hs ac,tion olf phe8iiylamtyl chlolrids on diphenyl in the presence of a,luminium chlolride has now belea sho'wn definitely to be the 4-derivaft.ive by it5 synthesis from 4-cyano-diphenyl a,nd magnesium benzyl chloride. I n additio'n 4 4'-d~~~he,i~yZdialcetyld~ph.e~~yZ which is not pro-duaed tot a,ny e'xtent in the Friede'l a,nd Craftls rela,ct,ion me8ntiioned above has b,e.eln prepamd from 4 4/-dicya.noldiphe1nyl. It is evideint from tb abwe tlha.t in all lrnown Friedel an STUDIES IN RIKQ FORMATION. PART 111. 1143 Crafts' reactions betIwee.n diphenyl and halogen compolunds 4-deriv-at'ives are obtlained a' fa,ot which justifiels Sohmidlin and Gascia-Baniis ( B e y .1912 45 3183) in their assumption als to t'he constit,ution of the diphmylyl a-naphthyl ketone prepamred bsy bhem. This inveatiigation into tihe ket,ones of t,he diphenyl seriels was made a,s t,he rwult of d,esiring t*ol determine the1 spa,tial reilation of the tlwo a4crehy1 groaps in 4 4'-dia'aeltyldiphe.nyl ; this. ke,tone might be expelcteld i f t,he Kanfler formula for derivat'ivea of diphenyl is valid t,o condense with 0,-phsnylenediamine to give1 a compound of the mnstitutlion (I). When the two substlances in question a m warmed together in acetic acid solution condensation occurs and a yelllow sollid is predpita*ted from the mixture on a,dding methyl or ethyl alcohol. As in the case of the condeasa-tion produot of benzil and bnzidine howevelr it has not been found pmibri to ascribe a definite consttitlutioln to the product.ombtained dt'hough the elvideince is prob'ably in favour of a corn-p o z d farmed by the condensatioln af two moleculee of keltone with one of diarmine. E x P E R I M E N T A L. GoYndensatim of B e n d with Bemidine. This condensation has been carried out as described by Cain and Micklethwait (loc. cit.) 1-84 grams of bnzidine 2.1 grams of benzil and 10 C.O. of glacial acietio acid being used. After twenty minutels' heating of this 1nihn-s on the boiling-water bath itl was cooleld and scratched when the canary-yedlow precipitate separated, further warming then causing further separation of precipitate. The yield was found to be increased by perioldicl cooling and scratch-ing.The precipitate was oodlscted washed with a little glaaial acettio acid and then with dilute amtio acid and dried in a vaouum over potassium hydroxide. The greenish-yellow solid so obtained (equivalent in quantity t o a 70 per cent. conversion to the suppoeed oompound) crystalliaed readily from benzelne but a lees green product was obtained using xylene as solvent the crystals being then washed with light petroleum [Found @=85.1; H=5.5. C=85-2; H=5*7. N-5-3 5.3 pelr cent. M.W. (by oryoscopic method in bromoform) =496] 1144 FERRISS AND TDRNER: The su6stamce is readily solluble in hob xylene benzene or pyridina and almost insoluble in add xylene benzene alcohol or glaaoid acetia add. An at'tempt ta obtain Cain a,nd Micklehhwait's ethyl alcohol additive m p a u n d was rna.de as folllows the co,ndensa.tion product was collected dissolved in hnzonei the solution evaporated to dry-ness after the additioa of a little aloolhol and the residue again t'reated with alcohol and the httelr eva,pora.teld.Evaporahion of the hnzeae solution obtlaineid as abwe withoutl a,dding alcoholl, gave a well-defineld product identioal wit.h that ob,t'ained in t'he presence od alclo~holl (Found C = 85.0 ; H = 5.5 ; N = 5.7 per cent.). The substmca meJteld ah 239-240° a mixtare with tIha produd from xylelne (above) melt'ing a t the sa,me tempelrattare. Simila'rly an a,ttempt was made to prepare Cain and Miokle thwait'e melt,hyl alcohol sddit'ive compound f o4owing t'helir deacribeid method m closely as possible.The product could not be melted undelr methyl adcoholl even 0 1 1 1 prolonged bloiling a,nd when dried melted at 231-234O (Found C=80*0; H = 4 * 2 ; N =5.8 The produot was a>gain trea;teid with melthyl alcohol (far the fourth time,) and the whale empoiratad (Found C = 80.4 ; H = 3.9 per cent.; m. p. 231-234O). It was then crystallised from xylene (Found C = 8'1.3 ; H.= 4.9 per cent.; m. p. 233-236O) a selaond clrystallisa.tTioln frolm xylene giving a product mdt,ing at 234-237O (Found C=83.7; H=5.0 per cent.). The preselnt autlhors a,ttribate the law melting paint etc. of tho first s f thew products to the fa,& that the green impuritiee were still presentl and the subselquent re'sults to the rmova.1 of tthme impurities. I n olrder if pmsib'le t'ol throlw mom light o a the aoadensa,t.ion just deeoribed the melting points od mixtures of b e n d and h z i d i n e have been deltRlrmine8d.The benzil used was purified by recrystldlisation frolm alcohoil and meltsd a4t 94.4O. The benzidine was purified by recrystlallisation successively f r m watelr and dilute aloohol and then several timels frolm alaohol. Pure belnzidine olbttaineld in this wa,y mdts a8t 127.4O. All mixtures oif bnzil a,nd benzidine melted below the1 lafter t,emperature the ourve of mixed metlting polints b,eing part of a,n invelrteld pasaboh the axis of which ran vertically froim the1 point. represent8ing two molecules of belnzil t,ol one olf bennidine. No1 e8videtnw folr t,he formahion of a compound was forthaoming. per ceint.) STUDIES IN RING FORMATION.PART 111. 1145 Condenmtiom of Benzdhe with Glyojxd. On effeating the coadensa,tion as described by Cain and Mickls thwait a dark broiwn amorphous precipit'ate was obtlained. On drying it gave a hard mass a a examina,tioa of whiclh gave no relsults worth reloolrding. Codematiron. of Totlidine with GlyoxaL. This mndelnsattlion gave the resdts published by Cain and Mickle-thwait (Folund C = 82.2 ; N = 5.9 ; N = 12.2. Calc. for CI6Hl4N2 : C=82*0; H=6.0; N=12.0 per cent.). It was not found possible to oarry out a deitelrmina8tioln of rnoledar weight so that the aolnstitation of the substanw camoh be deduced. Codematilorn of A cetylacetome with p-Toltuidine. A mixture of p-tohidinel and aoetylamtone in moleimlar propor-tions was gently boileld for a,n hour.On cooling the whole set solid a mall polrtion after being left in contact with porous porcelain melting atl 64O and a t the same temperature after crystallisation frolm light peltroleurn. Almost the theoretiodly potssiblei yield of 2 4 6-trimethylquinodine was thus obtained (Folund N=8.2. Calc. N=8-2 per mntl.). M o s f L o o c e t y l i s o ~ o ~ ~ l i d e ~ e t o l l ~ ~ ~ ~ a d its p-Nitrolb enzylidene Deri;vative N0,*c6R,*CH:NgC6H,Me~*C6H3Me*N:CMe*CH2Aa. A boiiling solutioln od 2.1 grams of tlo;lidine in 15 C.U. of xylene was slowly treated with 1 gram od amtylambne dissolved in 5 C.C. olf xyleinel heating being continued folr a further hour. On dis-tilling off the xylene a dark viscid liquid was obtained which could not be aanwd t o orystallise.In order tlo confirm its con-stitution it was convelrtsd into the pnitrobenzylidene derivative by boiling it in alcohollic solutioin with a slight excess od p-nitro-benzaldehyds. The brick-reld preoipitate obtained in this way was clrystallised frolm a mixture of pyridine and alcolhol (Found : N = 10.5. The high pelrmlnt.age of nitroigeln foand was due to the preeenw of a m a l l quantity od di(pnitrobelnzy1idenel)-tolidine which when wolrking with. barelly sufficient material cannoit readily be relmoved. N - p - N i t r o i b e n z y l ~ ~ e u n e m o i n o a c e t y l i s o l ( p r o ~ y l ~ ~ n ~ t ~ l ~ ~ e melts a t 245-24707 is readily soluble in hot. pyridine and sparingly so in cold adcolhol or acetione. C,H,,03N3 relquires N = 9.8 per cent.) 1146 FERRISS AND 'TURNER: Dia ce t y 1 isolpro~pylideme t o~lidke ( C6H3Mel* N CMel* CH Ac) .A sodution olf tolidine (8 grams) in 15 grams od aceltylaoeltone was heated a t the boliling point folr three hours tihe excms of diketone distJlled off and the1 yellow crystalline! residue obt aiiied on cooling crystalliseld from a mixture of xylene and light p&roletlm from which i t sepa,rateld in yebw needles meltling a t 108O (unoorr.) (Found N = 7.7. C,HB0,N2 requires N = 7.4 per cent;.). 2 :4 8 21 41 81-Hexamethyl-6 61-d~pinolyE. The prelwding oolmpound was heated with ten times its weight of concentrated sulphuric asid a t 125O for tlwo holurs the cooled solutioln poureld int'ol water the1 result ing sollution relndelreld alkaline, and the white preloipitatel collledeld and orystadlised from :rylene (Found N = 8.4.The base crystallises from xylene in minute cubes melting at 252*5" and is almolst insoluble in eithelr hot ocr colld alcolhholl carbon tetir achlolrid el or toluene . The platzhichlosdde was obtained in the usual ma,nner and folrms brownish-yellow needlee (Found Pt = 26.2. C,H2,N,,~I,PtCl, requirels Pt = 26.14 per cent'.). C24H24N2 require8 N = 8.2 pefr centl.). Molno b enzoylisolp-o pyldene 6 enzidine, NH,*C,H,*C,H,*N:CMe,*CH,Bz. A sdutioln of 3'24 grams of beazoyla8mtonei in 15 C.C. of xylene was added gra,dually to a bo3ling solut'ion of 3.68 grams' od benzidine in 15 0.0. olf xylelne the heading continueld f o r a further hour the sollventq remotveld by distillation and the yelllolw residue orystallised from a mixture of pyridine and alaohol when it sepa<rated in slender pale yellolw neleldles me'lting at! 179O (Foand : N = 8.7.C,,H,,ON requires N = 8.5 per cent.). A ce t y Zisopropylideme b e m o yliso F o p y lideneb eitzidine, CH,Ac* CMe:N* C6H,*C6H,*N CXZe8* CH~BZ. A boiling solutioln of the1 preceding compolund (0.761 gram) in 10 C.C. otf xylene was sloiwly treiakted with a sollution of 0.232 gram of amtylamltoae in 5 C.O. of xylene and the reacrtioln allowed to complete itself during a further sholrt boiling. On removing the xylene by distillattion a yelloivrr regidue relmainsd which was arystlallised frotm EL mixture of pyridine and alcohol (Found: N=7.0. C,,H,O,N requires N=6.8 per wt.) STUDIES I N RING FORMATION.PART 111. 1147 The compound fosms yellow le'aflelte melting a t 234-236O and is sparingly soiluble in alcohol relaclily so in cold chlolrolform and dissollves in hot pyridine. Mocnolb e n z o y l i s o ~ r o ~ ~ l i d e n e t olidine, NI-I,.C,E43Mel*C,H3Mel*N:CMe*CH~~z. This substaiioel was olbtained in a manne'r similar tol tthat described folr the1 corresponding benzidine compolund and crystal-lises from a mixture of pyxidinel and alco4holl in pale yellow needles meltling at 170O. It acquires a grelen colour in nio$istl air owing to partial oxidation (Found N = 8.0. C,4H2,0N2 requiree N = 7.9 pelr cent.). Com2ensatio.n of A cetyl Chlol.i.cFe with Diphenyt. (a,) Pmpraltion o f 4-Phenylacetophenome.-A~~tyl chloride (8 grams) was mixed with 100 O.C.of carbon disulphide and al hrge excess of diphenyl (35 grams) and 20 grams of anhydrous aluminium chloride were slowly added. The reaction was carried to1 mmpleltioa by helating and the coded mixture decolmpmeld with ice and dilute hydrochlorio acid. The carbon disulphide was removeld in a current of steam and the rwidue cooled filtered, and dried. The whitel solid sol obtained was extractejd with boil-ing light petroleum until a sample of the residue oln drying mellted a t 115-120O. The residue oonsisting of almostl pure phenylacetoc pheiione was crystallised from aloohol and melteld a t 120-12lo (uncorr.). It possessed the properties asaribejd to it by Adam (Zoc. cit.) (Found C=85-2; H=6*2. Calo. C=85-7; H=6.1 per cent.). (13) Preparaition of Phenylaicetophenone and 4 4I-DiucetyZ-dipkenyl .-Anhydroas aluminium chloride1 (26.7 grams) was covelred with a mixture of 100 C.C.of carbon disulphide and 15-4 grams of diphenyl. Awtyl chloride (15.7 grams) was then slowly added and the evolution of hydrolgen chloride allowed to become complete by subsequent heating in warm water. The carbon disulphide was evaporated the mixture decomposed as bef orel and the resulting white! solid collelcteld and drield. Elaborate1 fractional crystallisation from alcohol gavel pheiiylacetophenmel (molderately soluble) and 4 4/-diucetyZdiphenyI (sparingly soluble). The latter was purifield by crystallisation successively from dilute aeetio aoid, alcohol and oarbon tetrachloride ; itl forms almost colourless leiaflets melting at 190-1910 (uncolrr.) (Found C=80*5; H=5*9.C,6Hl,0 requires C = 80.7 ; H = 5.9 per wnt.) 1148 FERRISS AND TURNER: P r e p r a t i m of 4-Cyanodiph en yl, The preparation of this substanae from diazotised 4-amine diphenyl and pot aasium cmproayanide proved unsatisf a,ctory a large quantity of a polymeride being formed. It is intelreating t o note thatl Kaiselr (Anmlem 1890 257 100) obtained a moldelratdy good yield od diphenyl-5-carbolxylic acid by the hydrollysis of the toltal crude p r d u d . The method dacTibeld by Rassow (Annalen, 1894 282 143) for the preparatJoln of the nitrils was finally adopted; it is however tedious and gives a large quantity od the polymeride. Prepwatiom of 4-Phenylacetophenone (4-AcetyUiphenyt). A solution of 0.3 gram olf 4-cyalno~diphenyl in 100 0.0.of benzene was added t a a Grignard relagelnt preipared frolm 1-5 gram od melthyl iodide 0.24 gram of magnesium and 40 C.C. of ether. The ether was then rmoveld by distillation aad the reaiduel heiated t a boiling for four hours them cooled deoomposed with water and acid and the benzene layer selparateld dried and evapolrated. The residue was extraatad witlh boiling alcohol in the presenm of wood char-coal the extracts filtereld waporateld and the residue t(reated as bedolre. In this way a small quantity oif EL white solid was obtained crystlallising f roan alcoho'l in colourl~s needles melting at 120-121° and producing no depression of the mellting point of the phenylaoetophenone prepared as described abolve. The la\tter is thered ore 4-phenylatceltophenone.Oxidation undelr the exact aotnditions described by Adam (Zoc. &t .) gave a mixtlure of unohanged ketone and diphenyl-4-earboxylia a,cid melting a t 220O. The latter was eixtraoted from the mixture by means of soldim hydroxidel and the extract filhred and acidified eltc. The law melting point (160-161O) found by Adam was evidently due to1 the preaenm od unohanged ketonel. Prfipwaitiorc of 4-Diphenylyl Benzyl Retom. (a) This substance was obtaineld by condensing diphenyl (1 moll.) with phenylamtyl ohloride (2 mods.) in carbon disulphide solution by means 04 aluminium chloride the resatioln mixture being tretated in the usual manner. The blaak ta'rry solid olbtainetd in tlhis way was edsacted relpeatedly with boliling alooiholl the extracts preoipitlated witlh waster and t,ho resulting yelbw soilid freed from phelnylamtia said by extra&ion with hot aqueous a m o a i a .The product was finally crystdised repelatredly fro STUDIES IN RING FOR*MATION. PART IU. 1149 adcoholl and then mellteld a,t 150". Its prolperties agreed with tlhose desoribetd by Fapcke (Zoc. cit.). ( b ) ,4 solution olf 0.9 gram of 4-cyanodiphenyl in 100 0.0. of benzene was added to1 aI Grignard relagent prepared from 2 grams of belnzyl chloride 0.36 gram of magnesium and 50 C.U. of ether. The1 latter solvent was removed by distillation the relsidue heated to1 boliling folr six hours and theln decomposeld in the usual manner. Extractioln of the1 solid finally obtaineld with light peltroleurn and benzelne gavel a white solid melting after crystlallisation from alcohol a t 150° and producing no depression of the1 melting point of the product from (a).The latter is thelrelfore 4-diphenylyl benzyl ketone. Prepav-altiom of 4 4/-Dicymodiphenyt. This substance has hithelrta only been prepared from tlhe mrre-sponding disulphonia aoid by fusion with potassium oyanide. The following method was found to1 be more convenient$. A solutqion of 17.2 grams of benzidine in 42.5 O.C. of concren-tlrated hydrolchloiric acid and 150 C.C. 09 watelr was diazoltised with a concentratled solution of sodium nitrite and the solutioln added gradually t a a warm solution prepareld by mixing 50 grams of cuprio sulphatei pentahydrats (in 200 U.U. of wa8br) with 55 grams of potassium cyanide (in 100 C.G.of water) benzene being added to prevelntl the accumulation of froth. The relaction was completed by helating to a holt water-bath temperature( the brown precipitake collleated washed with boiling water and drield and then extracted repeatedly with much boiling alcohol; the filtered extracts were predpitated with water and the combined precipitakes dried and orystallised from pyridine. The pure nitrile obtained in this way melt8 a t 2 3 5 O (uncorr.) as stated by Doebner (Bev. 1876 9 272). 4 4t-Diacetykdiphenyl. A sohtion of 2 grams of 4:4/-dicyanodiphenyl in 150 0.0. of benzene was atdded to a Grignard reagent prepared from 6 grams of melthyl iodide 1 gram of magnesium and 50 C.U. of ether. The et'her was remowd by disti!!ation and tho rcsiduei healtd to boil-ing f o r six hours thein treated with water and exms of dilute sulphuria acid and the mixture again heated for an hour it being thought possible that otwing to the extreme difficulty of hydro-lysing the dinitrile (see Doebnsr Annalen 1874 172 116) the inhrme1diat.a magnesium additivs compolund f omed in the present reautio~n would mly slowly be deaomposed by cold aoid (see Forste 1150 STUDIES I N RING FORMATION.PART 111. and Judd T. 1905 87 368). The benzene layer was finally separabd and dried. When elvalpoNrated slightly it deposited the diacetyldiphenyl in olusters of nezdles or leaflet,s melting a t 190°, and producing no depreBsion of the mellting polinti oif the diamtyl-diphenyl prelpareld from diphenyl atnd aceltyl chloz5del (above). The lakter is therefore the 4 4/-delrivative.4 4I-Diphenyldiacet y1dGphenyl. A solution of 2 grams of 4:4/-dicyanodiphen;yl in 200 0.0. of benzene was added tlo a Grignard reagent prepareid from 7 grams of belnzyl ohlolride 1 gram of magnelsium and 60 0.0. of ether, when a reddish-brown precipitate wa8 formed. The ether was removed by distillation the rmidue belated to boiling f o r :our holurs decomposed wit'h water and dilute1 acid again helated and fina,lly filtereld and the two laeyers weirel separated. The1 residue from the filtration was combinetd with the residue obtained by eva,porating the benzene solution drield and mystallised from pyridine when it formed white lelaflets melting a t 2 2 4 O (unclorr.) (Found cO=86.7; H=5*6. C,,H,,O requires C=86*2; El-5.6 per cent.).Both of the ket+onea just dworibsd reaot normally with phenyl-hydraxine. C d m s a t i o m of 4 ; 41-Dkcetyldiphenyl with o l - P h e n ? / t e ~ e ~ ~ ~ ~ i n e . When the ketone and the diamine are gently hefated togeither for a few minutes a reld colour is developeld owing to! the folrm-ation of a substame which is prelcripitated by aloohol and is insoluble in tlhe latiar. Condelnsatioa in slightly diluteid glacial aaeltio aaid (to preclude the formation so far as possible) of benz-iminazole) gave WE- en equim olemlar quantities of the reacting substances were tqakein an orange-yeillow proiductl obtained by p r e aipita,tlion of the amt-ic acid sollution with methyl aloohol. On dissolving i t in pyridine and precipitating with light petroleam it was obtained in a miorocrystalline condition (m. p. [indefinih] about 1 5 0 O ) (Found C = 84.7 ; H = 5.7 ; N = 4-2. C,,B,O,N, [2 moils. of ketone condensing with 1 mol. of base with elimin-ation of 2 no3s. of water] requires C=83*2; H=5.8; N=5*1; C2,HI8Np [l mod. of ketone 1 mol. of base elimination of 2 moils. of warbr] require C=85*2; H=5.8; N=9*0 per cent.). The small quantity of t<he product rendered a tholrolugh investi-gakion kpoiwible but' itl is tbought tihat the evidence indicates the formation of a compound of the iminexolQ type by the condensa NIERENSTEM THE CONSTITUTION OF CATECHIN. PART 11. 1151 tlim of two moilmula of the diketone with one of ol-phenylene-di amine. We desire to thank Mr. R. G. Hook for some help with olne od tlhe experimelnts and the Research Fund Committee of the Chemical Sooielty far a grant which has partly defrayed the mt of this investigation. THE UNIVERSITY CHEMICAL LABORATORIES, SYDNEY N.S.W. [Received August 30th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701140

