摘要:

346 SENTER: REACTIVITY OF THEXXX1X.-Reactivity of the Halogens in Organic Corn-pounds. Part I I? I n t e r a c t i o n of Rromoacetic,a-BrornopropiorLic, and a-Bromobutyric Acids andtheir Sodium Sults with Silver Salts in A~UL'OWSSolution. Cutalytic Action of Xilvey* Halides.By GEORGE SENTER.IN previous papers (Trans., 1907, 91, 460; Proc., 1908, 24, 89;Arrhenius Jubelband, 1910, 11, 511; Trans., 1909, 95, 1827) theresults of an experimental investigation of the rate of displacementof the halogens in the lower members of the series of halogen-substituted fatty acids have been communicated, and the mechanismof the respective reactions has been discussed. The present paperdeals mainly with the interaction of the first three members of theseries of a-bromo-fatty acids and their sodium salts with silvernitrate and silver acetate in dilute aqueous solution.It was shownmany years ago by Beckurts and 'Odd0 (Ber., 1881, 14, 576; 1885,18, 222) that the reaction between silver nitrate and the lowermembers of the series of bromo-fatty acids in aqueous solutlion isrepresented quantitatively by the equation :R*CHX-CO,H + AgNO, + H20 =R*CH(OH)*CO,H + AgX + HNO, (I),in which R represents hydrogen or an alkyl group, and X a halogenatom.In the course of the present investigations, the remarkableobservation was made that reactions of the above type are verymarkedly accelerated by silver bromide; even when the solutionis only 1/300 molar with reference to silver bromide (which is, ofcourse, mainly present in the insoluble form), the rate of thereaction may be doubled or even trebled.This action appears toaccount for a number of hitherto unexplained observations madeby previous investigators.The other more important results of the investigation are thatthe rate of reaction increases very considerably with the increasein complexity of the alkyl group R, and that the sodium saltsreact more rapidly than the free acids. Nitric acid exerts a verypowerful retarding effect on the reactions in which silver nitrateis concerned. Silver acetate reacts with the bromo-fatty acids morerapidly than does silver nitrate under equivalent conditionsHALOGENS IN ORGANIC COMPOUNDS. PART IV. 347EXPERIMENTAL.Method of Measurement.-The reacting substances were mixed a tconstant temperature in small tubes of Jena glass, which werethen corked and kept in a thermostat a t a temperature keptconstant to within Omlo. A t definite intervals the contents of atube were poured into a slight excess of a N/50-solution ofammonium thiocyanate, which a t once stopped the reaction, 5 C.C.of a concentrated solution of iron alum and 5 C.C.of concentratednitric acid, free from nitrous fumes, were then added, and theexcess of thiocyanate estimated by titrating with N / 50-silvernitrate.It is known that the afbove method of titration does not giveaccurate results for chlorides, owing t o the solubility of the precipi-tated silver chloride in ammonium thiocyanate. Theoretically, how-ever, there should be no appreciable error in the case of bromides,owing to the much smaller solubility of silver bromide, and thisconclusion has been confirmed experimentally by Rosanoff andHill ( J .Amler. Chem. SOG., 1907, 29, 1467). I n order to ensurethat no error arises in the present case owing to the presence ofprecipitated silver bromide, the method of titration describedabove has been tested in various ways, and has been found to givequite accurate results.The tubes in which the reactions were carried out held about15 c.c., and in all cases the reaction mixture measured 12 C.C.The titration values quoted in the tables are throughout (exceptin table I) the mean of two simultaneous expeTiments. Themeasurements were made at 26'0O.Reaction between a-Bromopropionic Acid and Silver Nitrate.The results of a typical series of experiments with a-bronio-propionic acid and silver nitrate are quoted in table I.The unitof concentration is t,he amount of silver nitrate contained in 1 C.C.of a N J 50-solution of the salt, and the concentration of the halogen-fatty acids (and their sodium salts) is expressed in equivalent units,in accordance with the experimental fact that R*CHBr-C02H (andR*CHBr*CO,Na) is equivalent to AgNO,. The constants in thelast column are calculated according to the equation for a reactionof the second order:I x k=--when the reacting substances are present in equivalent amounts.I n all cases, a- x in the tables represents the concentration of thet 'a(a - x348 SENTER: REACTIVITY OF THEsilver nitrate a t the time t , as this is the substance which is actuallyestimated.I f it is desired to refer k, the velocity-coefficient or velocityconstant of the reaction, to a concentration of 1 mol.per litre, thevalues of E given in the tables must be multiplied by 12 x 50 = 600,since the values quoted are obtained by titrating 12 C.C. of thereaction mixture with 1 /SO molar thiocyanate.Throughout this paper, the concentrations given refer to thereaction mixture; thus, in the experiments quoted in table I, thereaction mixture was initially N l 3 0 with reference to boththe reacting substances.TABLE I.Silver nitrate, AT/ 30. a-Bromopropionic acid, N / 3 0 .t (min.). a-x. k. a - x. k.0 20.0 - 20.0 -10 18’1 0.00050 18.0 0*0005630 14’7 0*00060 14-7 0-0006090 10.2 0.00058 10’0 0’00056These figures show that the results of parallel experiments are ingood agreement, and the fair agreement of the velocity-coefficientsin the course of a reaction is in accord with the assumption thatthe reaction is bimolecular.It will be shown in the sequel, how-ever, that the latter result is only attained owing to il combinationof two factors which influence the reaction in opposite directions.It is well known that one of the best methods of deciding the“order” of a reaction is to measure its velocity with varyinginitial concentrations ; in this way disturbances arising in thecourse of the reaction are to a great extent eliminated. The resultsfor the reaction under discussion are given in table 11, the valuesof k, when the concentrations are not equivalent, being calculatedby the general formula for a bimolecular reaction :where the symbols have the usual significance.TABLE 11.Concentration of Concentration ofsilver nitrate.bromopropionic acid. k.N i l 0 N/40 0.00047N/20 N/40 0-00059N/40 N/40 0’00054N/20 N/20 0-00053N/20 N/10 0*00051The above results appear to show that, in spite of certainirregularities, the rate of the reaction is in the first instancHALOGENS IN ORGANIC COMPOUNDS. PART IV. 349proportional to the initial concentration of the reacting substancesthrough a range of concentration from N/10 to N / 4 0 in each case.It was soon noticed that when the aqueous solution of the acidwas not freshly prepared, the reaction was considerably more rapid.This is illustrated by the results quoted in the accompanying table.TABLE 111.Silver nitrate and bromopropionic acid, each N / 3 0 .(Acid solution, two hours old.)t (min.). a - x. k.0 20 .o -10 18.5 0.0004130 15.4 0 *0005090 10.5 0*00050(Acid solution, kept two days at 26".)t (min.). n-x. k.0 20.0 -10 16.4 0 -00 11 030 12.0 0.001 1190 8'3 0*00080It is clear that the initial velocity is nearly three times as greatwhen the acid solution is kept two days before the rate of reactionis measured.It is well known that a-bromopropionic acid is slowly decomposedby water, according to the equation:CHMeBr*CO,H + H,O = OH-CHMe-CO,H + HBr,and in an earlier paper the results of an experimental investigationof this reaction have been communicated.A little hydrobromicacid is formed during the reaction, and a t once reacts with partof the silver nitrate on mixing the reacting substances. As thespeed of the reaction is deduced from the rate a t which the silvernitrate is used up, the apparent speed in the presence of hydro-bromic acid will be greater than the actual speed with whichsilver nitrate and a-bromopropionic acid react. I n order toestimate the error thus caused, the rate of hydrolytic decompositionof bromopropionic acid a t 2Go has been measured a t 2 6 O with thefollowing results (table IV). The concentrations of bromopropionicacid and of hydrobromic acid are expressed in terms of the numberof C.C.of N/2O-sodium hydroxide required to neutralise 5 C.C. of thesolution, which was approximatelyTABLE IV.Concentration of HBr formed.Five C.C. of acidTime (days). solution titrated.0 19-703 20'106 20.359 20.6012 20'80The reaction at 2 6 O is thereforeI 3 In C.C. ofNJ20-NaOH. Normality.0'00 -0'40 0.0010'65 0-00160.90 0'00231.10 0.0028extremely slow, and the amoun350 SEPU'TER: REACTIVITY OF THEof hydrobromic acid formed is much too small to account directlyfor the results given in table 111.There would appear to be at least two plausible explanations ofthe results in question: (1) that the silver bromide formed inthe course of the reaction exerts a catalytic influence; (2) thatthe bromopropionic acid in aqueous solution undergoes a slowchange into a second more active modification. The first suggestioncan a t once be tested by adding some hydrobromic acid orpotassium bromide to the bromopropionic acid before adding thesilver nitrate. Some of the results obtained in this way are givenin table V.TABLE V.Composition of Mixture I.I Composition of Mixture 11.t (min.). a-2. k.0 20'0 -10 18 5 0*0004130 15.4 0~0005090 10.5 0.00050t (min.). n - x. k.0 20 .o -10 15.7 0.0018720 13 '3 0.0012640 10.0 0'00125The data in-the above table show that, after mixing, the twosolutions are exactly equivalent in concentration ; the only differenceis that in the second mixture a small amount of silver bromide(and potassium nitrate) is present. The mixture is only 1/150molar with respect to this salt, and doubtless the greater p%rt ofit is present in the insoluble form, yet the remarkable result isobtained that this trace of silver bromide more than trebles theinitial speed of the main reaction.Moreover, this by no meansrepresents the maximum catalytic power of the silver bromide, asthe greater part of it coagulates and rises to the top of the solutionsoon after mixing the reagents.Reference t o the data in table I11 shows that the solution ofbromopropionic acid, which had stood two days at 2 6 O , cannothave been more than 1/1000 normal with reference to hydrobromicacid, so that the small amount of silver bromide formed by inter-action of the acid with silver nitrate has a very powerful catalyticaction.The catalytic acceleration of reactions of this type by silverbromide and iodide is further referred to in a later part of thepaper (pp.357, 358)HALOGENS IN ORGANIC COMPOUNDS. PART IV. 351Effect of Acids and of Sodhm Nitrate o n the Reaction Velocity.( a ) Nitric Acid.-Nitric acid, even in very dilute solution, verymarkedly retards the reaction between silver nitrate and a-bromo-propionic acid. Some of the results, typical of an extended seriesof experiments on this point, are given in the accompanying table.TABLE VI.Silver nitrate, N / 2 0 . Bromopropionic acid, N / 2 0 .No nitric acid. Nitric acid, N/30. Nitric acid, iV/15. - - 7t. a-x. k. t. a-32. k. t. a-x. k.- 0 30.0 - 0 30.0 - 0 30.010 26.7 0*00041 20 28'0 0*000120 30 28'45 0.00006030 21'5 0.00045 60 25.0 0~000111 90 25.75 0'000062The figures show that in the presence of N/15-nitric acid therate of the reaction is diminished to about 1/7th of its originalvalue.( b ) Benzenesulphonic Acid.-For comparison with nitric acid,some experiments were made with benzenesulphonic acid under thesame conditions.It was found that the latter acid retards thereaction to a rather greater extent than nitric acid. The initialvalue of the constant in the presence of N / 15-benzenesulphonicacid is 0.000053, as compared with 0*000061 for ~'V/15-nitric acid.It is probable that benzenesulphonic acid is a rather strongeracid than nitric acid, but the difference in the reactivities seemsrather greater than can be accounted for on this basis.(c) Lactic Acid.-As lactic acid is one of the products of thereaction, its influence on the velocity was measured with thefollowing results :TABLE VII.Silver nitrate, N / 20.Bromopropionic acid, N / 20.No lactic acid.t (min.). a - 2. k.0 30.0 -10 26.1 0.0005030 20'4 0-0005380 14'9 0 '00056Lactic acid, NJ5.t (min.). a - x. k.0 30 +O -10 26-9 0 0003830 22.1 0.0004060 18'4 0'00036(d) Sodium Nitrate.-The results of a series of observations withthis salt amre given in the accompanying table; much higher con-centrations were used than in the case of the acids352 SEN'I'ER : REACTIVI'rY OF THETABLE VIII.Silver nitrate, N / 30. Bromopropionic acid, N / 3 0 .No sodium nitrate. Sodium nitrate, ml2.Sodium nitrate, mil. - - - t (min. ). a - x. k. a - 2. k. n - 5. k.0 20 -0 - 20-0 - 20 -0 -10 17'9 0*00060 18.3 0,00045 78.7 0*0003530 14.6 0*00062 15-7 0-00045 16-2 0.00039The facts that nitric acid and benzenesulphonic acid, which areboth highly ionised in solution, retard the reaction to about thesame extent, and that the NO,' ion has only a very slight reta,rdingaction, indicate that the effect in question is mainly due to theH ions. This is confirmed by the fact that lactic acid, which is acomparatively weak acid, has a very slight retarding action. Thebearing of these results on the mechanism of the reaction isdiscussed later (p. 361).Effect of Alcohol and of Acetone on the Rate of Reaction.A few experiments were made in which half the water used LCSsolvent was displaced by alcohol and by acetone respectively; theresults were as follows:TABLE IX.Silver nitrate, ZV/ 30.Bromopropionic acid, N / 3 0 .Solvent.. . Water. Water + alcohol. Water + acetone. - - c-0 20 '0 - 20.0 - 20 -0 -10 18.0 0-00056 17-5 0*00071 17'4 0.0007330 14.6 0.00062 13.9 0.00073 14.3 0-00067It is interesting to note how small an alteration is produced inthe reaction velocity by the displacement of half the water byalcohol or by acetone. It has already been shown by Euler (Ber.,1906, 39, 2726) that the rate of reaction between chloroacetic acidand silver nitrate is approximately the same in water and in 45 percent. alcohol.t (rnin.). a - z. k. a - x, k. a - x. k.Sodium Bronzopropionate and Silver Nitrate.The reaction in this case is represented by the equation :CH,*CHBr*CO,Na+ AgNO, + A,O =CH,=CH(OH)*CO,H + AgBr + NaNO,.The sodium bromopropionate was prepared just before thereaction by careful neutralisation of a solution of bromopropionlcacid with sodium hydroxide.The results of one series of experiHALOGENS IN ORUANIC COMPOUNDS. PART IV. 353ments, in which the relative activities of the acid and its sodiumsalt are compared, are given in the accompanying table:TABLE X.Silver nitrate, N/30. Silver nitrate, N/30.Bromopropionic acid, N/30. 1 Sodium bromopropionate, N/30.t (min.). a-x. k.0 20.0 -10 18-0 0.0005630 14'7 0'0006090 10-2 0 *00054t (min.). a - 5. k.0 20.0 -5 16.6 0'002015 11'0 0.002745 6 ' 4 0.0024The velocity-coefficients, k,, for a bimolecular reaction in thecase of the sodium salt are only in moderate agreement, a resultwhich is doubtless to be anticipated.The initial velocity is aboutfour times that obtained for the free acid. The considerableincrease of th6 coefficient between five and fifteen minutes is nodoubt due to the catalytic influence of silver bromide. A fewmeasurements were also made to determine the influence of theinitial concentration on the reaction velocity, with the followingresults :k. ......... Sodium bromopropionate, N/30 } 0*0020 Silver nitrate, 3/30 ........................Silver nitrate,:N/60 ........................ } 0.0030 Sodinm bromopropionate, N/60 .........showing that the initial velocity is the greater the more dilute thesolution.Bromopropionic Acid and Sz7uer Acetate.I f the conclusion drawn from the experiments already described-that silver bromide exerts a catalytic influence on the rate ofreaction-is valid, the velocity-coefficients calculated for a reactionof the second order ought regularly to increase, owing to theincrease in the amount of silver bromide as the reaction proceeds.However, nitric acid, another product of the reaction, exerts aretarding influence, and the result of these two effects is that inmany cases the reactions follow the law for a bimolecular reactionfairly accurately.In order to eliminate the retarding influence ofnitric acid, it was considered desirable to perform ilr few experimentswith the silver salt of a weak acid, and for this purpose silveracetate was chosen.The reaction in this case is represented by theequation :CH,*CO,Ag + CH,Br*CO,E + H,O =CH,*CO,H + AgBr + OH*CH,*CO,H.Some typioal results are quoted in table XI354 SENTER: REACTIVITY OF THEF?*esli B.r-omopropionic -4 cid.Bromopropionic acid, ~V/30. I Broiriopropionic acid, N/30.Silver acetate, iV/30. Silver acetate, N/lOO.f (mill.). n - x. Jc .0 20.0 -5 18.2 0 '001 0015 14.0 0'0014330 9-5 0.00186t (iiiin.). n -- 2. k.0 6'0 -10 4.75 0.0013030 2-75 0.001450-00156 60 0-70Bromopropionic A c i d (kept two days at 26O).Bromopropionic acid, NJ30. 1 Bromopropioriic acid, iV/60.Silver acetate, N/30. Silver acetate, N/30.t (min.). a - z . k.0 20'0 -5 16.8 0*0020015 10.5 0.0030730 7.6 (0.00272)t (min.).n - x. k.0 20-0 -10 16.5 0'0025030 12.8 0.00327It will be observed that in all these experiments t,he velocity-coefficients calculated for a reaction of the second order increasevery considerably during the reaction, doubtless owing t o thecatalytic influence of the silver bromide. The same effect is seenin the solution which has been kept two days, and in which, there-fore, a little hydrobromic acid has been formed. The very smallamount of silver bromide produced as soon as the two solutionsare mixed is sufficient t o double the initial speed of the reaction.This catalytic effect is also illustrated in the following table; inone case a small amount of potassium bromide is added t o the acidbefore mixing :TABLE XII.Silver acetate, N/25 ............Bromopropionic acid, N16.25.2 ,,Water .............................. 2 ,,t (min ). a-x. k.0 16.00 -5 14.20 OvO015810 12.40 0*0018120 9.65 0*0020630 7-00 0.002688 C.C. Silver acetate, NJ25 ............ 9 c.cRroniopropionic acid, N16.25. 2 ,,Potassium bromide, N/25 ...... 1 ,,t (min.). a-x. k.0 16.00 -6 11.30 0.0052010 9'80 0.0039520 7-00 0.00402These results indicate that 1/300 molar silver bromide morethan trebles the initial speed of the reaction, but that the velocityfalls off somewhat as the reaction proceeds. This is doubtlessconnected with the fact that the greater part of the silver bromidesoon coagulates, and rises to the top of the solution; it can thenexert no catalytic influence.Relative Velocities with Silver Nitrate and Silver Acetate.HALOGENS IN ORGANIC COMPOUNDS.PART IV. 355Simultaneous measurements were made with silver nitrate and silveracetate in equivalent concentration, in order to obtain an accuraterecord of their relative activities with, bromopropionic acid. Theresults are as follows:TABLE XIII.Bromopropionic acid, Nf30. 