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

NIERENSTEM THE CONSTITUTION OF CATECHIN. PART 11. 1151 CXXX.-The Constitution of Catechin. Part IT By MAXIMILIAN NIERENSTEIN. IN the previous communication (this vol. p. 971) prowisional formulze wetre suggested for ca;teclhin (I) and for the methylated relducltim profduct' (111) obtained by Kostaneclri and Lamps (Ber., 1907 40 720) fro'rn. oadechin tetrarnelthyl ether. At- the same time it was shown that Kostanecki and 1,ampel's substance may be olxidiseld to 3 4 21 41 6~-pelntametho~xydiphenyla~tic acid (IV). 0 \A/ HO CH 'i L O H OH >JeO/\OBre M e d ' OMe I ICH-CII,.CH !,),H*C02H ()OMe ()Me MeO/ \/ I MeO/ OMe 0 Mo (111. ) ( IV. 1 The preeent communication describes the synthe'sis 3 4 21 41 6/-pentrnethoxy-aa-&phemylpro~pne (111)) which of Wa 11 52 NIERENSTEIN THE CONSTITUTION OF CATECHIN.PaRT 11. found ~ Q I be identioal in evelry respelat with t'he melthylahid reldue tiofn product of Kost8anefcki amnd Lanpe. The1 synthesis was ca'rrield olut a,aclording ttol the folllolwing scheme 3 4 21 41 6I-plen'tam.eth-olxydiphemylacetyl chlo&de (V) oip? t.re~atment with dia,zolme8tlha,ne (compare Clibbens a'nd Nierenstein T. 1915 107 1491) yie1de.d 3 4 21 41 6~-pentalmethoxydipF,enyhzethy2 ke:tone (VI) which oln reductlion wit'h metallia soldium and adaohol gave 3 4 21 41 6~-psntaune.t~hoxy-u~diphenylpropane (111). chlovromethyl M ~ O ~ ) O M ~ MeO/)OMe (/CH*CO*CH,CI MeO/ \/YH*CC)C1 M&/\ I )OMs \/ I lOMe OMe \/ OMe (V-1 VI.1 The interrneldia,te 21-hyd~oxy-3 4 41 6f-te8traim,ethozy-au-di-phemy@ropn~~ (11) has prelviously noit been investligated ; thus, Koistla.neicki and Larnpei (loic.cit.) only refelr t a itl as an oil with-out further mentioln. It has now beeln obt,a8ineld as a crystlalline substla.nos which yields oln onida,tioa 21-hydrolxy-3 4 41 6I-tetra;-rnethoix~~i~heinylacetic acid (VII). The la,tcter substance behaves normally towards m&hyl sulpha,te dia,zomethane and acetyl ohlolride a8nd pyridinei yielding the c;ocresponding delrivativels. On digelstlion wit'h acetia aahydridel and anhydrolus sodium a,aelt8aftle, howelver 3 5 31 4 ~ - t e t r a ? n e t h o ~ x y - 2 - p h e n ? / l ~ o ! u ~ ~ ~ ~ ~ ~ - ~ - o ~ ~ ++ (VIII) is formeid which is a,lso pro\duc;crd whea 3 4 21 41 61-pent8ameth-o,xydiphelnylamtia a,cid (IV) is t4rea;ted with a8celt8yl ahlorida ac,oolrd-ing to Stoerrner and Friderici's method (Ber.1908 41 340). 0 M~O/\OH MeO/\/\CO I 1 ICH M e O / j Met /\, \/- I I ,,!CH.OO,H I b & l e OMe \/ (VII.) (VIII.) OMe * The numbering of the coumaran nucleus is as suggested by Stoermer (Annalen 1900 312 258) MERENSTEIN THE CONSTITUTION OF CATECKIN. PART II. 1153 E x P E R I M E N TAL. 3 4 2' 4/ 6/-Pentarnzetholxy&phenylecetyl Chlo.ride (V). Six and achalf grams oB 3 4 21 4' 6~-pentlme~tho~xydiphanyI-acetia acid are heateid on a water-bath for three hours with 10 grams of thionyl chloride. As muoh as pomible olf the un-ohanged t'hioayl chloride is distilled olff under diminished preesure and the residue dissolved in dry benzeae.The sollid obtained by elvapocating the benzene is left olvelr solid poltassium hydrolxide in a vitouurn folr some time sol as to remolve the adhelring t'races of thiolnyl ohloride. The product crystallises from benzem in small clusters olf prisma,tia nesdles which meltl a,t 76.5'. The1 yielld is 98 pelr mat. of the thelotretical (Found C1=9.6. CI9Hz,O6C1 requirea C1=9*3 per aent.). 3 4 2/ 4/ 6f-Penta;methoxyd~pFYe.nylmeth~~ Chlogomethyl getone (VI). Tot a sol-ation of 6 grams of the acyl chloride in dry ether (accorcling to1 Grignard) an elthelreal solution of freshly prepared diaeomethane from 30 O.C. of nitrosomethylurethane is added. Wheln the evollution of nihrogen teasels the same amoant of diazo-meltlhana is again added and the solution allowed to remain folr several days moisture1 being excludeld.The1 ether which colntains an excess of diazomethanel is distilled off and tlha residue cirystal-lised from benzenei. Large glistening platee separate which malt a t 1 0 2 O and hatvet the characteristic odour of the ohlolroimethyl ketlones. The yield is 94 pelr cent. olf the theoretical (Foand*: C=60*6; H=5.9; C1=8.9. C,,H,,O,Cl requires C=60-9; H=5.8; C1=9*0 per cent.). 3 4 2' 4' 6/-Pen~tametko~xy-aa-diphenyZpropme (111). A sollution 09 6 grams of the1 lreltone in about 200 C.O. alcohol is hela,tefd on a water-bath with 20 grams of m~ttallio soldium until the latter disappelars. The solution is subsequently reduced to abolut 50 c.a. and diluted with water. The precipitate crystadlisee from alcohol in small needleis which melt ah 83-84O.This mellt-ing point is not depresseid when mixed with the methyla,ted rsduo-tion product of Kostaneicki and L a m p (Found* C=69*2; €3 = 7.7. Cala. a. C = 69.3 ; 13 == 7.5 per cent.). * Dried ovcr paraffin in a vacuu 1154 NIERENSTEIN THE CONSTITUTION OF CATECHIN. PART II. 2/-Hydrolxy-3 4 41 6 f - t e t r a m e t ~ o c y - a a - ~ ~ ~ h e n l ~ l ~ o ~ ~ e (11). By distdlling Kostla8nec!ri a'nd Lampei's relductdoa prolductl (deoixy-hydrooatechin tet,ramethyl elthelr) under diminished prmsurel tlh,e grelater propostioln is obtaineid as an olil boiiling a t 235-238O/ 10-11 mm. After remaining on ice folr a' sholrt t'irne itn readily solidifieis. A felw c;ryst,als of this subst,ance a8re sufficient t'ol ca'use the1 ail of olth.elr prepa,rations t.01 become semi-soilid without previous distilla,tlon.Prepred by t'his melthod a.ny adheiring obl may be removed by washing with light peltroleurn and subsequeat drying o1n a polroas plafel. Three prepara,tions from 10 grams of catelchin telt-ramethyl e1thclr ga,vve 7.8 6.2 and 8.1 grams relspe&vedy olf the1 sotli d.* It oryst8alliseIs frolm alcohol in rect'angulas pla.tes which feel oily a,nd meflt atl 106O. The su.bst,ance 1s solluble in the usuaJ olrga,nic sollvelntlsi witlh the1 eixcelptciofn 09 light peltrolcnm in the1 colld. The a,lcolhollic solut'io'n turns violet1 with ferric chlolride (Found f : C = 68.5 ; H = 7-4. C,,H,O relquires C = 68.7 ; H = 7.2 pes oelntl.). On tsea,tmelntl with met.hy1 sulphate t,he t.helolretticd yielld olf 3 4 2' 41 6/-pe1nt~ame~tho~xy-aa-diphenylpr~o~pa~ne1 (111) is obtaine'd.It melts a.t+ 83-54O a,nd this melltiiig point is iiolt depresseld when mixed wit,h thei me,thyla.teid reduction pro,duct of Kosta,necki and L,ampe. 2/-Hyd~oixy-3 4 41 6 / - t e t r a m e t h o l z y ~ ~ ~ h ~ y l ~ c e t i c Acid (VII). Nine grams of 2/-hydraxy-3 4 41 6/-tetlramelthoxy-aa-diphenyl-propanel suspelnded in 300 G.C. off a 20 pelr sent. solution of poltassium hydrobxidel in water are midised on a boiling-watelr bath folr four holurs with 9 grams of potassium permanga>nate dissolved in 200 a.0. of water. The solution is filtemd while hotl and after aoloding aoidifield with dilute sulphuric acid. The dark-coburad preclipitatle is not filteaed butl the solution eatraoted several times with eltheir in whioh the precipitate dissolveis.The ethereal extract dried over anhydrous soldiuin sulphatel leavea a solid on eivapoiration which after selvelral orystlallisaltions from water, * The reduction of catechin tetramethyl ether according to the method of Kostanecki and Lampe (Zoc. cit.) is apparently accompanied by some decomposition since the cruds reduction product has an odour of acetic acid. Several attempts were made t o isolate some of the disintegration products by extracting the porour plate with alcohol. A small crop of needles was obtained from the alcoholic extract. They melted a t 178-180" which is the melting point given for veratric acid but there was not enough material t o establish their identity.t Dried over paraffin in a vacuu MERENSTELN THE CONSTITUTION OF CATECHIN. PART 11. 1155 animal charcoal being used yields lolng prismatic needles mellting at 168-169' carbon dioxide being evolved. By prolonged drying olvelr phosphoric oxide in a vacuum or heating a t l l O o onel mole-oule of water is lost (Found* H2Q=5.0. Calo. H,O=4-9 per mint.). The anhydrous product is powdery in appearance and mellts at 172-173" carbon dioxide Feing eivolvcd. The substanoe is also soluble1 in alcohal o r ethyl acetatei but insoluble1 in benzene or toluene. Both the aqueous and alcoholic solutions turn bluish-violet with ferria chloride. The yield is 78 per cent. of tlhe theoretical (Found ++ C == 62.2 ; 13 =5*9. Cl8H2,0 requires C = 62.1 ; H=5.7 per oent.).On metlhylatioii with methyl sulphate 3 4 21 4' 61-pe1nta-mettholxydiphenylacetia acid (IV) melting a t 150-151° is formeld. Diazoinethanel colnverts 2/-hydroxy-3 4 41 61-htrametholxydi-pheayladia aoid quantitatively into the colrrelsponding methyl ester which mdts at 119O. Neither of these melting polints is depresseid when the compounds are mixed with ths corresponding substances previously described (Zsc. cit. p. 879). The acetyl derivative is prepared by the action of acmtyl ohloride (3 grams) a,nd pyridine (30 grams) on the anhydrolus acid (3 grams). It crystallisels from alcolhol in prismatio needlee which melt at 183-184O carbon dioxide being evollved (Found * : C=61*5; H=5-7. C2,H,,Q require@ C=61-5; H=5*6 per mnt.). 3 5 31 4 f - T e t ~ ~ ~ m e t h o z y - 2 - ~ ~ ~ e n y T c o u l t l a l .n l e (VIII). One gram of 2f-hydroq-3 4 4/ 6/-tetirametho~sydiphenylace~tic acid is digested with 30 C.C. of acietic anhydride aiid 3 grams of anhydrous sodiuin aceiate aiicl t h e niisture subsequelntlly diluted with water. The1 precipitate1 obtained in this way crystallises from absolute alcohol in stoat prismatic needles whioh melt a t 117O. The yield is 85 per cent. of the theoreticlal (Found -f C=65*4; H = 5 - 5 . C18H180 requires C=65.5; H=5.4 per mnt.). The same! product is also1 olbtainecl when 3 grams of' 3 4 2/ 4' 6/-penta-nzethoxydipheiiyla~ltic acid dissolved in 20 C.C. oif glacial acetic acid are kept at the1 oirdinary temperature1 f o r forty-elight hours with 50.4 O.C. of a solution of 100 U.C.glacial acetic acid and 2.12 grams off acetyl chloride (1 mol. od acetyl chloride). The greater part of the aeetia acid is removeld under diminished pressure1 and the residue precipitated with watelr. The product cry~t~allises from absolute1 alcohol id stout prismatic needles which melt at 117O, * Dried at 110". f Dried o w r paraffin in a v&cuurn 11 56 NIERENSTEIN THE CONSTITUTION O F CATECHIN. PART II. and this metlting point is not1 altelred on mixing with t'he preiviolus prepa'ratim. The yield is 91 per oent. oC the theolretical. The autholr is indebted to1 the1 Colston Society of the University of Brisbol for a grantl which has colvereld the etxpelnses of this research. BIO OHEMICAZ LABORATORY, C m MI CAL DEPARTMENT, UNIVERSITY OF BRISTOL.[Received September 9th 1920.1 Note added Octolber l s t 192Q.-Since this c80~mmunica8tio~n was submitted a p a p r by ,Frelu.delnbelrg (Ber. 1920 53 [B] 1416) has appeased in which he desaribes 3 4 21 41 6f-pe~nt~ame~tlhoxy-ay-diphenylpropaael as meilting ah 87-88O which is t'he melting point given b.y the autholr (this vol. p. 972) folr this subst'ance. Freudelnbeirg states furt?lier thatl Kost,aneicki and Lampe's methylated retduct,iovn prolduc,tl alsot melts at 87-88O which is not mrrel&. This subst8atnce melt8 a t 83-84O' as givea by Kostlanecki and Lampa (Ber. 1902 $0 720). The aut'hor has o1n five separab olaaasiolns prepreld t,his prolductl a'nd has alwa,ys folund it to melt at 83-84O. No diff etrelncx od t'hel melting polint has b,een re,colrdeNd by Ryan and Walsh (Sci.Pmc. Roy. Du,bZin Sofc. 1916 16 lZO), who have1 allsol prepred Roet,amneicki and Lampe's prolduct. In vielw of Freudelnberg's aesumption t,hat Kot&anelcki and Lampe's methylated relductlioin productl is ideIntdc!aJ wit$ 3 4 2/ 41 6/-peata-meltholxy-a,y-diphelnylprolpa,nel t,hel follolwing mixeld meiltdng points welrel tla$eln. They clela,rly dis,prolve his colntentlions. (1) Koe-ta(necki and Lampel's m,et?hyla.ted re8duotioIn produck (m. p. S3-84O) and 3 4 2' 41 6f-pe~ntame1t~hoxy-a,y-diphe1nylproipa,ne (m. p. 87-88O) giving a delpretssiotn of 9 to1 11 delgrew. Similar relsult8s were o;bt.adnetd (Augustl 11 t,h 1919) when three mixeid meltdng points of thelsei t8wol substances welres takeln. (2) On the olthelr hand, a mixture olf Kost8a,nelcki a'nd Lampe's product (m. p. 83-84O) with 3 4 21 41 G~-pe~ntlalm~e~tboay-aa-diphenylpropane (m. p. 83-8'4O) described in the prewnt communicatioln melted a t 83-84O wit'hout t,he slight,eat depressioa as alrea8dy obselrved (April 26t,h 1920) when tlwot mixed mellting poiintls of these subst'anceis were taken

ISSN:0368-1645    

DOI:10.1039/CT9201701151

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

FORSTER EMIL FISCHER MEMORIAL LECTURE. 1157 EMIL FISCHER MEMORIAL LECTURE. DELIVERED ON OCTOBER 2 8 ~ ~ ~ 1920. By MARTIN ONSLOW FORSTER F.R.S. Trelasure'r. To a world confused and lamrated by the bitter conselquelnceB o,f protlra,oted warf a.re a,t a time1 wheln every element of const8ructive aad ha#rmonising influence was mo,st sorely needed thelre came without prmonit,ion t,he announcement thah Emil Fischer was dela,d. Inureld as t'hel na,tio8ns had beoolme t'o loss and disa'ster it was probably wit'h surprise tha,tl t'hel scientifio co:mmunities found the misfolrtnne wihh which they were now confronted t,o be one in common with t'helir former etnemies. For the pla<ae which he occupied in our minds first atkaineld by his mastlery of our subject, waa haClloqwod b,y regard for his sterling disposition compasslion for his grieds admira'tion for his outsta.nding power.Emil Fischer was b,orn oln October 9th 1852 a,t Euskirchen, some twenty-five miles from Cologne on the south-weatxtlerly high-road to the Eifel abolut twenty mil= from Bo'nn. Preceded by five sisters he wits the only son of Laurelnz Fischer and Julie Polensgen. Aftelr leaving school1 a t Bonn in 1869 he was appren-t.icsd to his brolther-in-la,w Ernst Friedrichs a tirnb,e,r mercha'nt, but the occupation proving uncolngenial he beoame a pupil of Kelkul6 in 1871 and prooeeldeld in the following yelar fro'm Bonn tIa Stsrasbourg. Here he graduated in 1874 undelr von Ba,eyea, wit'h whom hel passed to Munich in 1875 as an assistant, becoming Privatdozent and .soon afterwa.rds succeeding Volhard as Ausser-ordemtlicher Profe,ssw in 1879.On tho tlransferelnae of Volhard to Halle he was called to t,he &air of che,mist,ry a8t Erla'ngen in 1882 whelnoe he proceeded in 1885 t'o Wurzb,urg in suocession to the elldelr Wislimnus. He remamined seven years at t-he Bavarian university and o n the delmise of von Hofmann in 1892 was appointed professor and director of t,he chemioal institntle in Berlin University a post which he f i k d with increasing distinction until his death which t'ook place in the night of July 14th 1919 a t Wannseq his country home. Such in the barest outline was Fischer's career-simple straightforward and honoarable like his nat'ure. Amolngst thse who came in contam& witb him tbe imprwio'n left by Fischer is indelible but the words to describe1 his personalit'y VOL.CXVII. x [To face page 1157 Trana 1158 BORSTER EM'CL FISCHER MEMORIAL LECTURE. do not readily come. Physically commanding his authority rested on the solid foundatlion of natural dignity unmarred by self-asselrtion. The1 brisk upright carriage marked thel man of action; the glowing eyee reivealeid his attitude of constant keein inquiry ; tlhe impatienoei with trivial; ties was one aspect of his dominating, steedfast control of esselntials. With ordinary human perception, i t was impossible for anyonel to escape his contagious enthusiasm, and yeit all the time the master did notl o h u r e the man; for although his daily demelanour was tinged with selverity his heart when relvealed was deeply kind and i n ciraumstances of relaxation, joyous.The1 alert presenoe, the ardent gaze and the resonant voice will not fade from the reciollection of those to whom they became the symbols od a treasureld experience. The salient quality of his life was unswerving singleness of pur-pose. Rapid satisf aotion of relasonable professional ambition and the fact that he was only forty when summoneld to Belrlin did not distraot him from his chosen path. The legitimate pride ocoasioned by the summons tlhe glad reaognitioii of increlased opportunities for reeearcih the happy anticipation of entelring an unlimited scientific environmelnt were tempered by anxiety lest the social and cwemonial demands of thel capital city should make serious inroads intlol the real work off his life.Even his sixtieth birthday celebration was by his express desire an almostl domestio affair. Had he sought their presence repreeentatives of f orelign academies, captains of industry and councillolrs of Statel would gladly have joined his less exalted admirers in their tribute tloi the1 master but the! master himself ordained otherwise; with one exclelptjon all the participants were former studeats old oolleagues or members of his household. Although the strictness with which Fischelr confined his energy to affairs of chemistry was t$elmperamental and duel primarily to his natural and cultivated taste1 f o r the science itl is probable that his colnditJon od helalth was a contributory factor. I n t7he summer of 1881 he suffereld an attack of mercury poisoning consequent on studying the action between mercuric oxide and diphatio hydr-axines; neithelr he nor Bosler noticeld until tool late that mercury diethyl is prolduced although the odour did nolt escape vcm Baeyer.The direct e&te of this incident lasteld three months and ten years later Fischer fell a viotim tol the insidious onslaught of phelnylhydrazine vapour. I n his own words ' I Diesels allelrliebste B-&&en war meine erste und dauelrndste chemische Lielbe. Wir haben uns 15 Jahre lang ausgelzeiehiielt miteinandeir veatragen, wahrend vielle andera Menschen glelich da,dur& zu Schade kmeu. .!hr dann brach auclh bei mir das Ungluok ein mit eJne FORSTER EMIL FISCHER MEMORIAL LECTURE. 1159 chronischen und ausserst hartnackigea V,elrgif tang und es hat 12 Ja#hrei geda.uert* bis die Folgen be,isei tigt waren." It is characteristio of the ma*n that his work is devoid of " popular " feafnres although conimo,n etxperience a t every turn traverses the1 ma,t,erials witb whioh he dealt'.The task of elxplain-ing the a,chievement,s of other great chemists Pasbur von Hof-mann or Sir William Peskin folr elxzmple is relatively simplet, but the f ellow-citdzea cannot hope to undelrstmand Fischer's chemistry of t5he brea,kfsst+ta.ble untdl he has leiarned that the operatdons of digestion acre asentia,lly che,mica.l transactions of a sub,tlle na,ture. To the ma,n whose sugar " melts " in tea and who bellieves in a second member of tlhe class beet-sugar and probably a third, namely saccharin how are the1 beauties of the sixteen stereo+ isotmeiric a'1dohe.xoee.s t o b,e revealed 1 H0.w is itl possible to explain t'ol a woman unverseld in ohemist-ry the family colnnaxion betlwem her silk drelss a,nd al scrambled egg? The relader is quickly ma,det a,warel of thel subjectl about to be de.veilopeld; in simple phra,ses t'he tjheme is pursued with a ma.rked abseinm of verbal ornament and the trea.tmelnt alt>hough c'omplete is so cofnaise that it wnduding summa'ry of retsults is unnecessary.By this relstraintl Fischer has ela.rnsd the1 gratitude; ocf all chemists for t,he la4bour of a.ssimila,ting his elnormous o,utput has befen reduc,eld thereby to a minimum. Failing t,horoagh discsipline in writing abst,racts 04 scientific memoirs a stndy of the literary method a.dopted by Fisohe'r offers the best possible training for the raearch chelmist old or young in preparing repoirts of his own invest.iga-ti0~D.S.By the time he hatd passeld from Erlangea to Wiirzburg Fischer's reputahion hard become magnetic and frolm t3ha'tl pelriod a.n incmas-ing number olf doictorandi soaght admission t o his laboratory. The aggrega,te cf these must' be sevelral huiidrejds inaluding ma.ny na.t,iona,lities and witb the passagel olf yelars he receliveld in addition to t,he cust,omary distinctions acoorde*d by his co'untrymen the honoiurs which it is the practice of forelign academies t,o offes. He became a,n Hoaosa,ry a'nd Folreign Memmb,er of the Chemical Socielty in 1892 a Foreign Member of t,he Royal Society in 1899, and an Honorary Member of t,he Rolya.1 Inst.it,ution in 1904; he remiveid the Davy Meldal in 1890 t.he Nolbel Prize for chemistry in 1902 and the Elliott Cres,son Gold MeldaJ fro'm the1 Fra.nklin Inetit,uttet od Philadeilphia in 1913.Alt.hoagh to'o ratrely seen in this count,ry he was warmly wellcome when he ca,mel a'nd there is every ground for beilie'ving tha,t the cordial feeling towards him which certainly existed I n literary style his pa.pers are1 uncompromisingly a,scetic. x x 1160 PORSTER EMIL FISCHER MEMORIAL LECTURE. amongst B rit'ish che8mista was r eci p roca.ted it concrelte illu s tlra tion of this being given by the fact that' his eldest son Hemann Fisaher, passed tlwo te'rms aftl Cambridge. A!Ioreosvelr the1 many Englishmeln who worked in his 1aboIra;tory welrel quickly made aware off the kindly feeling toiwasds them which he cherished an expelrienee adding appreciably to! t,he be'nefit they deIrive,d frojm t,hel a.s,socia-tion.Thus t,he velneration surrounding his name in this colunt,ry could scaroely ha,ve been less in dept'h and sinoelrity t,haa that acknowledged by his fellolw-countrymeln. It t~he~relfore gave lustre to the Perkin Jub,ilele in 1906 whea a.s Preeident olf the Gelrman Chemical Sooie'ty he conveyeld t'he cotngratulatioas off that bo'dy t,o the vetelran whilstl coafelrring 0111 him t,he Hofmann Meldal. The fo,llo(wing yeas in which he dedivereld the Fasaday Leoture, markeld another memoIra& olccasioq postponed from 1895 when his c,onditbon od health did not permit a,cceptanm of the invit,aticm t,hen given.The t,itle of this a.ddress namely "Synthetical Chemistry in Re.lation to Biology," crystrall+es in a single phrase t>he profoiund s,ignifica.nm olf his own wolrk; fob wheln relviewetd as a chapptelr which is clolsed tlhis must be refgasded as having &ab-lished on a firm b,a.sis the fundamenbal bat bewildelring saience od bio&emist<ry. The assimilation of carboln dioxide1 and water by plants the variety and complexit,y of sccharide mollecules pro-celeding theredrom the degra(da<tdon of the proteins the proba,ble course of their synt'hesis from amino-acids a.nd the polwer of assemb~lage or olf disruption etselrted by elnzymes on all them building mattsria81s olf the animal a'nd vegeltable kingdo,ms me subjeotls which Fischer nolb melrelly illuminated but which he was tthe first.to place in ciolhelrent arrangeme:ntl and intelligible selqueince. Reloognition of the fa& that all this was a,ccomplished not by rsvollutdona4ry pro8cesses osr t'ortaous theories b,ut by dexterous development of the tholughts and olpelrations expandeld by Liebig, voln Hofmann Pasbur and von Baeyer is pelrhaps t!he highest t,ribute which oa,n ble paid t'o his genius. Indeeld it offers t.he grea,test inspirattion t'oi lelss giftled workers who1 ma.y thus be encouraged to1 percelive opport'unities for disoolvsry in adroit a'ppli-aa,tions of classical princip1e:a and pursuing methods olf sudh simplicity ma,y even arrive( by those devious paths which unfold themselves wit'h delight and refmshment to a.n ea,rnestl inquirer, unejxpeidetdly as oin the lifting of a aurtain direlatly a't the threahold of a fundament,a,l truth.The na.t,ural curiosity which seeks to account for the biolchemical trend o'f Emil Fisc,helr's relse'arches can only take refuge in pre-dilelction. There is nolthing to e,xplain it discoverable in family a*ssociat'iorns or in the t.asks of his young mashoold. Lauren FORSTER EMIL FISCHER MEMORIAL LECTURE. 1161 Fischelr who passed the1 age of ninety-four was an active and elntelrprising general merchant engaged in supplying the require-ments of the peasant farmers inhabiting the Eifell; associated with his brothers he was also concerned in a spinning mill and a briak-works close to1 his native1 town and in the foundation of a brewelry a t Dortimund.Thus there existed every inducemeat for his only soln to pursue a business careelr and Ernst( Friedrichs was quite positive in deolaring his omviction that no good would come of Emil when the young apprentice relinquished an opportunitly which appeared to him so full of promise. During this abortive attempt to transform him into a timber merchant Fischer had been occupield with expelriments in a home-made laboratory and contemplated devoting himself to1 a study of physics; but his father attracteld by the handsome returns which the Rhenish chemical factloriee were1 alrelady beginning to1 show finally persuaded him to become a chemist. His prepossession in favour of biochemistry was destined t o resist anothelr contrary influeaoel. The doctorate the& dealt with fluorescein and the phthalelin of orcin whilst his work on rosaniline in the Munich days would almost certainly have confirmeid a less resolute mind in the pursuit of coilour chemistry then in the early flush of active growth.Molreover this direction would have! been a natural sequence to the powerful influence of von Baeyer a t that time immelrseld in the prolblems of indigotin synthelsis. Indeed it is a noltioeable felature in the1 devebpment of his character that Fischelr’s wolrk detached ibelf so completely f rom household autholrity and so rapidly frolm eiarly chemical einvironment. The only conspicuous mark of the training which he owed to von Baeyer was ma.nipulatire skill of the very highest order ; this was revealed by results achieved with uninviting matelrials frequelntly used in very mall quantities by the inception and adaptation of ingenious experimental device6 and by the rarity of occasion to revise earlier conclusions of his own.Fortunate he undeniably was but the gooid fortune was thoroughly well earned by ceaseless industry. He wgs folrtunats for example in the fact that nothing resembling the Walden inversion that bBte noire of optical activity disturbed the! aldohexow aonfiguration. Imagine the1 confusioln which would have arisen if gluconic and mannonic acids instead of being smoothly intelrconvelrtible when heateld with quinolinel had given mixtures of idonic gulonic galactmic talonie altronic and allonic acids. Phenylhydrazine was a tremendous coup; but the prepar-ation was according to plan although its remarkable properties were fortuitous a happy illustration of “ t o him that hath shall be given.11 62 FORSTER ; EMIL FISCHER MEMORIAL LECTURE. Nevertheless that mysterious counterpoise of destiny from which t.h0 grelatest and the humbleet cannolt escape plungeld him into profound sorrow at the1 meridian of his aareelr. I n 1888 he had marrield Agnee Gerlach but the1 happy union was cutl short by heir deahh in 1895. Thereafter his three bolys were tendejd by Frln. Masgarete Barth who administelreld his household f o r the8 remain-ing twenty-four yejars of his life with watchful solicitude. Early TV o r k . Fischer entered the field of organic chemical research at the ofpening of ite bright& epoch. Largely in consequence of Kelkul6’s theory of beazene structure the; ground was ready f o r systematic cultlivation the1 advent of peace encouraged a willing and increas-ing band of workers to prepare themselves for fruitful labour; tsgethelr they stood at the threehold of the imposing structure which was destined to1 arise during the1 next forty years.The1 act of relading in 1920 the paper on phenylhydrazine corm-municated from the Strasbourg laboratory in 1875 elngendess the sensation od contemplating the moldestl source of a mighty river. I n 1871 Strelcker (with Romer) had treiateld belnzeinediazonium nitrate with elxcters of hydrogen potassium sulphite obtaining a salt which he represented by the formula C,H,*NH (:NIT) SO,K,H,O, and giving t o diazotiseid aniline the expression since asscrciazcted with his name.I n 1875 Fischer showed that two1 sadts arise from the diaaotised bass and neutral potassium sulphite namedy, C H,*N2*Sn3K and C,H,*N,TT,*S03K + H20 Potassium phenylhydrazino- Pot ci ssi u m benzene di az onium sulphite. sulphonate. The lattelr was identical with Strecker’s and Fisclher carried the inquiry to anothelr stage1 by acting on i t with benzoyl chloridel, producing a substance (dibenzoylphenylhydrazine) which gave belnzoic acid and phenylhydrazinel hydrochloride when heated with hydrochlorio acid ; in this manner phelnylhydrazine itself wa8 first obtaineld a5 an oil which ultimately became solid. Latelr in the same yeiar het simplified the preparation of the base by adding exceiss of sodium sulphite to benzenediazonium chloride completing the reduction by means of zinc dust and hydrolysing the phenyl-hydrazinosulphonats with hott hy$rochloric acid.Extending the procelss to diazotised sulphanilic acid he prepared phenylhydrazine-sulphonic acid which had been actually obtaineld by Strecker and Romer (1871) because in this case they had heated the initial prcduct with hydrochloric acid t o remove excess of alkali sulphite FORSTER EMIL FISCHER MEMOBIAL LECTURE. 1163 Owing to the readiness with which hydrogen replaces the nitroso-group in secondary nitrosoamines attompts by other chemists to prepare aliphatic hydrazines had failed. Fischer succeeded in reducing nitrowdimethylamine to dimethylhydrazine and having prepared diethylhydrazine and phenylethylhydrazine he repre-selnted the primary hydrazine derivative by the folrmula C!,H,*NH*NH,.A t the beginning of 1876 he delscribed ethylhydrazine which arose from hydrolysing dielthylsemicarbazide and expresed the intention of applying this process to the production of hydrazine itself. Throughout this and the succeeding year the simplelr changes undergone by pheinylhydrazine wer0 studied and i t is notewoathy that a t this perioid Fischer preferrod the Kskul6 formula for diazonium salts ; he had regenerated poltassium phenylhydrazino-sulphonate from phelnylhydrazins and potassium pyrosulphate and, converting it by oxidation into1 the diazonium sulphite was so imprelssed by the1 close experimental relationship betweeln the two substmceB as t~ cofnsidelr this an obstacle to the Strecker formula.A survey of these early papers indicates the curious faat that although the powelr of phenylhydrazine to combine with aldehydes was quickly observeid by Fischer he does not appear to have recognised its tremendous value as a general ageat for the carbonyl group until nearly ten years after discovering the base. This is probably due to the distraction oflered by roaanilina (see below) and minor inveBtigations by his translation from Munich t o Erlangen and by tlhe work on caffetine (1881) which was destined to lead him to the classifiaation of purine derivatives. It is true that the aotion of aoetaldehyde benzaldehyde and furfural had been noted but it was probably the formaltion of the sparingly soluble and beautifully crystalline phenylhydrazone of pyruvic acid (1883) which revived the interest in his original discovery.The outstlanding feature of 1884 an extraordinarily fruitful year is the application of phenylhydrazine to carbonyl compounds in general and the sugar group in particulhr. I n that year also he explained the first transformation of a phenylhydrazone into an indole, Pyruvic acid phenylmethyl- 1 -Methylindole. hydrazone. induceld by the adion of hydrochloric acid and he1 re-assembled the evidence supporting his constitutional formula f o r phenyl-hydrazine Erlenmeyer having advocated the alternative expression C,H,*NH,:NH 11 64 FORSTER EMIL FISCHER MEMORIAL LECTURE. Another int?ereating point1 in the elarly history of the phenyl-hydrazones is that the name for these important1 prolducts of con-densation doles not appear to have1 beten introduceld by Fischer until 1888 when he represented them by the general expression NH >C:N*NHR instelad of >C<kR ; altholugh many attempts some of which are1 quite recent have1 belen made tot resuscitate the cycloid repreeentatioln Fischer did nolt take part in the discussions and the ba(lanm of evidence in favour od his formula preponderates.Even forty years ago( when the boundariels of olrganio chemistry were comparatdveily limited the discovelry of an entirely new class of highly reiactive compounds by a novice must have beeln recog-nised a5 a portent; but the hydrazinee were1 not the only subject with which Fisahelr’s name came to be associated in the1 telxt-books with relspect to1 woirk accomplished bedore he1 was twelnty-five1 years of age.While in Munich he belgan collaboration with Otto Fischer and in 1876 the oonainsi published their first joint palper on the rmaniline baseB olbtaining f rolm di azoltised leucaniline th0 hydrocarbon CZOHl8 melltbng a t 58’. These experiments welre made with the commercial product and on repeating them with the dye prepared from purifisd p-toluidina and aniline they showed in 1878 that the corresponding leueol-basel gives triphenylmethane, CI9Hl6 melting a t 9 3 O as recordeld by KekulB Franchimoat and Hemilian. I n view of its production from ptoluidine the dye was named somewhak unf ortunatelly ‘‘ pararosanilinel,” and they proceeided to1 regenerate it from triphenylmethane by reducing Hemilian’s trinitro+derivative and oxidising the parale~ueaniline thus obtained.They oolncluded (1) that the rosanilines producible from aniline and the toluidines are homologues olf which the simplest pararosanilinel has the1 compositioln C19H17N3 whilst com-melrcial fuchsine is a. mixture! of which tahe principal constituelnt has the formula C,H,,N, assigned by Hofmann and (2) that the parent hydrocarbon of the whollel group is tripheaylmethane of which or of its homolopea the1 various lelucanilines are triaxninoi-derivatives. Be,forei proceeiding to review the! special branchee with whioh Fischer’s name1 is most conspicuously linked it will be convenient herel to1 notice a few devellopmeats of his elarlier experiments which are nolt appropriately included in the following sections.For example# the oonversion of suitable phenylhydrazones into1 deriv-atives ot indole was elxtended in 1886 when itl was found that anhydrous zinc chloride sol greatly facilitates the removal of ammonia that the condensation products of primary and secondary arylhydrazines with all saturated ketones or ketonic acids con FORSTER EMIL FISCHER MEMORIAL LECTURE. 1165 taining the methyl or methylene group adjacent to carbonyl can be transformeld into1 the colrresponding indole delrivativea by loss of ammonia ; as an illustration acetonepheaylhydrazone gives 2 -melt hylindolq A similar change proceeds with phenylhydrazonea of aldehydes containing the methylene group next to the aldo-nucleus and dimethylindolle methylethyl- phenylmethyl- and pheaylscatde, together with indoleoarbolxylic dimethylindolelaoetic and dirnethyl-indolecarboxylic acids were prepared.Ot*her examples of ring-formation weirs brought to1 light by Fischer. I n 1883 he found that benzoylaceitone is proiduced by hydrodysing benzoylamtic estefr and utilising this reaction tlol pre-pare o-nitrocinnamylacetone he reduced this tol acet8dnylquinolinel, Furthermore nitrosolathylarninohydro~cinnamic acid gave elthyl-h y drmarb a,zm tyril, yo \ ,,,,,C13,*CH2*C0,H I I \/\N Et NO \/\N E t-N H/ N==QH whilst phen y lpyrazoline C,H,* N < was obtained in 1587 CB,*CH,’ frofm the phenylhydrazons of aorolelin by the! action oif dilute sulphuric acid. Carbohydrates Glucosides and BepsicFes. I n the year 1886 chemist6 recognised two1 aldolhexoses (glucose and galactose) two ketohelxoses (fructose1 and sorbose) and one aldopentofse (arabinow) ; threie hexobioses (sucrosel lactose( and maltoise) were1 also known to be definitel individuals and one1 helxol-trime (raffinom).The general stlructure of glucose and galactose as thatl of straight-chain pe~ntahydroxyalde~hydes and of fructose as a pentahydroxyketone also unbrancheld had been determined by the work of Kiliani who relegated to its proper poeition as a tetrahydroxyaldehyde the pentasel arabinose erroneously classified by its discoverer as an isotmeride of glucose. I n them few lines may x x 1166 FORSTER EM= FISCHER MEMORIAL LECTURE. be surnmariseld the exact knowledge of crystlalline carbohydrate6 at the time1 when Emil Pisoher approlacheld the subject and a true measure of the character and magnitude of his construative achieve ment may be gained by comparing the foregoing synopsis with the modern classification of the hexose group as reipresentleid by projeotion formulze.From that classificatioin it is wen thatl amongst the sixteen optically active aldohexoses theoretically redisable tweilve have been either synthesised o r configuratled or both by Fischer and his collaborators. His work on ribose made1 it possible to include d-allow and d-altrose in the list of which there thus remain only tehe I-forms of these two aldoses unknown. It involves also the statement that six amongst the eight possible1 dl-aldohexoses have beeln realised whelncei it follows that 1- and dl-allow with I- and dGaltrose are.the1 only missing membelrsl of the twenty-four optical isomeridea comprised in the category. Highly as this admirable1 wejb o€ theory and practice must be valued its description is not a complelte estimate of his finished contribution to aldohexose chemistry. The1 foregoing computation of possibilities takes no account of the oxide rings now accepted amongst members of this class. His discovery of y-methylglucoside, and the consequent recognition of cyclic relations distinct from that occurring in a- and &glucose have opened the way t o a multitude of contingent isomerides &hose of d-glucose alone numbering ten. Thus Fischer n o t only elaborated his own sugar chemistry but he added to this the foundation of a new carboc hydrate classification the development of which will coatinue to inspire the prosecution of inquiry by generations following his epoch.The instrument which enabled Fischer to bend his experimentd deftness and his theoretical penetration to the purpose of elabor-ating so delicate a structure was phenylhydrazine. In 1884 he found that with this agent glucose and fructose yield phenylglucois-azone C18€12204N4 whilst an isomeridel arises from galactlossel; under similar conditions maltose and lactose1 resemble thel hexosea form-ing individual isomeric osazones C,,H,,O,N, whilslh sucrose at first indifferent gradually undergces partial hydrolysis generating phenylglumsazonel from the products of inversion. Closer study showetd that this reaction has the1 peculiarity of presenting a fully hydrogenisled compound phenylhydraxine in the light of an oxidising (dehydrogenising) agent.The1 first product is the phenyl-hydrazone which owing t o structural diff erenoe between glucose and fructosel is not the same frolm both sugars; a second molecul FORSTER EMIL FISCHER MEMORIAL LECTURE. 1167 of phenylhydrazins now remolves hydrogea from the tlwo phelnyl-hydrazones yielding two structurally different phenylhydrazones of glucosonel which then undergo1 conde4nsation with a third molecule of phenylhydrazinel to1 produce the osazonel, HO*CH,*[CH*OH],-C( :N*NHPh)*CH:N*NHPh, common to1 both. The1 extension of t,his reaction t o aJl aldwes and ketoses the formatioa od phelnylhydrazides from sugar-acids alnd the anadolgous a,p p 1 i cati o a of subs t i t,u t.ed p h e,nyl h y d r a zin es have reindereld i nval u-able service! in the1 ide,ntification and isolatlon of carbohydrates in ge'nera'l because1 altholugh the latter wheln crystalline are quite delfinite in purified form they a,re amongst the1 most difficult.materials to manipula1b on ac.count of thelir kndeacy to relmain as a' syrup in mixt'ureei. Eveln more. impoNrta.nt though less immeldiatelly olbvious has beeln the opera.tion of t,his process in a synth&ical direction. The aspirahion a,rt,ifioially t80 produce grape]-sugar is coeval with olrganic chemistry it,setlf. Lieb,ig had indicat'eld tlhe fascination of this problem but the first practical step was t,aken in 1861 by Butletrow, whom methylenit8an was a sweet+ pale ye'llow syrup responding to common tests for glucose but opt,ically inaoltive and unfermentable by yeast,.He poilymelrised t,riolxymet,hylene with hot limewater, and twelnty-fivel ye'aas later Loew having convelnieintdy modified Hofma,nn's melthod of prelparing f ormaldehydel sub je,cted t'his com-pound to the a.ction of cold lime.