1 Bromopropionic acid, N/30.Silver nitrate, N/30. Silver acetate, N/30.t (min.). a-x. k.0 20.0 -10 17'8 0 -0006230 14'2 0-0006890 9.5 0 -00 0 6 1t (min. ). a - x. k.0 20'0 -5 17.9 0.0012017 12-6 0*0017045 6-6 0*00220It follows that the initial velocity with the nitrate is about halfThe bearing that with the acetate under corresponding conditions.of this result on the mechanism of the reaction is considered later.Reaction between a-Bromobutyric Acid am? Silver Nitrate.Corresponding measurements to those just described for bromo-propionic acid have been made with bromobutyric acid, but not inthe same detail.CHEtBr*CO,H + AgNO, + H,O = OH*CHEt.CO,H + AgBr + HNO,.The results are similar to those obtained for bromopropionic acid,except that the velocity-coeflicients diminish more rapidly duringthe reaction.The data for experiments in which the initial con-centrations were varied are given in table XIV, the initial valuesof the velocity-coefficients being given in the third column :The reaction is represented by the equation:Concentration ofsilver uitrate.N/60N/40N/20N/10N/40N/40TABLE XIV.Concentration ofbromobutyric acid.k.N/60 0 -0060N/40 0'0034Nj4Q 0.0014A7/20 0.0034N/10 0.0028N/40 0'0021It is clear from these results that when the concentration ofsilver nitrate is kept constant, and that of the bromopropionic acidvaried, there is not much alteration in the magnitude of thevelocity-coefficients; in other words, the rate of the reaction isapproximately proportional to the concentration of the bromo-butyric acid. On the other hand, the coefficients diminish con-siderably as the initial concentration of silver nitrate is increased,which indicates that when the silver nitrate concentration isincreased, the rate of $he reaction does not increase in the sameproportion. This does not correspond with the behaviour of silverVOL.XCVII. BB356 SENTER: REACTIVITY OF THEnitrate and a-bromopropionic acid, where the velocity-coefficientsretain approximately the same value with varying concentrationEfect of Nitric d cid.-The actual observations are quoted inthis case, as they illustrate very clearly the falling off in themagnitude of the velocity-coefficients as the reaction progresses :(p. 348).TABLE XV.Silver nitrate, AT/ 20. Bromobutyric acid, 8 / 2 0 ,No nittic acid. Nitric acid, N/15. Nitric acid, N17.5.6 A - i F * ' ----- t (min.) a - z. k. t (min.). a - z. k. t (ruin.). C6 - X. k.0 30.0 - 0 30.0 - 0 30.0 -5 23'4 0*0019 15 24'6 On0O048 30 25.3 0.0002016 18.8 0'0013 45 21'5 0.00029 90 22'6 0'00012These results show that the retarding effect of nitric acid isconsiderable, and is approximately proportional to the concentrationof the acid.Sodium Brombutyrate and Silver Nitrate.-The magnitude ofthe constant in 1/30 molar solution of each of the reacting sub-stances is 0*0060.The speed is therefore about 2.5 times thatwith the free acid, for which the constant is about 0.0024.Bromoacetic Acid and Silver Nitrate.As this reaction has already been investigated to some extentby Euler [Zoc. cit.), it has been considered sufficient for the presentpurpose to make a few measurements with the object of comparingthis acid with the two higher acids as regards its reactivity withsilver nitrate, and, further, to determine if this reaction, like theothers, is catalytically accelerated by silver bromide.The resultsare given in table XVI:TABLE XVI.Silver nitrate, N/12'5 ......... 5 C.C.Bromoacetic acid, N/5 ......... 2 ),MTeter .............................. 5 ),t (min.), a - x . k.0 20.0 -240 19.5 0 *00000481200 17'6 0 ~00000572760 13'4 0*0000089Silver nitrate, NI12.5 ......... 6 C.C.Bromoacetic acid, N/5 2 $ 9 Potassium bromide, N/25 ...... 2 ,,Water 2 $ 9.......................................t (min.). a-x. k,0 20.0 -180 18.1 0 '0000291200 11-6 0 '0000302760 9 -6 0~000023The data quoted in the table show that &he rate of reactionbetween silver nitrate and bromoacetic acid is very slow at 26O,the rate is only about 1/100th of the corresponding reaction withbromopropionic acid.Further, silver bromide greatly accelerateHALOGENS IN ORGANIC COMPOUNDS. PART IV. 357the reaction-in a solution 1/150 molar with respect to this salt,the initial velocity is about six times that in the absence of thesilver bromide.Sodium Bromoacetate and Silver Nitrate.-The results given intable XVII show that sodium bromoacetate reacts with silvernitrate about three times as rapidly as does the free acid.TABLE XVII.Bromoacetic acid, iV/30.Silver nitrate, N/30.t (min.). n - x. k.0 20'0 -240 19.5 0 '00000541200 17-52 0.00000682760 13'8 0 ~000005 1Sodium bromnacetate, iIT/3O.Silver nitrate, Nj30.t (min.). a - x. k.0 20'0 -240 18.6 0'0000 161200 13'2 0 ,000n212760 7'4 0*000031Methyl Zodide mad Silver Nitrate.As this reaction has been measured by several previous observers,who, however, did not detect the catalytic influence of the silveriodide, it has been considered desirable to repeat the measurements,with special reference to the effect of silver iodide in aqueoussolution. Some typical results are given in the accompanyingtable :TAELE XVIII.Solvent :I.Silver nitrate, N/20 .....Methyl iodide, NJ20 ...5 ,)5 c,.c....................... Water.. 2 Y Yt (min.). n -x. k.0 12.50 -15 11 -60 0.0004230 10.95 0.000:3960 9-70 O*OOOY9120 8 -30 0*00034180 6.80 0.00037TVat er.11.Silver nitrate, N/20 ........Methyl iodide, A720 5 Y9Potassiiim iodide, Nl20.. 1 > )6 C.C. .............t (miii.). a-- x. k.0 12.50 -15 10.70 0 *O 008030 9.65 0'0007660 8 -00 0*00075120 G 7 0 0*00058180 5.10 O'OUOi15S o l vent : Alcohol.I V (composition as 11). I 111 (composition as I).t (min.).a -a. k.0 12 *5 -10 10.75 0 *OO 1 3 030 8.50 0.0012660 6 -73 0.001 16120 4 *go 0.00104t (rnin.). n - x. k.0 12.5 -10 10.4 0*0016230 8 -3 0-0013560 6.4 0*00127120 4 -5 0*00119These results show that the reaction in aqueous solution is con-siderably accelerated by N / 240-silver iodide, and there appears toB B 358 SENTER: REACTIVITY OF TEEbe a corresponding, but much smaller, acceleration in alcoholicsolution. The latter result, however, is of a preliminary nature,as only one series of measurements was made in alcohol.I n all these cases it has to be remembered that the amount ofsilver iodide distributed through the solution is only a smallfraction of the total amount, as the precipitate, especially inalcoholic solution, soon coagulates, and then rises to the top or sinkst o the bottom of the solution, being thus to a great extent removedfrom the sphere of action.I n experiments I11 and IV, besides silver iodide, a, littlepotassium nitrate (1/240 molar) is formed on mixing the solutions.Direct experiment shows, however, that even in 1 / 20 molar solutionpotassium nitrate exerts no appreciable influence on the rate ofthe reaction in aqueous solution, and the same may safely beassumed as to its effect in alcoholic solution in so small con-centration.According to the above table, the rate in ethyl alcohol is to therate in water as 3 : 1, a result not in satisfactory agreement withthe recent measurements of Burke and Donnan (Zeitsch.pltysilcal.Cl~en~., 1909, 69, 148), who find the ratio to be about 6 : 1.DISCUSSION OF RESULTS.(1) Tke Cntalytic ZiLfEuence of Silcer Haloyen Salts.-In theprevious pages it has been shown that silver bromide and silveriodide, even in extremely small concentration, exert a markedaccelerating effect on reactions in which silver salts and halogencompounds are concerned. The conclusions drawn by previousobservers as to the mechanism of such reactions require revisionin the light of this observation.The magnitude of the effect under favourable conditions is shownby the fact that 1/1000 molar silver bromide (about 0.002 gramin 12 C.C.of the reaction mixture) doubles the initial rate ofreaction between silver nitrate and bromopropionic acid. Unfor-tunately, an accurate investigation of this effect is rendered verydifficult by the fact already mentioned, that the precipitate sooncoagulates and is withdrawn from the sphere of action by risingto the top or sinking to the bottom of the solution.I n order to find whether the catalytic influence pertained to thehalogen compound in all forms, about 0.1 gram of freshly pre-cipitated and carefully washed silver iodide was added to a mixtureof silver nitrate and methyl iodide, and the rate of the reactionmeasured. The mean value of the velocity-coefficient in thepresence of the added iodide was 0.00041, in its absence 0*00035,a comparatively small acceleration.The data quoted in tablHALOGENS IN ORGANIC COMPOUNDS, PART IV. 359XVIII show that 1/8th of this amount of iodide, precipitated inthe reaction mixture, produces a much greater acceleration.It seems probable, therefore, that the catalytic power is connectedwith the fineness of division of the silver iodide, possibly with itsoccurrence in the colloidal (hydrosol) form. Lottermoser andRothe (Zeitsch. physikal. Chem., 1908, 62, 359) have shown thatsilver iodide hydrosol is much less stable when the silver nitrateis in excess than when excess of potassium iodide is present. Asthe silver salt is necessarily in excess in the reactions now underinvestigation, the comparatively rapid coagulation of the precipitateis accounted for.The view that the acceleration is connected withthe colloidal form of the silver iodide appears to be supported bythe observation that the catalytic effect is much smaller in alcoholicsolution, in which the hydrosol appears to be less stable.These observations are interesting also in connexion with theexperiments of Miss Burke and Donnan on the reaction betweenthe alkyl halides and silver nitrate in alcoholic solution. Theyfound that whilst the velocity-coefficients calculated for a reactionof the second order remained more or less constant with variationof the initial concenhtion of the alkyl iodide, they increased withincreasing concentration of the silver nitrate. I n other words, ifwe consider a reaction-mixture originally N / 2 0 with regard toboth components, at the moment when the concentration has fallento N / 4 0 , the reaction is found to be proceeding more rapidly thanin a solution in which the reacting substances are originally N / 4 0 :I n spite of a very detailed investigation, the results of which havejust been published (Zeitsch.physilal. Chem., 1909, 69, 148), theauthors have obtained no satisfactory explanation of thisphenomenon, although they favour the suggestion of Wegscheiderand Frank1 (Monatsh., 1907, 28, 91) that it is the non-ionised silvernit.rate which enters into reaction.It is evident, however, that the results could be a t once accountedfor if silver iodide exerts a catalytic action in alcoholic solution,as it has been proved to do in aqueous solution in the presentpaper.The experiments in alcoholic solution quoted in tableXVIII are, as already mentioned, of a preliminary character, andthe matter is now being further investigated by Miss Burke. I f theabove explanation proves tenable, there will no longer be anyexperimental justification for Wegscheider’s suggestion (Zoc. cit.)that it is the non-ionised silver nitrate which reacts.(2) The Mechanism of t72e Reactions.-The mechanism of thesereactions appears to be rather complicated, and the full discussionis postponed until the results of further investigations are available,more particularly the rate of reaction of the halogen-substitute360 SENTER: REACTIVITY OF THEesters with silver nitrate in alcoholic solution. It will be sufficientfor our present purpose to summarise the more important resultscommunicated in this paper which have a bearing on the mechanismof the reactions.Reactions of this type have often been discussedby previous observers, but no very definite conclusions as to theirmechanism have been drawn. All that can be said with certaintyis that the relatively great velocity is conditioned in some wayby the tendency t o formation of the halogen silver salts (compareEuler, Ber., 1906, 39, 2726; Wegscheider, Monatsh., 1907, 28, 79).I n this connexion it is interesting to note that definite compoundsof silver nitrate with certain organic halogen compounds (forexample, AgNO,,CH,I.CN and AgNO,,CH,I,) have been preparedby Scholl and Steinkopf (Ber., 1906, 39, 4393).The fact that silver bromide and iodide exerts a catalytic effecton the reactions renders the interpretation of the results somewhatdifficult, as we are not entitled to assume that the observedvelocities are proportional to the intrinsic velocities.Pendingfurther investigation, however, it may be assumed that the nearestapproach to the relative intrinsic velocities is obtained by takingthe initial velocities of the respective reactions.It has already been pointed out that as regards compounds of thetype R*CHBr*CO,H and their sodium salts, the velocity increasesgreatly with the complexity of the substituting group R. Undercorresponding conditions, the relative reactivities of the first threeacids and their sodium salts with silver nitrate are as follows:CH,Br 'C0,H.CHMeBr'C0,H. CH E tBr'C0,H.0-0000055 0 *00055 0.0025Ell r1001 14501CH,Br'CO,Na. CH McRr'C0,Na. CHEtBr'C0,Na.0 *000016 0-0025 0'0060[41 [4501 [1100]The numbers in brackets give the relative reactivities of thecompounds referred to the slowest as unity. The relative velocitiesdepend to some extent on the concentrations for which the measure-ments are made-the above values are valid for N / 3 0 solutions ofthe reacting substances.The velocities of these reactions have already been compared witht.hose in which the halogen has been displaced in the presence ofwater alone, and when the sodium salts are acted on by alkali, andit has been pointed out that the reactions in which silver salts areemployed are much more rapid.The reactions now under con-sideration also differ from those described in the previous papersas regards the magnitude of the difference in the reactivities. Itis not usually considered that the substitution of a methyl grouHALOQENS IN ORGANIC COMPOUNDS. PART IV, 361for hydrogen makes a very serious difference in the reactivity ofadjacent groups, and yet bromopropionic acid is a hundred timesmore active than bromoacetic acid as regards silver nitrate. It ishoped that measurements with the corresponding esters will throwsome light on the causes of this remarkable difference.The fact that the sodium salts of the bromo-fatty acids reactmore rapidly than the free acids with silver nitrate is doubtlessconnected with the fact that the concentration of silver salt ishigher in the former solutions than in the latter. The equilibriain the case of brornopropionic acid are represented by theequations :CHMeBr*CO,H + AgNO, CHMeBr*CO,Ag + HNO, (1).CHMeBr*CO,Na + AgNO, t CHMeBr*CO,Ag + NaNO, (2).As bromopropionic akid is a relatively weak acid, the equilibriumfor reaction (1) will be displaced towards the right to a smallerextent than in equation (2), and therefore the concentration ofsilver bromopropionate-perhaps the substance which really reacts-will be smaller in the former case than in the latter.Similarconsiderations account for the fact that the initial rate of reactionof silver acetate is greater than that of silver nitrate (p.355). I nthe former case, the equilibrium is represented by the equation :CHMeBr*CO,H + CH,*CO,Ag t CHMeBr*CO,Ag + CH3*C0,H (3).and owing to the fact that acetic acid is a much weaker acid thanbromopropionic acid, the equilibrium will be displaced towardsthe right, and the concentration of silver brornopropionate will berelatively great.Another way of interpreting these results is to assume that it isthe CHMeBr-COO’ ion which reacts with silver nitrate. It caneasily be calculated that the ratio of the CHMeBr-COO ion con-centration in sodium bromopropionate and bromopropionic acid inN/30 solution is about 4.5 : 1, which approximates to the ratio oftheir reactivities with silver nitrate. Similarly, the CH,Br*COO’ion concentration in sodium bromoacetate and the free acid isabout 4 : 1, whilst the ratio of their reactivities with silver nitrateis about 3 : 1.The suggestion that it is mainly the ions of the bromo-fattyacids which react with silver nitrate is further supported by theexperiments with nitric acid (p.351). It can readily be calculatedthat the CHMeBr-COO’ ion concentration in N / 20-bromopropionicacid is reduced t o about 1/7th of its value by the addition ofN/15-nitric acid, which is just the ratio in which the reactivityof bromopropionic acid towards silver nitrate is reduced by thesame proportion of nitric acid.The fact that the rate of reaction is approximately proportiona362 BARNETT AND SMILES : DERIVATIVES OFto the concentration of the bromopropionic acid instead of to thesquare root of the concentration (p. 348) appears at first sight tobe opposed t o the view that the ions are the active agents, butthis may be due to complications arising from the catalytic influenceof the silver bromide.There is no conclusive evidence as to what function of the silvernitrate is concerned in these reactions, but the fact that sodiumnitrate retards the reaction considerably speaks rather for the viewthat the Ag ions are the main aceive components. Should thissuggestion prove, on further investigation, to be well founded, aninteresting explanation of the great reactivity of bromo-f atty acidswith silver salts may be given on the basis of considerationsdeveloped in a previous paper (compare Trans., 1909, 95, 1839).It has been suggested that the relatively slow reaction betweenCH,*CHBr*COO’ ions and OH’ ions is connected with the mutualrepulsion of the negative charges, and it may therefore be antici-pated that the reaction between the CH,*CHBr*COO’ ion and apositively charged ion (in this case the Ago ion) will be relativelyrapid (compare table, Zoc. cit., p. 1835).The interpretation of the results is complicated by the equilibriarepresented by equations (l), (Z), and (3) (p. 361). An attemptwill be made to prepare pure silver bromopropionate and measureits reactivity, but owing to the great instability of the salt it willprobably be difficult to obtain trustworthy results.I n conclusion, I desire to thank Mr. R. W. Davies andMr. T. J. Ward, of St. Mary’s Hospital Medical School, for valuableassistance in the experimental part, of the work.CHEMICAL DEPARTMENT,ST. MARY’S HOSPITAL MEDICAL SCHOOL, W