-watelr tlhus producing a syrup which he called formosei. I n 1888 by melans of phenylhydra,zine, Fischer showed t<ha.t formose is a mixtsre od at. least thrm aldelhydio or ket,onio pdyhydric alcohols of which one has the cojmposition C6HI2O6 and yields a normad osazolnel C,,HnO4N4 also procduuble from methylelnitan. Fisoher himself has st.a,te,d tha.tj the dire8ctlive influence on his work amongst carb.ohydra,tefs was the discovelry of a- and /3-acrose.I n 1887 associated with Ta.feil he o'btained from aurollein dibromide and baryta a syrup which yielded two mazones isomerio witqh on0 anothelr and wit,h phenylglucosazoae. Them were called a- and P-phe.nylaerosa,zone correlspoinding t,ol the1 two synthelt.icad suga'rs a- and &amorme having t'he composition C&&6. The fmme'r suga,r he subse8quelntlly idelntified wit,h dl-fruct-ose whilst P-acrose, which he suggested resembleld sorbose has been sinoe recognised as the &form of that ketose (E. Schmit'z 1913). Thus w&S accom-plished the first definite synt,heais in their dl-modifications of the nahurally occurring suga,rs fruatwe and sorb,ose, x x* 1168 FORSTER EMIL FISCHER MEMORIAL LECTURE. HO- -H H-OH H-H-/-OH HO- -H HO-H-/-OH HO-H -OH HO- -H -$i H- -OH H-OH HO-€ FORSTER EMIL FISCHER MEMORIAL LECTURE.1169 Hc)-HO-H Fisoher to produce the artificial sugars Z-glucose d-talose and d-idme through Z-ma,nnonic &galactlonic and d-gulonic acids, respectively and the aldopelntoses Z-ri bow and d-lyxose through Z-arabonio and I-xylonia acids respectively. The oyanolhydrin reaction although actually devised by Kiliani (1885) was widely applied by Fischer who rega\rded it as a grelat a,dvanoe in the study of the1 sugar groap. A tlypical example of its aqplication is the conversion (1891) of Larabinose the dextrol-rotatory pent- derived f rom cherry-gum into Z-mannonia and Z-glucolnic acids, H-Oa HCN followed H-OH HCN,followed H- -OH - H -- by hydrolysis HO- -H by h y d r a HO-1-H HO-H HO-I-H CO,H H 0-1- H CH:O CO,H H-1-OH a-Cflucoheptose a-Gluco-octose , d-G1ucose+ (P-Glucoheptose % (p-Gluco-octose 2 Ghco~onose.* d-Mannose + Mannoheptose + Manno-octose + Mannononose Rhamnose -+ a-Rhamnohexose + Rharnnoheptose+ Rhamno-octose In 1891 an attack was made on the cmplelx problem of con-figuratioin the1 system of which it Bas beeln necesary to assume hithelrto in order to give it coherent synopsis within rejasolnable limits of spaael.Fischer's procedure was based on the requiremelnts of van't Hoff's theory from which i t follows t<hat the! pentahydroxy-aldehyde of an unbranched carboa chain in which five carboln atoms are each assoldated with one hydroxyl groap should appear in sixtelen stereoisomeria fosrms eight oef these being eaantiomorphs of the remainder.The projection formula= oif the sixteen possible1 aldohexoses are thein assembled in conjunctJon with the eight pmsibla aldopentoses thus indicatling the trihydroxyglutario acids * Subsequently extended to glucodecose by Philippe (191 1). '6 12'6 C7Hl a 0 7 C8 €1 160 C9%309 C6H 1 2 0 5 % 14'6 CsHuP7 CPHll30 1170 FORSTER EMIL FISCHER MEMORIAL LECTURE. H-H-HO-H -( )H CH:O CO,H -OH -+ H-OH -+ H-OH HU-\- HO-1-4 FORSTER EMIL FISCHER MEMORIAL LECTURE. 1171 of mosn* di- and t,ri-rne,thyl derivatives of glucose (Irvine and Scott' 1913). Whilst Fischer indicated the probability of isomerism f d1olwing tlhe asymmelt'ry of the methoxyla-teld ca8rbon atom the seoolnd methylgluc'oaide wa.s brought t o light by van EkensGn (1894).The mechanism of glucolside formation in which it s-d convenient tol make an a.rbitrary select.ioln of altornative f ormulz for the a- aad /3-moldifioa,tione wa,s then tentatively repreenM it9 foll0,ws : CH,*O 0 CH, / CH(O*CH,) HU-\ CH-, H&OH ! H&OH Hd.OH i 0 0 H(j--' H O ~ H L- H O ~ H - HOAH ~6.08 I -7 I I t- I HC-J H ~ O H Hb-OH HAOH I I CH,*OH d 4 2 * ~ ~ UH,*O H a -Me thylglucoside. " Glucose B -Me thy1 -[a] 157". dimethylacetal " glucoside (SYJ-.UP). [a] -33". This prolposal was in aocord with Tolle,ns' y-oxide (preferably butyleae oxidel) formula for glucose (1883) and offered a sub-st8a.ntliafl baasis f o r the highly probable explaaations by E. F. Arm-st,rong aad by Lo,wry of t,he long obsesved mutarotmation of that sugas.The isola,tion 09 gluoose in a second form was achieved by Tanret (1896) and it was subsequently accepted t,hat a-glucose, wit,h [aID l l O o and P-glucose with [a], 19O pass on dissollution in water ta an equilibrium mixture ha,ving [aID 52.5O. Simon's view (1901) of a- aad P-glucose as Iower hmoilogues of a- and /3-methylgluco&de respect,ivedy has bmelea confirmed by E. F. Arm-strong (1903) who correlated elach meltlhylglucoside with its parelnt glucose1 t,hrough the agency of an appropriate1 ebnzyme. Thelrel the quest,ion re:mained during the next ten yelam when the seeld of revolution was solwn by Fischer himself. I n 1914, J. U. Nef who had beein occupied with a protracted survey of the oxidation unde,rgonel by sugars in alka<line sojlution challengeid the foregoing coaceptdon of methylglucmide isolme8rism by claiming this tto be structaral in pla,ce o'f stelria and represelnting the fl-fo'rm of melthylglucloeide and of pent.eacetylgluoow as propylens oxides instea,d 04 butylena oxides.Stsong arguments against t,his dis-turbing proposal welrel brought folrwasd by Fischer who simulta.neoasly (1914) dwribeld a t,hird melt,hylglucoside. The syrupy mjmpa,nion of a- and ;B-metlhylglucosidel hitherb assumed to be the dimethylaaetal was distilled under 0..2 mm. prMsure m 1172 FORSTER ElML FISCHER MEMORIAL LECTURE. found to be isolmeria with thean; it reeembled them in stability towards alkali and Fehling's solution bmut reveded a profound om-trast in ite behaviour towards acids which hydrollyse it with extra-oirdina.ry realdinem.Motreover whilst a-metlhylglucmide is hydro-lyseld by maltase (no,t by mulsin) and fi-meltlhylgluoosids is hydro-lysed by emulsin (not by ma'ltase) y-methylglucmide is indiff elrent ta b'oth. Fisoher coaoedeid the prolb~ability of the mw glucoside owing itls individuality t,o another form of oxide ring aad was inclineld t,a regard it as a mixt,ure of t'wo or molre such ismerides. Bolth possibilitJes ha.ve been suppotrted by Irvine Fyffei a,nd Hogg (1915) from a stludy off teltramek,hyl-y-gluc;oside a'nd tetratmetChyl-y-glucose in which emphaais is laid on tlhe retadiness with which i t undelrgoes cotnde,nsaition with aceltone and o a the instantaneous oxidat,ion of tqhe new melthylglucoside by cold a,lkalins potassium pemanganate an agelnt which hae no effect o a the ce and &methyl-gluoosidei.This remaskable behaviour t'owasds pelrmanganate invites c m -pa,rison b,eltwelen the1 deriva,tivee of y-glucose and glucal obtlained as the triacetyl dedvahive oa reducing P-a,ce~tylbromoglucose (Fjschelr and Zach 1913). The conversion of tria80etylglucal through t,he dibro'mide and the reila.teld b,romohelxo,se intlo phenyl-glucmazoaei and the oxidation by ozone to ttriacetyl-cF-ara,binose (post,humous publica'tioa with Besgmaan and Schot'te 1920), indicaf,e the first a,nd seaond ca,rbon atoms as pa$rtJcipa.nts in the double linkage of gluoal the relationship of which to dglucm and d-a,rabinme is consequently reprewnted as f ollolws : HC-1 H&OH I H 8 0 I HO*HC-HC-' HC-) H&OH j H&OH H&OH HC-' ~ H * O H &H,*OK ~ H - O H 'I HO*HC-1 HO&H I H O ~ H I H O ~ H I I I I d - Gluc ose .Glucd. d- Arsbinose. Gluoa,l is t'hus a dsriva,tive od dihydrofuran and gains piqua'ncy from having beguiled Fischer into using rare words of enthusiasm when describing its production which he de,cla.red ' I vom Stand-punkt der Sttruktlurchemie b,etrachtet eineir deir melrkwiirdigstea Vorgange id9 die man bi&elr in deir Zuckergruppe kennen gelernt hat. Sia b,eweist voln neaen welch wunderbaser St,off der Trauben-zuokelr ist." Although Fischer did noit commit himself t o the partioular folrm of oxide repraentd by y-glucose which has not yeh been isolated FORSTER EMIL FISOHER MEMORIAL LECTURE.1173 a point has been reaohed which indiaatea an ethylene. oxide-ring struoture for this compound. Before passing to the next branch of the subject it should be ment-ioned that the experiments of Boesekeln (1913) on the conductivity olf boiric acid as influenced by polyhydroxy-compounds have thrown some doubt1 on the accepteid configuration 04 the a- and P-methylglumside in which according to his deduchions the relative positions off the terminal methoay-group and hydrogen atom should be inverted and the oorrwpond-ing relarrangement made in a- and P-gluoow. I n conformity with his observations on artificial glucosides, Fischelr represented the1 disaccharides as helxosiides compmed of the heixmes into1 which they are resolved by acids o r enzymes one hexolse moleoule playing the1 part of the melthyl grolup in the less complelx derivatives.Thus maltosei and lactom were repreaentecl (1893) by the structural formula HO*CH,*CH(OH)*CH [CH*OH] ,*CH* O*CH,*[CE* OH],*CH:O, of which the lelft-hand polrt,ioa stmds for gluaolse in ma,ltose and for galactose in ladosel whilst the remainder is gluoose in both. Moreover the relationship t.0 t-he melthylgluooeides was shown (1894) by t8heir behaviour towa.rds emulsin which hydrolyses lactose (gluoose&ga.lactosideI) and is without a'ct'ion on maltose (glucose-a-glucosidel) . Struotura,lly this agrees with the oxidation of lactose to t,he molno;b.asic 1a.ct'ob.ionic acid C12H22012 a,nd of maltose t<o the isomeria maltobionic a,cid (1889) which on hydromlysis yield ga,la.ctose and glucose reepe.ct,ive51y a.ssocia'ted in s c h case wit,h gluconio a,cid ; moreove,r lactoseoarboxylia and ma,ltoseca.rboxylic acids obtained frm the reispelctivs disa.cchaside! by the cyanohydrin rea,otion yield t,he abo,vei-ment8ioneld hexoses in company with a-glucoheptonio a.cid wheln hydrollysed.Sucrose (canel-suga,r) b,eing devoi d od addelhydio oc keltnnia a#ttrib,ut,ea is a.t onoe a' fruct,oside and a glucosidel. Fischelr's formula (1893) bawd on tha.tl c,oxweption remaineld unchallenged unt,il his isdaftion of y-met~hylglucoside whein he drew attention to the similar behaviour olf thew two substa,nceB t,owalrds acids. Whilstt it is assure'd tha,t the glucose re'sidue ha's the1 samel type of oxide ring as tha8tl oE t,he a- and P-glucosides his inference that the fruct,ose component is in the y-form (tha.tl is a'n ethyleae oxide) is supported by Hawosth a,nd La,w (1916) who a,ddumd new argu-melnts in favour of relpreselnting sucrose by a folrmula.in alccordanoe therewith subsequent'ly confirming (191 9) Fischer's origina,l re'pre-sentation of ma81t,oae( in which the free aldelhydic groiup is modifie4d to the now conventiolnal butylene oxide. By a*pplicat.io,n of the met,hylat,iojn prcmws with which the St. Andreiwe labora,to,ry ha 1174 FORSTER EMIL FISCHER MEMORIAL LECTURE. bele'n so conspicuously associa,ted Haworth (1918) was led to refer Fischec's modified lactme' fo,rmula (1893) t.0 mejlibime. With so constructive a mind a.nd an armoury of synthekical method so full of welapons t'he rnagnebic problem of elaborating polysa,ocha.ride molelcules wa,s not like'ly to be neglect.ed by Fischelr.The individuality of isomaltose produced by the aotbo,n of cold fuming hydrochloric acid on glucose! (1890 and l895) was a,atively aritJcisd; indeed it Wacs shown later by E. F. Armstrong that although isomalt'olse is formed in this process it is accmmpanid by ma,ltosel. Subsequent a.ttempts holwever were based o'n unassail-a8bb.le foundaflims. The first of tlhese in association with E. F. Armstrolng (1902) depends oa t'he atction of ~-acmtylchlo~rogluao~e an the sodium derivative of gala8ctosei and of P-aoeltylchIor~galaact,~ei on the sodium deriva,tives of glucoss and galactose the result'ing dis aach amrides forming otsazonejs. T h e; gal admid oglu co,se closely reselmb,led melibiose; in ita behaviour towards eazymea and the less dellica8te chelmioal ageats but) the glucosidogalactlose was distinct from laot~me; all three resembleld the B-glucosides in being hydroL lysed by emulsin.Frolm P-ah?elt~lb,romoglu~o~e and silver carb.olnate thelre was produced the oct,a.-acetlyl derivative of a dismcharide oa,lled is&seha,losel (Fischer and Delbriick 1909) from it's oloee resemblance to t,he carbohydrate which is folund in many fungi, alnd which appea.rs to play in them t'he part of sucrose in chloro-phyllamous and stasch-beasing plant6 ; applioaction of this melthod to a~cetylbromolactose ga,ve distinct evidelnce of a' telt,rasaccharide being formed (1910) but t'his compound was not defined. The group olf a.o&yl-hadoigetn derivativels typical rneimbers otf which a8re involved in the reiactioas just described waa deatined to pesform impolrt.a,nt service in Fischer's lafm wo,rk.When the action of hydrogea bromide on penta-a.ceitylglucow is protracted beyond the pe$riold required f 0.r comwrsioin into1 t,etira-aaeltylbromol-glucosei a selaoad acetoxy-group is displa#md by brolminel and B-tri-a~oeltyldib.romogluacm arise6 (Fischer a,nd E. F. Armstrong 1902). Excha,nge of one halogen ahom for the1 mehhoxy-group lea.ds to triamtylmet2hy1glucoside brojmohydrin converted by warm balryta into the1 anhydromethylglucoside C,HI2O5 which is hydrolysed by acids to anhydrogluoose (Fisohelr a.nd Za.ch 1912) : r---O--l CHBr*[CH.OAclO.CIH*CH.(OAc)'CHPBr Triacetyldibromoglucosa Anh ydroglucose FORSTER EMIL FISCHER MEMORIAL LECTURE.11 75 H-AcO-H-H-This is cirystalline prolduaes colour in Schiff's relagent and forms crystalline derivatives with phenylhydrazine whilst reduction with sodium amalgam give6 anhydrosorbitol ; anhydrogluconic acid follows oxidation by bromine. The relsult of relducing tria~~tylmethylglucoside brmohydrin is noteworthy also because i t enabled Fischeir to ellucidate the con-figuration od the undeltermineid carbon atlolm in rhamnose (1912). With Zach he found that replacement olf bromine by hydrogen gave a triaoe~tylmethylglucosidei leading to a methylpentow on complete hydrolysis proving that1 the bromine atom in tsiacetyl-methylglucosida bromohydrin olccupies the1 teiminal position in the cihain.It was further discovered that the nelw methylpentow is the optical antipode of isorhaninoss which is relatled to d-glucose as is rhamnom to1 I-mannose; thus rharnnose itself is I-rhamnose: -0Ac -EX -OAc -0- __ j H-AcO-H-- 0 A c -H -0-H-OAc HO-H-Anolthelr rema,rkable application 04 acetylb~romogluoose led t'o t,he sy n t'heais of m a(ndell o ni t r il e- g lu cosi del which had b,een olb,taineld by Fiscihe'r (1 895) 8,s a cryst'a.lline lzvorot,atory non-reducing prolduct olf hydrolysing with yeast-ma1t.as.a the disa,ooharide group in am y g d a,li n without s evelri ng the c onnetxi on betw eeln man del mi tlr il e and tlhe reaidual hexom ; subsequently two isomerides wetre isolated, name,ly smbunigrin from t,he lelaves of Sa;mbuczcs niger by Bour-quellot and Dan j ou (1 905) a.nd prulaurasin from Prunus Zaruro-cerasus by HQrissely (1 906).Caldwell and Court'auld (1 907) relcognisad all threle a8 P-glucosides Fisahelr's being I-ma.ndeilo-nitrile-p-glucoside ; they reprdeld sa,mbunigrin as d-mandelonitrile-/3-glucoeide and prulanrasin as the dLf orm. This f olrsmst was colnfirmed by tlhhe syntlheais (Fischelr and Bergma.nn 1917) whiah f ollolweld the a,ction of silve,r ca,rbolnata on acetiylb,romoglucose in molteln ethyl dZ-mandellatel the product giving dl-mandelamids gluaosidel wit.h nmthyl-a.lcoho1ic ammonia ; debydra,t.ioln f olllowing reso'lutioa gives the mandelonit,rilel-glucoside in botlh active forms. It is to bet regreitted tha,t Fischelr himsellf did not survive to extend tfhis pr0ce's.s to the synt.hesis of amygda,lin which in 1895 he belieweid t o be1 "ein Derivak deJr Malt,ose older einetr ganz Shnlich coinstruirteln Diglucose." One1 of his last.papers ho,wever deecribpes -H H-OH -0-J 0- -H H-OH HO-1176 FORSTER EMIL FISCHER MEMORIAL LECTURE. the synthesis of glycollonitrile-glucoside (1919) the simplest of the oyanogelneltic glucosides immediately f ollolwing that of linamarin (from flax) the glucmide of awhoneoyanhydrin. Recalling the manifold parts played by the substituted amino-group in animal and vegetable metabolism i t is a singular fact tlhat so1 few amino-derivatives od a glucose type have been encoantereld amongst the produots. It was natural therelf orel that glucosamine isolated frm lobster shellls by Ledderhose (1878), should attract Fischer’s attention beclause its empirical relationship to gluoosel is expreisseid by a simple interchange1 off hydroxy- and amino-groups ; the1 actual aonnsxion howelver is ellusive folr whilst indirelctl processeis of replacemelnt (Irvine and Hynd) lead variously to d-glucose (1912) and d-mannose (1914) thus pointing t o a Waldeln inversion the dire& action of nitrous aoid involves dehydration in addition t o the1 nolrmal elxchange, The oompoaent of lolbster shells which yiellds glucosamine having been called chitin the sugar-like produotl C6H1,0, from the base and nitrous acid was called chitolse; this was o x i d i d t o ohitonic aoid C,H1,06 by Fischelr and Tiemann (1894).By the same change they relateld glucosamine itself to1 chitamic acid this being syntheeised from d-arabinose (1903) by Fisclher and Leluohs who theln reduced i t tot 6-glucosamine; later in the same year Fischer and Andreae conneoted chitsset and chitlolnia acid experimentally with hydroxymethylpyromucic acid, which is a h relateld ohitaric aoid the produat from chitamic (glucolsamic) and nitrolus aoids.Thus chitose whether regarded as an aldehyde or a butylene oxidel is delrived from tetrahydrofuran. The triamtylmelt.hylglumsids bromohydrin already mentioned was utilised by Fischer in relatioln to1 glucosamine. With Zach (1911) he found that ammonia convert6 i t into a P-methylglucosids in whioh the amino-groap has replaced hydroxyl ; but hydrolysis, instead of producing glucosamine led t o an isomeride. It has to be admitted thatl this branch of sugar chemistry retains a some-whatl perplexing aspelat t o which the! lolose nomenclature involved in such expressions as ‘‘ aminogluoose,” ‘‘ aminofruatosel,” and “ methylglucosamine ” contributes.This is all the more regrettable in view of the grelat biochemical interest1 atltlaohing tot gluaosamine as a conneloting link bstween carbohydrates and amino-acids. Before closing this chaptelr there1 remains t o be described onel olf t.he mostl remarkable aahievelments in a selries unsurpasseld by any organk c3hemistl namely the1 synthesis of tannin. I n 1908 Fischer required the chloride of ohloroawtyltyrmins for the synthesis of glycyltyrosylglycine and being embarrasseld by the1 presence of the P - X “ to HO*CH,*C*O*CH*CO,E BORSTER EMIL BISCHER MEMORIAL LECTURE.1177 phenolia group protected this prior to treatment with phosphorus pelntaohloride by substituting the melthylcarbonato-groiup for hydrogen. Imrneidia,teily applying this device tio pheinolcarboxylio acids he prepared phydroxyhippurio acid (the isomelride of salioyluria acid) with galloyl-p-hydroxybenzolic and p-hydroxy-benzoyl-phydroxybenzoic acids. Anhydrides analogous t o the last-named wetre ra,pidly multiplied and were named “ depsides ” by Fischer and Freudenberg (1910) owing to the resemblance which many display towards the tannins; in parallell with ths poly-peptides and polysaocharides such compounds may be classified as didepsides tridepsides etc. typified by the f ormulze HO * C,H,*CO-O C,H,* CO*O*C,H,- CO,H and (HO*C,H,*CO*O),*C,H,.CO,H.The1 only recognised natural solurces of the depsides are the licheins od whioh the best knolwn oonstituent is lecanorie acid the1 depsidel of orselllinic acid and in aonjunction with his son Hermann Fischer syntlhesised lecanolric acid (1903) and represented it as the pester, of which eveirnic acid is the p-methyl ether. The history of the tannins dates from the elighteenth century, but frolm the stlandpoint of this review the earlieat year od import-ance is 1852 whea Strelcker deduoed the formula C27H2201 for gallotannic acid o r gall-nut tannin which he regarded as a oom-pound of grapesugar and gallic acid in the molecular proportion 1 3. For half it centlury there prevailed a conflict of opinion as to the presenoe of a glucose relsiduei the production of sugar on hydrolysis being delnisd by seveiral chemists and the propofrtions in which it was obtained by the follolwers of Strecker varying much amongst theimselves.In aonsequence of this uncertainty SchiB’s vielw (1871) of tannin as consisting principally of digallia acid pre-pondelrated until reoently. The1 conductivity measurement6 by Waldeln (1897) however paved a way f o r the unquestionable differentiation of th0 two materials by Fischer who! synthesis& digallic add in 1908 and found it to! be crystalline although astringent; moreover in 1912 having adopted a method of purify-ing the principal constituent of Chinese tannin and of prolducing specimens having constant optical activity he and Freudelnberg prolcieeded to show that when hydrolysed with sulphuric acid it yields 7 to 8 per cent.04 glucoM1 an amoant which they regarded as probably tolo low in view of the elxtended period ocaupied in oompleting the operation. They then expressed the opinion that khe principd constituent of tannin is not a glucosidei b u t a suga 1 17 8 FORSTER EMIL FISCHER MEMORIAL LECTURE. es'telr oompasable with pelntabenzoylgluoosel in which t,hel acyl grolup is that of digallic a,cid. such al aompolund having the1 molecula8r welight 1700 would yield 10.6 per celnt. of gluoolse and 100 pelr aentt. of gallio acid on h y dr ollys,is. A t the time olf making tlhis velry peaeft,rating spewlation they synthesiseld pentlagallo~ylgluc~e~ which they found tol be a tannin, not identJcial with gall-nut tannin but remnbling it dosely in taste solubilit'y amorphism optical activity and feeble acidity ; moreover it prelcipit,atels gellat,in and alka,loids becomes gelatinous with a'rwnia arcid atnd devedops collonr with ferric ohlotride.I n the course1 of this investiga,tio~ii t,hely prepared hepta((trib.eazoly1-g alloy1 ) - pioidophen y lm a,l tm a.zolne a freak mo~leclule of gig antlic dimensions (M.W. 4021) vastly exceeding those of any other synt,heltliio pro&&. Valuable as the use oh methylcarbolna(ttdee.rivatives had proved, itn did not suffice to perfeiot the1 aJm in vielw namely to synthesis8 the madn pririoiplel of Chinese tannin. This was accotmplished in 1918 following tlhe observation that the correspolnding a,cxtyl oom-pounds are superiolr t.0 the) melthylca.rbonattol-delriva,tbives for delpsi de production.I n making t.his a,dva.nce! Fischer elxplained tha.t the atcetyla.ted phenoloa,rbolxylia acids would mrrtainly have b,wa used much elar1ie.r had not he1 beln misled by t'hs stlatleme4nts olf previous worke\m a's t.o the diffioulty of removing the a.wltyl groap which actually proceeds quite smoothly. The chloride of peata-acetyl-nzcgallio acid unlike t>hei melthylcarbonaf,o+detriva,tivel is crystalline, a,nd with &glucose yiellds the compound, C6H70,[C,H,(OAc),*CO*O*C,H2(OAo)2'CO],, whioh is de-amtylated by mld a,queolus sodium hydroxide at 0", giving pe~nt,a~(m-digalloyl)-P-glucose (Fisclhelr and Bergmann 191 8). The reeemblanoe bmeltween this artifioiad tannin and the principal constituent of Chinese t'a,nnin is much clowr t'han tha.t olffwed by pentagalhylglucose ; the two materials are in fa.&$ indistinguish-able excepting with respect' to optical aotbvity and the same remark applies t{o pentla(m-diga,lloyl)-a-gluoose the recorded [aID in water being 43*8O and 4 2 ~ 3 ~ for the derivative6 of a- and &glucose relspechivedy and 700 f o r the purifield Chinese t.a,nnin.The corrwpondenoei betwelen the potlamiurn salts (1919) is even dwr t,hwe fro,m Chinem tannin pentadigalloyl-a-glucose and pntadigallolyl-P-glucme having [a] 46*3O 56.6O and 33.7' It is therefore justifia.ble to olaim that gallotannic acid or gall-Expressed by t,he formula C6H706[C6H2( OH),*CO*O C6H2( OH),*CO],, re6 p d v e l y FORST’ER EMU; FISCHER MEMORIAL LECTURE 1179 nut tannin has been synthenised.Incidentally to this remarkable conclusion it was observed that when acylated p-digallic deriv-atives are hydrolysed even by the most delioate methods the galloyl nucleus is transferreld from the1 para- to1 a meta-hydroxy-group; f o r instanoe under the influence of alkalis ammonia or mineral acids, CO,H CO,H /\ /\ \/ AcOl lOAc changes to HO!,,!OGa, and henoe pentla-aoetyl-p-digallic acid yields m-digallio acid. Thus was brought t o a concllusion in tha closing months of his darkened life that illustrious chapter of ohemistry with which Emil Fisaher first dreiw on himsedf the admiration of his coin-tmmporarie8. It1 reprewent6 the fruit of thirty-five years’ un-remitteld labour and the ripening of an intellectual and experi-mental technique! but rarelly delveloped in the1 history of scientifio endelavour.Begun in the1 vigorous days of his elarly manhood, when domestic happiness suffused his prodessional activity and adorned the promise of a brilliant careelr it suppolrted him in his first tragedy stirred to the1 utmost the1 deep remuroes of his mind, and finally solaced those1 concluding years in whjoh he was com-pelled tol witn-s the pillars of Prussianism crumbling at the feet of his disillusioned and bewildered countrymen. OH O~CO*C,H,(O Sc), Picrin e D e riuat iu es . Some) of thel most nottable figures in chemioal histotry have devoted the;msellves to the problems which cluster roiund uric acid and its allies. Scheele Bergmann Fourcroy Prout Lielbig Mitscherlich, Wohler von Baleyer Strecker Stenhouse and Gerhardt are found in the list of names connected with tlhe subject and t’o a high place of honour in this galaxy Fischelr is most assuredly entitleld.Between 1881 when he resolved caffeine into( methylcarbamide and dimethylallo~xan and 1914 the yelar in which he synt.he&ed a nucletdide in the form of theophylline-d-glucosidephosphorio acid, the literature was enriched by a sucwsion of systematio observ-atiolns which reaohed a climax in 1898 when he derived purine from uric acid by melans of indireid deloxidatioln. Although u r i o acid was discovered in 1776 fifty-eight years elapsed before its composition was eatablished and four yelars later, in 1838 Liebig and Wohlelr published their comprehensive survey o f its oxidation produots; the true! nature and significance of thes 11 80 FORSTER EMIZ FISCHER MEMORIAL LECTURE.were reveakd by von Baeyer's experiments describeld in 1863 and 1864 thus preparing the ground f o r the1 now aoclepteld constitu-tional formula proposeid by Meldicus in 1875. This was confirmed in 1888 by Behrend and Roosen whose1 synthesis of uric acid unlike ite predecessors was achieved by definite steps at feature also of that by Fischer and Ach in 1895. The modern system of notation, a#c;oording to which the1 diureides are1 classified as delrivatives of purine and referred t o the bicyclic nuoleus, was promulgated by Fisclher in 1897 thirteeln yea,rs after his intro-duction of tlhel name! (purum uricum) in conneixion with the melthyl deirivatbve.The rellationship C A N 4 Purine. c5 H4N40 C,H,N402 CA**O Uric acid. Xanthjne. Hypoxanthine. (2 6 8-T.t-i- (2 6-Dzoxy- (6-Oxypurine.) oxypurine. ) purine.) wa,s thus consolida,te:d the. ca,ta,loguei 04 purine delrivativea cm-tributed by Fis,cher and his codlasbolrato'rs prior tlol 1900 embracing upwasds of 130 individuals. The readiness with which oaffeline lends itself t o eixpeil-imelntlatl tlrea3tment led Fischer to olpe'n a,tt.a,ck on the problem of uric arcid by first! elucidating the cojnstitutlio,n of thah base a.nd a prelimina,ry wmmunicat,ion therelon appeaseld in 1881. His introduatory wolrk delalt also with xanthine the,obromine a8nd guaninei. By oxidising a8quelous caffelinel with chlorine Rochleide,r ha,d olb,taineld amalic acid (te~tmmelthylalloxantin) which Fischelr showed t o be prelcedeld by chloro~oa,ff eine and tlo arise frolm t,he action of hydrochlorio acid oin dimelthyla,lloxa#n ; tlhe latter subst,a,nce a.nd melthylea,rbamide were found to be the principal pro,ducts of olxidising aaffeine in the ma,nner indicated and itq was proved convenielnt t'o prepare chlorol-caffeine by acting wit!h the halogen in abseacei of water.Simila8rly, theobromine was o,xidised t'ol m.ett,hylaa,rbarnide and methylasllolxan, shotwing that when ca,ffeine is prolducmd by methyla,ting t'heo-bromine the elnt.ra.nt methyl grotup b,elcmles a,tta,ahed to the1 a'lloxan ring. Next improving the1 prelpa,ra,tioln of xanthine from guaninel, Fisches olxidised i t to1 allolxan and carbamide and by addng on the lead deriva.tive1 with melthyl ioldide obtqa,ined theob,rolmine ; omn the basis of these and subsidia,ry elxperimelnta he assigneid t'hei folloiwing constitut,ional f ormulz (sele howelvec lafer) : Caffeine.The obr omins. Xanthine FORSTER EMIL FISCHER MEMORIAL LECTURE. 1181 It is noteworthy that even at this period (1882) the produots intereated him from the standpolint of relation between cheimical constitution and physiological action ; moreover Dr. Ludwig Knorr is mentioneld as his assistant. I n 1864 Strelcker stated that Itheineck had relduced uric aoid to santhine and sarcine (hypoxanthine) by means of sodium amalgam: but1 he nelvelr mentioned the subjeot again and did not include the observation in his Lehrbuch.” Fischelr found that uric acid is not changed by sodium amalgam and likewise that contrary to the statement of Kossel hypoxanthine is not converted into xanthins by nitric acid.Thus in 1884 uric acid xanthine and hypoxanthinel so similar in origin behaviour and compoaition had no direlot elxperimental csnnexion with one another. I n that year Pischeir studied methyluric acid in the hops of eatablishing the foregoing rellationship with respect t o the melthyl deaivatlives o;f xanthine and hypoxanthine. To the existing compound which give4 carbamide and methylalloxan on oxidation he addeld an jsomeride which yields methylcarbamidel and alloaan when oxidised and is converted by phospholrus pentachloride into tri-chloromethylpurine from which methyluric acid can be regenelr-ateid.Complaelntary also1 to1 the dimethyluric acid which gives methylcarbarnidel and melthylallosan when oxidised he discovelred an isolmeric dimethyl derivative yielding oholestrophan (dimethyl-parabanic acid). It was thus establisheld that in addition to the, ring which appears in the form of alloxan (melsoxalyloarbamide), uric acid oontains two imino-groups associateld witlh one another as in carbamide itself. The methylatioa of uric acid was thea carried to the trimethyl derivative apparelntly isomeric with hydroxy-caffeine (see1 later) and to tetramethyluric acid isolmeric with metholxycaffeine but having all the1 melthyl groups attacheld to nitrogen thus indicating the1 preaencel of four iminol-groups in uric acid as requireld by the struotural formula previously advanced by Meldicus.This was further confirmed in 1895 when Fisclier and L. Ach addeld the final step in the transformation, Uramil. Pseudo-uric acid. >GO. TK*CO-8.KH C 0 - N H*C*NH Uric acid. Then applying this process t o diniethylpseudourio acid they pro-duced a third dimet hyluric acid convertible] by phosphorus penta 1182 FORSTER EM[L FISCHER MEMORIAL LECTURE. chloride into clhloro~thelophylline from which theoiphyllinel arises on exchanging halogen for hydrogen : Dime t h yluric acid . Chlor otheophylline. This completed the synthe8is of theolphylline and incidentally of caffeine. Then arose a situat*ion which is rarely encountlereld in the course of Fischelr’s investigatiolns. He was compellleld by his own elxperi-meats to rewise the structural formulz which he had assigned to xanthine and its derivatives caffeine\ thelobromine and theo-phyllinei.I n 1895 he had produced a fourth dimethyluric acid by exchanging halogen f o r hydroxyl in bromotheobrolmine and the simplicity of this procedure1 did not harmonise with the1 profolund structural rearrangement apparently iiivolveld. A more rigid examination of hydroxycafleine believed to1 be isomeric with tri-methyluric acid showed it to be idelntJca1 with that substance and by varying the conditions of methylatioln tetramethylurio acid was obtained from it. Moireolver hydroxyaaffeine was produced without difficulty from the corresponding trimelthylpsezdoaric acid and finally by direlct mekhylation of uric acid itself. I n consequence od theisel disooveries Fixheir modified his previous expressions and assigned the following in 1897 : Caffeine.Theoph ylline. Theobromine. During his investdgatioln of methyluric acid in 1884 Fischer had fotund that phosphorus pelntachloride in preseam of the oxy-chloride easily replaces two and finally all three) oxygen altoms by chlorine producing tlrichloromethylpurine. I n 1897 assisted by L. Ach he convertead uria acid by tlhe same process into 8-0~xy-2 6-dichloropurine relducible t o 8-oxypurine isometric with h y p xanthine and convelrtiblej by ammonia into 6-amina-8-oxy-2-chlore purine ; this was reduced to 6-amin0-8-oxypurine isomerio with guanine from whiclh nitrous acid produced 6 8-dioxypurine isomeric with xanthine. The coznpleite replacemelnt of oxygen by chlorine was much more difficult butl by heating 8-oxy-2:6-dichloropurine with seventy parts of phosphorus oxychloride at 150° Pisohes obt8aineld trichloropurinei a basio substance giving the 7- and 9-melthyltrichloropurines on methylatioln and providing him with material for coimplelting the synthesis of hypoxanthin FORSTER EMIL FISCHER MEMORIAL LECTURE.11 83 (6-oxypurine) xanthine (2 6-dioxypurine) adeaine (6-a;minc~ purine) aad guanine (2-amino-G-olxypurine) . The goal towards whioh Fischelr first directed himself in 1884 was nolw rea.ched. Purine! the! parelnt of the grotup and on which the nome'nclature and not7ation olf t,hel whole series had been based, lay open t,ol isolation; the aocomplished fa,ds weire described in 1898. Trichlosopurine was re.duced in two1 st,ages the first depend-ing on the1 a'ctio'n of hydrogen and phosphmium iodides a t 0" and producing 2 6-di-iodotpurine from which purine it,self ww ob'tained by the a,dion od zinc oln a boiling a'que'ous soilution : 2 6 8-Trichloro- 2 6-Di-iodopurine.Purine. Purine was thus found t o be1 it definite entity amphoteric in character and harmonising completelly with its position in the selries . Attention has been dra4wn t o the difficulty with which uric acid is converted into trichloropurine and to the fact tha,t only one halogeln atom in this coampound is exchanged for oxygen by alkali hydroxides. Alkali sulphides however rapidly displace all three, producing trithiopurins (1898) and of the1 two tautomeric formul2, purine.Fischer prefelrred the latter. Another by-path was pursued in 1900 when he prepared 9-pheayluria acid frolm the corresponding phenylpezcdoluric acid which resultsl from the aation of phenyl-carbimide on uramil ; this was follolwed by 9-pheaylpurine. The series of six dimethyluric and four trimethyluric acids was completed with assistance from F. Ach by the1 preparation of 1 9-dimethyl- and 1 7 9-trimethyluric acids but the monomethyl derivathes preseded a curious anomaly. According to the lactams folrmula for uric acid there should be four methyluric acids in which the alkyl group occupies the position I 3 7 or 9 rmpectively, but the existence of two additional ones was claimed. Of these six methyluric acids Fischelr and F. Ach (1899) showed that three appear to have the1 alkyl grotup attached to the same nitrogen atom numbered 3 in the1 purine nudeus giving the same methyl-allantoin (on olxidation) and tetramethyluric acid.The mysttelry remained unsolvetd until 191 6 when an indelpendent examination of the materials by Biilmann and Bjerrum Biltz and Heyn showed that the supposed difference is due to the contamination o 1184 FORSTER EMIL FISCIIER MEMORIAL LECTURE. 3-methyluric acid with a varying propolrtion of the 9-methyluric aoid. Although for many years displaoed from his experimental atten-tion the purines becamel involved in Fischer's synthesis of nucleotides. It has already belen seen that acetylbromoglucose is a valuable agent in elaborating glucosides and in 1914 assisted by B. Helferich he brought this compound into1 action with the silver derivative of numetrous oxypurinea producling the1 6-glucosides of theophylline tlheobromine adenine hypoxanthine and guanine ; the outstanding feature od these compunds is the1 readiness with which they are hydrolysed thus being distinguished from deriv-atives of glucosamine.Finally by adding a cold mixture of phosphoryl ahloride and pyridine to1 a solution of theophylline-d-glucoside in pyridine he prepared later in the same year, theophylline - d - glumidephosphoria acid the first synthetic nu cle o t ide . Amino-ac& Polypeptides and Proteins. I n vie'w od their extent' and the( f alr-rea.ching biolcheuniaad con-clusions which halve beein ba,sed on t'hem the hbours. of Emil Fischelr in the regioln of proteJns will make1 the same appeal to the imagination a8nd evoke the same] dellight in araftwanship a,s his activities amongst carboshydra8tes.Owing t o t,he muoh grea,her complelxity olf the subje,ot howe.ver the intrinsic relsulte may a,t first a.ppelar less oomplelb; but the rellative success is elqually relma,rkabslei beca8us.e his tTre,atmelnt4 oif this bra,nch reve'als the skilful macnipula.tioln oC selnsitivel ma#terials the deft' a.pplica,t,ion olf expetri-melnta,l indioa.tiojns and the constmckive diligenae in synthe.t,io achievement' adrela,dy SOI a8dmira;bmly displapd by his ela.rlie,r woirk . The amino-acids betas to tlhe pro,teins a relatbonship recalling %hat of a hexose to a pollysacchamridel. Accordingly it wa,s wit'h those matemrials tha,tl Fischelr bega'n in 18'99 expelrimelnt.s which wetre destined t o reveal the chemical na,tarel of tjhe prolteins the'm-selves and ts furnish mattelrial which indic!a.te8s a t leastl the manner in which lifelless prot.etin may ultimateily be syntheeised.Itl had then been reaognise,d tlhat nine amino-aciids three) dia.mino-acids, a,nd cystine welrel olbt'ainable by hydrollytda 011- elnzyrnio disruptioa of protein molemles ; the synthesis oC glycine alaninei a-amino-valelrio acid leacine) aapartic acid glut,amio a.cid pheaylahnine, a.nd tyrolsine all in their dl-f arms ha,d been a,ccomplisheld ei t.helr by St'recker's meltahold or by substituting the amino-groap for ha,logeln in t'he reapedive a-chloroi- and a-bromoca'cids but sennet, altholugh discovelred in 1865 was notl synthesised untail 1902 (Fische FORSTER EMIL FISCMER MEMORIAL LECTURE.1185 and Leluchs). The resolutio,n olf these prolduds into their optically active' oomponextts ha.d been limited by their amphohk nature, aad wa,s ela,sy olnly in the ca8e od aapastdc a8clid Piut't'i having shown, in 1887 that aspa,ragine is resolved by simple! cryst,allisaf8ion frolm water. By suppretwing the basic aspe,ct of the! amino(-acids and thus e(nco1uraging thefir ca,paaity tlo form re,e.cryst'aUisable salts wit.h t,he natural alkaloids strychnine1 a.nd bruoine Fisoher and his collabora,tors first resollveld into1 t,heir antipodal compone,nt8s the dZ-f orms of ahnine a-aminobutyric acid leuaine a-amino-rt-caproio a!cid phenylahnine tlyrosinel amspartic and glutamio acids valine, serine ismerrinel and prolline.The de'vicei by which this was etffeotmd consists in benmylat'ing (1899) formyla8ting (1905) alnd in the case of serine p-nit'robelnzoylating (1906) the aminoigroap, redving the dZ-a,cylaminol-acid by recrystallising its salt,s with shyohnine o r brucine and hydrolysing sepratetly the antipoLdal 'benzoyl fmmyl or pnit,robe,nzoyl derivative od t'he d- and Z-amino-amaid. I n t'his ma.nnelr we're acmmulateld in grea'tejr quantity and variety optically active units which thus became a8va,ila*ble as bmuilding materials for t'he constlrustion of polypelpttJde.s approa.ching t,he peptlones in p h y s i d cha,racteristics. The f oregoling a . y l deiriva,tives in oolmmoln with others depending on the relactivity of the amino-group with phenylcarbimide and beazenesulphonyl chloride are useful for idelnt'ificat,iioin as well as isolat,ion of thelir pare'nt mmpounds b'ut some still belt<ter for the folrmer purpose followeld from cornblination wit'h P-naphthale,ne,-sulphonyl chloride (1902) ; the1 resulting de,riva,tives a'ret formed in good yield a,re sparingly sollublei and crystqallise sufficient.Iy well to f acilitlate the reico,gnition of hydroxyaminoLacids aad evea poly-pelptlides t8he,msellves in addit,io;n to! the aompounds from which the la.t,tR.r are built.Thus t,o a minor extent, /3-naphtshaJenesulphonyl chloride assume,s t'he pa,rt playeld by phenylhydrazine in the suga,r group a.ff olrding an instrument f olr isolla#t.ing f redy soluble aad elusive subst.anms. Early attempts t'o elxplain the1 structure of proteins had bee'n hampelred by experimental obstacles to the separation od amino-a,cids prolducmd in suoh comple,x mixtnre by hydrolysis ; with the exception of tyrosine and cyst,inel which a're sparingly soluble in wa.br the majolr portion of the mixture remains as a syrup after the principa,l constituent has cryst,allised.It was t,hus a pra,ctical a,dvance of the first magnitude which .Fischsr made as t'he result olf his inquiry (1900) into t.he esters which owing to t,he suppression of the oasboxylio function have the properties of aliphatic amines ; this fea~tare had beein reoognised in 1883 by Curtius whose prow 1186 FORSTER EMIL FISCHER MEMORIAL LECTURE. for isohting the eatetrs was modifie'd by Fische'r and app1ie.d by him to separat'ing the amino-acids in a cwplelx mixture through fractiona.1 distlllation.The prooedure offe'rs considelrable expesi-menta.1 difficulty but it is tlhhe olnly one which has beeln relally successful and its purpow has noiw beten a8chieveld with a large number of elab,orate molemles. Edegtin elastin fibrin globin, gluten kelratin aad t,he a.lbumins of egg serum a,nd milk asre exa.mples of the zeal with whic.h Abdelrhalde,n has pursued this line, of inquiry whilst Osborne; and his colla,borattors b'y similar met'hods, have awertalneld the1 compoaent amino!-acids olf amandin elxcelsin, gliadin glycinin hordein phaseolin and zein. Particularly to Fischer himself is due t.he re'aolutioa of t,he fibsrolin produced by silkworms a,nd spiders incidelnttally elmphasising the reima8rkable bdollogica.1 faat t,hat' t'heae is only slight! cheznica,l diffelrence betwee,n tlhe synthetic products 0.f two crea,t,ures whose diet is so vastly divergent.He showeld (1907) thab tlhel silk of the Madagascar spidelr gives per oent,. glycinel 35.1 d-ala.nine 23'4 I-leucine 1.7, I-tyrosine 8.2 proline 3.7 d-glutlamic a.cid 6.1 diaminoi-acids (calculated a.s argininel) 5.2 ammonial 1.1 and fat,ty a,cids 0.6; thus the prinuipad diffe,renoe is the la,rge prolpolrtJon of glut'amio a,cid, which has not h e ' n derived from ordina.ry silk and the a.bseaoe of serine. Some indiaa,tdon of the1 na,ture and va,riety of the ahemiaal unitas froim which the prolteins are1 constructeid ha,ving been given atten-tion must now be directed towards the nottab~le att,ermpts ma'de by Fischer artifi&lly tot ehb,ora,te protein molecules from thelir ciom-ponent edelme,nb.It is a note:wolrthy felatarel oif the protebns tha5 in spite of certain baxia properties a,nd the1 prompt appe'aranm od the amino-group on hydrollysis t,hel amoiunt olf nit'rogen libesateld by nitrous a,oid is. trifling compared with the pescwntage olf that, ekment in the original material. This. fa.& in conjunction with the ea,rly rscognitbon of hippurio acid as bejnzoiylglycinel gives a clue to t,he manne8r in which amino-a,oi d molelaulee adel associaf,ed in the natural prolducts n0.w under considelratiotn and wvelra.1 observations by the elarlier invest.igators confirm it. The1 simplest of these is the product4ion of a bimohda,r anhydride of glyuinnel b,y the a.ut,ol-condensa.tion oif the ethyl ester (Curtius 1888).Two such anhydridea are cloncelivabkt, yH'CH2*f!o and NH,-CH,*CO*NH*CH2*C0,H C 0. C H,-NH Di ket opiperrtzine. G1 yc ylgl ycine. aocording to the proportion olf watelr edimina.t,eld a,nd Curtlius's anhydride bdongs to1 the folrmer olass. I n 1900 Fischer obt.aine FORSTER EMS FISCHER MEMORIAL LECTURE. 1187 analogous produck from the esters of a-aminolbutyrio a-amino&-aaproic (leucine) and a-amino-n-caproio acids and classified t h a as diketopiperazinea in conselquence of an observation by Mylius (1884) who prepared the1 anhydride of sarcosine. Realisahion of the alternative type glycylglycine came in 1901 when in con-junotion with Fourneau Fischer hydrolysed diketopiperaine with-out detaching the two glycinel moJeoules and therefafter began that astonishing series olf elaborations which clulminated (1907) in the synthesis of an ostadecoapelptide, NH,*CH ( C4HS)-CO*[NH* CH2*CO],-NH* CH (C4H,) CO* composed of glyoine (15) and I-leucine (3) moleoules and having the molecular weight 1213.The name " polypeptide " was adoptsd to1 emphasise the similarity to pelptones displayed by the properties od the nelw class whilst recalling the manner in which poly-saooharides are compounded oif simple carbohydrata molecules. Subsequelntly to the process just rewiewed namely arrethd hydrolysis of a oyalio anhydride[ two general methods were emploiyefd by Fischelr to1 elffeet these impolsing syntheses. Briefly stlated tqhey depend on ejlolngating the amino(-acid chain a t the basio and acidia terminals respectively.By the f ojrmer mechanism a ohlore or bromol-aoyl chloride acting on the1 aminol-acids (or polypeptides already synthesised therefrom) produces a halogen delrivative which only melds trelatment with ammonia to become, oonvelrted into the] corresponding amino-compound f o r instance, glyoylalanine : CH,Cl*COCl+ NH,*CHMe*CO,H + CH,Cl*CO*NH*CHMe*CO,H. In this manner the glycyl alanyl a-aminolbutyryl leuoyl phenyl-glycyl phenylalanyl and prolyl (a-pyrrolidinecarbolxylic) groups welrel introduced (1903-1905). The complementary process arose from the discoveiry (1904) that chlolrides of halogenated aoylamino-acids could be preparkd by the actJon of phosphorus pelntachloride on the add dissolved in aoetyl chloridel; when such acyl chlorides aotl on tlhe ester od an amino+ acid or a polypeptide the product only requires to be hydrolysed and trelated with ammonia in order to yield the highelr polypeptide corresponding to its component molecules : C4H9-CHBr-CO*NH*CH2*COCl + NH,*CH,*CO*NH-CH,*CO,Et Bromoisocapronylglycyl chloride.Glycylglycine ester. [NH* CH2*CO],*NH*CH (C4H,)*CO*[NH*CH,*CO]s*NH* CH,*CO,H, + C4HS*CHBr*CO*NH-CH,*CO*NH*CH2-CO-NH*CH2*C02Et -+ C,H,*CH(NH,)*CO*[NH*CH2*CO]2*NH.CH,.C02H. Leucyldigl y cylgly cine 11 88 FORSTER EMIL FISCHER MEMORIAL LEC!FURE. Althongh this process is eIla&ic thelrei preselnted it,sedf an e,xpe,ri-melnttal obstdel to1 grela,t eixtensioa namelly the1 solubility of maay such acyl Chlorides in acetyl chloride arnd t,he colnsequeiitl difficult,y in sepaaating t'hem frolm soilutioln withoiut delcompositdon.This was overoo*me by pre'paring thei acyl chloIride8 obf the am.ino-a,aids or od the polypeptides themselves ; tlhese chlorides ha,ving the gelnelral formula. R*CH(NH,Cl)*CQCl are1 also ammonium chlorides, and are geaelrally not rmdily sollub,le in acletyl chlolride. As t,hey a.ct smoiothly oln t,he e,stlers off aminaa'cids and podypeptides the device has been a most fruitlful onel a,nd part,ioula,rly useful in applica8tio'n to1 the d- aad 2-amino-a,oids with oonse,que!ntl synt.hegis od optically a,ative pollypept8idee. St1raight.f o,rwa,rd a's these relac-tions appelar in demriptioa t h y relpreselnt a velry remaskab,le felat elxperimelntaJly the rigid e1xclu.sion of wates being ne8ceasa.ry throagholuti.Anot4her advant,age offelred by this process is t,hel fa.clility with which it ca,n b,e aqpplield to elabolratting polypeptides of divewe, unit's such a,s glycyl-d-ala.nylglpoy1-Z-tyrosine (1 908) isomeric with the tIetrapptide which Fischer olbt,ained in the previons year from silk hydrolysis a,nd herein liejs the coanelck.ing link beltweten thelse nota,ble synt-heltic opemratljons and the peptoaea arising from inc,omplete disruptiojn of protelin molemles. The f sr-rea,ohing cionselquelncel of tlhhe; meithod provideld by Fischer t80 separate t,hel c.ojmpoinents of aln a,mino+acid mixtare has already beeln indicated but the esters thus isolated we'rel until 1902 those of amino-a.cida only una,ssoci a,tetd with polypeptide,s.I n thalt yea'r, howwmr a,ssistad by Besgell he prolduced from silk fibroin b,y suooessive hydrolysis with hydrochloric a'eid t'rypsin a.nd b,aryta a dipeptide which appeamd to be glyoyl-d-aJa,ninel although i t coluld not be identifield with the synthetio product; but in 1906 with Ab,derhaldeln he obtaineid frolm t'he same1 sosuroe a met,hyldiketoi-N H--C €3,. f 0 identical with that producible from ~ O ~ C R M ~ * N H * pip erazine, glycine and d-alanine thus indioating that glycyl-d-alanine is amolngst tlhe dejgradatioln prolduots od silk fibrolin. Then followed the recognition of glyoyl-d-tyroline (silk fibrolin) glyoyl-Z-leuaine and d-alanyl-Z-leu&.m (ellastin) Z-leucyl-6-glutamio acid (gliadin), amd glycyl-6-alanylglycyl-Z-tyrosine (silk fibroin) .It is obvious tha,t the field od inveetigation olpened by the fore-going experiments is limited only by matesial coinsidesa,tions and an interesting calm la tioln of the polssi bili t ies prelsen t ing t he1msdve.s was made by Fischer in 1916. According tot this the octadec& peptide has 81 6 possible isomelrides whilst a polypeptide comprising 30 amino-aoid mollecules of whiah 5 are glycine 4 alanine FORSTER EMIL FISCHER MEMORIAL LECTURE. 1189 3 leucine 3 lysine 2 tyrosine 2 phenylalanine and 13 various other descriptions has a number of possible isomerides reaching 1 . 2 8 ~ 1027. In these cornputatlions it is assumed that the mechanism of linking the amino-acid groups is limited to that of glycylglycine but further complexity would arise from alternative junctions such as that of diketopiperazine the! possibility of which was not excluded by Fischer.Moreover he recogniscd that h y d r ox y amino-a cid s such as t y r osine selrine and h y d r ox y p r oline , may participate in the linkages pelculiar to esters and ethers. Although the aggregate number of synthetic polypeptides must be well in excess of 200 this only serves to illuminate the gulf which still separates the chemical investigator from his goal. That Fischer appreciabd this baffling factor to the fullest extent appears not only from his frequelnt references thelretol but also from the na,ture of his lates synthetic operations. Following the octadeca peptide these were directed more particularly to the association of optically active Bmsteime which welre varied amongst themselves as much as possible wit,h a view t o synthaising those peptide frag-ments which possess the natural configuration a property to be revealed by zymolysis.Dreahsel's iodogosgonic acid from coral (1896) having been found identical with 2 5-ioclotyrosine7 was linked with glycine (1908) whilst 6-valine a-aminoatearic acid, P-aminobutyric a,cid a-methylisoserine I-histidine and I-prolins were introduced a,lso in the lather yelar followed by I-cystine and I-phenylalanine ; po1ypept.ides containing d-tlryptophan isoserine, lysine arginine asparagine ctglutamic acid and aspartic acid as components have since been prepared. Although the simpler polypeptides are crystalline and in that aspect bear no resemblance to the protelins their tendeacy t o amorphism increlases with moilesular weight and aqueous solutions of the motre complex ones are opalescent yieilding precipita,tss with ammonium sulphatq phosphotungstic acid and tannin.Naturally, they do not respo'nd to the d o u r test depelnding on tryptophan and tyrosinel whem those groups are absent but they give the biuret re(a&ioln and these fea,tures in conjunction with their behaviour tolwasds enzymes (see later) a f h d the strongest possible1 evidence in suppolrt of the protein diagnosis outlined by this chapter of Fischelr's work. One passes to the nelxt with the sensations of an explorer liberatied from the perplexing entanglements of a dense forest to find himsellf on the shore of a limitless ocean.VOL. CXVIT Y 11 90 E’ORSTER EMIL FISCHER MEMORIAL LECTURE. Zynzo-chemistry. Since chemistry emerged from the crucible of alchemy its association with biology has become inareasingly intimatel. Viewed matezially life is a process in which alternations of growth desay, and regeneration present themselves in the light of chemical trans-formatiom delipate manifolld and inscrutable. Within the tissues 04 a living olrganism there proceed perpetual analyses and syntheses of which we gain an oocasional glimpse! but cannot hopel by the aomparative brutality of the testrtube to &age the likeness. Nature’s agents are photosynthesis and enzyme action magic wands whioh transform carboln dioxide watelr and nitrogen into carbo-hydrates f a,ts and protelins and which having synthesised these materials in plants empoiwelr animals to analyse them and assimilate bhe products of disintegration.I n the words useid by Fischer during his Faraday Lelcture 1907 “the ultimate aim of bio-ahemistry is to gain complete insight into the unending series of changes which attend plant and animal mekabolism.” Having noiw reviewed some of his most important oontributions to olur knowledgel of the building materials and proceeding to aonsidelr tlhe use which he made of the enzymes themselves it is notelworthy thatl this began oln a by-road of the great thoroughfare which he1 out through the relalm of carbohydrates. I n 1889 having shown that the ‘‘ seminose” prolduced by Reiss from vegetable ivory (Phytelephas macrocarp) is identicd with mannose he isolated alcohol from the produ&s of fermenting that sugar and in the following year cultivated yeast in solutions of dl-mannose and a-acrose (dZ-frzictosel) ; in each case the d-component was devoured, and thus Lrnannoss and .!-fructose were isolated.In 1894 assisted by Thierfelder Fischer made a comparative study of natural and synthetical monosaccharides in respect of thelir attitude towards various families of yeast from which it followeld that whilst d-mannose &fructose and in loiwer degree d-galactose reaemble d-glucose the yeasts are indiff elrent towards d-tlalose, .!-mannose I-glucosei sorbose I-arabinose rhamnose a-glucoheptose and a-gluoo-octose. This indicated thatl the f elrmentative principle od yeast is an asymmetrio agent which is capable of attacking only those molecules of which the geometrical form does not differ tool widely from that of d-glucose.It suggested also the possibility that by persuasive taotics a reluctant yeast might be tempkd ultimately to moldify its inherited taste1 and to accept as nutriment a sugar with which the asymmeltry of its enzyme was not originally harmonious. This possibility has noit yelt been definitely realised. Pasteur’s notable discovery in connexioii with Penicilliunz wa FORSTER EMIL FISCIIER MEMORIAL LECTURE. 