ISSN:0368-1645    

DOI:10.1039/CT9109700346

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

362 BARNETT AND SMILES : DERIVATIVES OFXL.-Derivatives of X-P~eny~henazot~~Lioniunz.Pccrt III.By EDWARD DE BARRY BARNETT and SAMUEL SMILES.IN two previous communications (Hilditch and Smiles, Trans., 1908,93, 145, 1687) the products obtained by the condensation of thenitrodiphenylamine sulphoxides with phenol and phenetole weredescribed. Reasons were then adduced for regarding these subS-PHENY LPHENAZOTHIONIUM. PART 111. 363stances as derivatives of S-phenylphenazothionium, the process bywhich they are formed being formulated as follows:NH NH8/\Ac C,H,*O€€I n the meantime the study of the intramolecular rearrangementof the diphenylamine o-sulphoxides (Trans., 1909, 95, 1253 ; thisvol., p. 186) has enabled us t o obt,ain evidence throwing furtherlight on the formation and reactions of these substances.Wehave therefore extended our experiments with derivatives of thisgroup in order further to discuss their constitution and chemicalbehaviour.I n the Grst part of this paper the constitution of these derivativesis discussed, and in the latter part the factors governing theirformation are considered.I.--The Constitution of the Derivatives.When dinitrodiphenylamine o-sulphoxide is treated with a phenolor its ether in presence of concentrated sulphuric acid, the sulphatesof t,he dinitro-compounds of the group are formed. In discussingthe constitution of these substances, it has been pointed out (Trans.,1908, 93, 1688) that on general grounds only three alternativestructures can be entertained ; these respectively involve theN-aryl (I), the C-aryl (11)), and the S-aryl (111) arrangements:ArH - N O A ~ N Ar/\A/\I I I I/\/\/\O"\/O"N(/\/"NO2 I l lS SAAc Ar(111.364 BARNETT AND SMILES : DERIVATIVES OFAmple reasons have been already given for discarding the formeralternatives ( I and 11) and for accepting the S-aryl structure as thetrue representation of these salts.Later experiments have servedstill further to strengthen this conclusion.The N-Aryl Structure.-In order further to test the validity ofthis structure, we have prepared N-phenylthiodiphenylamine bymeans of the reaction devised by I. Goldberg (Ber., 1907, 40, 4525)for the phenylation of aromatic amines, and we find that theproperties of this substance and its nitro-derivatives are entirelydifferent from those of the compounds the structure of which is inquestion.N-Ph e n y 1 t hiodiph emylaniline.A mixture of 10 grams of iodobenzene, 5 grams of thiodiphenyl-amine, 4 grams of potassium carbonate, and 0.5 gram of copperiodide was boiled with excess of bromobenzene for eighteen hoursin a flask provided with a reflux arrangement. Water was thenadded, and the volatile benzene derivatives were removed with theaid of a current of steam.The solid residue was boiled withalcohol, and the solution was separated from the residue byfiltration. The product reEaining in the filtrates usually containsa considerable quantity of unchanged thiodiphenylamine, but bycrystallisation of the more soluble portion, N-13iLenyZt?Liodiphenyl-amine was obtained in short, yellow prisms, which melted at89-90° :0.2006 gave 0.5'790 CO, and 0.0906 H,O.I n chemical behaviour the substance closely resembles N-methyl-thiodiphenylamine.It is soluble in concentrated sulphuric acid,giving a crimson solution, being then partly oxidised to the phenazo-thionium salt. The basic properties, if, indeed, any are manifest,are very weak, since no salts could be isolated. When nitratedunder the conditions required to obtain the dinitro-sulphoxide fromN-methylthiodiphenylamine, the substance furnishes a mixture ofpolynitro-compounds, which could not be satisfactorily separated.However, it is sufficient for the present purpose to recordthe properties of the nitrated substance.It is crystalline,yellow in colour, insoluble in and unattacked by aqueous alkalihydroxide, and, like the corresponding N-methyl derivative, maybe condensed with phenetole in presence of concentrated sulphuricacid. The followingtable is given in order to emphasise the distinction between thesederivatives and the condensation product obtained from dinitro-diphenylamine o-sulphoxide and phenetole ;C=78.7; H=5*0.C,,H,,NS requires C = 78.5 ; H = 4.7 per cent.It is very soluble in cold glacial acetic acid8-PHENY LPHENAZOTHIONIUM. PART 111. 365Condensation productN-Phenylthio- Nitro- from phenetole and dinitro-diphenylamine. derivatives. diphenylamine sulphoxide.Colour of base ... .,.,,,... Yellow Yellow Crimson and fluorescentAction of acids on base.No salts formed Stable green salts ob-Action of H,S04 and - Condensation Salt formed, but noin solution.tained.phenetole. further action.The fact that N-phenylthiodiphenylamine and its nitro-derivatives do not form salts, whilst the green salts in questionare quite stable, is alone sufficient to show that the latter do notcontain the N-aryl structure. Moreover, if these salts contain theN-aryl structure (I), it is clear that the action of alkali mustfurnish a dinitro-N-phenylthiodiphenylamine, but instead theyyield crimson, fluorescent bases (Trans., 1908, 93, 151, 1693), whichare entirely different from the nitro-derivatives of N-phenylthiodi-phenylamine. For these reasons the N-aryl structure for thesecompounds must be finally rejected.The C-AryZ Structure (II).-It was previously shown (Trans.,1908, 93, 1689) that if this structure were correct, the substancemust be formed by simultaneous oxidation of the phenol and thephenazothionium salt (IV) :NOHVV.1According to this view, the latter substance would appear as anintermediate product formed from the dinitro-sulphoxide (I) by theaction of the concentrated acid (see Trans., 1909, 95, 1261).Muchevidence has already been adduced for abandoning this view, but,since it is now possible to obtain the dinitrophenazothioniumhydroxide in the pure condition, we have been able to submit thequestion to direct test. Numerous attempts were made to effectthe condensation of this phenazothionium hydroxide with phenetoleby means of concentrated sulphuric acid both without and inpresence of a mild oxidising agent, but they were unsuccessful.In these experiments the greater portion of the phenazothioniumhydroxide was unat*tacked, whilst the remainder was converted intoa tarry material from which no definite product could be isolated.However, more cogent argument against this structure is furnishedby a comparison of the properties of the dinitrophenazothioniumhydroxide and the phenolic compound the constitution of which issought.It has been elsewhere shown (Trans., 1909, 95, 1256) tha366 BARNETT AND SMILES : DERIVATIVES OFin the former substance (IV) the basic function of the azothioniumgroup is depressed by the presence of the nitro-groups in theadjacent benzene nuclei; in fact, the substance does not form saltswith aqueous mineral acids.But on examining the formula (11)which represents the C-aryl structure for the phenolic compound,it will be seen that, if this were correct, the substance must exhibita similar lack of basic properties, for it cannot be supposed thatthese would be strengthened by the linking of a phenolic residueto one of the aromatic nuclei in the azothionium complex. Sinceall the dinitro-compounds of this group which have been obtainedexhibit well-defined basic properties, it is clear that they cannotbe derived from the C-aryl structure, which for this and otherreasons (Trans., 1908, 93, 1689) inust now be finally rejected.The S-Aryl Structure.-This constitution now remains as theonly possible alternative, and, as previously shown (Trans., 1908,93, 1687), it is to be anticipated from the characteristicbehaviour of the thionyl group in aromatic sulphoxides, since thelatter substances are converted into sulphonium salts by treatmentwith aromatic compounds in presence of phosphoryl chloride orsulphuric acid.It will now be shown that the S-aryl structure isfurther justified by the analogy between these substances and theparent phenazothionium compounds.I n discussing the mechanism of the change of the ifnino-thionylstructure into the azothionium arrangement, it has been demon-strated (this vol., p. 186) that in this reaction the thicmyl salts arefirst formed, and that these are subsequently converted into thequinonoid compounds.The process, reduced to its simplest terms,is represented as follows (V and VI):NH N/\OH U1 dl+ H,O/\/\\A/\/t 1 - 1 IS S/\HO Ar kr(VII.) (VIII.)Now, when the S-aryl salta are treated with aqueous alkalihydroxide, they are converted by loss of the elements of mineraS-PHENYLPHENAZOTHIONIUM. PART 111. 367acid into crimson, fluorescent bases (Trans., 1908, 93, 145), forwhich the quinonoid structure (VIII) is accordingly the only repre-sentation possible. It is clear that in this process the sulphoniumhydroxides (VII) must be first produced by the action of thealkaline reagent, and on referring to the formulae it will be seenthat the conversion of these substances into the quinonoid baseis strictly analogous to the change of sulphoxide salt into thequinonoid sulphonium salt (V and VI).I n either case thequinonoid arrangement is produced by removal of hydroxyl fromthe quadrivalent sulphur group.I n both series it is possible to obtain the quinonoid derivativesin the hydrated condition. I f the green 8-aryl salts are boiledwith water or treated with cold aqueous sodium carbonate, thecrimson hydrated bases are formed (Trans., 1908, 93, 151, 1693).I n a, previous paper dealing with the salts and hydrates ofphenazothionium (this vol., p. 186), we have shown that there isgood reason for representing this additional molecule of water asforming the ammonium grouping (as in I X ) :HO-NOHS(TX.)61If this hypothesis is extended toformula (X) forecasts the possibilityHO-N-H/\//\/A! I l l\A/\/ sAir)the S-phenyl derivatives, t,heof the existence of two seriesof salts: the green or yellow sulphonium salts (type 111), asobtained with the dinitro-derivatives, and a red series, which wouldbe the ammonium salts (type X).We have been able to showthat the latter exist. The sulphonium grouping in the dinitro-derivatives which give the green salts is of moderate basic power,and it is evident that if these red ammonium salts exist they mustbe sought for in derivatives where the basic properties of thesulphoniurn group are still further depressed. With this object inview the tetranitro-derivative of this series was investigated.Tetranitro-Sphenetytphenuzothionium.Finely powdered tetranitrodiphenylamine o-sulphoxide was mixedwith a large excess of concentrated sulphuric acid.Some of thesulphoxide dissolved, but the greater portion remained in suspen-sion. Excess of phenetole was then gradually added to the coldmixture, which was constantly agitated and kept within the limitsof atmospheric temperature. As increasing quantities of th368 BARNETI' AND SMILES : DERIVATIVES OFphenolic ether were added, the suspended sulphoxide dissolved,forming a deep red solution. When renewed addition of thereagent produced no further change, the mixture was passedthrough glass wool, and then poured on a large bulk of meltingice. The now insoluble reddish-brown material was collected, wellwashed with cold water, and finally dried at.the atmospheric tern-perature. This crude material was purified by rapid extractionwith acetone in a Soxhlet apparatus. The acetone solution result-ing from this operation was concentrated on the water-bath, andthen, when cold, it was mixed with a little ether. The first pre-cipitate was removed by filtration and rejected; but on adding afurther quantity of ether to the filtrates, tetrunitro-S-p7LenetyZ-p7~enazotlzioniurr~ sulphaie was gradually precipitated in minute,reddish-brown crystals, Analysis was conducted with two samplesfrom different preparations :0.1877 gave 0.2728 CO, and 0.0553 H;O. C = 39.65 ; H = 3.2.0.1328 ,, 0.1937 CO, ,, 0.0391 H,O. C=39.8; H=3.2.C,,H,309N,S,H2S0, requires C = 40.2 ; H = 2.5 per cent.The substance does not melt below 250O; it is insoluble in wateror cold alcohol, and soluble in acetone.The solutions in the last-named solvent are not fluorescent, like those of the dinitro-compounds.The base is readily obtained in the hydrated form by boiling thesulphate with water. A sample, which had been dried in thesteam-oven, was analysed :0.2014 gave 0-3404 CO, and 0.0652 H,O.Tetrunitro-S-phenetylphenazot?Lioniurn hydroxide is insoluble inFinally, on comparing the dinitro-compounds of the S-phenylC =46.1; H = 3-6.C20H,,0gN,S,H,0 requires C = 46.4 ; H = 2*9 per cent.water, and very sparingly soluble in boiling alcohol,series (XI) with those of the parent series (XII):N Nb,H,*OEt 6H(XI.) (XII.)it is seen that in the former class the basic function of the sul-phonium group is appreciably increased by the substitution ofaryl for hydroxyl at the quadrivalent sulphur.But it may beremarked that this increase in basic power is to be expected fromthe general influence of this substitution in simpler compounds oS-PHENY LPHENAZOTHIOKIUM. PART 111. 369quadrivaleiit sulphur.this effect:The following series is quoted to illustrateHO c! H *OEt HO C,H; OE t g > s < g HO>S<OFi-I HO>S<C, H, 0 Et(or tho) S ul phiirous (or tho) Phenetylsal phinic (ortho) Phenetyl-Very weak base.acid. acid. sulphoxide.HO C6H,*OEtEtO'C,Ii4>s<C,B;OEtTriphenet ylsulphonium.Strong base.and it is clear that the successive replacement of the hydroxylgroups in ortho-sulphurous acid gradually increases the basic powerof the group in question.From these considerations it is seen that the chemical behaviourof the condensation products agrees very closely with that whichwould be expected for them on the basis of the S-aryl structurefrom analogy t o the simpler phenazothionium hydroxides. Moreover,since all other possible structures have been shown to be untenable,the S-aryl constitution must now be regarded as finally established.11.-Formation of the S-Arylphenazothionium Arrangem\en,t.The factors which control the formation of these derivatives areto be found in the nature of the diphenylamine o-sulphoxideemployed and in the group which is to enter the thionium arrange-ment.( a ) The Influence of the Character of the Sdphoxide.--It hasbeen previously mentioned that the derivatives of the 8-aryl seriesare obtained by the condensation of a diphenylamine o-sulphoxidewith an aromatic compound in presence of concentrated sulphuricacid (see formulz on p.363). But by no means do all thesulphoxides of diphenylamine behave in this manner. Previousexperiments (Trans., 1909, 95, 1253) have shown that, whentreated with acid reagents, some of these sulphoxides are imme-diately converted into salts of phenazothionium (V and VI), andthe latter substances are incapable of undergoing the requiredcondensation. It is therefore evident that the answer to thequestion whether a given sulphoxide can yield the S-aryl derivativesby this reaction must depend on the stability of the sulphoxidein presence of the strong acid.If the sulphoxide is instantaneouslyconverted by the acid into the phenazothionium salt, the 8-arylderivative will not be formed; but if this conversion does not takeplace, or if it is sufficiently slow to enable the condensation to beeffected before it has proceeded far, then the S-aryl derivativesThese will be considered separately370 BARNETT AND SMILES : DERIVATIVES OFcan be obtained.the six sulphoxides which have been examined :This is entirely borne out by the behaviour ofSulphoxide.Diphen ylaminc o- sulph oxideN-Methyldiphenylamine ),pp-Dinitrodiphenylamine ,)Diisonitrodiphenylaniine ,,Dinitro-N-methyldiphenylamineTetrariitrodiphenylariiine o-sulph-o-sulphoxide.oxide.In concentrated H2S04In concentrated H2S04.with phenetole.Immediate rearrangement No condensation.Rearrangement slow Condensation withfresh so111 tions.fresh solutions.fresh solutions.* ) 9 ) Y ) 9 9$ 9 1, Condensation with3 7 $ 9 Condensation withNo rearrangement ap Condensation.prtxiable.Of these six cases, those of the dinitro-derivatives are the morenoteworthy. When phenol is added to freshly prepared solutionsof these substances, the 8-hydroxyphenyl derivatives are readilyformed, and the yield is almost quantitative; but with solutionswhich have been kept some hours, the required reaction does nottake place. The intramolecular rearrangement of these sulphoxideswhich thus militates against the formation of the S-aryl derivativesis favoured by the increase of the basic function of the thiodi-phenylamine nucleus (this vol., p.186). Hence it is clear that theintroduction of basic groups in the sulphoxide will tend to hinderthe formation of the 8-aryl compounds, and the addition of acidicgroups will tend to exert a favourable influence. This favourableeffect seems to attain a maximum in the dinitro-compounds, forthese are more reactive and furnish better yields than the tetra-nitro-derivative. It appears that in these substances the thionylgroup is still sufficiently basic to yield readily the sulphoxide salts(V) which form the preliminary stage of the reaction (Smilesand Le Rossignol, Trans., 1906, 89, 697). The more sluggishcondensation of the tetranitro-derivative may be ascribed to thelessened tendency to form these salts, which is due to the furtheraddition of acidic substituents.( b ) The Nature of the Groups zuhLich may enter the ThLionium,4 ~ralzgem~ent.-Experiments have shown that the chief types ofsimple aliphatic compounds do not furnish these sulphoniumderivatives under the normal conditions of the reaction.Theformation of these derivatives seems confined to compounds con-taining an aromatic complex or an arrangement similar thereto.The capability of an aromatic compound to condense with thediphenylamine sulphoxide is determined by the reactivity of thearomatic nucleus in the compound in question, and this, in turn,depends on the number and nature of the substituents present.Of the aromatic hydrocarbons, benzene and toluene are inactive,but if suitable groups are introduced, the condensation can bS-PHENYLPHENAZOTHIONl UM.PAnT 111. 371readily effected, for example, m-xylene acts very sluggishly, butfrom mesitylene the sulphonium base is easily obtained.Dinit ro-S-m esit ylphenaao t hionizcm.Excess of mesitylene was slowly added with constant agitationto a freshly prepared ice-cold solution of pp-dinitrodiphenylaminesulphoxide in concentrated sulphuric acid. After each additionof the hydrocarbon, a sample of the liquid was withdrawn andpoured into cold water. When the precipitate obtained in thismanner was of a pure green colour, the addition of the hydro-carbon was interrupted, and the reaction mixture was poured onpowdered ice.The sulphate was then collected and washed, firstwith water and then with ether, to remove adherent mesityleneand other oily impurities. After renewed washing wit’h water, thesalt was triturated with a cold aqueous solution of sodium car-bonate. The solid base was collected, and washed with water untilfree from alkali. After purification, diiLit4.o-S-mesitylphenazo-thionizcm hydroxide was obtained in minute, chocolate-browncrystals of high melting point. A sample which had been drieda t looo was analysed:0*2024 gave 0.6660 CO, and 0.0868 HiO.The base is sparingly soluble in hot water, giving purple solutions,and readily so in cold acetone.Generally speaking, however, the reactivity of the hydrocarbonsis sluggish in comparison with the hydroxy- and amino-derivativesc-if benzene. Qualitative experiments made with a wide range ofmaterial have shown that almost all aromatic compounds containingthese groups alone readily furnish the 8-aryl derivatives with thedinitro-sulphoxides.But since the products obtained from thesesubstances for the greater part resemble the h‘-hydroxy-phenyl and-phenetyl derivatives which have already been described in detail,no particular interest would have been served by the isolationand analysis of each compound. However, the case of theS-salicyl derivative is worth especial mention, since it occurs as atrue carboxy-thetine.C=59*8; H=4*7.C2,H,,04N,S,H20 requires C = 59.3 ; H = 4-47 per cent.Dinit ro-S-salicylyl~enazo ghionium.The condensation of ppdinitrodiphenylamine sulphoxide withsalicylic acid was effected in the usual manner.The crude product,after being well washed with cold water, was dissolved in diluteaqueous alkali hydroxide. The solution was then clarified byfiltration, and then mixed with dilute sulphuric acid in exactlyVOL. XCVII. c 372 BARNETT AND SMILES : DERIVATIVES OFsufficient quantity t o precipitate the thetine. No suitable solventcould be found for the recrystallisation of this substance. It issoluble in hot nitrobenzene, but on cooling the solution it is pre-cipitated in the amorphous condition. Analysis was made witha sample which had been washed with alcohol and dried in thesteam-oven :0-2036 gave 0.3858 CO, and 0.0608 H,O.0.1510Dinitro-S-salicylplenazothioniu~~~ hydroxide forms a mustard-yellow, amorphous powder of high melting point.It is worth observing that the substance obtained in this manneris not the sulphate of the S-aryl base which might be expectedfrom analogy to the S-hydroxyphenyl derivative.Evidently thesulphonium salt is internally formed with the carboxyl group, theadditional molecule of water being present as with most thetinesand betaines :C=51*6; H=3*2.,, 12.5 C.C. N, at 2 3 O and 750 mm. N=9.4.C,,H,,O,N,S requires C = 51.6 ; H = 2.9 ; N = 9.7 per cent.NHThe substance is more stable than the salts of the S-hydroxy-phenyl series, being unattacked by boiling water; but it is solublein alkali, giving deep red solutions of a, sodium salt.Turning to the condensation products obtained from naphthalenederivatives, it has been found that the wide scope of the reactionobserved with benzenoid compounds is well sustained.Althoughnaphthalene itself does not react with the dinitro-sulphoxides, allhydroxy- and amino-derivatives which have been examined readilyform the 8-naphthyl derivatives. These possess well-defined tinc-torial properties, and when sulphonic groups are present thecompound is readily soluble in cold water j but the simple hydroxy-and amino-derivatives are sparingly soluble. Some of the chiefexamples of the S-naphthyl derivatives are described in the follow-ing table:Condensation of the pp-Dinitro-sulphoxide with Colour.a-Naphthylamine .............................8-Naphthylamine .............................a-Naphthol .......................................2-Naphthylamine-6 : 8-disnlphonic acid ..2-Naphthylainine-6-sulphonic acid......... Crimson ; , ,2-Naphthol-6 : 8-disulphonic ,, ......... Brown ; ,, violet in alkali.2-Naphthol-3 : 6-disulphonic ,, ......... Crimson ; ,,2.Naphthol-6-sulphonic , , ......... Olive green, violet in alkali.Purple ; sparingly soluble.Beddish-brown ; sparingly soluble.Blue ; sparingly soluble.Crimson ; solubleS-PHENYLPI-IENAZOTHIONIUM. PART 111. 373Attempts to purify and t o obtain these derivatives in thecrystalline state have been unsuccessful, since they persistentlyremain in the colloidal condition. The physical properties of thea-naphthol derivative are perhaps worth special mention.Afterundergoing a process of purification, this substance was finallyobtained as a blue, viscous jelly, which, on being broken by shock,exhibited a dry fracture.These S-aryl derivatives of phenazothionium are not formed byall aromatic compounds, the most prominent exceptions being thesimple nitro-derivatives of benzene and naphthalene. From ageneral point of view the reaction may be said t o be controlledby conditions similar to those observed in the process of sulphination(Trans., 1908, 93, 745), but hitherto the influence of the so-calledsteric conditions has not been observed. The resemblance betweenthese processes is not surprising, since the formation of the S-arylphenazothionium salts from the sulphoxides is evidently analogousto the third stage in the ordinary process of sulphination wherethe triaryl-sulphonium salt is formed from the sulphoxide.Finally, it is necessary to point out that the condensation ofthe thionyl group in the dinitro-sulphoxide is not confined solelyto aromatic compounds.For example, thiophen readily furnishesthe 8-thienyl derivative.S-Thien~llphenazothtionizsm.The condensation of thiophen with pp-dinitrodiphenylaminesulphoxide was effected in the usuaI manner; but since muchcharring takes place during the reaction, the reagents were employedonly in small quantity a t each operation, and the temperature waskept below 5O. The impure sulphate, obtained by pouring theunited reaction mixtures into water, was collected, washed firstwith water, and then with alcohol, and finally triturated withaqueous sodium carbonate. The impure base was collected, washed,and dried in the steam-oven. The dry product was crushed t o afine powder, and rapidly extracted with a little acetone to removesoluble impurities. The remaining product was crystallised fromboiling phenetole, which, on cooling, deposited dinitro-S-thienyt-phenazothionium hydroxide in large, led prisms, which exhibited asteel-blue lustre. The substance is very sparingly soluble in cordacetone, and does not melt below 250O:0.2032 gave 0.3828 CO, and 0.0330 H,O.C,,€I~0,N3S,,~H,0 requires C = 50.5 ; H = 2.6 per cent.From the analytical data it appears that the normal sulphoniumhydroxide has lost water during the recrystallisation from the highC=50.6; H=1%c c 374 DIXON AND TAYLOR : APPARATUS FOR DEMONSTRATINQboiling solvent; unfortunately the quantity of material was toosmall to enable the analysis to be repeated.I n conclusion, we desire to express our thanks to Dr. Cain forkindly lending us samples of the various amino- and hydroxy-sulphonic acids of naphthalene which were employed in this investi-gation. We also wish to thank the Research Fund Committee ofthe Society for a grant which has defrayed the expense of thisresearch.THE ORGANIC CHEMISTltY LABORATOKY,UNIVERSITY COLLEGE, LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109700362

出版商:RSC    

年代:1910

数据来源: RSC

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374 DIXON AND TAYLOR : APPARATUS FOR DEMONSTRATINQXLI.-Apparatus for Demonstrating the Electrolysisof Hydrochloric Acid.By AUGUSTUS EDWARD DIXON and JOHN TAYLOR.THOSE who have occasion to use Hofmann’s apparatus for showingthe electrolytic decomposition of hydrochloric acid into equalvolumes of its constituent gases, soon become aware that its com-parative simplicity has been attained only a t the cost of somedisadvantages. Of these it is sufficient to mention (i) the leakageof the acid electrolyte at the bottom of the H-shaped tube; (ii) adifficulty in ascertaining when the saturation with chlorine iscomplete ; and (iii) the possibility, in certain circumstances, ofthe two gases becoming mixed. Various devices have been proposedto obviate these troubles; they are, however, not very satisfactoryin practice, and in any case, when it comes to the final demonstriltion, there is always distinct inequality between the volumes ofthe liberated gases.In L.Meyer’s improved apparatus (Ber., 1894, 27, SSO), thesimplicity is abandoned ; for, whilst Hofmann’s original form ofvoltameter is retained, the gases are delivered apart, underdiminished pressure, into separate tubes, one of which, containingwater, serves to collect the hydrogen; the other, filled a t firstwith saturated chlorine-water, receives the chlorine ; each of thesetubes, open below, stands in a trough of the liquid with whichit is charged. Over the earlier form Meyer’s modification has onedistinct advantage, since by means of it the equality in volume ofthe resultant gases may be demonstrated; on the other hand, notonly must saturated chlorine-water be prepared, and the collectinTHE ELECTROLYSIS OF HYDROCHLORIC ACID.375tube filled with it, but also the exposure, on the lecture-table, ofan open dish charged with this liquid is not free from objection.Moreover, the three disadvantageous features mentioned above arenot eliminated.The apparatus here figured, although less simple than that ofHofmann, is sufficiently compact to be set up on a single stand,and in practice has given results that are satisfactory. Briefly,it consists of two parts: A, the electrolyser, and B, the vessel forAreceiving and measuring over concentrated sulphuric acid the gasesdelivered from A.The electrolyser is a U-tube of 1-inch bore, having near each enda delivery tube, as shown; a well-paraffined cork in each neckcarries a half-inch carbon cylinder, one foot long; to the projectingfree end of this rod a brass binding screw is clamped.The collecting and measuring vessel is a tall U-tube, of somefiveeighths to three-quarters of an inch in bore and about 1376 ELECTROLYSIS OF HYDROCHLORIC ACID.inches long, to the lowest point of which another tube (thepressure-tube) is sealed as shown, to end in a bulb above thehighest point of the U ; a t the foot of the pressure-tube, just whereit begins to be,nd upward, is sealed on a light glass tap, having itsaxis parallel to the plane of the U-tube.Into the top of eachmeasuring tube is ground a hollow glass stopper, which terminatesin an obliquely bored two-way tap, communicating at will, either.with a short stand-tube of about one-eighth of an inch in boreand an inch or so in length, or with the bent receiving tube, justalongside; the distance between the latter and its fellow of theopposite side is such that each is in a, straight line with thecorresponding delivery tube of the electrolyser.By suitable pieces of glass and rubber tubing, the two mainparts are connected as shown, the hydrogen-connexions being madewith butt-joints and thick-walled rubber tube, well smeared insidewith glycerol; between the chlorine delivery tube and the corre-sponding receiving tube a T-piece may conveniently be introduced ;this, when provided with rubber connexion, pinchcock, and glassdelivery tube, serves to pass the waste chlorine, when desired, tothe table-draught, or into a beaker of lime.When the electrolyser is filled, the electrolyte may reach to withinan inch of the delivery tubes.The receiver is charged in allthree limbs to the level of the bottoms of the stoppers,. whereground in to the measuring tubes; the sulphuric acid used forfilling may be stained, if the operator wishes, by a, method givenbelow. The parts are now connected; the pinchcock is opened,both gas-taps are turned into position for receiving, and the plugof the one for hydrogen pulled out sufficiently to allow this gas,when liberated, to pass freely out from the electrolyser into theair.The current is now turned on, and maintained until the chlorineis seen to be escaping freely.To ascertain if saturation is complete,the pinchcock is closed, the chlorine-tap pulled out for a momentfrom its seat to equalise pressure, then both taps are pushed homesimultaneously, and the lowest tap is turned on, so that the gasesmay accumulate in the collecting tubes under a pressure notgreater than the atmospheric, or less, as may be desired. There isno difficulty in knowing if saturation is complete, for, when thisstage is attained, the two tubes fill at exactly the same rate fromstart t o finish.To recharge the collecting vessel, the pinchcock is opened, theplug of the hydrogen-tap pulled out as at first, and the sulphuricacid, which was drawn off, is returned to the apparatus throughthe bulb a t the top; after this the procedure is as before.WheSOLUBILITY OF POTASSIUM SULPHATE. 377the production of the two gases in equal volumes has beendemonstrated, the acid may be returned to the bulb, and t.he gases,displaced through the two short stand-tubes, may be proved, inthe usual way, to be hydrogen and chlorine respectively.It is scarcely necessary to mention that the slowness (one canhardly call it speed) of saturation with chlorine varies considerably,according to whether the electrolyte is hydrochloric acid alone, thesame saturated with salt, or saturated brine; in every case thetediousness is, of course, much reduced by preliminary saturationof the electrolyte with chlorine.The gas-taps shouldbe smeared with vaseline as lightly as will suffice to render themgas-tight; otherwise more or less chokage may occur; the butt-joints, etc., are recommended for the hydrogen connecting tubeson account of the facility with which this gas escapes throughrubber; and the cork joints, of course, must be made tightwith paraffin or other suitable luting; also, the carbon rods,when done with, should be well washed and dried, to preventdisintegration.It is not easy for persons sitting a t a distanceto see clearly the accumulation in a narrow tube of colourless orf aintly-coloured gases over a colourless liquid. With the apparatushere described, this difficulty may be overcome by dissolving inthe sulphuric acid enough chrome-alum to stain it deep green;if between the collecting tubes and the pressure-tube a sheet ofmilk-glass be interposed, with a light close behind, the filling ofthe former is rendered easily visible from any part of an ordinarylecture-room. The glass parts of this apparatus were made byMessrs. Baird and Tatlock, in accordance with drawings suppliedto them.I n conclusion, a few points may be noted.UNIVERSITY COLLEGE,CORK

ISSN:0368-1645    

DOI:10.1039/CT9109700374

出版商:RSC    

年代:1910

数据来源: RSC

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XISOLUBILITY OF POTASSIUM SULPHATE. 377X.- The Solubility of Potassium S d p h a t e in Concen-tqvrnted Aqueous Solutions o f NowElect7-olytes.By JOHN JACOB Fox and ARTHUR JOSIAH HOFFMEISTER GAUGE.IN a recent communication (Trans., 1909, 95, 885) one of usshowed that the solubility of potassium sulphate in water at 2 5 Owas decreased markedly by the presence of potassium acetate.Since the rate of the decrease is much greater with the moredilute solutions of potassium acetate, which are dissociated electro-lytically to a greater degree than the stronger solutions, th378 FOX AND GAUGE : SOLUBILlTY OF POTASSIUM SULPHATE INpresence of the potassion due to ionised potassium acetate mightbe considered as being the main factor in decreasing the solubilityof potassium sulphate as distinct from the general effect of thesecond substance in solution, in this case non-ionised potassiumacetate.With the view of gaining some further knowledge as tothe action as precipitant of the second substance in solution, itwils thought desirable to determine the effect on the solubility ofpotassium sulphate of a number of non-electrolytes, and to ascertainwhether the nature of the non-electrolyte was to any marked degreeconcerned in the action. I n the case of potassium sulphate a fewdeterminations of this character have already been carfied out,and the general result, both with electrolytes and non-electrolytes,is that the solubility of potassium sulphate in aqueous solution isdepressed. From the point of view of the present communicationthe results of most interest are those of Girard (Bull.SOC. chim.,1885, [ii], 43, 552) for the solubility of potassium sulphate inaqueous ammonia, and of Rothmund and Wilsmore (Zeitsch.physikal. Chem., 1902, 40, 619) for the solubility in aqueous aceticacid and aqueous phenol.While these results are similar to those described below, a strictcomparison cannot be made, since the alteration of solubility byvolume has been used by these observers, whereas we prefer thealteration in solubility referred to a fixed quantity of water. Afair approximation to the depression of solubility by volume can,however, be deduced if it is assumed that the total of the volumesof the potassium sulphate and of the liquid in which it is dissolveddoes not alter.This gives a volume too great by rather more than1 per cent. in the stronger solutions of potassium sulphate, andpractically correct in the weaker solutions. Thus it was found thataqueous alcohol, I):: 0.9913, yielded a solution containing 7 percent. of potassium sulphate, and having a density of 1.0499. Thedensity of finely powdered potassium sulphate was found to be2.656 at 2Oo/2O0. Hence 100 C.C. of the saturated solution should,from the composition, occupy 101.3 C.C. Similarly, a solution ofglycerol and water, containing 7.2 per cent. of potassium sulphate,possessed a density of 1.1029, the original glycerol and waterhaving a density of 1.0420. The calculated volume of 100 C.C. is101-2 C.C. As most of the solutions contain less than 7 per cent.of potassium sulphate, the errors introduced are less. Using thesecalculated volumes, it will be found that the nature of the curvesobtained is similar to that of Rothmund and Wilsmore referredto above.The substances used by us were ethyl alcohol, ethylene glycol,glycerol, mannitol, chloral hydrate, sucrose, acetone, and pyridineCONCENTRATED AQUEOUS SOLIJTIONS OF NON-ELECTROLYTES.379The solutions were examined partly from the point of view ofthe possible formation of definite hydrates, since it was thoughtpossible that if with any mixture a simple hydrate was formed,a change in the solubility curve at this point would be found.With this object, mixtures with water in all proportions were taken,and the solubilities plotted against the percentage composition ofthe aqueous solution.This method of plotting was chosen in preference to the methodof reference to a fixed quantity of water, because of the difficultyof deciding whether water should be considered as solvent or solutein concen trat.ed solu tions.*It is obvious from the curves that as the number of hydroxylgroups in the molecule increases, the precipitating effect of thenon-electrolyte decreases, and if the curves are drawn with moleculesof potassium sulphate as ordinate and non-electrolyte as abscissae,taking 1000 molecules of water as fixed, the result is the same.Whether this would be found to apply to other salts cannot, ofcourse, be decided without further investigation.None of thecurves give any indication of discontinuity, so that on this viewthe existence of definite simple hydrates is negatived.This doesnot, of course, imply that the substances dissolved do not formcomplexes with more or less water, but the most the results setforth here can be said to indicate is that the non-electrolyte andwater exert a material influence on each other, the action prevent-ing the water from dissolving the full amount of salt. There isone consideration, however, which is in a measure opposed to theresults obtained by Jones and Getman from observations of thedepression of the freezing point of aqueous solutions of non-electrolytes (Amer. Chem,. J., 1904, 32, 308). From theseobservations, Jones and Getman conclude that the deviations ofthe observed values of the freezing point from the theoretical valueare due t o the formation of complexes of the solute and water;that in so far as some of the water is used up to form hydrates,less water remains to function as solvent for the hydrate, and thattherefore abnormally high results for depression of freezing pointare obtained.It should follow that if some of the water is pre-vented from acting as solvent in the case of hydrates, the sameeffect should be shown when a second substance (for example,* During the course of this work, a paper by Rothmund appeared (Zeitsch.physikal. Chem., 1909, 69, 523), dealing with a somewhat similar problem, butusing csmparatively dilute solutions of the various alcohols and other organic sub-stances.Their effects as precipitants were studied in the case of lithium carbonateand other sparingly soluble salts. Rothmund used fixed volume, and this is justifiedsince the volume of the original solutions could be altered but slightly by thedissolution of sparingly soluble salts380 FOX AND GAUGE : SOLUBILITY OF POTASSIUM SULPHATE INpotassium sulphate) is dissolved in the solution. Philip hasdemonstrated this to be the case when hydrogen is dissolved inaqueous sucrose solutions (Trans., 1907, 91, 711). Now, accordingto Jones and Getman, alcohol, chloral hydrate, and mannitol do notshow any marked tendency to form hydrates, whereas sucrose, andparticulasly glycerol, show considerable hydration. We shouldtherefore expect alcohol, chloral hydrate, and mannitol to exertless influence on the solubility of potassium sulphate than eitherglycerol or sucrose. As will be seen from the results here given,the reverse is the case, both alcohol and chloral hydrate beingmuch more marked in their action than glycerol or sucrose, whetherthe curves are drawn up on the percentage basis as in the figure,or on the basis of a fixed 1000 molecules of water.It may beargued that the results are in part explicable on the assumptionthat unless ions are hydrated they cannot exist in aqueous solutions,and consequently that the potassium sulphate will not dissolve ifthe ions derived from it are subjected to conditions which tendto dehydrate them. The presence in solution of hydrated non-electrolytes might be supposed to act in the direction of preventingthe ions from obtaining the requisite quantity of water.I n suchcircunistances the ions could only obtain sufficient water a t theexpense of the hydrate of the non-electrolyte, and the final resultwould depend on whether ion or non-electrolyte was most effectivein obtaining water (see Lowry, Trans. Famduy Soc., 1905, 1, 197).It would also follow that with the increasing concentration of thenon-electrolyte the proportion of hydrated non-electrolyte f orniedwould increase, with a corresponding decrease in the hydrated ions.Such an explanation is, however, merely surmise, and does notaltogether apply to the strongest non-electrolyte solutions wherethe water is insufficient t o form any hydrate.EXPERIMENTAL.The solutions used were made up by weighing both the substanceand the water in which it was dissolved. Saturation was obtainedby cooling the saturated solution in contact with solid from asomewhat higher temperature to 2 5 O in a thermostat, and byshaking a t 25O.The amount of potassium sulphate was determinedby direct weighing of the salt after evaporation and ignition, orby estimating the amount of sulphate by means of barium chloride.The percentage composition of the solutions and the number ofmolecules of solutes per 1000 molecules of water froin which thecurves are drawn are as followsCONCENTRATED AQUEOUS SOLUTIONS OF NON-ELECTROLYTES. 381A queous Alcohol-Potassium Sulphate.AlcohoL1-354'807.809 *7012.3414-5115'2620.5026-9135.9743.9069'26Pyridine.4.2313.9024'5134-1946'2955-9375-90Potassiumsulphate.9-176'904'964 *323.572.712.661-830.970 410'220.016Water.89.4888.3087.2485.9884-0982.7882-0877-6772'1263.6255.8830-72Molecules per1000 molecules of water.PotassiumAlcohol.sulphate.5 -9 10.621 '3 8 -135.0 5.944'2 5.257 '4 4'468'6 3'472'7 3 '3103'2 2'4146'1 1'4A/ \- -- -- -Aqueous Pyridilze--Potassium. SulpJLat e.Molecules per1000 molerules of water.Potassiumsulphate.7 *954 -772.751.470 '450.120.006Water.87'82S1'3372'7464 -3453.2643-9524.09cPyridine.11.038.976.8121-1198.0---.PotassiumsulIihste.9.46.13.92.40-9--A queous Ethylene Glycol-Potassium Sulphate.Molecules per1000 molecules of water.E thyleiie Potassium hthylene Potassinni'glycol.sulphate. Water. glycol. sulphate.3-16 9 *67 87-17 10.5 11-59-78 7.69 82.53 34'4 9.618'47 5 '74 75.79 70 '8 7.832.1 1 3.57 64.32 145.0 5.749.03 1'83 49'14 280 7 3.382 FOX AND GAUGE : SOLUBILITY OF POTASSIUM SULPHATE INAqueous Chloral Hydrate-Potassim Sdphate.Chloralhydrate.6 *449.0912-3813'2022.0733.1544'4047'3062'8270.2880.368526Glycerol.8'9613-3620-3424'1533-7340'4043 *5250'18572267'9478-1898 '28Potassiumsulphate.9-138'417 -797 '315'884 *543-362-922.001-751'401-08Water.84'4382'5079.8379.4972.0562.3152.2449.7835.1827 *9718'2413.66Molecules per1000 niolecules of water.Chloral Potassiumhydrate.sulphate.8 '3 11 '212'0 10.516.9 10.118'1 9 *533.4 8 '458-0 7'592'6 6-6108-5 6'1194'5 5 -9273.8 6 -5.A/ \- -- -Aqueous Glycerol-Potassium Sulphate.Potassiumsulphate.8.871-696 '475-884'413.653.382'692 *071-530.980.73Water.82.1778.9573.1970.0261.8355.9553-1047-1340'7130.5330.840.99Molecules per1000 molecules of water.PotassiumGlycerol. sulphate.21.3 11'233.1 10'154'4 9.167 -5 8'6106'8 7'4141'4 6.7160'4 6.6208 '4 5'9275.1 5.3A/ >- -- - - -Aqueous Mannitol-Potassium Sulphate.PotassiumMannitol.sulphate.3 20 10.325 *82 10 -078 *35 9-6111 -26 9.1914-30 8.6617.22 8 -35Molecules per1000 molecules of water.PotassiumWater. Mannitol. sulphate.86.48 3.7 12.384'11 6'8 12'382.04 10'1 12.179.55 14'0 11.977-04 18.4 11'674.43 22 '9 11.6/-hCONCENTRATED AQUEOUS SOLUTIONS OF NON-ELECTROLYTES. 383Sucrose.9'5618'5528-1637 '2247'5557'00Acetone.4.9210.0616'2324.3137'1946-2962'40A queous Sucrose-Potassium Sulphate.Molecules per1000 molecules of water.Potassiumsulphate.9-658.657 '426'355%4'24PotassiumWater. Sucrose. snlphate.80.79 6.2 12.372'80 13'4 12.364-42 23.0 11.956'41 34-8 11%47'24 52.9 11.438.76 77 -5 11.3.4 qu.eous Acetone-Potassium Sulphate.Molecules per1000 molecules of water.Potassiumsulphate.7-205-022-961-500'470 '200.03Water.87-8884-9280-8174-1962'3453-5137-57Potassium'Acetone. sulphate.17.4 8 - 536-7 6.162 -3 3 -8101.7 2 '1185-2 0.8268-5 0'4- -Certain of the curves (p.384) require some consideration. Pyri-dine dissolved in water affords some evidence of the formation of ahydroxide from the fact that it precipitates ferric hydroxide fromaqueous solutions of iron salts. When drawn up on the basis ofa fixed amount of water, this curve cuts the alcohol curve. Itwas observed that above the temperature of 4 5 O two liquid phasesformed at all concentrations above 5 per cent. and below 46 percent. approximately. The position of the chloral hydrate curveclose to the glycerol curve appears to us to demonstrate that thecause of the depression of solubility is similar in both cases, whichdoes not support the deductions of Jones and Getman (Zoc.cit.) asto the remarkable difference in hydration of these two substances.It will be seen that if the chloral hydrate curve is expressed mole-cularly with reference to 1000 molecules of water, the end of thecurve begins to rise slightly, suggesting that potassium sulphateis soluble in absolute chloral hydrate. An actual determinationwith liquefied chloral hydrate at 4 5 O gave the solubility as 0.38per cent. of potassium sulphate.Glycerol of 99.0 per cent. strength dissolved 0-73 per cent. ofpotassium sulphate, an amount which is much greater than wouldbe dissolved by the water present.It must be concluded thatglycerol also dissolves potassium sulphate384 SOLURILZTY OF POTASSIUM SULPHATE.Both the mannitol and sucrose curves are practically straightlines. I n other words, the decrease in the solubility of potassiumsulphate in concentrated solutions of these two substances variesdirectly as the amount of solute present originally, so that thedecrease, if due at all to hydration of the solute, requires thesame degree of hydration a t all concentrations. This is inadmissibleon the usual assumption that the degree of hydration depends uponthe amount of water. The mannitol curve could not be carriedfurther than the point shown, which is very close to the saturationpoint of mannitol.The solubility in aqueous acetone of varying concentrationsexpressed per 1000 molecules of water gave a curve which followed100 2water.60 100 %lion-electrolyte.1.Alcohol, 2. Py?*idine. 3. E'thylmc! glycol. 4 . Glycerol.5 . Cl&wal hyd?vtc. 6. Mftnnitol. 7. Sacrose.the alcohol curve closely, but fell somewhat below it. Acetone wastherefore found to possess the greatest precipitating effect of thenon-electrolytes examined.Both pyridine and absolute alcohol dissolve minute quantitiesof potassium sulphate, but the amount was too small for accurateestimation. Schiff (Annalen, 1861, 118, 362) determined the solu-bility of potassium sulphate in aqueous alcohol at 1 5 O , and gavefour points only. This curve, as far as it goes, runs parallel withand a little below the one given here.It is of interest to compare the curve for solubility in potassiumacetate solutions with the foregoing curves. The position occupiedis well below the alcohol curve, a result which may be accountedfor if to the main action of non-ionised potassium acetate aACTION OF CALCIUM AND LITHIUM ON ORGANIC HALIDES. 385precipitant is added the influence of the potassions from theionised portion.J3ydration of the ions of the salt might be considered as a con-tributory cause of the depression of solubility. .As the rate ofdecrease is for most of the curves greatest with the dilute solutions,this assumption appears to receive some support; but it cannotbe considered quite satisfactory as an explanation, if it is bornein mind that the decrease is continuous even in the strong solutionswhere there is not sufficient water to form hydrates. Dilute solu-tions are, however, the limiting cases, and here again we find, asusual, that the rules deduced from the dilute do not apply to con-centrated solutions. It is hoped that the results of an investigationnow proceeding as to the influence of one non-electrolyte on thesolubility of another may throw some light on the possibility ofthe hydration of ions being a contributory cause of the depressionof the solubility of salts by non-electrolytes.EAST LONDON COLLEGE,UNIVERSITY OF LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109700377