1191 thus recalled and 011 extending the inquiry to natural and artificial glucosides Fischer found thatl these materials arrange themselves into distinct# groups in reepect of their behaviour towards air-drield yeast extract (maltlase) and emulsin the a-d-glucosides being hydrolysed by maltase and indifferent to emulsin; th0 latter, however hydrolyses the /3-d-gluoosides which are not attaoked by maltase both enzymes being without action on Lglucosides, dgadactosides arabinosides xylosides rhamnosides and gluco-heptoaides.Maltose is hydrolysed by tlhe yeast extract not by a u l s i n whilst lactose displays the converse behaviour. It was by observations suoh as these that Fischer was led to emphasise the close relationship connecting the configuration olf a sugar with that of the enzyme which attacks it and to1 depict the mechanism of enzyme actJon by the simple analogy of a look and key. In the same year one of the many rocks which await the unwary voyager on this particular wean was charted by Fischer.The ‘(invelrtase” of that period was precipitated by alcohol and did not hydrolyse maltose but Fischer replaced the soilid material by an aqueous extract of air-dried (Frohberg) yeast; this does hydrolysel maltlose but neither the disacoharide nor a-methyl-glucosidel is affected by an aqueous extract of the fresh yeast which has not been dried although cane-sugar is inverted. After being ground with powdered glass the same yelast yields an extract capable of hydroflysing maltose and a-methylglucoside but tha action is much more feeble than when the glucosides are left in contact with the suspendeid organism which has been narcotisd. I n colnsequence of divergent observations by G. H. Morris it was found that complications are introduoed by the proportion of chloroform employed and this leld t o the use of toluene in its place.The foregoing imbroglio emphasised the importance of spelcifying an enzyme by some refereiice to its origin because an enzyme from on0 source is almost invariably assooiatd with others differing frojm those which aocompany it when the origin is different. Fischer showed that whilst the extra& of dried yeast hydrolyses both aane-sugar and maltose the enzyme producing the latter effect clannot be invertase because individual yelasts which contain invelrtase fail to hydrolyse maltose ; molreovec invertlase purified by alcohol is also indifferent towards t’his disaccharide. The specific mdtodastic enzyme had been called glucase by other workelrs and it was for this name that Fischer substituted maltasel previously used by Bourquelot.Ladom whioh is indifferent towards brewer’s yelast is fermented by the milk-sugar yeasts 8. Kefir and S. Tyrocoka. It had been claimed by Beyeriiick on somewhat slender evidence thatl tbese V Y 1192 FORSTER EMIL FISCHER MEMORIAL LECTURE. contain an enzymel lactase capable of hydrolysing lactose prior to fermelntation ; this was established by Fischelr who showeld that the same reeultl intensified was produced by kefir granules. Other observations od this period related t o trehalose and melibiose and it appeared to follolw as a general conclusion that disaccharide3 are1 not fermented as such but only in consequence of a preliminary hydrolysis by a specific enzymel. In 1898 Croft Hill showed that the hydrolytic adion of yeast maltase is reversible at disaccharide being prolduced when that enzyme acts on glucose in concentrateid solution ; subsequently, Emmelrling regenerated amygdalin by the action of yeast maltase on a mixture of mandelonitrile-glucoside and glucosel whilst Hanriot revelaled the elsterifying effed of lipasel.In 1902 Fischer and E. F. Armstrong subjected a mixture of glucose and galactose to the action of kefir lactase and having removed the unchanged monosaccharides by ferment ation found in solution a disaccharide, which tliely called isolactose observing that in its behaviour moreolver the kefir lactase which links its generators has the power tlo separate them. Impreesed with the differences in chemical behaviour revealed by the enzymes of micro-olrganisms Fischer turned attention to secretions of animal origin and in 1896 assisted by Niebel studied the attitude of starch glycogen maltom lactose suarow trehalosei, amygdalin and some artificial glucosides towards blood serum from several sources and a great variety od tissue1 extracts and juices.It was in the domain of proteins and polypeptides howevelr that the principal use was made of these ageintls. I n 1903 when his fruitful association with Abdelrhalden began casein was subjected Lo protracted hydrolysis by the! pancreatia enzyme with the sur-prising re8ult that proline and phenylalanine although liberated from the protein by acid and alkaline hydrolysis were not recognisable amongst the products. These were tyrosine alaninel, leucine glutamic acid asparticl acid and a poflypeptidel matelrial which when hydrodyseid by hydrochloric acid gave an amount of the two missing amino-acids in close correspondence with the quantity obtainable from casein itself together with alaninel, leacine glutamio acid andsaspartio acid.It was also found that edestin hzemoglobin egg-albumin fibrin and serum-globulin reMmble casein in the foregoing aspect and thus was revealed a produot oC hydrolysis lying between the peptones and the amino-acids. Acceptanw of the relationship between proteins and aminocacids, abablished by the1 interposition of polypeptides involves ths towards enzymes i t stands midway between lactose and mel'b' I 1 lose FORSTER EMIL FISCHER MElKORIAL LECTURE. 1193 susceptibility of theee materials to zymolysis and as their number grew Fischer accumulated many studies olf such action.Thus with Bergelll (1903) he found that under conditions which favour the tlryptolysis olf naphthaleneeulpholglycyl-E-tyrosine and carbe eithoxyglycyl-61-leucine there is no change with glycylglycins, naphthalenesulphoglycyl-d-alanine and hippuric acid ; later it was shown that glycyl-Z-tyrosine and leucylalanine may be tryptolysed, the disruption of the latter resembling thatl of carboetholxyglycyl-le~ucine~ hy giving rise to active products. This branch of inquiry was greatly extendeld with the assistance1 of Abderhalden in 1905, when twenty-nine pollypeptides were differentiated by their behaviour towards the1 tryptic eazjrme leading to conclusions baseid on the numbelr individuality and configuratdon of tihe aminobacids involveld.A t the! same1 time it was found that glycyl-Z-tyrosine, dialanylcystine leuoylalanine leucylglycine and leuoylleucine are not hydrolyseld by pepsin-hydrochloric acid. Thelreafter the devellopmentl of this fiefld has beten left to other workm-s of whom Abderhalden is recognised as the piolneer and the remarkable achielvements of the1 subsequent period are a splendid tribute to Fischer’s foresight and genius in laying the foundations oif a branch of science a t once so complex and sol fundamental. He it was indeed who first clothed with systematia experimental observations and established facts the! dictum of Berzelius (1837) “thatl in living planta and animals there take plam thousands of catalytic processes beltween tissues and fluids.” Prior to 1895 the conversion olf an optically active substance into its enant<iomolrph had been accomplished only by racemisation preliminary to relsotlut8ion by one of Pastear’s methods.The system of cyclic changes dating from that year and classified as the “ Walden inversion,” exhibited a direlct reversal of rotatory power, and olffereld pelrhaps the most elusive amongst the many interesting problems conneIcteld wit’h opt’ical activity. Walden showeld thaj each chlorosuccinic aoid will give both malic acids according to thc agent seileded for replacing halogen by hydroxyl; silver oxido leaves the sign unchanged whilst potassium hydroxide produces ail acid of oppositel sign.As the regenelration of chlorosuccinic acid from malio acid by phosphorus pentachloride also invollves a change of sign the typical Walden inversion is represeuted as follows 1194 BORSTER EMIL d-Chlorosuccinic acid B’ISCHER MEMORIAL LECTURE. Ir ’ 2 KOH PCI, ‘x /” I-Malic acid M 2 0 4 d-Malic acid Ir ’ h\ PC1 KOH ARzO I-Chlorosuccinic acid t-During the years 1907-1 91 1 Fis&er describeld numerous examples of sign-revelrsal arising from the study of amino-aoids for instlance, d-a-Bromopropionic acid E$ d- Alanine I YBr IiOBr? I I- Alanine NHs 2-a-Bromopropionic acid +-I n the foregoing cycle it is a matltelr of indiffemnce whethelr the repla’mment of halogen by an aminol-group takes place in tlhe acid or in the eekr buti the1 converse change attelnded by relversal ot sign when alanine is transf ormeld into1 a-bromopropiolnic acid, proloeeds withoat revelrsal when alanine elster is colnverted into a-bromoprolpioaic e8stler the latter yielding when hydrolywd an acid having the same sign as the alanine employeid.Other aminol-acids such as leucinel aspartic acid and phenylalanine are disr tinguisheld from their esters in the same1 way but I-valine (a-aminob isovalerio acid) whilst giving with nitrosyl bromide d-a-bromoiso-valelric acid is regeneratfed by the action of ammonia on that sub-stanoe. Fischer found also that whilst I-lactic acid arises from I-a-bromopropionic acid by actdoa of silver oxide this agent con-velr ts I - a-br olmopr olpion y lgl y cine into a h ycl r olxy - colm pound which gives d-lactic acid on hydrolysis.Furthermorel althoagh I-valine is prolduaed wheln ammonia aots o1n d-a-bromoisovaleria acid, d-valine arises f rom hydrolysing the product of d-a-bromoiso-valerylglycine and ammonia. At first itl was believed that this type of change is associated only with a-substitution Fischelr and Scheibler sholwing that the following transformations are free from retvelrsal olf configuration : PC1.j - I-p-Hydroxybutyric acid +- .? d-/3-Chlorobu tyric acid, Ag20or H 2 0 I n 1911 however thely found that each P-aminolbutyrio a,cid will give both P-hydroxybutyric acids according tot the melthod of changing the substituents thus : d-Hydroxyl I-Chloro- d-Amino- + I-Hydroxyl. HNO FORSTER EMIL FISCHER MEMORIAL LECTURE. 1195 The same1 year witnessed a comprehelnsive survey of the subject by Fischer (Annden 1911 381 123) who described an ingenious model in which the central carbon atom and the1 movable groups have bristlle-coverefd f ace6 to) f acilitatei their attachment in sellected positiolns; thus the four substituents may be moveld a t the same time over the spherical surface of a eentral carbon atom o r they may be transfelrred singly to positions adjacent to those which they prelviously occupied.He represelnteld substitution as pre-ceided by the1 foirmation of an additive compound which on disrup-tion may or may not had to a relative distribution of the sub-stituents; thus the entrant group neled not take the1 place of the one it dislodges and if it assum- anothelr position the configur& tion of the product will differ from that of the original material.Vielweld in this light the Walden inversion is a nolrmal process deltermined by the chemioal agentls employed and by the nature of the other groups attacheld to1 the asymmetric carbon atom. Simultaneously the problem was discussed by Wernelr from the standpoint of supplemental valency and criticisms by Biilmann in the following year led to a rejoinder by Fischelr; it is not the purpose of this referelnce howeves to do more than indicate his contact with thO subject which still awaits a complete explanation. Two important deductions from the theory of the asymmetric carbon atolm receivead experimental confirmation a t the hands of Emil Fischer by meithods which the Walden inversion cannot vitiate because the involved groups remain attlached to the central nucleus throughoat the changes.Assisted by F. Brauns in 1914 he showed that optical activity disappears when two of the different groups become identical prolducing ethylisolpropylmalonic acid (inactive() from d-elthylisopropylmalonamio acid. He next made the following transformations : d-isoProp yl- Methyl ester. d-isoPropylmalonic malonamic acid. methyl ester. I-isoPropylmalony1- I-isoPropylrnalony1- I-isoPropylmalonamic Since the original d-isopropylmaloaamic add has [a] 48*8O and the resulting I-acid [a]D -44‘4’ agreement is suffioient31y close to prove that the expectation of sign-reversal following systematic interchange of two substitnents in a,n asymmeltric system has beein expe’rimentally re(a1ised.hydraside acid. azide acid. acid 1196 FORSTER EMIL FISCHER MEMORIAL LECTURE. 2‘e c hn o ~ o g y . Fischer’s rellationship to the chemical industry was intimate and beneficent. Viewed superficially the subject,s on which is foundeid his unrivalled reputation as an investSgator do1 not appear to have much bearing on factory problems; but the! value of a lifewolrk cannot bs estimatetd with accuracy unless the qualities of the worker are1 takea into account. It is a common observation that absorption in labolratsry practice coupled with unretmitted study and theoretical reifledion telnd to draw the oh-ical investigator 80 much away from practical affairs as t-o diminish his pelrception of commercial and industtrial factors. Either beoause of his elarly t?raining or owing to his inborn love of knowledge in all its branches Fischelr was unusually free from this disability and thO relianm placed on his opinions by leaders of the Gelman ahernical industry ultimately grew into an attitude of trust which was quite exceptional.S s early as 1883 he was a marked man for in that year the chairman of the1 Badische factory selected E m as directfor of research in succession tot Cam atl a salary of 25000 but the offelr was not accepted. Whilst it is impossible to mmpute the results which might have accrued from his occupancy of the post., it is equally impossible to regret the decision which he then made. Although so tempting a proposal could noh detach him from his chosen course he remained throughout life in close communion with factory operatiolns becoming and oontlinuing persona gmta with the chemical indushial magnate@ and exerting a profound influence on the industry.Probably his greatest dire& cont-ribution to teahnology lies in the stream of young chemists passing regularly from his laboratory to1 t,he factories men soundly trained in the melthods olf systlernatio inquiry and in whom a love of chemistry had belen made fruitful by the radiation of his galvanising personality. Nevertheless, more concrete associations with manufaaturs emerge from time t o time. Phenylhydrazine was destined to become one of these, although its contact with industry through antipyrine pyramidolne, and tartrazine was made by other hands. As already noticed it might have been eixpected thatl the subject of his theais for the doctorate fluorclsmin and the important con-tribution to the structure of triphenylmethane colouring matlters for which he and his cousin were1 responsible so early in life] would have committed him definitively t o the chemistry of dyes; but his interest in biochemistry rapidly became absorbingly predominant, and it was consequently in the field of synthetic drugs that hi TORISTER ElllIL FISaHER MEMORIAL LECTURE.1197 personal connelxion with chemical industry became most fruitful. Based on principleis developed in his laboratory methods were adopted in the Bohringer and Bayer factories for the manufacture of cafieine theophylline and theobromine whilst the practicability of replacing atropine by a synthetical substitute may be traced to his elarly work on triacetondkamine.A very definite contribution tlo manufacturing practice was made in 1903 when the1 improvement which he effected in the produc-tioln of dietbylbarbiturio acid arising from his work on purines, led to that substance becoming one of the most valuable hypnotics in pharmacy undelr the name velronal the mmufacture being under-taken by the Merck Bayer and Hochst* factories. His collaborator in that work von Mering was associated with him also in 1907, when calcium ioadobehenate or sajodin was brought out as a tssts-less preparation olf iodine easily tolerated by the organism. This was followed by calcium dibromobehenata or sabromin as an instrument for introducing bromine and the production of both remedies was undertaken by the1 Bayer and Hochst factories the latter developing also the prelparation of strontium chloroarsinor behenolate or elarson in aonneixion with which the preliminary experiments were made by Fischer and Klemperer.When war broke out he was taking part in the search for a carcinmia remedy, that path so thickly strewn with hopes deferred. It is not difficult to imagine the demands which were made on his energy and wisdom during the five yelars which were destined to be the cloaing period of his life and them have been delineated by A. von Weinberg. It is now known that the war could not have beten continued by Germany beyond the middle of. 1915 had not synthetic nitrio acid begun to take the place of Chile saltpetre.The probable course of events revealed itself to Fischer in September 1914 wheln he urgeld on the Westphalian manufacturers the need of prolmpt action and was rebukeld in consequence by the military authorities; but on October 1st he1 made a detailed report t o the War Ministry with referenm to the pmsibi1it.y of increasing the supply of ammonia from coke-ovens and his services were in constant requisition during the growth of the synthetic nitric acid industry which subsequently reached such enormous proportions. Two months later the diminishing store of camphor led him to recommend the usa of dimethyl- and diethyldiphenylcarbamide in powder stabilisation them being actually adopted and in February, 1915 he was presiding over a commission for stimulating the pro-duction of benzene.and toluene by gasstripping. Whilst the com-mission accomplished iix original purpose before the end of that year it) rmained in being to deal with such matters as the proi-Y Y 1198 FORSTER EMIL FISCHER MEMORIAL LECTURE. duction of heavy oil from naphthalene the extraction of phenol and cresol from coke-olven tar and a t the beginning of 1916 with a search for applications of the1 superabundance of benzene which then etxisted. By the end of that year however the Hindenburg programme had shattered the technical scheme f o r providing a sufficiency of this hydrocarbon and convelrteld plenty into famine; Fischer then demanded the demobilisation of 50,000 coal-miners. As early as 1915 his attelntion was direicted to Lhe dwindling of pyrite8 reserves and he1 became president od a gypsum and kieserite commission charged with.inquiry into means f o r utilisiiig the sulphur content od those minerals ; although teichnical diffioultia preventeld the1 application of kieselrite to this purpose the! olbstaclea connected with gypsum were overcome and much valuable information was obtained. A t the beginning of 1916 Gelmany found it necessary to limit the1 saponification of fats and Fisoher was invited to examine more closely the alternative source^ of glycerol. His first! idea being t o replace thatl substance by glycol he recommended the construction of a fadosy at Essen for that purpose but the subsequent process of Coanstelin and Ludeakel f o r producing glycerol by felmentation obviated the need folr this measure.He took an aotive part in developing the new industry in utilising the aldehyde+alcohol which offered itself as a by-product and in solving the cognate prolblem of convelrting fatty acids to service as food the result of which. was estermargarine. It was the food shortage1 in all its aspelcts howevelr which claimed his atlt+entioln motre and more pressingly. Interwoven with the demands oif the explosives industry came the call f o r nitrogen fertilisers and in January 1917 associated with Nernst and Haber, ha urgeid on the War Ministry the need f o r a foloidstuffs com-mission to assume the task of stimulating food prolduction on behalf of men and animals. With terrible earnestness he portrayeld the secondary position occupied by patriot,io heroism in relation to physiological law tlhe negleot of which must lead inevitably to psychological breakdolwn.From that time until its final session in 1918 the commission atltacked with fevelrish elnergy a multitude of diverse problms amongst which the convelrsion of straw into a digestible fodder for horses and cattle took a prominent place. The possibilities oaf wolod also were1 explored from this point of view the utilisatioa of leaves rushes and couchgrass (quitch) the germination of grain and the preservation of vegetables. With special attefntion Fischetr devoted himself toi providing a coffee substitute imgroving considerably on the knowledge which he had wcumiiiated prior to the war whilst attempt8 to rtugmest th FORSTER EMIL FISCHER MEMORIAL LECTURE.1 109 supply of albuminoid esculentsl emerged in '' mineral yeast " and the utilisation of lupines. I n spite of all t h m efforts however Fischer and his oolleagues foresaw the inevitable results of increased disease diminished capacity for work and impaired moral resistlance arising from the lamentable] condition of the pelople. They embodied their con-dusiolns in a memolrial addressed tot the heads of military and civil government in January 1918 explaining the1 helplessness of soienm and technology t-o me& the situat'ion but their repretientations were unheeded. Harassed by tqhese distractions and anxieties tormented from time to time by bodily pain and bowed down by the loss of his selcond and third sons his inextinguishable spirit found relfuge in the1 calm pursuit of scientJfic inquiry.It was during this period that his life(-long work on oarbohydrates and the correlation of thelw with depsides reoeiveld many decisive additions and in the closing months oS 1918 he ~it~neasetd in the establishmentl od the " Delutsche Gesellschaft zur Forderung des Chemischen Unter-richts," the launch of an enterprise velry near to his helart. As the war continued he had become gravely concelrned a t the diversion of young chemists t o it4 relquirements and tjhe coinsequent injury to the scientific spirit of the new gelnelratioln. To assist in com-bating this danger and the accompanying embarrassment tol teach-ing institutions arising from the diminished value of money he raised a oonsiderable fund which in his olwn words constituted " der 1eItzt.e Dienst den ioh der deutschen Wisselnschaft lelisten kann." In this ccmnexion it should be remembered also thah it was largely by the inspiration and energy olf Emil Fischer that the idea of establishing a relsearch foundation independelnt of teaching duties ultimately took shape in the Kaiser-Wilheclm-Institut fur Chermie.Associated with Nelrnstl and Ostwald he had invitsd a oompany amply representing both science and industry t o discuss preliminaries in October 1905 hut it was not until March 1908, that the " Verein Chemischs Reichsanstalt " was legally registered for the purpose1 of advancing chemical science and technology. Altholugh a suitable site. at Dahlem was allocated by the Prussian Treasury and many substantial donations had beein made it was not until the projected foundation of the Kaiser-Wilhelm-Gesellschaf t in 1910 and the1 subsequelnt co-operation of this body with the Verein that constructive steps could be taken.These culminated in thei oermony witnessed by the German Emperor on October P Y" 1200 PBRSTER EMTTJ FISCHER MEMORTAL LECTURE. 23rd 1912 when Fischer in the name1 of the Vei-@in Chemische Reichsanstalt as president of the1 exeautive committeel transferred the1 building to1 the president of the1 Kaiser-Wilhelm-Gesellschaft. His lifehwork has nolw been revielweld but only another generation can grasp it& full significancel. We shall not survive1 to witness tihe1 momentous consequences of its impulsel but we can pelroeive that Emil Fischer in onel branch of science the master gave a new meaning to another branch physiology inasmuch as he placed biochemistry on an assured basis.The germ of this profound influence may be traced tot a remotel inquiry completely detached, as i t would then have1 selemed in the1 mind of its author from the trend of its ultimate development. The effeot which was destined to be produced on physiological chemistry by the discovery of phenylhydrazins in 1875 offers but anothelr example of the constant interplay beltween fact and thought. Although twelve years elapsed belfolre that base enabled him to claim the synthesis of a natural sugar progress tthereafter was rapid and sweeping. The array olf synthetical carbohydrates which had been assembled by the yelar 1894 provideld him with the matelrial nelcessary for the fundamental discovery that the spelcific aotion of an enzyme is intimately related to the configuration of the substrate.In the wealth of praotical achievemelnt which followed this discovery the applications of its underlying principle constantly recur. The classification of the glucolsides was a substantial consequelnce but far more important was the1 utilisation of tissue extracts in the study of artificial polypeptides showing thatl itl is only those con-structed of the amino-aeids supplied by nature which yield to the attack of pelptoclastic enzymes. Thus i t may be olaimed for Fischer that he forged and perfected a new and delicatle instrument with which the1 investigator may solve abstruse problems in biochemistry, for when oince the technique1 is acquireld the use of enzyme8 in configuratioln diagnosis is unapproaohed by ordinary chemical processes in respect of precision and rapidity.Reflecting on t h e elsselnce of life in its chemical aspeict regarding the actl of living as a complex alternation of digestion assimil-ation and oxidation the mind begins to arrange in one beautiful fabric the coloured strands from which is wovein Fischer’s contri-bution tol the knowledge of the centuries. He not only regularis4 the most fruitful of laboratory methods for studying life processeis, but he assemblefd more richly and in greater variety than any other chemist the materials on which those prommeg depelnd. Carbo-hydrates glucasides depsides purines and polypeptides have, ddring the yeaxs of his activity been broughtl to our delighted vision amd ranged in perspective by his control of mzpa. A FORSTER EMIL FISCHER MEMORIAL LEOTORE. 1201 interpreted by him we recolgnise amino-acids as the basis of our being. All this knowledge will give definite form to countleiss inquiries dealing with digestion and assimilation and by shaping ths prolblems connected with such changes will assist in tlaking that first and most important step towards solving them. Indeed it is not unjustifiable to hope that further advanoes along the lines now firmly laid by his life-work may bring biochemist8 of a$ future period to a clearelr view of that. ellusive province in which hormones and advitants (miscalleid vitmines) exercise their subtle influence on the alchemy of living bodies. Even when due allowanm has been made for the storehouse of accumulated faots on which the chemists of his era were empowered t o draw and for the variety of technique which was a t their cam-mand itl can scaroely be claimeld that in welalth od revelation and rnanipulat'ivel skill Emil Fischer is eclipsed by any of his pre-decessors. It is difficult to imagine that he can be surpassed by any of his succemors; but whether this be sol or not his atchieve-m a t will remain fos all time a monument of industry a master-piece of symmetry and a gospel of inspiratioln. Ris contem-poraries who have) watched the1 growth of a wonderful structure with admiration and pride may lelave to postmity in happy con-fidence the office of enshrining his work in the1 history of thefir beloved science : '' For Time shall with his ready pencil stand, Retouch your figures with his ripening hand, And give more beauties than he takes away." To future ages shall your fame conve