出版商:RSC    

年代:1910

数据来源: RSC

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ACTION OF CALCIUM AND LITHIUM ON ORGANIC HALIDES. 385XLIIL-Tlie Action of Calcium and Lithium on OrganicHalides.By JAMES FREDERICK SPENCER and GWYNNEDD MARY PRICE.IN a previous paper (Spencer and Wallace, Trans., 1908, 93, 1827)mention was made of a preliminary experiment in which lithiumreacted with a-bromonaphthalene with the formation of naph-thalene. The present communication describes a series of experi-ments in which the action of calcium and lithium on organichalogen derivatives has been studied. Lithium reacts with a largenumber of organic halogen derivatives when the two substancesare heated together. I n many cases this reaction takes place atthe boiling point of the organic compound, but with some sub-stances, notably methyl iodide and bromobenzene, higher tem-peratures are required, which necessitate the use of sealed tubes.With isopropyl iodide and methyl y-bromobenzoate, no reactiontook place.The reaction may be regarded as proceeding in the two directionsindicated by the equations :1.RX + 2Li =RLi + LiX.2. 2RX + 2Li = R-R t 2LiX.The products obtained in some cases showed that the reactionhad proceeded according t o equation 1, for example, those obtaine386 SPENCER AND PRICE: THE AC!I’ION OFfrom p-bromotoluene, pchlorophenol, pchloroaniline, and p-bromo-acetanilide, whilst in other cases the products indicated that thereaction had taken place in both directions. None of the reactionsinvestigated proceeded along the direction indicated by the secondequation alone.I n all cases white, deliquescent compounds wereformed, which reacted with water with the evolution of heat andthe formation of the parent substance of the halogen derivativeemployed. The reaction with water can be represented by theequation :LiR + H,O = LiOH + RH.The white, deliquescent compounds obtained, on the basis of theabove equations, consist of mixtures of lithium halide and thelithium derivative of the hydrocarbon. It has been found prac-tically impossible to separate these two substances owing to theease with which the lithio-hydrocarbon is decomposed by solventsand the atmospheric moisture, but an analysis was made of thewhole solid product in the case of the reaction between propyliodide and lithium, and the results point to the presence of lithio-propane.The yield of the product in these reactions varies considerably,from about 80 per cent.of the theoretical in the case of mchloro-aniline to about‘ 8 per cent. in the case of octyl iodide, but generallythey are good.The reaction products, in all experiments where anilinederivatives were employed, had a strong odour of carbylamine,but this substance was not present in quantity large enough to beisolated. The reaction products in the case of pbromoacetanilidecontained much aniline, which is attributed to the hydrolysis of theoriginal product, acetanilide, by the lithium hydroxide during thesteam distillation.The reaction between iodobenzene and lithium was also tried inabsolute ether solution under the usual Grignard conditions. Nocompound other than diphenyl and lithium iodide could be isolatedfrom the reaction products, so that it may be taken that lithiumand halogen derivatives in ether solution react according to theWurtz reaction and not according to the Grignard reaction.Calcium did not react very readily with organic halides, and inthose cases where reaction did occur, the products rarely exceeded40 per cent.of the theoretical amount. The reaction may beregarded as taking place along two lines, analogous to those of thecorresponding reactions with lithium and magnesium (Trans., 1908,93, 69):1. Ca + RX = R*CaX.2. Ca + 2RX = CaX, + R*RCAT,Cl'IJhf AND LI'THlUM ON ORGANIC HALIDES, 387I n many cases, although indication of a reaction wits given onheating the two substances at the boiling point of the organichalide, it was necessary to employ higher temperatures and pressureto cause the action to proceed to any large extent, and in all suchcases a considerable quantity of gas was evolved on opening thesealed tubes.The gases evolved consisted of hydrogen and bothsaturated and unsaturated open-chain hydrocarbons. The solidproducts were generally white, crystalline, deliquescent substancesof the formula RCaX, which were coloured brown by the productsof the pyrogenic decomposition of the organic halide.The products from the reactions with aniline derivatives alwayshad a strong odour of carbylamine, but this substance was notpresent in sufficient quantity to be isolated.The intermediatecompounds of the formula RCaX were extremely difficult to isolate,but in the case of p-chlorophenol it wits found possible to isolateand analyse the derivative, which agreed well with the formulaOH*C,H,*CaCl.E. Beckmann (Ber., 1905, 38, 905) states that ethyl iodide andcalcium react very readily in ethereal solution, with the formationof the compound C,H,*CaI-O(C,H,),, the whole reaction beingcomplete in a few minutes. We have repeated this reaction andalso the reaction with iodobenzene under similar conditions, andhave obtained in both cases products of the type It*CaI*O(C2€15)2,but the reaction took place very slowly, requiring about twentyhours for completion. The addition of a trace of iodine acceleratedit somewhat, but even then it was much slower than indicated byB ec kmann .Metallic calcium, even in inorgznic reactions, is difficult tomanipulate owing t o the insolubility of its derivatives, whichgenerally coat the metal, and thereby stop or greatly impede thereaction.This probably, in addition to a possible superficial coatingof oxide on the metal employed, may be the reason for the difficultyexperienced in these experiments, and may also explain the pooryields obtained.EXP ERI MENTAL.I n the experiments with lithium, the metal was cut into smallpieces under ether, then quickly dried with filter paper, and addedto the organic halide. Equimolecular quantities of the metal andhalide were used in all cases. The reactions with all the substancestried, except bromobenzene and methyl iodide, took place whenheated in a quartz flask, fitted with a condenser, a t the boilingpoint of the halide for periods varying from three to twenty hours.The reaction products were in all cases white, crystalline,deliquescent solids, which decomposed on the addition of waterVOL.XCVII. D 388 ACTION OF CALCIUM AND LITHIUM ON ORGANIC HALIDES.with the evolution of heat. The products, after treatment withwater, were distilled in a current of steam, and the distillate andthe residue in the distilling flask investigated. The results, togetherwith the yields of the products, are given in the table below. Thereaction between lithium and iodobenzene was also carried out inethereal solution, and the sole product formed was diphenyl in smallquantity.The reactions between lithium and bromobenzene and methyliodide only took place when heated in sealed tubes for about sixhours a t 250O.The tubes were then cooled in liquid air andopened, and the gases evolved on warming collected and analysed.The residue was then treated with water, and in the case of methyliodide further quantities of gas were evolved with the evolutionof heat.this was distilled over in steam:In the case of bromobenzene,Reacting substance. Experimental conditions.Iodobenzene . . . . . , . . . . . . . . .Bromobenzene . . , . . . . . . . . .p - Bromo toluene . . . , . . . . .p- Chlorotoluene . . . . . . . . .m- Chloroaniliue . . . . . . . . .p-Chloroaniline . . . . . . . ..p-Bromoacetanilide.. . , . .p - Chlorophenol . . . . . . . . .a-Chloronaphthalene .. .Methyl iodide ... .. . .. . . , ,?t-Propyl iodide . . . , . . . . ,sec. -0ctpl iodide . . . ... . . .Heated 1 hour a t 188"Heated in sealed tubea t 150" for 8% hoursHeated 14 hours a tHeated 49 hours a tHeated + hour a t 230"184"3 50"Heated 1& hours a tHeated 2 hours a t 210"230"Heated Yeveralniinutesat 217"Heated 173 hours a t263"Heated in a sealed tubefor 4& hours a t 200"Heated 1& hours at46'5"Heated 20 hours a t220"benzene was formed, andProducts.70 per cent. benzene & diphenylBenzene and diphenyl24 per cent. toluene7 per cent. toluene ; p-ditolyl80 per cent. aniline; rn-dianiino-diphenpl, traces of carbyl-aniinc68 per cent.aniline, traces ofcarby lam ine40 per cent. aniline, 12 percent, acetanilide14 per cent. phenolNaphthalene ; a-dinaphthyl27 per cent. ethane, 33 per cent.iiiathane mixed with 10 percent. hydrogenn-hesctne ; n-propane9 per cent. octane ; 17 percent. httxadecane, m. p. 20"The calcium used in these experiments was the rasped varietysupplied by Kahlbaum; it was quite bright and metallic-looking inappearance, but occasionally had a slightly bluish tinge, whichmay have been due to a superficial coating of oxide. The reaction8were first tried at the boiling point of the organic substance used,and as in no case did the reaction proceed t o a marked extent, theywere then carried out in sealed tubes a t temperatures varyingfrom 160° to 250O.The substances were mixed in equimolecularquantities. After cooling, the tubes were immersed in liquid airand opened. No gas was evolved on opening, but on warming tUSHER : RADIUM EMANATION. 389the at.mospheric temperature, gas was evolved, which consistedmainly of hydrogen with small quantities of methane, acetylene,and carbon dioxide. This indicates that calcium, like magnesium(Trans., 1908, 93, 1823), has the property of absorbing largequantities of hydrogen a t low temperatures. The solid productswere then cautiously treated with water, and any gas evolved wascollected and analysed. The aqueous mass was then distilled in acurrent of steam, and the products, indicated in the table below,collected. The crystalline product of the reaction between pchloro-phenol was pressed on a porous plate and then washed with smallquantities of absolute ether to remove any unchanged chloro-phenol, dried, and analysed :Found, Ca = 23.1.OH*C,H,*CaCl requires Ca= 23-7 per cent.The lower alkyl halides reacted with calcium when heated at250° in a sealed tube, but the products could not be obtained, owingto the bursting of the tubes.No matter what precautions weretaken, the tubes always burst after they had been heated for aboutone hour, indicating that a violent reaction had suddenly takenplace.The following table gives a brief summary of the reactions carriedout and their products:Reacting substance. Experimental conditions. Products.Iodobenzene .. . . . . . . , . . . , , . Heated in a sealed tubeat 200" for 16 hoursp-Chloroaniline.. . . . , . . , . . , Heated in a sealed tubea t 155" for 14 hoursp-Chlorophenol.. . . . , . , . . . , Heated in a sealed tubea t 160" for 124 hoursp-Bromoacetanilide . . . . . . Heated in a sealed tubeat 200" for 15 hours40 per cent. benzene ; 2 pcrcent. diphenyl31 -5 per cent. aniline36 per cent. phenolSmall quantities of aniline andacetanilide, with a trace ofcarbylamineCHEMICAL LABORATORY,BEDFORD COLLEGE, W

ISSN:0368-1645    

DOI:10.1039/CT9109700385

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

USHER : RADIUM EMANATION. 389XLIV.-The In$uence of Rudiurn Emanation onEpuilibriuni in a Gaseous System.By FRANCIS LAWRY USHER.SOME interesting deductions concerning the nature of chemical changeinduced by radium emanation have lately been recorded by Cameronand Ramsay (Trans., 1908, 93, 966) as the result of quantitativeexperiments on the decomposition of water, ammonia, hydrogenD D 390 USHER: THE INFLUENCE OF RADIUM EMANATION ONchloride, and the oxides of carbOIi, and on the combination ofhydrogen and oxygen and nitrogen and hydrogen in presenceof theemanation.The principal conclusions drawn by these authors are (1) that thechanges observed are due almost entirely to the a-particles, and (2)that each particle of ernanation in disintegrating produces, ceterisparibus, the same amount of change.The experiments described areregarded by the authors as preliminary, and the results havequalitative rather than quantitative significance. At the suggestionof Sir William Ramsay, the investigation t o be described in this paperwas undertaken with the object of obtaining a more definite knowledgeof the mechanism of chemical change produced by the emanation,FIG. 1.based on an accurate study of the course of some simple reaction. Forthis purpose, five series of observations have been made, three withpure dry ammonia, and two with a mixture of hydrogen and nitrogenof the composition 3H, + N,.EXPERIMENTAL .It will be convenient to describe in detail the method of procedurein the two cases.Fig. 1 represents the apparatus used for theexperiments with ammonia. I n the Erst place the tap B was closed,arid the whole apparatus exhausted by means of a small mercurypump. Ammonia, prepared from pure ammonium chloride and sodiumhydroxide, was than introduced through B and condensed in thEQUILIBRlUM IN A GASEOUS SYSTEM. 391vessel D, which was surrounded with liquid air. B mas again closed,and the apparatus once more exhausted in order to remove traces ofair. The liquid air was removed from D, which now contained pureammonia, and a convenient quantity of this (about 1 c.c.) was pumpedoff and collected over mercury in a carefully dried gas-tube. D wasonce more cooled with liquid air, so as t o condense the ammoniaremaining in the apparatus, the tap E was closed, rtnd the system onthe pump side of 3 thoroughly exhausted.Radium emanation, accumulated duringfour or five days from a solution contain-ing 0.21 11 gram of metallic radium, andmixed with about 0.5 C.C.of hydrogen,was now introduced through the capillarysyphon H, and E was then surroundedwith liquid air. After about fifteenminutes, in which time all the emanationhad condensed, the hydrogen was removedthrough the pump, and the requiredquantity of ammonia, prepared in theway described, was introduced throughH and frozen in Pon top of the condensedemanation, If the pump was worked atthis stage, traces of gas continued to passover indefinitely, and an analysis of thegas thus collected showed it to consistsolely of hydrogen and nitrogen, so thatit appears that solid ammonia is decom-posed by the emanation, even at - 190'.The drying tubes, C and K, containedlime freshly prepared from marble.Themixture of ammonia and emanation masnext introduced into the apparatus shownin Fig. 2. This consisted essentially ofa short length (about 5 cm.) of glasstubing of 1 cm. bore, containing an opaqueglass point sealed in so as t o form aconstant-volume gas chamber, B, theFIG. 2.Lvolume contained between a mercury surFace set to the point andR mark, a, OLI the capillary stem being previously accurately deter-mined by calibration with mercury. The constant-volume chamberterminated above in a capillary syphon, S, and at its lower endwas sealed to a piece of narrower glass tubing about 80 cms.long,including a stopcock, T, the only one used in the apparatus, whichwas permanently below the mercury surface and never came int392 USHER: THE INFLUENCE OF RADIUM EMANATION ONcontact with the gas. A mercury reservoir, R, of the samediameter as the chamber B, mas connected with the apparatus bya length of rubber pressure tubing. The greatest care was taken todry the inner glass surface thoroughly, and for this purpose, beforethe stop-cock was greased, the entire apparatus was placed in a largeair-oven and kept at a high temperature for several hours while acurrent of dried air was passed through it. I n order to introduce thegas, the apparatus was filled with pure dry mercury, and the tubecontaining the gas was brought over the end of the syphon, 8, ina mercury trough.By lowering the reservoir, R, the gas wasadmitted, and the end of the mercury thread which iollowed it was setto the mark a on the capillary tubing. The thread was then frozenin the horizontal portion of the capillary a t 6 by means of a paper-cupcontaining solid carbon dioxide, and the tip of the syphon was thensealed with a small blowpipe flame. Finally, the apparatus was fixedup against a glass scale ruled in millimetres, and frequent readingswere taken of the pressure exerted by the gas when the mercurysurface was set exactly to the point. During the interval betweeneach successive reading, the tap T was closed, so that the reactionproceeded at constant volume.It happened, on a few occasions, thatafter the capillary tip had been sealed and the mercury threadhad thawed, the latter was no longer set exactly to the mark a, andin such cases the distance between the two was measured and acorrection on the volume was made, as the capillary had previouslybeen calibrated by weighing out mercury. I n making a reading thetemperature of the gas and of the mercury column was carefully noted,and the barometric height was read a t the same time,The above description refers to the experiments with ammonia, butthose with nitrogen and hydrogen were carried out in exactly thesame manner. The gases were obtained by sparking pure ammoniaover mercury in a glass tube. The undecomposed ammonia wasremoved with a few drops of phosphoric acid, the residual mixtureof nitrogen and hydrogen was carefully dried, and a convenientquantity was collected in a tube in the same way as the ammonia, thecalcium oxide, however, being replaced by phosphoric oxide.Thesubsequent procedure differed slightly from that employed in theexperiments with ammonia. The apparatus shown in Pig. 1 wasmodified to some extent, but it will suffice here to say that, afterhhorough exhaustion of the apparatus through t h e mercury pump, thepreviously dried emanation, accompanied by its excess hydrogen, wastaken in through a capillary syphon, the emanation was frozen withliquid air, and the hydrogen removed through the pump. Finally, theliquid air was removed, and the sample of nitrogen and hydrogencollected for the experiment was admitted and allowed to mix witEQUILIBRIUM IN A GASEOUS SYSTEM.393the emanation, the mixture being then pumped off and transferred t oone of the reaction vessels already described.It will be obvious that throughout the whole of the operations justdescribed there is no possibility of serious contamination. It is truethat during the process of purification, gaseous emanation was broughtinto contact with the stop-cocks H, G, and E (Fig. l), but the totaltime of contact between tap grease and emanation was certainly lessthan thirty minutes, and it was proved by a blank experiment withemanation and some of the same rubber tap grease that if oxygen isexcluded, the only gaseous product of the action is pure hydrogen,the amount of which produced in half an hour would be quitenegligible.Each experiment was allowed to proceed for at Ieast four weeks, a tthe end of which period the amount of emanation still present wasinsignificant.During the first two days, readings were taken everyfew hours, and afterwards at the rate of about one every twenty-fourhours.At the conclusion of each experiment, the gas was removed fromthe reaction vessel and analy sed, the ammonia, nitrogen and hydrogen,and gases absorbable by potassium hydroxide being determined.Reference will be made to those analyses in tbe discussion of theresults.Experiment 1.-Volume o€ reaction chamber : 2.1 187 C.C. Initialvolume of ammonia at 0' and 760 mm. = 0.4514 C.C. About half thequantity of emanation taken for this experiment was accidentallylost, so that the proportion of ammonia to emanation is not known :CorrectedPOI. of gas.Time i n days.0.0 0'45140'56 0.48010.77 0'49201 '56 0.51831'83 0.52352 '58 0'54364'54 0.57655 5 4 0'58387'56 0'59569 -67 0'602012-58 0.604840-00 0-627Volumeincrement.0.00.0290-0410'0670.0720.0920-1250.1320'1440-1510.1530.176l/Aog. Yo/ v,.-0,05160.05380.04480.04130.03840-03010'02720'02210.01830'01430.0054l/E,tlog Yo/ vt. -0.05710'06200-05940.05710.06150.07070.0740.0860.1030.137 394 USHER: THE 1NFLUENCE OF RADIUM EMANATION ONExperiment 11.-Volume of reaction chamber : 3.1655 C.C. InitialInitial pressure = volume of ammonia at Oo and 760 mm.= 1.843 C.C.474 mm. :Time in days.0.00-0420'0830'1040.1350.1910-8651-0311-19s1.8542.042tL.185'L.8403'2303.8403'9585 -8406.8967'8408.84012.88636-0009 -8.10Correctedvol. of gas.1.8431,8541.8711'874l.8811-8912.0682'1042.1452.2622.3022.3232.4162'4552'5122.5232,6522.7032'7242.7572.7752.8042-871Volumcincrement.0.00.0110.0280.0310-0380.0480-2250-2610'3020.4190.4590 ~4800-5730.6120.6690.6800.8090.8600.8810.9140'9320.9611 -028l / t log. Yo/ vt.I0.06190.08010.07080.06700.06010.06540.06430'06490.06050.06100.06000.05700.05430*051@0.05050.04300.03960.03500.03370'03110.024 80.00981 /El,( 1 og.Yo/ Yt.-0.06230'08120.07200.06650'06210.07640.07770.08080.0540.0580.0890 -0950.0970.1020.1030.1230.1360.1470'1650-1830.253 -Expeviment 111.-Volume of reaction chamber : 2.406 C.C. InitialInitial pressure volume of ammonia at Oo and 760 mtn. = 0.909 C.C.= 306 mm. :Time i n days.0'00.0310'0730-761-081-752.082.783.754 '756-757-168.759-7510.7611-7613-7714-71?15-7632.00Correctedvol. of gas.0-9090'9140.9231.0371 '0831'1541 '1 881.2371'2911'3251.3771 '3871.3971 '4011.4081'4191'419[1'440]1.4191.433Voluiiieincxenien t.0.00.0050.0140.1280.1740.24502790'3280'3820.4160'4680.4780.4880 4920'4990'5100'5100.5100'524[O .53 11116I0g. Vo/ V*.-0.07720.09230.08680.08550-07790.0766O * O i O O0'06320.05590.04660.04180.03820'03470'03210 03040'02600'02270'0117I O ~ O ' L ~ S ]11 E~tlog. Fro/ Vt.-0.07760-09340 '1 0000.1030.1080.1100.1160'1240.1320.1560.1680.1840 '2020.2210.2530.310[ 0,35910.392EQUILIBRIUM IN A GASEOUS SYSTEM. 395Expe&ne)tt I \'.--Nitrogen and hydrogen. Same t u b e as in Exp. I.Initial Initial volume of mixed gases a t 0' and 760 mm. = 1.602 C.C.pressure = 615 mm. :Time in days.0.00.1350.698273982,9903.6784-0104.69811.8031 *89Corrccted vol. of gases.1,6021.5851.5401-4621 -4601'4421'4411.4251.4031.362Volnmc incrcnient.0 '0- 0'017- 0.062- 0.140- 0'142- 0'160- 0.161- 0.177- 0.199- 0'2.10Experi.rnent V.-Nitrogen and hydrogen.Same tube as in Expt. 11.Initial Initial volume of mixed gases a t 0' and 760 inm. =2-323 C.C.pressure =594 mm. :Time in days.0.00.71.i2.74 -75-76.730'0Correctcd vol. of gases.2.3232.2732'2472.2302'2412.2282.2252*18lVolume iii cwiiien t.0.0- 0.050 - 0.076 - 0 '093 - 0.082- 0.095 - 0 '098 - 0'142The analysis of the gases at the conclusion of each experiment wascarried out by means of a small glass burette, provided with a stop-cock and capillary syphon, and containing six opaque glass points.The volume between a mercury surface set to each of these pointsand a mark on the capillary fitem mas accurately determined bycalibration with mercury, and measurements were made by observing,against a glass scale, the difference between the level of the mercuryin a reservoir connected with the burette and that of the mercury setexactly to one or other of the points.The measurements are in allcases correct to within 0.003 C.C. The gas was always measiired dry,and was, if necessary, for example, after explosion or treatment witha wet reagent, pumped through a small tube of phosphoric oxide.Ammonia was cietermined by absorption with a few drops of phos-phoric acid, hydrogen by explosion with a measured excess of oxygen,and carbon dioxide by absorption with a lump of fused and moistenedpotassium hydroxide." The residual ga3, after removal of excessoxygen by phosphorus, was measured and cousidered to be nitrogen.The treatment of the gmes with liquid and solid reagents took placein small gas tubes, the gas being completely freed from the reagent* Any other acid gases, oxides of nitrogen, etc., arc consequently called ''CO2.396 USHER: THE INFLUENCE OF RADIUM EMANATION ONand dried before introduction into the measuring burette.Thefollowing table gives t8he results of the analyses of the gases at thetermination of the experiments :I. 11. 111. IV. V.c. c. c. c. c. c. C.C. c. c.NH, ...... ........ 0,173 0.78 0.312 0'006 0*010H, ... . . . . . . . , . . . . . . . 0,327 1 *56 0.814 0'980 1'321N, ..............I . . . 0.121 0.56 0'298 0'356 0'669 co, . . . . . . . . . . . . . . * 0 -002 0.014 0'000 0'019 0-185CO .............. ... 0.004 0.004 0'009 0*001 0'003Discussion of Besults.It is interesting to compare these results with the figures given byCameron and Ramsay, and for this purpose it is convenieut t ocalculate the values of the expression: Q = 100 -'L -'' and thecorresponding logarithms, as' is done by these authors. These valuesare given in the following table for Expts. I and 111; the reasonsfor omitting Expts. 11, IV, and V will be given presently.'a -KJEXPERIMENT I.Time in days.0.000.560 -771 '561-832.554 -545 '547'569.6712'58Time in days.0.000.761 '081.752'082-783.754.756.757 -768 -759.7510.7611-7613.77YoO - Yt.0.1760.1470.1350.1090.1040-0840.0510.0440.0320.0250'023Yo0 - Yt &=loo- va - Yo'100'083 '676.862-059.147-729'025.018'214.213-1EXPERIMENT 111.0.5240.3960-3500.2790-2450.1960-1420-1080-0560-0460.0360'0320-0250'0140.014100.075.666.853.346'837-427 -120'610.78 -86'96.14-82.72'7Log.Q.2'0001 '9221.8851-7921.7721-6791 -4621.3981-2601-1521'117Log. Q.2.0001.8781-8251 *7271-6701.5731'4331.3141 '0290'9440.8390.7850-6810'4310'431Log. Q/100/t = - k.-1,3921'4941'3341.2451-2431.1851.0860.9790.8770'702Log. Q / l O O / t = - k.-0'1610.1620.1560.1590.1540.1510.1440'1440.1360'1330'1250-1230.1 330.11EQUILIBRIUM IN A GASEOUS SYSTEM.397The figures in the last column of the preceding tables represent theconstant in the equation 'd = e - k t , or, rather, the constantcalculated with common instead of Napierian logarithms. It will benoticed that the value of - k diminishes fairly regularly with time,and that the underlying assumption, which would require it to remainreally constant, does not, therefore, strictly represent the facts.The time of half action is in Expt. I, 2.4 days, and in Expt. 111,1.9 days, both considerably less than the half-life period of theemanation, which is 3.86 days (Sackur). It seems, therefore, thatthe simple hypothesis that each atom of emanation in decaying pro-duces the same amount of change, that, in fact, the effect is at anytime proportional to the amount of emanation present, although i tmay be true under certain conditions, requires some modification'to make it agree with the experiments here recorded.Let us assume that the velocity of reaction a t any time, t , isproportional, both t o the amount of emanation and of ammoniapresent at that time.Now, during avery small space of time, Et is constant, so that the above expressioncan be integrated by keeping KEt as the constant, and the resultingexpression can be subsequently corrected for the variation of Et. We'03 -'od V Then -x =kEtk'Vt= HEtVt.get then : llog yo = KEt.t P+For the sake of comparison, we may consider that the velocity ofdecomposition depends only on the amount of ammonia present, andis not influenced by the decay of the emanation.We should then1 To find that -.log- was constant. The reaction has been treated as ant vtirreversible unimolecular one, since it is obvious from the analysis ofthe gases a t the end of Expts. IV and V that recombination takesplace to an almost inappreciable extent. Whereas in Expt. 111, 65.7per cent. of the ammonia put in was decomposed, in Expt. IV,starting with nitrogen and hydrogen, only 0.75 per cent. of themixture was recombined.1 1t vt E:tt v, The values of - log 5 and of -. log 5 have already been tabulatedfor Expts. I to I11 on pp. 393, 394, and it is interesting to note thatwhile the constant becomes smaller with time when no correction forthe decay of the emanation is applied, it becomes larger when thecorrection is introduced.Obviously, it is unreasonable to omit thecorrection for decay of the emanation; nevertheless, when the fullcorrection is put in, the constant changes in the opposite direction,although at the same time a distinct improvement is noticeable. I398 USHER: THE INFLUENCE OF RADIUM EMANATION ONis here suggested that a third factor, namely, the eficiency of theemanation, is required in order to explain the increase of the velocit1constant with time. Since an a-particle is effective over a range ofabout 8 cm. in ammonia gas under the pressures employed i n theseexperiments, a large proportion of its energy must be wasted when i tis enclosed in a tube of 1 cm.bore, although this waste need not beproportionately greater at one time than another; but on0 atom ofemanation is capable, as will be shown later, of decomposing at least134,000 molecules of ammonia, It is, therefore, highly probable thanwhen, as in Expt. 111, the emanation is present in the proportionof 1 atom to 10,850 molecules of ammonia, the efficiency of an a-particlewill be greater, as its chance of colliding with a larger number ofmolecules increases; in other words, each a-pnrticle will do morework when there is mor0 work to do.It is possible to make an approximate correction by assuming thatthe efficiency is proportional to the ratio of the number of emanationmolecules to ammonia molecules at any time, although of course thiscannot be expected to hold over an extended period.We may assume t h a t - - dv = KEtV&, where Pt is the efficiency.dt1 VEt' Vft v+ Then if Ptm ' we get -.log 0 = constant. This expression givesa much better value for k over a" period of six or seven days, startingat one day from the commencement of the experiment, but it after-wards becomes smaller again, a result which is to be expected for tworeasons: first, because the assumed correction is the most drasticpossible, and can only be strictly valid over a very short range ; andsecondly, because as the reaction proceeds, the energy of the emana-tion is more and more used tip in useless work, namely, in impartingincreased velocity to the accumulating products of decomposition.W ecan, t,herefore, make the further assumption that the efficiency isproportional, not only t o the ratio of the amounts of emanation andammonia, but also to theactualquantity of ammonia present. I n this case,pt = -.Vt, vt and the velocity constant becomes R= 1 log 5.Et &Vt. t" vtThe constants calculated in the two ways suggested are tabulatedon p. 399 for Expt. 111.The correction appears to be rather too great in the first case, andslightly too small in the second, but on the whole both sets of constantsare much better than when no correction for change in efficiency isintroduced. It would doubtless be possible by suitably compromisingbetween the two methods t o obtain a still more constant value of K ,but is it probably not worth while to attempt this, because there arEQUILIHHIUM IN A GASEOUS SYSTEM.399Time in days. K = l/Yttlog. Yo/ Yt. K =0'0730.761 -081 *762-082-753.754 -756.757 -768.759.7510'7611.760.1030.1110.1160-1170'1210.1200.1200.1130.1060.0970.0910,0830,0780.0761- - Iog. Yo/ vt. J7m. t0.0980.1060.1090.1110.1160-1180'1210'1210.1290-1270-1270'1250.1340'138slight complications in all the experiments, and these will nowconsidered.It will have been noticed in Expt. IV that if the amountbeofnitrogen and hydrogen recombined is calculated from the observedchange of pressure, there should be 0.240 C.C. of ammonia at theconclusion of the experiment.As a matter of fact, the analysis showsthat only 0.006 C.C. was formed. The gases and the apparatus wereboth very carefully dried, there was no contamination by air, and nopossibility of leakage during the course of the experiment; the gaswas under considerably reduced pressure the whole time. Clearly,then, nearly a quarter of C.C. of gas had ceased to exert anypressure. We can make up a balance sheet with respect to the totalquantity of hydrogen and nitrogen put in a t the commencement, andfound a t the termination, of two typical experiments : Nos. 111 andIV, reckoning as hydrogen and nitrogen these gases in combinationas well as free. This balance sheet gives the clue to the observeddiscrepancies.Hydrogen Nitrogenput in at put in at Hydrogen Nitrogencomniencement. eommencemcnt, found at end.found a t end.c. c. c. c. c. c. c. c.Espt. I11 ...... 1.363 0'454 1 '282 0.454Hydrogen lost in Expt. 111 ............... 0.081 C.C.Nitrogen ,, ) ) I V ............... 0.041 ),I n Expt. 111 a small quantity of nitrogen mas probably lost, forthe &st reading was made as soon as possible after, but not atprecisely the same moment as, the emanation mas mixed with theammonia. The initial volume therefore refers to a mixture ofammonia with a trace of its decomposition products, and not to pureammonia, as is assumed for the purpose of the above calculation.)) IV ...... 1.201 0'400 0'989 0-359Nitrogen ), ) ) 111 ............... 0'000 ,)Hydrogen ), I V ............... 0'212 ,400 USHER: THE INFLUENCE OF RADIUM EMANATION ONIn Expt.IV we find, as one would expect, that a larger proportionof hydrogen and nitrogen is missing, because the partial pressure ofthese gases is considerably higher than in the preceding experiment,in which no free hydrogen or nitrogen was introduced initially.Now this missing gas can only have disappeared in three mays : (1)it may have reacted chemically with the glass of which the apparatusmas made; (2) it may have been driven into the walls of the vesseland remained there, or (3) it may have gone completely through theglass. The first possibility is very unlikely, because nitrogen waslost as well as hydrogen, and the glass did not present the appearanceof having been attacked ; only the usual brownish-violet coloration wasobserved,In order to settle this question definitely, it was decided to carryout a blank experiment with pure hydrogen and emanation, arrangedso that any loss of gas could be observed and measured, and so as todetect any gas which might pass right through the glass.In themeantime, the three reaction chambers employed in the fiveexperiments already described were coarsely powdered, placed in apiece of Jena glass tubing, first exhausted cold by a Topler pump,and finally heated to redness and again exhausted; nearly 2 C.C.of gas were pumped out of the heated glass, and its composition wasas follows. The measured total volume was 1.817 C.C. :CO, 1.416 C.C.CO 0.340 ,,H, 0.096 ,,N, 0-066 ,,Total ... 1.818 C.C.The experiment was rather unsatisfactory, as the powdered glasswas not treated with chromic acid to remove traces of grease,dust, etc., before being heated; nevertheless, nearly 0.1 C.C.ofhydrogen was recovered, and a rather smaller quantity of nitrogen.The apparatus used for the blank experiment was made of glass ofabout the same thickness as that used in the previous experiments.It is diagramatically sketched in Fig. 3. The constant volumechamber, C, containing an opaque glass point, was itself sealed intoa wider piece of glass tubing, A, which was drawn out at the top andconnected, through a small phosphoric oxide tube, with a Toplerpump, no taps being used. The space between the reaction chamberand this outer tube was at the commencement of the experiment verythoroughly evacuated, and the pump with which it was connected masworked from time to time during the experiment in order to collectany gas which might be driven througn from the reaction chamberEQUILIBRZUM IN A QASEOUS SYSTEM.401The latter was sealed, immediately below the inserted join, to a pieceof narrower glass tubing about 80 crns. long, the lower end of whichwas connected through an air-catch with a length of rubber pressuretubing attached at its distal end to a mercury reservoir, H. A smallcapillary syphon, 8, was sealed on shortly below the inserted join, andwas used for taking in the hydrogen and emanation. Another pieceof tubing was sealed onabout 4 crns. below thesyphon, and was con-nected through the tap 17with a second Toplerpump*Mercury was firstpoured into the reservoir,and the rubber tubingwas clipped when themercury stood a shortdistance below the T-piece carrying the tap T,The end of the capillarysyphon was sealed, andthe apparatus was thenvery thoroughly ex-hausted through T, Thelatter was then sbut, andt h e reservoir was raiseduntil the mercury stoodin the tubing betweenthe lower T-piece andthe capillary syphon.Theend of the latter was thenscratched with a glassknife, and the point wasbroken off inside a smallFIG. 3.gas tube containing the emanation mixed with about half a C.C. ofhydrogen, carefully purified and dried. The gas entered the apparatus,and the reservoir mas again raised, until the hydrogen and emanationwere forced up into the reaction chamber, and the mercury in thereservoir was level with the tip of the capillary syphon ; the latter wasthen sealed in a blow-pipe flame.The entire apparatus was fixed up infront of a glass scale, and frequent readings were taken of the pressureof the gas when the mercury was set to the point. The volumeof the reaction chamber was subsequently determined by measuringthe pressure of Y quantity of dry air introduced into it, and afterward402 USHER: THE INFLUENCE OF RADIUM EMANATION ONremoved and re-measured in a constan t-volume point burette alreadycalibrated.Throughout this experiment no gas passed through the wa!lsof the reaction cbamber into the surrounding vacuous space, whichremained quite empty.The amount of hydrogen in the tube decreased,however, from 0.610 C.C. to 0*4S7 C.C. The following table gives thereadings :Correctedvol. of hydrogen. Time in days.0.00 0-5731-15 0.5301'81 0'5142.81 0.5073-81 05104.81 0.5056-81 0'4958.81 0'49415-81 0'49025-82 0.489Volumedecrease.0'0430'0.590'0680'063O'OGS0.0780.0i90'0830-084-K= l/Et. t log. Yo/ Yt.-0.03630'03550.03150.02610.02iO0 03130 03600 07110.267The results are not sufficiently regular to admit of their applica-tion as quantitative corrections to tho experiments with ammonia andwith nitrogen and hydrogen. It is even possible that aEter some timethe glass walls of the containing vessel become so pitted by thebombardment that the surface is appreciably altered, and, in anycase, the problem is probably much more complicated than it a t firstappears.A t the conclusion of this last experiment, the reaction chamberwas powdered, and the powder was carefully cleared with hot chromicacid, washed, dried, and put in a clean Jena-glass tube andexhausted cold, It was then exhausted at, a red heat, and inthis way 0.076 C.C.of gas was extracted. Its composition mas :CO, 0.014 C.C.H2 0.061 ,,--Total 0.075 ,,There can therefore be no doubt that hydrogen, and, to a smallerextent, nitrogen, is driven into the glass walls of its containingvessel when mixed with radium emanation, The greater part ofsuch gas can be recovered when the glass is strongly heated,I n calculating the velocity constants and the values of theexpression &, it was stated on p.396 that the reasons for omit-ting Expts. 11, IV, and V would be given later. 1V and V wereof course omitted because the observed pressure changes do notreally iudicate recombination of nitrogen and hydrogen, as hits justbeen shown. It will be seen on referring to the analysis of thegas from Expt. 11 that, although there is an apparent loss oEQUILIBRIUM IN A GASEOUS SYSTEM. 403hydrogen, there is more nitrogen at the end than there was at thebeginuing, and the same is true for Expt. V. There was noordinary leakage during either of these experiments, but the sameapparatus was used for each, and this curious result may be explainedon the hypothesis that there were bubbles in the glass vessel at itsjunction with the capillary tubing at its upper end, and that the glasswas so thin in the region of these bubbles as to become perforated bythe a-particles, and so allowed a slow diffusion of air from without.Unfortunately, the discrepancy was not discovered until after thetubes had been ground up.Chemical E’ciency of the Emnncction.It has been pointed out that in all the experiments hithertodescribed, the emanation probably brings about only a fraction of theamount of decomposition which it could effect under more favourableconditions.I n Expt. 111 the total volume of ammonia decom-posed was 0.5‘37 c.c., and the emanation which mas mixed with itwas the product of six days’ accumulation, and therefore, accordingto the recent work of Gray and Ramsay (Trans., 1909, 93, 1073),0-000081 C.C.I n this experiment, then, the ratio of the volumes ofemanation and ammonia was 1 to 7380, or, in other words, eachatom of emanation decomposed on the average 7380 molecules ofammonia.In order t o get some idea of the amount of chemical work whichcould be done by the emanation under favourable conditions, an ex-periment similar t o those. described above was carried out on a muchlarger scale. A large round-bottomed flask of 2 litres capacity wasfilled with ammonia a t about 260 mm. pressure, andjmixed with sixdays’ accumulation of emanation. The course of the reaction couldnot, of course, be followed, but, at the end of a month, the gases werepumped out and the quantity of nitrogen and hydrogen produced wasroughly estimated.It was found that 10.9 C.C. of ammonia had beendecomposed. This is, in every sense, a minimum value, for no accountis taken of the fact that that portion of the emanation wbich wasnear the walls of the flask was not entirely used up in decomposingammonia, and no carrection is introduced for gas driven into theglasP.There is, however, no doubt that the conditions of this experimentwere extremely favourable as compared with those of the precedingones, and were probably such as to secure a t least 90 per cent. of themaximum amount of decomposition. In this case, one molecule ofemanation decomposed 134,300 molecules of ammonia.If we take this as an approximate measure of the chemicalefficiencyVOL. XCVII.E 404 USHER : RADIUM EMANATION.OF the emanation, we can calculate the fraction of the total energyof the emanation which is used in effecting chemical decomposition.It is reasonable to assume that the a-particles are mainly respon-sible for the effects observed, and, further, that their power to decom-pose ceases when they no longer produce any other physical effect,that is, when their velocity is reduced to 64 per cent. of their averageinitial velocity of projection.On this hypothesis, the total kinetic energy of one atom of emana-tion available for chemical work will be that of three a-particles, sincethe atoms of radium-A, -23, and -C are projected with less than thecritical velocity.Now, the total kinetic energy of one a-particle is 6 x 10-6 ergs.,hence the energy available for chemical work = (6 x 10-6) x (0.64)2 =about 2.5 x 10-6 ergs.Therefore one atom of emanation produces about 7.5 x 10-6 ergs.available energy.Taking the mechanical equivalent of heat as4.182 x lo7 ergs. per calorie, this amounts toNow, 134,300 molecules of ammonia (which are decomposed by oneatom of emanation) require for complete decomposition about2-02 x lO--15 calories, hence the chemical efficiency of the a-particle inthis exneriment isor a little more than 1 per cent.As regards its influence on equilibrium in the system ammonia-hydrogen-nitrogen, it can only be said that if any definite state ofequilibrium were reached under ideal conditions, it would be onecorresponding with a very high temperature.Under ordinary con-ditions there is no true equilibrium, but only a state of rest dependingon the proportions of ammonia and emanation, surface, and possiblyother factors as well. The emanation cannot be called a catalyst inany sense, and the effects produced are probably mechanical or electricalin origin.The principal conclusions arrived at in the course of this investigationmay be summarised as follows :(1) Ammonia is decomposed by radium emanation at the ordinarytemperature, and the decomposition is nearly irreversible.(2) Recombination was not observed to take place to a greaterextent than 0.86 per cent,(3) Decomposition of solidified ammonia by solidified emanationproceeds with appreciable velocity a t - 190'ATTEMPTED RESOLUTION OF IlACEMIC ALDEHYDES. 405(4) The decomposition a t the ordinary temperature follows approxi-mately the course of a unimolecular homogeneous reaction whencorrecting factors for the decay of the emanation and alteration of itsefficiency with time are introduced.(5) If t h e ratio of ammonia to emanation molecules does notexceed 10,000 to 1, the statement that each atom in disintegratingproduces the same effect is not strictly true, on account of the wasteinvolved when t h e system is rich in emanation.(6) The largest effect observed mas the decomposition of 134,300molecules of ammonia per atom of emanation,(7) The energy required to produce the largest effect observed wasabout 1 per cent. of the energy actually expended during the productionof that effect.(8) All experiments with gases in glass vessels in presence of theemanation are complicated by the fact that gas is driven into theglass, and can only be recovered by heating strongly.(9) Hydrogen is driven into glass t o a greater extent than nitrogen,and as much as 0.24 C.C. of the former gas has been thus lost duringa single experiment.I wish, in conclusion, to express my indebtedness to Sir WilliamRamsay, who kindly placed at my disposal thethe experiments, and whom I have also to thankcriticism.UNIVERSITY COLLEGE,LONDON.emanation used infor his advice an