ISSN:0368-1645    

DOI:10.1039/CT9201701157

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

1202 SINQH STUDIES IN SUBSTITUTED QUATERNARY AZONIUM CXX X1.-Studies in Substituted Quaternary Axonium Compounds coutaining an Asymmetric Nitrogen Atom. Part 111. Resolution of Phenylmethyl-ethylaxonium Phenylbenzy~propylazon~u~~ and Phen?llBerLzyIallyla~onium Iodides into Optically Active Components. By BAWA KARTAR SINGH. IN Parts I and I1 od this selries od rmearchm (T. 1913 103 604; 1914 105 1972) t,hel a'utholr has deecrib,e\d t,he resolution of t,wo members of a new type of ena(ntio1morphous compounds, R,R,R,XN*NR,, the asymmetry a,nd oonselquently the optical actiivity of whiuh is associated with the presence of an asymmetrio nit,rogen afom. The prewnt investigation which is a cotntdnuation of this work, is uoncwrneId with the resolut,ion of phe~nylme~tlhylet~hyla,zoniurn iodide the previoasly determined value oQ t,he moleioular rotmatory power of which was considered t'o be ra'ther low (Zolc.cit.) in a,dditJoln to! t,hat of tlwo other meimbelrs namedy phenqlb e m ylpopyl-azmiu,m and phenylb e~zyEaUyZazonim~ iodides. Phenylmethylet8hyla.zonium ioldide was resolved with tlhe aid of silver &u-b,romooampht-fl-sulpho~na~te. The IBdA d t being less soluble sepasa,ted in a crystalline form and gave for t'he I-basio ion [MI - 2 3 O tlhe maximum rotation of -3OO' having a h a d y been olbta,ined froim t'he hydrogeln tlartrata (Zoc. c i t . ) . It is thus very probab'le tha,t t'hs folrmer vadus of -30° is the maximum molecular rota%toil.y power of t,he Z-b,asio ioln. Anohher point od interelst is t,hat I-phenylmet8hylelthylazolnium pimate has aJmost identical va,lues of [MI in chlorodoirm and meithyl alcohol solutions (sees p.1206) a.nd it thus stands in note worthy contrast with phenylbenzylmethylaaonium picrate t$he va,lue of [MI of whioh is t,hree times as high in chlolrofosm as in msthyl dooholl (T. 1914 105 1984). This polint,s t'o mole,cula.r assooiation of the la,ttm piorate in chlolroform but so fa'r this view has not been colrro;boil.ated by a detIelrminafio~n ovf molecular weighte in the t'wo solvents. Pheinylbenzylpropylazolnium iodide coald olnly be1 obtlaineld in olne way namely by the1 a,ction oB b.enzyl iodide on phmylpropyl-hydrazine. I n tfhis reaction a very small amount of a hydrioldide was also folrmed as a by-product The action of propyl iodide o COMPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM.1203 phenylbsnzylhydrazine ga,vve t'wo hydriodides mejlting at 146-147' a4nd 162-1 63O respectivealy h i d e s ammonium iodide. No azolnium iodide was however formed in this reaction. The action od propyl iodide thus seems to be a.bnormal and was further studied on two otlher hydrazines. In the case osf phenylmethyl-hydraxine the sole product of t h s a.&ion of this iodide was ammonium iodide and in tha.t off phenylpropylhydrazine at first no product was formed but on keeping the! mixtnre f o r some time a very minute quantit.y of ammonium io'didel was isohted. It' may be suggabd tha,t t'he secondary hydrazine is slowly reduceld t,ol a a amine and ammonia, and the la,tteIr substlanoe combinw with hydriodio acid to form ammonium iodide.The hydriodia a'cid ma,y be produced from the hydrolytic delcomposit'ion of propyl iodide a,nd itl velry prolbably act8 also1 ass the relduoing agent. Phenylbenzylallylazo~nium io+dide was prepa.red from the action olf benzyl iodide on phenyladlylhydrazine. This reaction was quite normal . I& esoll.2~ ti,on. -P henylhnzy1pro;pyl azoniurn iodide was resolved by t'he aid of silver d- camp holr- fl-sul p holn at.e and d-a-brom oomp hor-P-sulphonats. In the case 04 the camphorsulpholna8tes the dBdA sa,lt, being lelss solubmle in a mixtlure of melt8hyl alcohol and ether, first separat,ed out. It hajs [MID +357*5O in met'hyl alcohol a.nd +300.5O in aqueous solution. The ZBdA sa,lt was oib,tlained by recrystallisa'tion fro'm wafer in whioh it is lelss soluble t,ha.n the other cmponelnt' and has [MI - 153'2O in melthyl a h h o l a.nd - 190'9O' in a,queous solution.Ta,king [MI folr t,he dcamphor-sulphonia acid ioa as +53O the! dBdA salt1 give6 +247*5O and the ZBdA sa.lt - 243.9O far the1 d- a,nd I-b'asia iolns in a,quelous solut'ioln re8p eutivsl y. On t-he &her hand if we assume tha#t the sa81ts dBdtA and ZBdA behave normally in rapedl of tlhe a.dditive character of the mole-culas rota8tolry power of t'he two ions in aque'oas sdut,ion the value of [MI, for the d-oampholrsulphonic a,cid ioin is deduced to be + 5 4 * 8 O and that for the basic ioa k245.7O (ses p. 1210). The agreemeIntl be'tween the above figures is sufficielntly dose, and t,he value of [MI for the d-campho~rsulphonio acid as above deduced furt,helr shoiws t,ha<the tlwwol salts dBdA ZBdA ha,vel beebn olbtained in a pure condition.It has adre'ady been polinted out in the case of the camphos-sulphonafw of phetnylbelnzylmelthylaao~nium (T. 19 14 105 1973) thati three cases .may occur when an e8xtlernally compeasated base is crystallised with an optioally a.otive acid (1) the two salts dBdA ZBdA crystlallise separately so tha't elach may be readily isolated; (2) a part'ly r a m i c compound dBZB 2dA may b 204 SINGH STUDIES IN SUBSTITUTED QUATERNARY AZONIUM formed in whi& case resolution is impoasiblei; (3) each crystal which s e p a r a b may wntlain both the salts dBdA ZBdA in vary-ing proportions; in other words the two salts form solid solutions, one in the other and resolution is very slow and incomplete.In the case of the oamphorsulphonatee of phenylbenzylpropylazonium, behaviour of two kinds (types 1 and 3) is observed. After some of the dBdA ZBdA salts are separated in a pure condition the r s i d u d salt having [MID about +35O consists of 46 per cent. of the dBdA and 54 per centl. of the ZBdA component. On further crystallisation from water rn well as from a mixture of methyl alaohol and ether resolution proceeds extremely slowly as is seen from the1 rchatioln colnstanta. It is t.hus clear that the two salts have formed solid solutions one in the other when their composi-tion comeisponds with 46 per mint. of the dBdA and 54 per cent. crf the ZBdA component. I n the1 case of the bromoaamphmsulphonabs the 2BdA corn-ponent which melts atl a higher tempelrature first crystallism from a mixture of melthyl alcohol and ether.The dBdA colmpolnelnt, on reorystlallisation is obtained a8 an olil which could n& be Itollidifisd. The pure ZBdA salt! melts at 178-179O and has [MI +71.2O in aqueous solutioa. Phe~nylbenzylallylazonium iodide was resolved with the aid s f silver d-camphor-P-sulphonak. The dBdA componelnt being lelss soluble in methyl alcohol first separated out. It melts a t 147-14B0 and has [MI +190-3O in aqueous solution +2650 in chlolrofolrm sojlution + 285.7O in rnelthyl alcolhol and + 319.20 in ethyl alcohol. EXPERIMENTAL. Phenyhe t hylet hyJazonium d-a-Brolmocamphiw-~-sulpho~at e, PhMeEt (NH,)N*S03*C,,H,40Br. Finely polwdereld azonium iodide (25 grams) was addeld in mall quantities at a time to m e mo~lelmlar proportion of silvelr d-a-broimoicamphor-P-sulpholnate (37.6 grams) dissolved in boiling melthyl alcohol on the water-bath.The1 oontents of the flask were kept shakeln and after the addition of the whole of the azonium iodide the heatling watj continueid for half an hour to complete the1 reaction. The methyl aloohol was distilled off and the residue, consisting of solid silver iodide1 and the syrupy brolmocarnphoc-sulphoinate was extlracted in the usual way with methyl alcohol. On evaporating the1 methyl alcohol an oily rwidue remained which did noit crystallise elven on keeping for six days. It wits again dissolved in almhol and precipitated as an oil by the addition of ether. After some time fine needle-shaped crystals began t COMPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM.1205 appear and a portion of the oil slowly became crystalline; this amounteld to 9.7 grams and melted a t 152-153". The remaining portion of the oil did not crystallise even on keeping under either for six months (Found C = 49.05 ; H = 6.74. C,,H,,O,N,Br requires C=49*46 ; €I = 6.29 petr centl.). The rotatory power* of the salt was determined a t 29O in acqueous solution : Substance. Gram. Time a,. [MID. 0.1738 - + 1.11O + 293.0' 0.1738 After 25 hours. 1-13 298.3 The above camphorsulphonate (8.8 grams) was dissolved in the least possible quantity olf rnelthyl alcohol and preoipitateld by gradual addition of elther with the1 following result: Yield. Substance.Fraction. Grams. M. p. Gram. UD. [MID. A ............ 2-2 154-155' 0.2960 + 1 0 8 6 ~ +288*3" €3 ............ 5.9 155 0.1792 1.12 286.6 Fraction B was submitted to the same procas and the1 rotatory power of fractions C and D into which it was resolved was determined with the following result: (in 20 c.c.) Yield. Substance. Fraction. Grams. M. p. Gram. ab. [MI,. c ............ 2-1 15G-156' 0.2184 + 1-41' +296-2' The rotatory polwer in all the1 abolve cases was determined in water a t 29-30'. The lowest value1 of [MI f o r the ZBdA salt is about + 287O and since [MI for silver &a-bromocarnphor-P-sulphonate (Pope and Rea,d T. 1914 105 809) is +31O0 the molelcular rotatotry power f o r the I-phenylmethyletthylazonium ion is -23O (287-310). ............287.8 D 3.0 154- 155 0.2454 1.54 dl-Yhen?j1912ethylethylcEzonlirum Picrate, PhhleEt (NH,)N O*C,H,O,N,. This salt wa4s obtained from the racemio azonium iodide in the usual way as yellow prisms melting a t 110-11lo. It is veiry reladily sohble in acetone less so in methyl alcohol ethyl alcohol, or ahlorodorm moderately so in water and insoluble in &heir (FoIund N = 18-63. * The given weight of the substance waa dissohed in 19.9 C.C. of solvent, and the rotatory power determination was made in a 2-dcm. tube about thirty minutes after solution. This applies to all the observations recorded in this paper unless the contrary is stated. C15H1707N5 requires N= 18.47 per aent.) 1206 SMGH STUDIES IN SUBSTITUTED QUATERNARY AZONIUM 1-Phemylmethylet hylazoniurn Picrate.The aotivs piorate was prepared by adding an alcoholic solution of the bromocamphorsulphonate of the I-base to an alcoholio solu-tion of picria acid. On concentrating in the cold water was added when yellow prisms separated which after on0 or mor0 recrystallisatiolns from aloolhol and ether mellted and deoomposed a t 114-115°. A mixture of the dl- and Lpicrate melteld at 107-108°. It is very readily soluble in acetone less so in methyl alcolhol ethyl alcohol o r chlocoform moderately so in water and insolluble in ethelr (Found N = 18.14. C,,H,,O,N requires N = 18-47 per wnt.). The1 rotatory-powelr determinatiions gavel the following values : Substance. Tem -Gram. Time. perature. un. 0.2748 (in 20 C.C. methyl alcohol) hr. 27.5" -0.16' - 22.06' 5 hm.27.0 0-17 23.4 0.2977 (in chloroform). . . . . . . . . . . . - 27.0 0.186 23-56 2% hrs. 27.0 0.18 22.08 y* 7 9 28.0 0-17 21-51 32 1 9 27-0 0.10 12.67 The rotatory power of the above picratet is practically identical in both the solvelnts. This is notelwworthy as phenylbenzylmethyl-azonium picrate has [MI three t i m a as high in ohlorotform as in melthyl alcohol (T. 1914 105 1984). This is probably due to assodation ot the molleoulea of the lattelr piorah in chloroform. as-Piz emy 2-a-propylhydmzk PhPraN*NHz. This was prepareld by dissolving sodium first obtained in a fine, granular condition by mellting it under xyleae a,nd vigorous shaking during ooding in thet calculated quantity of phenyl-hydrasinel a t 1 80° under diminished pressure and t8retating the1 resulting sodium phenylhydrazine with prolpyl bromide1 (Michaelis, Bey.1897 30 2815). The selcondary hydrazina wm punfield by ooaversioa into1 its hydrochloride (silky nesdles) which melts at 147O and nolt at 135O as stated by MiChadis (Found C1= 18-89. Cah. Cl= 19.57 per mat.). Phe.n?lI-a-plro~ylh.ydrazirte hydrofe.rrocyamide, ( P hPraN ONH,) 2H,Fel( CN ) 6, is obtained as a white preoipitlake by the addition olf a colncmntlrateld solution of potassium felrrolcyanidet to a ooammtrated solution of phenylpropylhydraxine hydroohloride acidifield with hydrochloric acid. It is suoaeasively washed with a lititle wa;ter alcohol and eltheir and dried in a vacuum deeicoator. It is very readily solubl COMPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM.1207 in watelr but less so in alcohol. On exposing it to t>he air for some tJme i t acquira a violelbblue d o u r (Found FEY= 10.67 ; N = 26.65. (C,H,,N,),_H,Fe(CN) relquires Fel= 10.85 ; N = 27.14 per cent.). dl-Phemylb emzyZprqyZazoniu8m Iodide PhPra(CH,Ph)(NH2)NI. (a) By the Action of Bemzyl Iodide om PA,anyIlrropy2hycFra,zine. -An ioe-cold ethereiad solution of phenylpropylhydrazine (from 30 grams of the hydrochloride^) wa,s a.dded to one imleoulas pro-portioln of an ethelreal solutioln of belnzyl ioldidei also1 coolleld in ic8e. The crude prolduct (33-5 grams) after recrysta(1lisation from melt,hyl a h h o l and ether mellted and delcomposeld a t 125-126". I n some experiment8s the yie'ld wa.8 even be'tter. Itl is very reedily soluble in melthyl adcoholl solmewhat less so in eithyl alcoholl stlill l.ess so1 in wa.t,er and insoluble1 in benzelnel or elthelr (Foand I = 34.61.Cl6€IzlN2I requires I = 34.49 per cent.). From the filtrate on keeping for scme time a very small amount of anckhelr subst,ance se'para,ted. This was noh an axonium iodide[, butl a hydriodide as it gave an oil on trelatmelnt with a solution off sodium carbolnak. ( b ) The Actiom of Propyl Iodide om Ph~zylbenz?llhyd9-a,zine.-The action o f propyl iodide on phenylbenzylhydra,zine did not give the axonium ioldids obtlaiaed under (a) but wha.t appearerd t'ol be a hydriodidel 8,s the produat gavel an olil o a treatment with sodium carbona,te. The! mother liquoa oln ke'eping for selverad weeks, deposited a sma.11 amount od a,nolthelr substance which did not melt, but evolveld ammolniao wit.h potassium hydroxide.It appea,rreld t'a be ammonium iodide (Found I=86.88. Calo. I=87*6 per celn tl . ) . dl-PhenyIbenzy1plro~ytazoYniu.m. chlo*ride, PhPra( CH,Ph) (NH,)NCl, is olbtained in the usual way from the corresponding azonium iodide a.nd mystallises from alcohol1 and &her in collourless prisms melting a.nd deoomposing a t 145-146O. It is very readily soluble in rnelthyl alcoholl ethyl alcohol a,aelt,onne olr watelr but insolub,le in ether (Found N = 10.53. C16H,,N,C1 relq,uires N= 10.15 per cent.). The oorrelspolnding @&nichZolride is a buff -ooloured substanaer It is insoluble in water olr organic media (Found Pt = 22.03. (C,,13,1N2C1)zPtlC14 requires Pt=21.93 per mnt.). The dl-a;nr&hlo&de is first obt~ajned as an oil which on rubbing and allolwing to remain beco'mea cryst.alline1.It recrystallises f r m posing at 151O 1208 SINGH STUDIES IN SUBSTITUTED QUATERNARY AZONIUM hot alcmhd in yellow prisms melting and decomposing a t 132-133°. It is very rea,dily soluble in acetone sparingly 501 in m0thyl alcohol, ethyl aloolhol olr chlorofoirm and insoluble in wa'ter or ether (Found Au = 34-08. C,GH2,N2C1,AuCl relquirels Au = 34.0 per celn t . ) . On keeping for a few days in a stoppelred bottle it decomposm to a dalrk brown semi-solid mass hydrogen chloride1 being evolved. Ph e n y 1 b e m y l p o py l m orzium d-Camphor-8-sullrho~at e, PhPrn( CH,Ph) (NH,) N- SO,*Cl,H1,O. Finely powdelreid phenylbenzylprolpylazonium ioldide (30 grams) was added in m a l l quantities a t a time1 t o one molelcular propor-tion of silver d-oamphor-P-sulphonate contained in iir mortar.Melthyl alcohol containing a few drops of water was a,dded t o moisteln the contents of the1 mortar and the mixtlure was carefully triturated. This procedure was adopted in plaw of the usual one in order to diminish the decomposition which raulteld when the constituents were helated together with ethyl aoetab olr alcohol. The mortar was kept in a vacuum desictcatolr and the soilid residue was extracteld with methyl alcohol1 in a Soxhlet apparatus. On maporating off the1 alcohol 33.8 grams of the camphorsulphoaate (tlheloretioal yield 38.4 grams) melting atl 185" welre obtained. It is velry reladily soluble1 in methyl alcohol ethyl alcohol acetonel olr chlorodolrm molderatdy so in water and insosluble in benzene or eltheir (Foand C = 65.88 ; H = 7.63.C,,H,O,N,S requires C = 66.12 ; H = 7.63 per cenlj.). d-Ph eny 1 b enz y 1 pro py laz omliulrn d - Cam ph o r - /3-su lph on& e . The oampholrsulphonate~ (32-8 grams) as prepareid above! was subjelded to fractional precipitlation by first dissolving it in the least polssible quantity of methyl alcoholl and then gradually add-ing pure. anhydrous ether. The following five fractions were obt'ained : Fraction. Grams. M. p. Gram. a,. CMIW 1 ............ 6.9 187' 0.1727 +0*76O +206-7" 2 ............ 6.8 190-191 0.1 858 0- 145 36.65 3 ............ 16.7 189 0-1 965 0.32 76-47 4 ............ 0-33 186 0.1982 0.307 72.75 5 ............1.7 184 0-1806 0.24 62-41 Yield. Substance. The ro'tatory powelr was determined in methyl alcohol at 30-31O. Fractioln 1 a<fter remystdlising several times gave the pure B d A salt melting a t 190° with tlhe following values for rotatory power COMPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM. 1209 Tern- Time. Substance. Solvent. perature. Hours. Gram. a * [MID. Methyl alcohol ...... 24.0' - 0-1340 + 1.02' + 357.5" Water .................. 27.0 - 0.0963 0.616 300.5 , .................. 25.5 0.0963 0.613 299.0 , .................. 26.0 47 23 0.0963 0.61 297.5 Thus the pure salt dBdA melts at 190° and has in metthyl alcohol and +300.5O in aqueous solution. +357*5' 1-Phenylb emx y Zpropylazoniunz d-Camph or-P-sulpihona<t e . Frachions 2 and 3 (amounting t o 23.5 grms) after several further fractliolnations in the usual way gave 6 grams od salt melt-ing at 189* which was olptically inactivei.The resolutioln in this way however proceleldeld very slowly and as a preliminary experi-ment showed that the ZBdA salt is lelss soluble in water the optically inactive fraction was relcrysta,llised from that solvent. Fraction. Grams. M. p. Gram. a,. [WP a1 ............ 2.0 188" 0.2280 - 0.45" - 92.69' a2 ............ 3.6 186 0-2073 + 0-26 + 58.92 Fractio'n n l was twioe again resryst,allised from hoit water : a3 ............ 0.55 190 0.1202 - 0.485 - 189.5 a4 ............ 0.2 189 0.1836 - 0.64 - 164.5 Fraction a3 similarly p v e fractions a5 and a6: a5 ............ 0.26 191 0.1459 - 0.59 - 190.9 After 20 hours 0.1459 - 0.58 - 187.6 After 23 hours - 0.47 - 167.6 Yield.Substance. a6 ............ 0.18 0.1317 -0.51 - 181.9 -The rotatory power in the above case6 was determined in water The! rotlatory power of fraation a5 was ailsol determined in methyl a t 26-2F. akoholl : Substance. Time. Gram. Temperature. Hours. a,. [ W D . 0.1159 25.5' - - 0.373" - 151.1' 0-1159 26.0 24 - 0.378 - 153.2 Thus tbe pure salt ZBdA melt6 at 19l0 and has [MID -190-9O in aqueous wlutlon and -151O in methyl alcolhol (Found: N=5-81. After the pure salts dBdA and tBdA were isolated there still remained about 15.6 grams of the subst'ance with {MI ranging from + 2 9 O tIa +72O. It was relpeate'dly crystadlised first from water and then from methyl alcohol1 and ehheir. Ultimately a salti with [MI +35O wa,s obtained when the rojtatmy power muld C2,H,,0,N,S requires N=5.93 per cent.) 1elO SINGH STUDIES M SUBSTITUTED QUATERNABY AZONIUM not be changed any furthea.It thus appears from the slow reaollution that the1 two1 salt's dBdA lBdA have folrmeid a soilid solution olne in the other. The1 rottattion cotnstant's indicate that this fraation consists oif about 46 per cent. of the1 dBdA and 54 per cent. od the IBdA salt. The Nolecular Rotatory Powers of the Optically Active Ims in Aqueous Solutiofi from that of the Cavnphossulphmtes. The mo'lecular rolta,tory poitvers of tlhe two carmpho~rsulphonates, dAdB and dAIB in less than 1 per centl. aque'ous solution are tdmlated blow : M. p. [MID. (1) dBdA ......... 190° + 300.5" (2) ZBdA .........191 - 190.9 The! algebraical s u m of t3he molecular rotattory poiwers of thew two1 salts in aqueous solutioln should be elquad tla twice the molecular rotatory powetr of the acid ion and the algebraical differeace should be etqual to twim that od the basicr ion. The value of [MID for the camphorsulphonic acid ion becomes 54*8O and that for the phenylbenzylpropylazonium ioln 245.7O. The agreemelnt between the value of [MI for the1 camphorsulphoaic acid ion as delduced a,bove and that obt,aineld directly as in the following table is fairly close : Temperature. [MID. 20° 51.4" ......... (Graham T. 1913 103 764). 20 51.6 (Thomas and Jones, 30 5 3 . 6 ) ' . ' ' * ' * * . ( T. 1906 89 284). I'h city1 b enay Jp-opy laz onium d-a-Bront o camphor-@-sulphomt e, PhPra(CH2Ph) (NH,)N*SO,*C,,H,,OBr.This salt was prepared by the gradual additioa of finelly powdered azonium iodide (36- 1 grams) to one molecular proportion of silver ct-a-bromocmphor-P-su1phonak.e disolveld in hot rneithyl alcohol. The heating was continued for half an hour on the water-bath under reiflux. On filtelring off the silver iodide and conmn-trating the methyl-aloohodic extraot on the water-bath an oil was obtaimd which a t first did not orystlallisa It wits kept under ether olvernightl when it solidified to colourless prisms (41.2 grams) medting at 144-148O. The compound is vetry reladily soluble in matbyl alcohol less so in ethyl alcohol aOeltlone o r ethyl aoetlate, sparingly so in water and insoluble in eltheir (Found C=57-22; H = 6-62 ; N = 5.27.C,Hs0,N2BrS require& C = 56-63 ; H = 6-35 ; Nr5.08 per cent.) CONPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM. 121 1 1- Phenylb em ylpropyhzon iurn d-a-Bromoca,nzplltol.-P-sz~~ho.na t e. The crude bromocamphorsulphonata (40.2 grams) melting a t 144-148* as obtained in the above way was subjected to frac-tional cryst'allisation as follolws. It was dissolved in the least possible1 quantity of melthyl alcohol and precipitated by gradual additlion of ether. I n several caes an oil separated which increlaseid the difficulty of resollution : Yield. Substance. Fraction. Grams. M. p. Grams. a.. 1 12.5 155-156' 0.1087 +0.54" +272*0" 2 2.3 150-154 0.1193 0.68 3 12.2 Fraotion 1 similaxly gave: 3 3.2 178 0-1183 0.15 69.44 4 5.7 156-158 0- I362 0.742 298.4 Fra8ctmiosn 3 after severa,l mom recrystallisatiors gavel : 6 1.0 178-1 7 9 0-1792 0.22 67.31 After 8 hours 0.22 67.31 After 234 hours 0.20 61.1 The rotatory-powelr dejtelrminations in the above1 cases were made in methyl alcohol at 30-32'.The rotatory po'wer was also determine,d in aqueous sollutioin in the ca,se of fractiotn 5 : Substance. Gram. a,. [MID. 0-0693 + 0 . 0 9 O + 7 1 * 2 O Thus the pure ZBdA salt m&s art 178-179O and has [MI0 +71*2O in aquelous solution and +67.3O in methyl alcohol (Foand N=5*13. C,,HsO,N,BrS requires N=5*08 per cent.). dl-Phenytme t h ylpropylalzmit~m lodkle PhMeSra(NH,)NI. (a) By the- Actiom of Methyb Iodide on as-Phenylpropyl-hydruzine.-Methyl iodide! (6 grams) was added t o olne molecular propolrtion of as-phenylpropylhydrazine (6 grams) dissolved in ether.Within a short time the mixture began to deposit a guinmy mass which o a keeping olvernight became crystalline. Thel crude1 substance (3.8 grams) after relcrystallisation from alcoihol and either sepasated in colourless prisms melting and decomposing a t 106-107°. It. is solluble in methyl alcohol ethyl alcoho3 or w a h r but insoluble in benzene or ether (Found: I=43.26. ( b ) A e t k m of Yropyl Iodide on as-PhenyEmethyt~ydr~z~e.-In CL,H,,N2I requirels I=43-48 per m t . ) 1212 SINQH STUDIES IN SUBSTITUTED QUATERNARY BZOWIUR'I this reaction the corresponding azolnium iodide could not be obtainetd but ammonium iodide was isollatetd (Found I = 87.87. Calc. I=87*6 per cent.). A ction of Propyl Zodde om as-Phenylpropylhydrazine.-In this reaction also the colrrespoading azonium compound (namely, phenyldipropylazonium ioldide) could not be1 obtaineid butl at small quantity od ammonium iodide1 was isolated.dl -Ph eny 1 e t h y lailly la z o niqi T n Zodide PhE t (C,H,) (NR ) N I. Ally1 iodide (5 grams) was a d d 4 to one molecular proportion of us-phenylethylhydrazine dissolved in ethelr and cooled in ice. The1 mixture was kelpt overnight when a gummy substance was deposiiwd which holweves solidifield oln rubbing. The orude pro-duat (2.4 grams) oln recrystallisatiotn from alcohol and either, separateld in collolurless prisms mellting and deoolmposing a t 107-108O. The salt acquires a viollelt. cololur at about looo (Found I =42-09. The corresponding platirziclzloride is obtained in the usual way, as a pale orange prelcipitate consisting of prismatia needles melt-ing and decomposing a t 1510.Itn is very sparingly soluble in oold methyl alcoholl but morel readily so in hot and insolluble in water, acettone ethyl alcohol benzenel olr ether (Found Pt = 25-71. (C,,H17N,Cl),PtCl relquirm Pt = 25.62 pelr oent.). C11R17N21 requires I = 41.78 per cent .). as-Ph emy laL l y lk ydra zin e P h ( C3H ,) N NH,. This is prepared in the usual way by dissolving sodium in a finely divided granular conditioa in pheaylhydraxine and treating the reisultJng sodium phenylhydrazine with ally1 bro'mide (Michadis aad C1a8essen Ber. 1889 22 2234). The secondary hydrazine is however beat purified by leiading hydrogen chloride into a chloroform solution olf the base.as-Phelnylallylhydrazine hydrolchlolride meltsl a t 149-150° and nolt at 137O as stated by Miahdis and Claessm (loc. cit.) (Found C1= 19.76. Calc. : C1= 19.22 per c,ent .). dl - Ph eny l b e n z y lall y laz o m k m ZdXe, Ph(CR,Ph>(C,H,>(NH,)NI. An icecold &hereal solutlioln of as-phenylallylhydraxine (1 9.5 grams) was added to one molecular proportion of belnzyl iodide (36.0 grams) also cooled in ice. Within a short timel oolourless prisms began to1 delpoeit. The mixture was kept overnight. an COMPOUNDS CONTAINING AN ASYMMETRIC NITROGEN ATOM. 1213 the crude substance (27.5 grams) melted and decompowd a t 115-1 16O. On recrystallisation from hot 'alcohol the tempera-ture of decomposition was raised to 116-1l'iO.The substance is very readily soluble in meithyl alcohol less so1 in ethyl alcohol very sparingly so in water o r benzene and insoluble in ether (Found: I = 34.89. C,,H,,N,I requirm I = 34.67 per cent.). Ph en y l b enz y lally laz miti m d - CampJa or- P-sulph onat e, Ph( CH,Ph) (C,H,) (NR,)N-SO,*C,,H,,O. Finely powdered azolnium ioldide (23 grams) was added in small quantitiea a t a time to one molecular propo;rtion of silver 6-camphor-P-sulphonate contained in a mortar. The mixture was triturated thoroughly in the prwnce of a little methyl alcohol in the cold in ordelr to1 einsurel complete double d-ecomposition. It was repeatedly elxtraetecl with methyl alcohol and o n evaporating the1 solveat by blowing air throlugh the mixture 18.1 grams of the camphorsulphonats (theoretical yield 29-6 grams) were obtained.It is very reladily solluble in methyl alcohol ethyl alcohol or acetone less so in ethyl aoetak or water sparingly so in belnzene, and insoluble in ether. d-Phenylb enzyla llylazonkim d-Camphoa- fl-sulpholnat e . The crude camphorsulphonaba (24.3 grams) as obtained in the above way was subjected to fractional oryst'allisation frolm methyl alcoihol and elthelr. The1 pure salt? dBdA melting a t 147-148O and having a colnstant rotatory potwelr was obtaine'd with great elasel. As t;he rotatory polwer of khis salt varies colnsidelrably with t'he nature of the1 solvent the effect od this was s t a d i d on the fraction of constant rotatotry power : Solvent. Ethyl alcohol ...... 9 9 9 9 9 9 Methyl alcohol.. .... 9 7 . Chloroform ......... 9 7 9 9 Water ............... Time. Aft,er 54 hours. Y 9 22 Y ) Y 9 514 1 , 3 7 219 1 9 ,* 96 ,. (Solution slightly coloured. ) After 33 hours Y ) 47 9 7 ----Substance. Gram. aD* 0.1143 +0*78" +319.2' - 0.74 302.8 - 0.72 294.6 - 0.62 253.8 0.0645 0.394 28.5-7 - 0.35 253.38 - 0-30 217.5 0.0971 0.55 265.0 - 0.53 255.3 - 0-51 245-7 0.0983 0.40 190.3 As tthel a,que,otus sol!ut8ioln became turbid on heping no further The1 mean tempelrature ot all the above readings could be takein 1214 READ AND HOOK THE PREPARATION AND olbseryations was 27-29O. There is a mmkeld mutasoltcifion in the case of melthyl aloolhol and ethyl alcohol bui; i t is much less in the ca'se od chloroform (Foand N= 6.28. C,,H,O,N,S requires N=5-96 per cent.). THE CHEMICAL LABORATORY, GOVERNMENT COLLEGE, LAHORE PUNJAB INDIA. [Received July 20th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701202

出版商:RSC    

年代:1920

数据来源: RSC

摘要:

1214 READ AND HOOK THE PREPARATION AND CXX XI1 .-The Preparation and Characterisation Xth ylenebromohydrin . of By JOHN READ and REXFORD GEORGE HOOK. ACCORDING to the1 somewhatl scanty relferences available in the literature it appears that eithylenebrolmohydrin h a hitherto been prepared only in an impure colndition. This remarkable fad in the case of so1 simple a substance is to be attributed not so much to instabiliby as to the nature of ths preparative metholds adopted Thus in the older meithods ethylene glycol was utilised as the startr ing point the second reagent being either ethylene dibromide (Lourenp Ann. Chzm. Phys. 1863 [iii] 67 275) hydrolgen bromide (Henry Jahresber. 1872 304) or phmpholrus tribromide (Demole Ber. 1876 9 48) ; whelreas more rejeelntly application has beein made of the interaction of elthylelneioadohydrin and brolmine (Henry ibld.1889 1321) and the direct additioln of hypobromous acid to ethylene (Mokievski J . Rziss. Phys. Chem. SOC. 1898 30, 900). Of the principles involved in these methods the last is undoubtedly to be preferred as least liable1 to1 give rise to impurities in the resultant ethylenebromohydrin and the advanoe which has lately been made in the experimental application of this principle (Read and Williams T. 1917 111 240; this vol. p. 359) has now enabled us t o undertake the preiparation of pure ethylenelbromo-hydrin in quantity. At the same time further study has bem directed to the course of the reaction between ethylene and dilute bromine water the investigation being facilitated by the oibservs-tion that as anticipated the amount of brolmohydrin formeld dunng definit\e intervals may be wtimated wit,h sufficient accuracy by a titrimetric determinatJon of the accompanying hydrogen bromide, produced in accordance with the folllolwing scheme! : HOH t Br HOBr + HBr -+ J.C,H4Br2 C,HE,Br*O CHARACTERISATION OF ETHYLENEBROMOHYDRIN. 12 15 The results indiaate a remarkable preponderanoe of bromohydrin in the initial stages of the reaction; thus when the concentration of brolmohydrin has reached 0*2N the molecular ratio of ethylene-brolmohydrin to ethylene dibromide is aboatl l O l and in more dilute solutions the value is still higher. 'The characteristics of the pure ethylenebroinolhydrin now obtained differ markedly from the data recorded by previous observelrs the density at 20° f o r instance being 1.7629 as compared with the value 1.7195 a t 18.6O given by Henry (loc.c i t . ) . I n view of the specifia interest of this substance as a simple derivative of ethyl alcolhol and of its general potentialities as a synthetic agent it seemed important to establish its main physical and chemical characteristics and the present paper records some of the results of inquiries directed tolwards these ends. E x P E R I M E N T A L. Yreparati,on of Pure Et hylenebromo hydrin. Bromine vapour and ethylelne were passed into 1500 C.C. of dis-tilled water under the1 conditions described previously (T. 1920, 117 359) the operatlion being continued for several days until 450 grams of bromine had reaoted.The\ rate of absorption of the bromine which was slow at first increased appreciably as the reac-tion progressed. Ultimately the liquid was neutralised in the cold by the1 addition od sodid sodium carbonate and the aqueous layer was separated frolm ethylene dibromide. The latter of which nearly half the total yield had volatilised in the course of the experiment, was shaken once with water in order to extract dissolved broma-hydrin and dried over calcium chloride; the yield amoanbd to 80 grams. The amount of hydrogen bromide produced in the reac-tion estimated by titration with standard silver nitlrate solution, corresponded with 35 per cent. of the bromine addeld and thus indicated it 70 per oent. yield of ethylenebromohydrin. I n order t o alloiw of the eventual recovery of the bromine present a.s bromide, the aqueous solution was saturated a t tlhe ordinary temperature m ith anhydrous soldium sulphate rather than with sodium chloride or calcium chloride.Extraction of the bromohydrin was acxom-plished vith three successive quantitiels of 250 C.C. of ether and after drying over anhydrous sodium sulphate the ether was expelled on the water-bath. Repelated distillation of the residual crude ethylenebromohydrin (180 grams) under atmospheric pressure demonstrated the impraa ticability of effeoting an adequate purification by suoh a method 1216 READ AND HOOK THE PREPARATION AND The results were however of intle8rest aa throwing some light upon the varying boiling points ra.nging from 1 4 7 O tlo 155O recorded for this substance by earlielr investiga,tors.On distilla.tioln the tem-pe'rature rose gra'dually to 145O and thel bulk of t,hel liquid distlilled bet8weeln 145O and 1 50° although distilla.tioln was incolmplete ewii atl 155O. The dist.illat'es welre pa,le yellow and t'he residue dark brown a.nd an appreciable1 a.mountl od hydrogeln bromide was pro-duaed during t,he distilla,tion. A f t8er setvera,l redistillatioas the purest mat'erial o1bt~aine.d in this. way distdlled beltwe,en 146O and 150° (n 1.4925; DY 1.7655 vacuum standard). On dilutiorn with wa,t,er to 60 per cent. strengt,h a slight opalescelnce appeared whilst a!i 50 per cent. a distinct second phase d l e d e . d and this persisted on further dilutdoln. ,The secolnd phase a t 35 per cent. had nEo 1.496 a,nd Wafs sholwn to contlain ethylene dibromide.The purest et,hylenelbrolmohydrin obtainable by t'his method thus contlains bolth et,hyle,nel dibromidei aad hydrogen brolmide as well as tlra,ces oif w ahr. By coin ducti ug t .h e d i s ti1 1 a-t ion ol f the crude e t 'hy 1 e,n eb r om olh y d ri n undelr diminished prelssure however these1 impurities are readily edimina,ted. After t'hel original reimoval of t'hhei et'her a lit& pure, sodium c:a#rbonat,e is a.dded if necessary to1 colrrect any acidity and on distilling under diminished pressure1 a sharp delimitatlon occurs bet4ween the portion of lolw boiling point and t'hs main fraction. I n three different prepa.rat,ions the la~t~ter boileld smoothly and con-st,aatdy at! 53'5O/14 mm. 54-'5O/14 mm.a'nd 48*5O/13 mm. respeo-tively and no1 cololur was delveloped during the distillation. The) pure substance is neutlral t801 litmus and gives no opalescence wheln diluted wit'h wa,tler olr silver nitra.te1 solut'ioln. As a rule one distil-lation under diminished preissure yields a product conf o'rming to these crit,eria but someitimee a se.cond distillation is necessa,ry. The average prima.ry yielld ot pure! ethylenebrolmohydrin obt,a.inablel from 450 gra,ms of bromine in t'he ma'nne'r 0ut~1ine.d above is aboatl 120 grams and furthe'r qua,nt,itiee may be elxt,ra.cted from t'he distillatto oif low boiling point and t'he original aqueous liquid. It may be mentioned t'hat the extlradJon with &her from the aqueous solu-tioln is rendered mom oolmplet,e by previously satarafing it wit.h sodium sulphate a,tl aboat.30° instea.d of ah the ordinary temperat-ture. Under such conditiolns a wcoad pha.sei consisting mainly of et,hylenebromohydrin separates frolm the solution concerned tba.t, is from an a,pproximat'ely 1.2N-solutdoin of ethyleinembromolhydrin cont'aining a,lso soldium bromide. This olbserva,tdon is in conf ormity with Golmberg's expelrieilzce with aqueous sohtio!ns of eShylenechloro. hydrin ( J . Amer. Chem. Soc. 1.919 41 1426). The volume of ethylene required in pra,ctice for this preparatioln amounts ac,coIrd CHARACTERISATION OF ETHYLENEBROMOHYDRIN. 121 7 ing to our apelrience; to be:tlween twice and thrice the oa.lculated quantity. Conditions affecting the Course of the Reactaon between Etltylene and Dilute Bromine Water.The efTect upon the course od t,he reaction utilised in the fore-going preparation of eert'ain factors which may be subjected to va;ria.tion ha.s been discussed in fo1rme.r colmmunicat,iosns (Zoc. cit.) ; supplemelnt8ary work of a qua,ntit,a.tdve nature has now been carried out in three! direations in order tot elstablish the influence upoln this process olf (1) concentmt'ion of the reaction-products (2) tempem-tme and (3) light(. (1) For the1 purpolse ot ascertaining accurately the amounts of ethylenebrolniohydrin pro'duced a t vasious st,ages of the rea.ct,ion, t'he delt,erminatJon from time t,o tJmel of hydroge,n bromide in an aliquolt partl of t'he reaction mixture1 proved to be satisfactolry. I n a control expe'rimeat bromine vapour was passed into 500 C.C.of u 4 e r undes the usual conditions the curreat of ethylenel being replaced by one of air; after an interval of seven hours during which al pale yehw tfintl had beein mainta.ined in the liquid the volume of AT/ 10-silver nitaat,e sollutJon required by 5 C.U. was less thaa one drop showing tha8t no1 me,a,surable decomposition of hypo-brolmous acid into hydr0ge.n brolmiclel and o,xygen had t'aken place under tlhe conditions adopted . 'In t'he succeeding prepara,t'ioas of eit'hylenebroimohydrin t'he cus-t'oma,ry proceldure wit9 observed elxcept t>hat t'he bromine was introc dumd in st'ages the a,mount used being det.elrmined in ela,ch ca,se by directl weighing. Atl the. e,nd of ea.ch st.age t.he liquid was stirred f o r ten minut'es aftle1r itl had become collo8urless and 5 C.C.oQ t\he liquid wa.s t8heln withdrawn and tltrated with st,a.nda,rd silver nitlrat4e sodutioln. Some1 of the1 resulta of t.wol inclelpendent setlies od elxperi-melnte are tabulafed beloiw. The cadculations tlake into account the chaages in vollume which occur throaghout the process but it was consi.dereld unnecessa,ry t,o apply a co1rre:ctioa f o,r the slight loss of brolmine by dif€usioin. The original volumeis of wa.t8er used were 530 C.C. and 550 U.C. re,spectively and in t,he secolnd selries a highe,r fina.1 coacent8ra.t'ion was a.ttained t,ha,n in the first) series. The two seats olf results a.re instruatIve as illustrating the order of the numeri-cal di'screpancies which may ocmr in determinations of this kind.It' should be added tha.t the t8emperature of t,he solutioln which was icemmled varied froom a.bout 7 O t o go and thab the expelriments were conduoted in diffused daylight 1218 Stage. 1 2 5 8 12 1 2 4 7 10 15 These READ AND HOOK THE PREPARATION AND Percent age Total of total bromine bromine Concentration of Total present as reacting ethylenebromohydrin. present +HBr C,H,Br*OH Grams per (grams). (grams). +HBr. litre. Normality. bromine C2H,Br'OH t o form -4.26 12.95 52-56 100.66 160.44 4-00 12.10 51-36 97-67 167.90 230.41 4.05 95.1 11-85 91.6 44.02 83.8 76.73 76-2 11 1.00 69-2 Series IZ. 5.9 0.048 17.5 0.140 65-0 0.520 112.4 0.899 161.8 2-294 3.77 94.3 5.3 11.09 91.7 15.8 43.26 84.2 61.7 75.06 76.9 106.6 11 1.29 70.5 156.9 148.3 1 64.4 207-6 0.043 0.126 0.494 0.853 1.255 1-661 da.h show that the relative velocity of reaction between bromine and ethylene and hypolbromous acid and ethylene respec-t i d y is displaaed to1 the advantage of the former relaction as the products accumulate a relsult which is probably connected with the great difference in solubility of ethylelne dibromide and ethylene bromolhydrin and the separation of the dibromide as a distinct phase.Nokwithstanding the change which has just been noted bhel molelcular ratio of bromohydrin to1 dibromide (which in the first stage was about 20 1) remained greatelr than unity througholut the range of concantrations invwtigated. By plotting conoentratiolns of ethylenebromohydrin in terms sf normality factor (2) against the correlsponding percentages (y) of bromine reacting ta form ethylenebromohydrin and hydrogen bromide a regular mrve is obtained (Fig.1) the major portion of which is alosely dsfineld by two linear equatlions namely, (i) y = 94-37 - 20.482 and (ii) y = 89-99 - 15.472. These equations embrace respectively the portions of the curve corresponding with (i) cr:=0*125 to 0.853 and (ii) 2=0'853 to 1.661. The approximate yield of ethylenelbrolmohydrin obt,ainable frolm a given amount of bromine over this range od colncentrations is thus capable of ready calculation. Attention was also directed to the rate of absolrption of the bromine in these eixperimente; this was found on the whole to increase with the concentration of the solution although irregulari-ties were1 noticed.Twenty-one successive polrtions of 8 grams o CHARACTERISATION OF ETHYLENEBROMOHYDRIN. 121 9 bromine took the following respective times expressed in hours for complete absorption when introduced with elthylene under the usual coditdons int'o a volume of water originally melamring 530 0.0. 1.9 1.6 1.6 1.1 1.1 1.1 1.2 1.0 0.9 1.1 1.1 1.1 1.3 0.8, 0.8 0.6 0.5 0.5 0'5 0-5 0.5. The gradual acceleration in .the ratel of absorption may perhaps be ahtributed to an enhanced solvent action of the brolmolhydrin solutions on the ethylene that is to a progressive increase of the molecular concentration of this reagent. I n othelr series of experiments t'he corresponding times were noticeably differelnt and i t seems possible that the acceleration or retardation was due to the presence of small amounts of foreign su bst ances.(2) I n order to1 telst the influence of temperature on the1 react3ion FIG. 1. Concentration of ethylenebrornohydrin (N). it wa.s conducted af 35O after a preliminary control experiment ha.d beleln ca,rried out atl the same temperatsure according tcm the prinoiple indicated above. A constant volume of 250 C.C. was maintalned throughout the expelriment water b&ng added to repla.cel the1 loss by evapomtion. The volume of N / 1O-silver nitrab solution required by 5 C.C. of tlhe liquid after the control experi-ment ha,d beeln continued f o r four ho,urs was 0.08 C.C. Thus at 3 5 O t h r e appeass t801 be a very slolw decomposition of hypobromous aaid intIo hydrogen bromide and oxygen and a corresponding corrdoln was introduced.Itl was also foiund nelceasa(ry when working at t'his tempera,ture to apply a correction for the loss of bromine by diffusion which amounteld to 1.20 grams in the control experiment. On passing bromine vapofur a,nd elthylener into 250 C.C. of wate 1220 READ AND HOOK THE PREPARATION AND under the conditions of the coatlroll experiment the! amount of bromine ut,ilised in the prepa,ra.tion od a 0*437N-solutdon of ethylenebrolmohydrin waa 28.2 gra,rns aft,er correcting for the loss by diffusion. Of this a,moluntt 62 pelr cent. rea.cted to form ethylenebrolmohydrin and hydrogen brolmide as compareid with 85-4 per cent,. reacting in this way for the same concentmtion in the ioe-cooled so~lutim.The time taken was 14.5 holurs the correl-sponding time at the lowes blrnpera,ture being 10.0 hours. It is themfore apparent thah by raising the telmpejratare t8he rea.ction takes place more slowly and tha8t at tlhel mrne time t,he molecular ratio of ethylenebromohydrin to ethylene dibro,mide is materially lessened. The effects just noltiaed were aocentua.ted at still higher t,empera-tures but olwing t,o the considerable loss od bromine by diffusion at tempelrafares much above 35O quantitative examinafion was rein-delrefd difficult in such cases. From further experiments to be described below the second effect is somewhat moire1 pronounced tha,n indicated by the above figures which take1 no account of the slow hydrolysis of ethylenebromohydrin occurring in warm aqueous solutbolns.The slower rate of re'acltion bet!weleJn et,hylene and brolmine: wa;telr in warm sollutions is probably to be attributed t'ol the diminish-ing sollubility of elthylene i n wa,telr as the tempeaat'ure rises. (3) I n the additioa olf hypochlolrolus slid hypolbromous acids t'oi unsa,tnrated 'subst'ances it ha.s usually belein assumeld t.ha,t t,he rea,o-tion is famured by coaduding t.he olpesation not only a.t a low ternpera,tnre but1 also in diffused light or prefe'rably in the dark. It was therefore of interest to investiga.te the influence of light upon the additive rea,ctioln beltween hypobrolmous acid and ethylene. I n the short series of experimsnts summarised below the icecoolled water (530 c.c.) was exposed to direct sunlight during the passags of t'he bromine vapour a.nd ethylene and the prolgress of the reae t i o a was fotlloweld in the ma.nner a h a d y desmibe'd.The result of a control experimeint indica.ted t,hat8 no a#pprecia,ble decolmpwitioa of hypobrolmous a.cid t,ook place undelr tlhe colnditioins laid down. Tohl bromine present Stage. (grams). 1 4-12 2 12-38 3 20.35 4 36.59 Total bromine present as C,H,Br-OH + HBr (grams). 3.81 10.97 17.80 30.75 Percentage of total Concen- bromine reacting to form C,H,Br'OH + HBr. bromohydrin In diffused ( N ) . In sunlight. light. 0.045 92.5 93.5 0- 130 88.6 91.7 0-2 12 87.5 90.0 0.368 84.0 86.8 tration of ethylene - 7-From t,he last two columns od t8he table it is seen tha.t the values obtlaineld in this eelriels of experimelntg for the molecular rafioi o OHAEAaTBRISATlON OR’ ETaYLlCNEBROlKOEYDE.1221 ethylenebromohydriin to ethylene dibromide are slightly lower than the values corresponding tvit,h the original conditions; the differ-en= howev~ are not marked. The time taken for the absorption wa,s 2.75 hours whkh is appreciably less than m y oorresponding period observed for an experiment mnduated in diffused light. On the whole therefore the rather reanarkable mndusion is reaahed that sunlight exerts an advantageous rathex than a detrimental influence upon the additive reaction betwean hypobromous acid md ethylene. Phyikal Properties of Pure Ethylenebromohpdrh. Ethylenebromohydrin is a collourlm mobile liquid miscible with watai- in all proportions.Demole’s statement ( 1 ~ . cit.) that it is only sparingly soluble in water indiaateg contamination with ethylene dibromide. The solubility in water dear- conaiderably in the presence of wrtain salts such as f o r example sodium chloride calcium ohloride and sodium sulphate. The a q u m solu-tions possess a sweet burning taste. The vappur of the pure sub-stance or of its aqueous solutions down to about 5 per cent; strength produoea a painful imtation of the eyes and nostrils shortly after inhalation. Ethylenebromohydrin diwlves readily in most of the common organic solvenh but forms a distinct phase when added to light petroleum. It distils unchanged under diminished pressure at the bmperatures noted above; when the pure mbstance is heatad under latmmpherio prwsure however it darkem 89 the temperature approach= the boiling point and decomposition ocmrs with the production of hydrogen bromide.Distillation commenoe8 at about 150° but the tempexature fluatusrtes and the boiling point is indefinite. The refractive index of several specimens was determined with the AbM refraotoaneter at 20° for the D line; the resulte were prautically identical the mean value being 1.4915. When the liquid was exposed for a few seconds on the p h this value sank in a typical instance to 1.479 ; this observation illustrates the pronounced hygrosoolpioity of ethylene bromohydrin. The observed mo1eoula.r r e f r d v e power at 200 wae 34.84 which stands in olme agreement with the d c u l a t d value 34.76.Determinations of specific gravity (reduced to a vaauum) were as follows : DS 1.7902 Di6 1.7696 Dfo 1.7629 I)? 1,7660 Q” 1.7494. The mean d c i e n t of dilatation between Oo and 30° oalaulated from the dak obtained in the above determinations is 0’00078. VOL. UXVTI. z 1222 READ AJXD HOOK THE PREPARATION AND The Belationship between the Refractive ZT&X and t h e Concentra-tion of Aqueous SolzLtions of Ethylenebrmohydrin. It has been shown by Irvine that measurements of refractive index provide a rapid and convenient method for the debrmination of the approximate strengths of aqueous solutions of ethylenechloro-hydrin; the method has also been adopted with useful reeults by Gomberg (Zoc. cit. p. 1418). For this reason and also in view of certain interesting thermal changes and related phenomena whioh ocou~ during the dilution of ethylenebromohydrin with water it was considered advisable to undertake a refraotometrio examination of a series of aque~us solutions of this substance.Soluticms of different concentrations were made by direct weighing of the con-stituenb and in each case the refraative index was determined with the Abb6 instrument at 2O0 for the D line. Some of the observa-tions are tabulated herewith: Percentage by weight of ethylene-bromohydrin. 100~000 96.340 90.032 80.007 72.201 60.686 53.620 nE* 1.4916 1.4801 1-4671 1.4464 1.4299 1-4096 1.3980 Percentage by weight of ethylene-bromohydrin. 49.179 40.372 30.999 22.441 18.810 10*010 3-361 0 (weter) n:.1.3916 1.3790 1.3667 1.3661 1.3517 1 *3422 1.3368 1.3330 When the whole of the data are representad graphically the resulting points lie on a regular uurve which d m not approximate to a straight line (Fig. 2). The character of the curve indicates that the refrautive index of aqueous solutions of ethylenebromohydrin ia always less than the value calculated from the admixture farmula, that is on mixing ethylenebromohydrin with w a k there is a am-traction in volume. It is also to be observed that the value of the refraotive index does not pass through a maximum as in the c888 of ethyl alcohol (Doroschevski and Dvorschantschik J . Russ. PhtyS. Chem. SOC. 1908 40 908). It is evident that the above curve furnishes a ready means of determining with close amuraq the concentrations of aqueous solutions of ethylenebromohydrin.The Distitlation of .d pueous Solutions of Ethylenebromohydh. From the gaieral characteristi= of ethylenebromohydrin it seemed probable thab its dilute aqueous solutions such as are obtained in the method of preparation outlined above might b CHARACTERISATION OF ETHYLENEBROMOHYDRIN. 1223 concentrated by fractional distillation. In order to test this point, solutioiIls of known strengt'h were submitted t s this operation the various fra,ctions being etxamined refraotome~trically. I n the case of a 5 per cant. solution a first fractioln containing 3 per cent. of ths t(otla1 bromohydrin had a concentration of 12 per cent. The concentrations of succeeding f ractions were lower ; when 20 per cent#.od t'he total bromohydrin had beleln collected the coaaentlra4tion of the next few drops of distillate was 9.5 per centl. and after the collleiotion of 50 per cent. the corresponding value was 7.0 per cent. FIG. 2. Percentage by weight of ethyzenebromohydrin. The boiling paint was originally 100.0°/766 mm. and it rose eventually to 1O0*lo. The boiling point1 of water at the same premure is 100*22*. With al 30 per cent. solution a first fraotion containing 11 per wnt. of the tots1 bromohydrin had a concentration of 34.0 per cent. and when tiwwocthirds of the total bromolhydrin had passed over the concentratlioln olf the next few drops of distillate was identiaal with that of the original solution that is 30 per cent. Meanwhile, the boiling point had risen from 99.0° to 99.4O; the barometric height was 768.5 mm.oorreeponding with a boiling point of 100.31O for water. 2 2 1224 READ AND HOOK THE PREPARATION AND Them observations suggested that ethylenebromohydrin forms a mixture of constant boiling pointl with water atq a concentration in the vicinity of 34 peir oeat. A similar distillatlion olf a 34 per cent. solutioln confirmed this conclusion the actual concentration oaf the constanbboliling mixture being 35.0 per cent. as is evidelnt from the fo'llolwing t'able : Fraction. 1 2 3 4 6 6 7 8 residue Boiling point. 99.1 99.1 99.1 99.1 99.2 99.2 99.2 99.5 -Weight of fraction (grams). 0.90 2.06 2-96 3.22 3.38 3.44 4-24 4.35 6.11 ,).&'LO 1-3718 1.3720 1.3717 1.3717 1.3716 1.3714 1.3708 1.3700 1.3700 I).Concentration Percentage per cent. of of total bromohydrin ,bromohydrin in fraction. in fraction. 35.1 3.0 35.2 6.9 35.0 9-43 35-0 10.7 34.9 11-2 34.8 11.3 34.3 13-7 33.7 13.9 33.7 19.6 The colmtlantl boiling point1 olf a 35.0 per cent. aqueous sollution of ethylenebromolhydrin is therefore 99*l0/ 762.4 mm. the drrwpond-ing boiling point ojf water baing 100*06°. The residue frolm the above distillation possessed a faint yellow colour and was distinctly acid ; titration with standad silver nitrate solutioa showed that it, mntlained 0.1491 gram of hydrogen bromide evidedy produced by partial hydrolysis oC tlhe bromohydrin during the distillatioa.The distillatw contained a mere trace of the acid and tlhus t!ha percant-age amolunt of the total bromolhydrin hydrollysed in the course of the operation was 2.2. Very interesting results were olbtlained by distilling more con-centrahed sollutiolns of the bromohydrin and a typical series of data is aooordingly summarised bellow f o r the case of a 74.9 per centl. wlutlion. The barolmetric height was 755 mm. corresponding with a boiling point od 99-82O folr water. Concentra-tion per Percentage Fraction. Boiling point. (grams). n:". hydrin. in fraction. 1 99.5O 1-0s 1.3798 41.0 3.0 2 100*0-101~0" 3.03 1.3838 43.9 6 1 3 101~0-102*8 3.70 1.3550 47.0 8-0 4 102*8-109*1 3.84 1.3982 53.9 9-6 5 109.1-137.0 3.81 1.4332 74.0 12.9 6 137.0-147.4 4.51 2.4840 97.0 20.0 7 247.4-149.0 5.26 1.4912 99.9 24.0 residue - 3.83 1.4905 99.7 17.5 Weight of cent.of of total fraction bromo bromohydrin When concentrakd aqueous solutdons of ethylmebrmohydrin a m distilleld the watles thus passes over in thel initia,l stages of the opem tioln and evsntlually almost pure bromohydrin distils. In th CHARACTERISATION OF ETHYLENEBROMORPDRIN. 1226 experiment desmibed it was ascertained by titration that 0.9 per cent. of the total bromohydrin present wa8s hydrolysed during the distillatioln. Of the hydrogen bromide formed it is interesting ta notl@ that 5 per cent. remained in the distlilling flask and 5 per mnt. was present in fraction 5 ; the bulk was found in fractiolns 6 (60 pm-cent.) and 7 (30 per cent.). As fractions 6 and 7 thus contained 1.7 and 0.7 per cent.of hydrogen bromide resps~t~ively the purity was distinctly lowejr than indicaked by the redractive index. From these investigatiolns it is seen that dilute aqueous solutions of ethylenebrolmohydrin might bo concentlrateld by frahonal distilla-tion but that in dealing with large quantitim of such solutiolns the loss by hydrolysis would be considerable. This objectionable feature could be partly eliminated by conduoting the distillation under diminished pressure. The Hydrolysis of Ethylenebromohydrin. The slight decomposition nohiaed during tlhe distillation of aqueous solutions of ethylelnelbrolmolhydrin seemed to indicate a greater susceptibility of this substance towards hydrolysing agents than is exhibited by etlhylenechlorolhydrin and accordingly further observations were made in ordelr to sekitle this point.In the first place when aqueolus solutions of ethylenebrmohydrin of wnmntrations ranging from 95 per cent. t o 3 per cent. were prepared and examined a t regular intelrvals no decomposition m l d be e&ablished until several weleks had elapsed. As a typical example a 50 per cent. solution after remaining for a month a t the ordinary temperature had developed a perceptible content of hydroc gen bromide corresponding with the hydrolysis of about 0.3 per cent. of the bromohydrin originally present; in the same period the refra,ctivei indelx had deolineid by 0.0007. With a 3 per c a t . solution the amount hydrolyseld in the same time approached 1 per cent. of the bromolhydrin and in general this very slow hydrolysis was most apparent in dilute solutions.At higher temperatlures the velocity of hydrolysis in aqueous solutioln was much accelerated ; on boiling a 6.25 per cent+. solutlion for thirty minutes under reflux, 19 per cent. of the bromohydrin was hydrollyseld and in ninety minutes 44 per cent. was hydrolyseld. Silver nitrate produced no immediate reactJon with cold aquemu solutions of the bromohydrin but in dilute sohtions an opdwnoe developed after fifteen or twenty minutes and quantitative estima-tiom made after longer intervals showed that the hydrolysis had undergone appreciable acceleration. Seaing that ethylenebromohydrin is prepared in acid solution it was of interest to ascertain the effeet of acid on the rate of hydro 1226 READ AND HOOK ETHYLBNEBROMOHYDRIN.lysis. A 1*8N-solutJon of hydrochloric acid containing 9.0 per cent. of ethyleinebromohydrin wits examined twenty-four hours after being prepared butl no pera&ptiblel hydrolysis hamd occurred in the mld. By boiling this solutioln folr thirty minut,es 51 pelr cent. of the1 brolmohydrin was hydrolpsed t>he prelsence of acid having there-fore accelerated the reaction. It was t,ol be1 a,nticipat'eld thah alkadi would exert ,a muoh more pronounced a8cceleratiolii tha,n acid a.nd in fa.& a 4.5 per mnt,. solut,ion od etlhylenelbromohydrin containing aBofut two equivale:nt proportlions of potassium hydroxide was hydrolyseld to the1 extent of 47 per centl. whe,n a,lTolwed to rema'in at the olrdinary tampera.ture for thirty minutes.By boiling a similar solution for thirty minutes 97 per cent. af the bramohydrin was hydralysed a.nd ninelty minutels' boIling broaght aboutl complelta hydrotlysis. Lastly an analysis olf a pure specimen of ethylenebrolmohydrin by alkalline hydrollysis may be quote'd 0.2935 gram after boliling for ninety minut,es with a.n excem of sodium hydroxide solution, required 23.5 C.C. of A T / 10-AgNO,. Br = 64.0. Cadc. Br = 64.0 per cent. Sunzmary . 1. Pure elthylenebromohydrin has been prepamred in .quantity by the action of codd dilute bromine water oln elthylene this method having been found preferable to1 a.ny other which has been described f o r the purpose. 2. I n t.he abwe reaction t'he mollecru1a.r ra.t,io of ethylenebrolmoL hydrin to ethylene dibromide detmeases colntlinuously with imreasing concentmtbn of ethyleaelbrolmohydrin a'nd hydrogen bromide in the solution aad a.lsoi with rise of telmpera.turei but ita is nolt influenced markedly by sunlight. The reaction is haatened by cooling or by exposure to1 sunlight. 3. The main physical chasacteristics of ethyledxomohydrin and also the relationship beltween the conc;entrat,ioln and re;fra,otive indelx of its aqueous solutions haw been est'ablished. 4. Ethylelnebrolmohydrin and wat4er form a mixtare olf mutant. boiling point (99.1°/762.4 mm.) a.t a conaelntra.tion of 35.0 per cent!. 5. Et,hylelnelbromohydrin is hydrollyseld mom reladily tha.n ethyle\nechlorohydrin. I n colld a.queolus solutions tqhe hydrolysis is percelptiblet alt'hmgh extremely slolw ; it' is greatly accelerat,ed by he,a,t also by the prersenm of acid a#nd notably olf alkali. DEPARTMENT OF ORGANIO CHEMISTRY, UNIVERSITY OF SYDNEY. Cognate inve&gations ,are in progress. [Received ~4ugust 30th 1920.

ISSN:0368-1645    

DOI:10.1039/CT9201701214

出版商:RSC    

年代:1920

数据来源: RSC