ISSN:0368-1645    

DOI:10.1039/CT9109700389

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

ATTEMPTED RESOLUTION OF IlACEMIC ALDEHYDES. 405XLV.-Atlemptecl Resolution of Racemic Aldehydes.By WILLIAN ORD WOOTTON.DURING recent years numerous investigations have been under-taken with a view to elucidating t,he relationship between thechemical composition and rotatory power of optically active sub-stances. Although considerable progress has been made in thisdirection by the study of homologous series of ethereal salts andalkyloxides, it can scarcely be claimed that any generalisations ofwide application have yet been established. This is no doubt to beexplained partly by the uncertainty attaching to the conventionalmethod of expressing optical rotatory power, and partly by thefact that with few exceptions the compounds chosen for examinationhave been of too complex a character to admit of great emphasisbeing laid on the conclusions drawn from them.Owing chiefly toE E 406 WOO‘rTON : ATTEMPTED RESOLUTION OFthe difficulty in preparing them, we are acquainted with bat fewstructurally simple substances which could be utilised in such work.The ideal substance from this point of view would be an easilyaccessible compound, of low molecular weight, having only oneasymmetric carbon atom, and containing no cyclic grouping; itwould be an additional advantage if it contained a chemicallyreactive group or radicle directly attached to tlie asymmetric carbonatom, through the agency of which the effect of substitution,addition, or of the introduction of double linkings could be studied.The value of a substance containing a single asymmetric carbonatom in connexion with the application of Guye’s modified equationhas been pointed out by Bose (Physikal. Zeitsch., 1908, 9, 860).The series of aldehydes of the type CHRR’*CHO fulfils theforegoing conditions, and since they are easily obtained by thegeneral method of Darzens (Corn@.rend., 1904, 139, 1214), itappeared to be of interest to ascertain whether these presumablyracemic substances are capable of resolution into optical antipodes,or whether by other processes they could be obtained in activeforms. The direct resolution of racemic aldehydes has been accom-plished by Neuberg and Federer (Bey., 1905, 38, 868), whoemployed d-phenylamylhydrazine, a substance not easy to prepaxein the pure state, and which, like most amyl compounds, might beexpected to form oily derivatives. I n a previous communication(Trans., 1907, 91, 1890) I have described the preparation of anoptically active amine, namely, 4-bromo-3-aminophenyl-a-camphor-amic acid, which it was hoped might be applied to the same purpose.The action of this base on hydratropaldehyde, CI’IMePh-CHO, hasnow been examined, but the results obtained did not seem towarrant the extension of its use.Attention has been drawn (Zoc.cit.) to the di%culty with whichcamphoric anhydride unites with the nitroanilines t o form thenitrophenyl-a-camphoramic acids. This combination has now beeneffected in the case of m-nitroaniline. The nitro-acid obtained hasbeen reduced to the amino-compound, and the beliaviour of theproduct towards a racemic aldehyde studied.For this purposebutylchloral, CCl,Me*CIICl*CHO, was selected, since Wheeler ( J .Amer. Chem. SOC., 1908, 30, 136) has found that chloral readilycondenses with primary aromatic amines, forming well-definedcompounds. I n the present instance, however, although con-densation between one molecule of tlie aldehyde and two moleculesof the base presented no difficulty, it was not found possible toresolve the product by fractional crystallisation into its opticallyactive components.A more promising method that suggests itself would be to resolvRACEMIC ALDEHYDES. 407a PP-substituted glycidic acid by the aid of an alkaloid, and then tod.ecompose the active salts by a mineral acid, when carbon dioxideis eliminated and the aldehyde produced.Experiments have beencarried out in this direction, but although a sodium salt of/3-phenyl-/3-metliylglj cidic acid has been obtained having [a], + 1 6 * 6 Oin aqueous solution, yet the corresponding aldehyde appears to beoptically inactive. This, however, may be due t o the fact thatthe acid itself contains two asymmetric carbon atoms, and it ispossible that resolution has only been effected in the case of thecarbon atom which ceases t o be asymmetric on conversion of thescid into the aldehyde:CMePh<b cH'Co2H -+ CHMePhCHO.I n the expectation of obtaining optically active bases by thereduction of nitro-derivatives of benzylidenecamphor, I haveexamined the action of 0-, m-, and p-nitrobenzaldehyde on sodiumcamphor.Albhough this line of inquiry has been abandoned onaccount of the very poor yields obtained, the results of the experi-ments are recorded in the sequel.A point of some interest has been noticed in connexion with theoptical properties of the derivatives of a-camphoramic acid. Ithas usually been found that the rotatory power of a cyclic com-pound is considerably greater than that of the correspondingopen-chain derivative. Thus the rotatory powers of esters of1-methyl-3-cycZopentanone-4-carboxylic acid are about thirty timesas great as those of the corresponding esters of methyladipic acid(Haller, Com.pt. rend., 1905, 140, 1205). The hexahydrophthalicacids have much lower specific rotations than their anhydrides(Werner, Ber., 1899, 32, 3046).Many other instances might bequoted. Camphoric acid and its anhydride, however, form anexception to the rule, the acid ha.ving [a], +46O in alcohol, whilstthe anhydride has [aJD - 7.7O. Similarly, a-camphoramic a,cid has[a], + 45O in acetone, whilst camphorimide has [a],, - 10.1O. I norder to ascertain whether this peculiarity was exhibited by theN-substituted amides and imides of camphoric acid, I have preparedseveral new members of this series, and determined their rotatorypower in acetone solution a t a temperature between 19O and 21O.Variations in the concentration of the solution between 1.5 and3 parts per 100 have very little effect on the rotatory power.The results arc3 summarised OK p.408.It will be noticed that the molecular rotatory power of the acidis always greater than that of its corresponding irnicle, except inthe case of the a-naphthyl aiid o-broniophenyl derivatives. Thedifference between the molecular rotatory powers of the acid an408 WOOTTOK : ATTEMPTED RESOLUTION OFDerivative.Me thy1 ........................Ethyl ...........................n-Propyl .....................n-Butyl ........................n-Amy1 ........................n-Hexyl .......................Ally1 ...........................O-Tolyl ........................P-Tolyl ........................B-Naphthyl ..................m-'l'olyl ........................a-Naphthyl .................4-Hydroxyphengl .........4 -E thoxy phenyl ............2-Chlorophenyl ............3-Chlorophenyl ............2-Bromophenyl ............3-Bromophenyl ............4-Bromophen yl ............3-Nitrophenyl ...............3-Aminophenyl ............4-Broino-3-nitrophenyl ...4-Bromo-3-aminophenyl ..4-Benzeneazophenyl ......4-Chlorophen yl ............*Camphoramic acid.-33.24" 70 *6O17-1 38.818.45 44-515-8 40 -318.9 50.816 -9 47 '813 *54 32.433 '9 98.031 '0 89'037.0 107 -07-46 24'264 '9 210.949'2 143'139.5 130.037.0 114'040-5 125-533-2 117-037.8 134'032.0 102.439.9 116.540'7 109.5 *87.7 332.5 *[alD'- 16.4 - 50'8- 31'8 - 41'8- 48'4 - 193'2 +tIn alcoholic solution.Camphorimide. - 7 '26" 14.1'8.87 18 510.9 24.312'8 30.37.7 19.310.8 28.67 -95 17'615.7 43.017.6 47 -012.7 34.026'34 so-718.0 55.218.5 55'014.1 41 *216'2 47 .o16'2 47'013 -3 44.715.4 51'015.7 52.01.7 5-1ra3D.[MID.- -.- -- - - (feeblydextrorotatory)- -imide in the case of 0-, m, and p-isomerides is always greatest inthe p-compounds. The homologous series of alkyl derivatives showno marked regularity; it is noteworthy, however, that the twoally1 compounds show distinctly lower rotatory power than thecorresponding n-propyl derivatives, in this respect resembling theallylamides in the rnalic and tartaric series, which show abnormallylow rotatory powers when compared with the propylainides (Frank-land and Done, Trans., 1906, 89, 1861).EXPERIMENTAL.Attempted Preparation of OpticaZZy Active Bydratropaldehyde.Hydratropaldehyde and 4-bromo-3-amino-a-camphoramic acid didnot interact in alcoholic solution, either in the cold or on warming,and attempts to obtain a condensation product with benzaldehydewere equally unsuccessful.Resolution of Sodium 8-Phenyl-8-methylglycidate.Preliminary experiments with the quinine salt of P-phenyl-P-methylglycidic acid having shown that this substance was unsuit-able for the purpose, the brucine salt was prepared by addinRACEMIC ALDEHYDES.409brucine hydrochloride (I mol.), dissolved in the minimum amountof warm water, to a warm aqueous solution of sodium P-phenyl-P-methylglycidate (2 mols.). On allowing the solution to evaporatespontaneously over potassium hydroxide in a vacuum, clusters ofradiating, irregular prisms separated, which were crystallisedrepeatedly froin absolute alcohol until optically constant, care beingta.ken to avoid prolonged heating with the solvent :0.2402 gave 10.4 C.C.N, at 23O and 760 mm.0.6475, in 20 C.C. water, gave, in a 2-dcm. tube, a - 1-14', whence0.6800, in 20 C.C. absolute alcohol, gave, in a 2-dcm. tube,a -0*60°, wlience [aID - 8'82O.When rapidly heated, the salt melts and decomposes a t141-142O. It decomposes on boiling with water or when heateda few degrees above its melting point, giving brucine and hydratrop-aldehyde. A good yield of the latter was obtained when the saltwas slowly heated under diminished pressure; the product wascollected in three separate fractions, but each of these proved tobe optically inactive when examined in ethereal or alcoholic solution.The mother liquor remaining from the preparation of the salt waspale brown in colour, and when kept in a vacuum deposited a smallquantity of the crystalline brucine salt, together with a resinoussubstance which appeared to contain hydratropaldehyde togetherwith the free alkaloid. Dilution of the liquid with water caused afurther precipitation of brucine. The hydratropaldehyde was foundt o be inactive.N=4.89.C,,H,,0,N2 requires N = 4.89 per cent.[a],, -17.7'.QH*CO,Na, w ~ s Sodium d-P-Ph eny 1-P-me t h y lgl y cidat e , CH3> "<oCGH.5obtained by grinding the foregoing brucine- salt with water con-taining the calculated amount of sodium hydroxide. The alkaloidwas removed by repeated extraction with chloroform, and thesolution allowed t o evaporate in a vacuum.The sodium salt wasfinally obtained in colourless leaflets after three crystallisationsfrom dilute alcohol :0'3002 gave 0.1097 Na,SO,.0.6000, in 20 C.C. water, gave, in a 2-dcm. tube, a + l*OOo, whenceNa= 11-88.C,H,O,Na requires Na= 12-10 per cent.[a],, +16*6O.When dissolved in water and treated with slightly less than thecalculated amount of sulphuric acid, carbon dioxide was evolved,and the solution became turbid through the separation of hydratrop-aldehyde. I n one experiment this was removed by steam dis41 0 WOOT1'ON : ATTEMPTED RESOLUTION OFtillation, and in another by extraction with ether; both specimens,however, appeared to be optically inactive when examined in 5 percent.solutions of alcohol, chloroform, or ether. The aldehyde,moreover, gave a semicarbazone identical with that obtained fromthe racemic sodium salt.Attempted Resolution of B~t?/Zc?tloraZ.-Condensation occursreadily when an aqueous solution of m-aminophenyl-a-camphoramicacid (see below) is shaken with butylchlornl. It is advisable? how-ever, t o add the butylchloral (1 mol.) to a solution of the sodiumsalt of the acid (2 mols.). The aldehyde dissolves immediatelywith considerable development of heat.Tric h lor0 b u t ylidene b is-3-aminoph emyl-a-camphorumic A cid,CMeCI,*CHC1*GH(NH*C6H4*NH*CO*C8H14~C0,H)2,separates as it bulky mass of colourless needles when the solutionof its sodium salt is acidified with acetic acid.After crystallisationfrom dilute alcohol, it melts and decomposes at 126-130° whenheated moderately rapidly. Attempts to resolve it by fractionalcrystallisation from this solvent and also from acetone were notsuccessful, successive fractions showing practically the same rotatorypower. Prolonged heating with solvents brings about decom-position :0.9081 gave 0.0510 AgC1.0.5110, in 20 C.C. acetone, gave, in a 2-dcm. tube, aD +1*40°,C1= 13.89.CssH4,0,N4C1, requires C1= 14.38 per cent.whence [aID +27*4O.Ni't ro-derivativ es of Benz ylid enecamphor.The only nitro-derivative of benzylidenecamphor hitherto knownhas been described by Haller (Compt. rend., 1895, 121, 36). Bythe action of fuming nitric acid on benzylidenecamphor, a colour-less compound wits obtained, to which he ascribed the constitution:C(NO,)* CHPh-NO,C*H,4<&-jThe nitro-groups do not appear to be attached to the benzenenucleus, since the substance furnishes benzylidenecamphor onreduction.Action of p-Nitrob enzaldehyde o n Sodium Camphor.-Thesodium camphor required in these experiments was prepared by theaction of sodium or finely divided sodamide on camphor dissolvedin dry ether, benzene, or toluene.The reactions appeared t o followthe same course whichever method was adopted, the use of sodamidewith ether, however, wits preferred as giving cleaner products anRACEMIC ALDEHYDES. 411a better yield. On adding two-thirds of the calculated quantity ofp-nitrobenzaldehyde to a well-cooled suspension of sodium camphor,a, vigorous action ensued, accompanied by development of heat.The mixture was kept below 5O for an hour, and then heated fora short time on the water-bath.The reddish-brown, pasty masswas extracted with water, the layer of organic solvent separated,dried, and finally heated on the water-bath until the solvent andthe greater 1 art of unaltered camphor had been removed. Theaqueous extract on the addition of an acid gave a voluminous yellowprecipitate consisting chiefly of p-nitrobenzoic acid. The residueleft after evaporation of the organic solvent appeared as a viscous,red oil, which slowly deposited yellow crystals. The oily matter wasremoved by extraction with cold alcohol and examined separately.The crystalline residue contained the following two substances.I.A compound, C,,H,~O,N,.-This product is sparingly solublein alcohol, ether, or benzene, and readily so in pyridine or carbontetrachloride, from which it separates in small, orange-red prisms,melting at 280-281O. The compound is distinguished by itsremarkably high rotatory power; it does not give Liebermann’sreaction, and develops no coloration with alcoholic potash. Twodeterminations of the moleculax weight in chloroform solution bythe ebullioscopic method gave 422 and 446 respectively, the aboveformula requiring 538 :0.0913 gave 0.2529 CO, and 0.0597 H,O.0.3559 ,, 12.8 C.C. N, at 18O and 744 mm. N=5*65.0.0939, in 25 C.C. chloroform, gave, in a 2-dcm.tube, a, +4.55O,II.--4--Nitrobenzylidenecamp/~or, c,H,,<X~ .-Thiscompound separates from alcohol in bright yellow, glistening leaflets,melting a t 156-157O; it is sparingly soluble in alcoholic potassiumhydroxide, giving a yellow solution. Concentrated sulphuric aciddevelops an orange-red coloration :C = 75-52 ; H = 7.25.C,,H,O,N, requires C = 75.82; H = 7-06 ; N = 5.20 per cent.whence [a], + 605O, and [MI, + 3255O.:CH*CGH,*NO,0.1012 gave 0.3148 CO, and 0.0592 H,O.0.1780 ,, 7.6 C.C. N, at 16O and 754 mm. N=4.82.0.3102, in 20 C.C. chloroform, gave, in a 2-dcm. tube, a, +3-55O,whence [a], + 437’, and [MI, +1345O.Examination of t h e Alcoholic Extract.-A deep red oil, havinga slight odour of camphor, remained after removal of the alcoholby evaporation.The oil is insoluble in water, but freely soluble inthe usual organic media; on adding alkali hydroxide to its alcoholicsolut.ion, an intense purple coloration is developed, which, onC = 71.71 ; H = 6-38.CI7Hl9O3N requires C = 71.59 ; H = 6-66 ; N = 4-88 per cent412 WOOTTON : ATTEMPTED RESOLUTION OFdilution with water, changes to red.acids, but restored by alkalis.contains an enolic form of 4-nitrobenzylidenecamphor :The colour is destroyed byIt is possible that this productc:c:c,H', : y oC,H,,<&O OH'A chromophoric oil having similar properties has been describedby Forster, who obtained it by the action of p-nitrobenzyl chlorideon isonitrosocamphor in presence of sodium ethoxide (Trans., 1908,93, 249).Decomposition occurs when the oil is distilled underdiminished pressure, and all attempts to isolate a pure compoundor prepare a crystalline derivative have failed.No chromophoric substance is formed if the temperataure ofreaction is allowed to rise during the preparation; under theseconditions, the main product is the compound C3,H3d0,N2, togetherwith a very insoluble brown substance which has not yet beenobtained in a state of purity. To ascertain whether the presenceof the camphor nucleus is essential for its formation, experimentshave been carried out on the action of p-nitrobenzaldehyde on thesodium derivatives of ethyl acetoacetate, carvone, and pulegone ;no chromophoric product was recognised, however, and this wouldappear to exclude the possibility of the colour having arisen fromthe action of the alkali on any derivative of dinitrostilbene.Itmay be mentioned that the sodium derivative of pulegone is veryreadily prepared by the action of sodamide on an ethereal solutionof pulegone. The action proceeds briskly without warming, and agood yield is obtained.Action of 0- and m-Nitrobenzaldehyde orb Sodizcm Camphor.2-1Vitrobenzylidenecamphor, C17H1903N, prepared in the same wayas the 4-nitro-compound, occurs as well-formed, light brown prisms,melting at 116-117O. A solution in chloroform gave [a], +50°approximately; owing t o the absorption of light, the rotatory powercould not be accurately determined. The compound itself gives nocoloration with alcoholic potassium hydroxide, but the oily materialfrom which it is separated develops an intense purple colorationwith this reagent:0.2633 gave 11.9 C.C.N, at 28O and 766 mm.C,,Hlg03N requires N = 4.88 per cent.S-flitrob enzylidenecamphor, C,,Hl9O3N.-This compound andm-nitrobenzoic acid are the only products of the action of maitro-benzaldehyde on sodium camphor. It was obtained as a yellowoil, which, on addition of alcohol, rapidly solidified. WhenN=4.99RACEMIC ALDEHYDES. 41 3crystallised from hot alcohol, it forms very pale yellow needles,melting a t 110-11lo :0.2024 gave 9.4 C.C. N, a t 19O and 748 mm.0.0934, in 15 C.C. chloroform, gave, in a 2-dcm. tube, a, +3*92O,N=5*13.CI7Hl9O3N requires N = 4.88 per cent.whence [a]= +31l0, and [MI, +783O.Alkyl Derivatives of a-Camplaoramic A cid, CO,H*C~H,,*CO*NHR.The following new members of the series were prepared by theinteraction of camphoric anhydride (1 mol.) with an alcoholicsolution of the amine (2 mols.).After purification by conversioninto the sodium salt, the free acid was regenerated by the additionof hydrochloric acid and crystallised from dilute acetone :Analysis.EmpiricalEthyl . . . . . . . . . Cl,H,,03Nn-Propyl.. . . . C,3H,303NDerivative. formula.n-Btttyl . . , . . . C,,H,,O,Nn-Amy1 . . . . . . C,,H,O,Nn-Hexyl . . , , . . C,,H,,O,NAlly1 ......... C,,H,,O,NCrystallineform.HexagonalleafletsHexagonalleafletsHexagonalleafletsCrystallinemassHexagonalleafletsLeafletsM. p. Found.173-175" Nz6.08187-188 N = 5-79124-125 C = 65 *71H= 9-48- C =66*58H = 10.25123-124 N= 5.21157-158 N=5.66Theory,per cent.6.175.8165.899 '8066-9110.034.955 *S7Aryl Derivatives of a-Camphoramic A cid,CO*NHRC*H,*<C~,HI n most cases these compounds are readily obtained by heatingan intimate mixture of camphoric anhydride and the substitutedamine for a few minutes at 150-180°.I n the case of m-nitro-aniline, a-naphthylamine, and ortho-substituted amines, it is neces-sary to heat for a longer period in sealed tubes.3-Nit rophenyl-a-canzlrhoramic A cid,CO,H * C,H ,* CO NH C,H,* NO,,is prepared by heating 13 grams of camphoric anhydride with10 grams of m-nitroaniline at 150° for one hour in a sealed tube.The crystalline mass is dissolved in dilute ammonia, the solutionfiltered after twenty-four hours, and then acidified.The first fewdrops of acid precipitate a brown, resinous product, but furtheraddition of acid yields the required compound in a state of purity.It is crystallised from acetic acid containing a little stannouschloride, and finally from alcohol, from which it separates in large414 WOOTTON : ATTEMPTED RESOLUTION OFcolourless, hexagonal leaflets, which darken at about 200°, and meltand decompose at 212-213O :0.3052 gave 18.6 C.C. N, at 20° and 754 mm. N=8.71.0.6178, in 20 C.C. acetone, gave, in a 2-dcm. tube, a, +1*97O,3-A minophenyl-a-camphoranzic A cid,C,,H,,O,N, requires N = 8.75 per cent.whence [a] +32*Oo.CO,H*C,H,,*CO*NH*C,H,*NH,,prepared from the foregoing compound by reduction with ferroussulphate in ammoniacal solution, forms small, colourless needles,melting at 196-197O :0-2000 gave 16.6 C.C.N, a t 21° and 766 mm.0-3908, in 20 C.C. acetone, gave, in a 2-dcm. tube, a,, +1-56O,whence [a], +39.9O.The acetyl derivative crystallises in silky needles, melting a t220-221O. The hydrochloride of the base is easily soluble in water,and on diazotisation yields a clear solution which, on the additionof alkaline &naphthol, furnishes a bright red azo-compound. Asolution of the base in dilute alcohol gives an immediate precipitateon the addition of an aldehyde; this arises from condensation oftwo molecules of the base with one of the aldehyde.N=9.53.C,,H,,O,N requires N = 9.65 per cent.4-H~d~oxypZLenyl-a-c~m~ZLoramic Acid,CO,H*C,H,,*CO*NH*C,H,*OH.A brisk reaction occurs when camphoric anhydride and p-amino-phenol atre heated together.The dark-coloured product containssmall quantities of a substance characterised by the intense purplecoloration developed with aqueous alkali hydroxides ; it wascrystallised from alcohol until the mother liquor no longer showedthis reaction. Recrystallisation from acetic acid, after treatmentwith animal charcoa.1, gave small, pale brown prisms. The meltingpoint was somewhat indefinite, the compound sintering a t 236O anddecomposing a t 250O. The product after fusion dissolved inaqueous alkalis, giving deep purple solutions, probably owing tothe formation of a phthalein:0.0986 gave 0.2385 CO, and 0.0648 H,O.0.3641, in 20 C.C.acetone, gave, in a 2-dcm. tube, a, +1.8Oo,The following aq-1 derivatives of a-camplioraniic acid were alsoC = 65.80 ; H =7-30.C,,H2,0,N requires C = 65.98 ; H = 7.22 per cent.whence [aID + 49.16O.prepared RACEMIC ALDEHYDES. 415A rial ysis./-----Derivative. formula. iorni. 11, p. Found. per cent.EinpiiicJ Crystalline Tlleory,o-Tolyl.. .......... C,7H,j0,N Long needles 194-196" N =4.72 4.84?)L-Tolyl ............ H,O,N Necdles 20S--209 N=4*76 4 84a-Naplithyl ......... C?,H=O,N Needles 233-235 N = 4.31 4.31B-Naphthyl.. ....... C',,H,,O,N Lustrous 210-212 3 =4%S 4'314-Ethosyphenyl ... C,sH,,O,N Long needles 195-197 N = 4.35 4.392-Chlorophenyl ... C,,H1,O,NC1 Minute 130-140 C1= 11-22 11'473-Chlorolhenyl ...Cl,FI,O3NCt Leaflets 207-209 C1= 11 *35 11'474-Chlorophenyl ... CIFH2,0,NC1 Prisms 192-194 Cl=ll.38 11'472-Rroniol)lienyl ... C,,H,,O,~Br Vitreous innss about 78 Br= 22.42 22.603-Rromopheuyl ... C,,H2,0,3NIZ.r Srriall tablets 215-217 Br= 22.54 22-60* This compound, together with t1ie:corresponding imidc, has recently been de-These authors give thep-Tolyl * ............ C,,H,,O,N Lcflflets 212-214 N z 4 . 9 6 4.84lI3afletSciystalsscribed by Abati and Notaris (Gazettn, 1909, 39, ii, 219).iiieltiiig poiiit 201-209" for the acid and 131" for the imide.N-Alkyl and Aryl Derivatives of Canbphorimide,By boiling a solution of a N-substituted a-camphoramic acid inglacial acetic acid with acetyl chloride for two hours, and pouringthe liquid into excess of dilute ammonia, the corresponding imideis obtained in almost theoretical yield. The following wereprepared :Analysis.Empirical CrystallineDerivative. for 111 uln . forill.n-Propyl ............ Cl,H2,0,N Prismsn-BIIty1 ... ... ...... ClJH230,N Lath-likeqL-Hexyl ............ C,,H,,O,N Oil;o-Tolyl ............ C17H,,02N Long needlesp-Tolyl ............ C1,H,,O2N Flat prismscrystiilsn- Amy1 ............ C,,H,O,N Oilm-Tolyl ............ C,,HzlO,N Glisteninga-Naphtliyl ......... C,,H2,0,N Stout prismsB-Naphthyl., ....... C,H,,O,N Sniall needles2-Chlorophenyl ... C1,H180,NC1 Plat prisms3-Chlorophenyl ... ClfiH1,O,KC1 Needles4-Chlorophenyl ... Cl,HI8O,N C1 Prisms2-Bromophenyl ... Cl,H180,NBr Sniall prisms3-Rromophenyl ... CI6H,,O,NBr Needles3-Nitrophenyl.. .... C,,H,,O,N, llliornbicleafletsprismsROYAL COLLEGE OF SCIENCE,SOUTH KENSINGTON, S. W.Theory,XI. p. Found. per cent.40-41" C ~ 6 9 . 9 2 69.9511=9-37 9.4261-62 N=6*13 5'91- N=5*50 5.58 - hTz6.31 5.28195-196 K=5*21 5.16117-118 N=5*27 5.16127-1 28211-212167-16s125-126172-173162-163139-140184-1851 4 6.- 147C=74'98H=7*61W=4'68N = 4.57C l = l l 97C1= 12.03N = 4'89Br = 23.57Br = 23 -68N=8*9775'267.754-564.5612-1812-184.8023.8023.809'2

ISSN:0368-1645    

DOI:10.1039/CT9109700405

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

416 CLARKE: THE RELATION BETWEEN REACTIVITY ANDXLVI.-The Relation between Reactivity and ChemicalConstitution of Certain Halogen Compounds.By HANS THACHER CLARKE.THE reactivity of the halogens in organic halogen compounds hasbeen studied by various investigators : Wislicenus (Annulen, 1882,212, 239), with ethyl sodioacetoacetate ; Hecht, Conrad, andBriickner (Zeitsch.. physikal. Chem., 1889, 4, 273), with sodiumethoxide ; Menschutkin (Zeitsch. physikal. Chem., 1890, 5, 589),with triethylamine; Burke and Donnan (Trans., 1904, 85, 555;Zeitsch. physikal. Chem., 1909, 69, 148), with silver nitrate; Slator(Trans., 1904, 85, 1286; 1905, 87, 482), Slator and Twiss (Trans.,1909, 95, 93), with sodium thiosulphate; Senter (Trans., 1907,91, 460; 1909, 95, 18271, with water and with alkalis; but nodefinite conclusions appear to have been drawn as to the relationsbetween reactivity and constitution.The present paper deals with compounds of the type X*CH,*R,the object being to study the influence of the nature of the group(R) on the reactivity of the halogen (X).The reactivity was determined by the measurement of thevelocity of the reaction between pyridine and the halogen compoundin absolute alcoholic solution, identical conditions being observedthroughout the series of experiments :TTC5H5N + X*CH,*R = C5H5N<gH2.R.From the scheme representing the reaction, it is evident thatiouic reactions are improbable.Attempts were a t first made with ethylaniline and dimethyl-aniline a t the temperature of boiling alcohol, but it was foundthat the values of ( ( R,” calculated for a bimolecular reaction,decreased with the progress of the reaction, this effect beingdoubtless due t o “ heterospasis ” :NPhMe, + X*CH2*R-+NPhMe,X*CH,*R-+NMePh*CH,*R + MeX.Pyridine was accordingly selected as a tertiary base in which nosuch decomposition could occur.Moreover, as pyridine is morestrongly basic than the above-mentioned derivatives of aniline, thereaction could take place with measurable velocity a t a lowertemper at ur e.Equal volumes of N/2-solutions of pyridine and the halogencompound were mixed and maintained at the temperature of55*6O, afforded by a water-bath surrounded with boiling acetonCHEMICAL CONSTlTUTION OF CERTAIN HALOGEN COMPOUNDS.417under constant pressure, aliquot portions being withdrawn a tintervals and the ionised halogen titrated with silver nitrate. Theconstant was calculated from the usual formula for il bimolecularreaction, namely :1 Ct A'= -.-C , . t c,-C't'In nearly every case the values of R did not vary from thoserequired for a bimolecular reaction by more than experimentalerror.The experimental results are set forth in the following table;they will be discussed in detail on subsequent pages:n-Propyl bromide ..................Benzyl , , ..................Cinnamyl , , ..................Bromoacetic acid .....................Methyl brommcetate ...............Ethyl $ 3 n-Propyl ,, ...............isoPropyl ,, ...............n-Butyl ), ...............tert.-Butyl ,, ...............Phenyl ,, ...............Benzyl ,, ...............Allyl ...............Ethyl B-bromopropionate .........Bromoace tal ...........................Chloroacetamide .....................Chloroscetanilide .....................Bromoacetanilide ..................Diphen ylchloroacetamide ........Chloroacetone ........................Chloroacetophenone ...............Bromoacetophenone ...............Allyl ,) .................................I ?X.R.Br'CH,'EtBr*CH,*CH: CH,Br 'CH,'PhBr'CH,*CH: CH'PhBr'CH,'CO,HBr*CH,'CO,MeBr*CH,'CO, E tBr'CH2*00,PraBr-CH,* CO, PrsBr'CH,*CO,'CH,*CH,EtBr 'CH,'CO,'CMe,Br*CH,'CO,PhBr'CH,*CO,'C H,PhBr'CH2'CO;C3H,Br.CH,'CH,f!O,EtBr*CH,'CH(OEt),Cl*CH,*CO*NH,Cl*CH,.CO'NHPhBr'CH,*CO*NHPhCl'OH,'CO'NPh,Cl'CH,*COMeC1'CH;COPhBr*CH,*COPhK.0.01791 *2535'1180-4720.6660.9191 '0040-7521 *0480.7700.9341'9271'2110.7680,02770'0120 *011150'02641.5350.03410.06860-13397.269The first fact established was that in a compound of the typeX*CH,*R the reactivity of the halogen, as determined by the abovemethod, was controlled by the residual affinity of the atom orgroup (R) directly attached to the methylene carbon atom.Thefollowing series will illustrate this conclusion :K.n-Propyl bromide .................. 0.0179Methyl brom oacetate ............... 0'919Allyl bromide., ..................... 1 *253Benzyl , , ........................ 5'118Monochloromethyl ether and bromonitromethane were alsoexamined.I n both these cases there are present groups towhich a large amount of residual affinity is attributable (OMe;NO,). Chloromethyl ether reacted so rapidly with alcoholicpyridine that no measurement could be obtained ; whereas bromo418 CLARKE : TlIE RELATION BETWEEN REACTIVITY ANDnitromethane formed a pyridine salt a t once, and very littleelimination of bromine ensued.Taking, then, this rule as a basis, an attempt has been madeto determine the degree of unsaturation in various compounds ofthis type in order to elucidate the nature of the different groupsinvolved.The effect of conjugation of a phenyl nucleus with an ethenoidlinking appears to diminish the total residual affinity inherent inthe carbon atom in the a-position with respect to the methylenegroup, the reactivity of cinnamyl bromide being less than one-halfof thak of allyl bromide:Cinnaiii y 1 bromide ............Ph 'C H: CH *CH, €3 r K = 0 . 4 7 2Allyl )) ............ CH,:CI-I'CH,Rr K= 1.253Turning now to the derivatives of chloro- and bromo-acetic acids,it was found that the reactivity of the halogen varied with thenature of the radicle to which the halogen-acyl group was attached.When equimolecular quantities of pyridine and bromoacetic acidwere mixed in alcoholic solution, it was found, contrary to expecta-tion, that elimination of bromine took place along the lines of abimolecular reaction. This fact would tend to point to the absenceof stable salt-formation in absolute alcohol :Bromoacetic acid ...............K= 0.666The reactivity of the haIogen inaliphatic esters was examined :Methyl bromoacetate ......... 0.919 ......... 1-004 Ethyln-Propyl ,)The phenyl, benzyl, and allyl9 ) ......... 0.752 K- 1examined in the same manner :the following series of saturatedK.1'048 isoPropy1 bromoacetate , . , , , ,~ B ~ t y l ...... 0.770tcrt. -Butyl ), ...... 0'934esters of bromoacetic acid were2 9K. ........... 1.9271 .n*Phenvl bronioscetnte ,. .Betizj.1 ) ) ............. 1,511Allyl .............. 0.768I n phenyl bromoacetate, which exhibits a greatly exaltedreactivity, the alcoholic radicle contains the greatest residualaffinity. In benzyl bromoacetate, in which a methylene group isinterposed between the phenyl and the bromoacetoxyl groups, thecff ect still persists, although considerably diminished. The re-activity of the allyl ester, when compared with that of the n-propylester, shows a slight exaltation-to a less extent, however, owingto the less powerful influence of the ethenoid as compared withthe benzenoid grouping.Since the values obtained from allyl bromoacetate and benzyl2 CHEMICAL CONSTITUTION OF CERTAIN HALOGEN COMPOUNDS.419bromoacetate indicate that the influence of the unsaturated groupis appreciable even when situated in the &position, the reactivityof ethyl P-bromopropionate was measured :Ethyl j3-bromopropionate ................. K=0*0277This value, when compared with the saturated standard, rt-propylbromide (X = 0.0179), is sensibly exalted.Bromoacetal, on theother hand, yields a value (K=0-012) which shows the reactivityof the halogen to be slightly depressed.In the series of halogen-acetylamides, the reactivity of the halogencompounds was measured :K.Cliloroacetamide ............ 0.01 115 Bromoacetanilide ............ 1 -533Chloroacetanilide ............ 0 -0264 Diphenylchloroacetamide . . 0 '0341In the case of the halogen-acetanilides, the reactivity constantof the bromine derivative is 58.1 times as great as that of thechlorine derivative. Taking this ratio, the value calculated fromchloroacetamide yields K = 0.648 for bromoacetamide, a substancedifficult to obtain in a high state of purity, and, moreover,insufficiently soluble in alcohol.The same rule thus holds good for the Br*CH,*CO*O* and theBr*CH2-CO*N: structures, the replacement of hydrogen by phenylgiving rise to increased reactivity of the halogen, as the followingtable shows :K.Bromoacetic acid............... 0'666 (Bronioacetamide ............ 0.648)The reactivities of halogenated ketones were found to be greatlyin excess of those of the corresponding carboxylic compoundsenumerated above :Yhenyl bromoacetate ......... 1 Ir- *927 I Bromoacetanilide ............ 1 -533R.Chloroacetone,. ...................... 0-0686Chloroacetophenone ............... 0-1339Bronioacetopheiione ............... 1'269from which the constant for bromoacetone can be calculated, beingapproximately K = 3.720.I n the case of the ketones, as in the caseof bromoacetic esters, the replacement of a methyl group by aphenyl group occasions approximately doubled reactivity.Two series of measurements were carried out in an aqueous-alcoholic solution (25 C.C. absolute alcohol diluted to 100 C.C. withwater), the substances examined being methyl bromoacetate andpotassium bromoacetate, and the initial concentration of thereacting substances N / 4 before mixing :Methyl bromoacetate ............... 14'61K.Potassium ,, ............... 9 007VOL. XCVII. F 420 CLARKE: THE RELATION BETWEEN REACTIVITY ANDIt will be observed that a far greater velocity of reaction ensuedin the presence of water than in absolute alcohol. The ratiobetween the constants obtained for these substances in aqueous-alcoholic solution is of the same order its that between thoseobtained for methyl bromoacetate and for bromoacetic acid inalcoholic soiution :Methyl broinoacetate (0.919) : broilloacetic acid (0.666) = 1 : 0.7759 9 ,, (14'61) : potassium bromoacetate (9'07) =1 : 0'621It would thus appear that no radical change in constitution occursduring salt-formation and esterification.Discussion of Results.The author inclines to regard the variation of the reactivity ofthe halogen in compounds containing unsaturated groups in theP-position as due to the weakening of the bonds attached to thea-carbon atom caused by the strengthening of the bond betweenthe unsaturated group and the a-carbon atom.To take the caseof ally1 bromide and benzyl bromide, all residual affinity of themethylene carbon atom (*):is absorbed by the unsaturated group, leaving the remaining threeatoms less strongly attached to the carbon atom.This is borneout by the observation of Wislicenus (Zoc. cit.) that the halogen invinyl iodide (CH2:CH*) is subnormally reactive. The subnormalreactivity of the halogens in aryl halides may perhaps be due tothe same cause. This view of the variable strength of affinities withvarying substituents has already been put forward by Claus (Ber.,1881, 14, 432), and fully discussed by Werner and by Flurscheim.Of the compounds containing the halogen-acetyl grouping, thegreatest reactivity of the halogen is to be found among the ketones.This tends to show that the ketonic carbonyl group possesses moreresidual affinity than the carboxylic and carbaniidic carbonyl group.It has long been suspected that in the carboxyl group the twooxygen atoms exert some mutual attraction, and in a recentpublication Miss Smedley (Trans., 1909, 95, 231) has assigned tothe carboxyl group a constitution, *C<g., in which the thirdand fourth valencies of the two oxygen atoms are united.Now, it was shown above that in the case of phenyl bromoacetatethe reactivity of the halogen is approximately double that of thecorresponding methyl ester, and this fact indicates that someinfluence must be at work which transmits the effect through aseries of atoms so as to exalt the reactivity of the halogenCHEMICAL COSSTITUTION OF CERTAIN HALOGEN COMPOUNDS.421Hitherto all formulation of the carboxyl group has beenessentially of a static nature. The old formula, *C<g., must bediscarded, since it furnishes no distinction between the carboxylicand ketonic carbonyl groups, and the formula advocated byGoldschmidt (Zeitsch. Elektrochem., 1904, 10, 221 j, -CiO-O-, isdifficult to reconcile with the chemical and physical properties ofthe group.Miss Smedley’s view of the constitution of the carboxyl groupis in harmony with the results above mentioned, except in so farthat its static nature gives no explanation of the variations inreactivity due to differences in the alcoholic radicle. The authortherefore suggests that this formulation should be modified insuch a way that the greater or less unsaturated character of thecarbonyl group is expressed.Thefirst is that the bond between the oxygen atoms is variable inThere are two possible methods of regasding the problem.intensity, resulting in a formula of this nature: * d o - the \& ’second being that while the attraction between the oxygen atomsremains constant, the bond between the hydroxylic oxygen atomand the carbon atom varies in intensity, requiring a formula of the0type dll .Considering the problem as a whole, the evidencet.0-tends to favour the first view.A co-mparison of the conditions obtaining in methyl bromoacetateand phenyl bromoacetate may serve to illustrate this interpretation.CH,B r C 40\&.MeI n the phenyl ester a greater proportion of the residual aflinityof the hydroxylic oxygen atom is absorbed by the phenyl groupthan in the case of the methyl ester, so that the attraction betweenthe oxygen atoms is lessened.A more unsaturated or, it mightbe said, a more ketonic form of carbonyl is thus produced, withconsequent increase of reactivity of the bromine atom.0A similar structure may be applied to the amides: -CHi . \N:Replacement of the amidic hydrogen atoms by groups rich inresidual affinity, such as phenyl, enhances the ketonic characterof the carbonyl group.The variations observed through the series of aliphatic estersF F 422 CLARKE : THE RELATION BETWEEN REACTIVITY ANDwhich were examined are interesting, and point to differences inresidual affinity of the several alkyl groups.The free acid is less reactive than any of the esters, whilst thereactivity increases from the methyl ester through the ethyl ester tothe isopropyl ester, that is, on successive substitution of thehydrogen atoms of the methyl group.Slator (Trans., 1905, 87,481) also has found that ethyl bromoacetate is more reactivetowards sodium thiosulphak than methyl bromoacetate. Thereactivity of the tertiary butyl ester, however, falls to a valueapproximating that of the methyl ester.On continuing substitution in a normal chain, the reactivity ofFIG. 1.Relative mass of alkyl radicle.the n-propyl ester falls to a strikingly low value, rising againslightly in the case of the n-butyl ester. Thus, both the butylesters examined display anomalous reactivity, breaking the con-tinuity of the curves.The curve furnished by the normal esters,however, perhaps displays the periodic rise and fall observed inmany of the physical properties of homologous series.It may here be mentioned that these resulta are strictly com-parable, as steric considerations can play no part in the eliminationof bromine from bromoacetic esters.The results found by Burke and Donnan (Zoc. cit.) for thereactivities of the alkyl iodides produce a curve, which, whilesimilar in appearance, leads to the opposite conclusion. ThCHEMICAL CONSTITUTION OF CERTAIN HALOGEN COMPOUNDS. 423author’s results tend to show that the residual affinity of the normalseries of alkyl groups rises from methyl to ethyl, and falls ton-propyl, rising again slightly to n-butyl.On the other hand,since the halides of groups rich in residual affinity, such as phenylor vinyl, have been shown to be distinctly sluggish towards halogeneliminating agents, it would follow from the work of Burke andDonnan that the residual affinity would be at a minimum in the ethylradicle, increasing towards methyl on the one hand, and towardsn-propyl and n-butyl on the other. A satisfactory explanationremains yet to be put forward to account for the discordant resultsFIG. 2.2402002 160 -8xc3.-G 120yoao I 20Relative VICCSS of alkyl radicle.obtained for reaction velocity measurements in so far as the alkylgroups are concerned.With regard to the variations in reactivity due to the structureof the alkyl radicles, no influence ascribable to ‘‘ alkylene” or“ akylidene ” dissociation (Nef, Annden, 1899, 309, 126) can bea t work, dissociation of this type being highly improbable incarboxylic esters.The measurements carried out with methyl bromouetate indicatethat the reaction with pyridine takes place with far greater velocityin aqueous alcohol than in absolute alcoholic solution. Slator an424 CLARKE: THE RELATION BETWEEN REACTIVITY ANDTwiss (Trans., 1909, 95, 99), on the other hand, find that sodiumthiosulphate reacts more rapidly with methyl iodide and withchloroacetone in aqueous-alcoholic solution than in pure water.In the halogen acetic acicis and their derivatives, the influencebetween the halogen atom and the carboxyl group may be regardedas mutual, since Lichty (Amer.Chiem. J., 1895, 17, 27) has shownthat the initial veIocities of esterification of chloro- and bromo-aceticacids by ethyl alcohol are greater than that of acetic acid. Lichty hasalso shown (Anmlen, 1902, 319, 369) that the initial esterificationvelocity and affinity constants of the a-halogen-fatty acids greatlyexceed those of the P- and y-halogen-fatty acids. This is in entireharmony with the decreased reactivity of the bromine in ethylP-bromopropionate as compared with ethyl bromoacetate.EXPERIMENTAL,The substances employed for the reactivity measurements werein most cases purchased from Kahlbaum, or prepared by standardmethods. Semi-normal solutions of pyridine and the varioushalogen compounds in absolute alcohol were prepared, 50 C.C.ofeach solution being mixed and maintained a t 55'6O. At definiteintervals of time, 10 C.C. were withdrawn and titrated withstandard silver nitrate (approximately N l lo), the pipettes beingstandardised for the temperature. In some cases, potassiumchromate was used as an indicator, in others, Volhard's thiocyanatemethod was employed t o determine the end-point. The 10 C.C. ofsolution were added to about 100 C.C. of cold distilled water,covered, when the substances were highly reactive, with a layer ofether to remove the unchanged halogen compounds from the actionof the silver nitrate.The following measurements were carried out in absolute alcoholicsolution ; temperature 55.6O ; initial concentration N / 4 ; t repre-sents the timeinterval in hours, Ct the, percentage decomposition,and liT the velocity-coefficient :n-Propgl Bromide.t ......0'000 16'750 19'500 21.584 24'000 c, ...... 0-00 6-80 8.00 8-80 9'80K ...... - 0-0174 0'0182 OS0179 0.0181Mean value of K=0*0179.AZZyZ Bromide.t ............ 0'000 1.000 1.333 2.333 2500 3'000Ct ........... 0.00 23'80 29.58 42-50 43-79 48.80R ............ - 1-248 i-25a 1-268 1.246 1.245Mean value of K= 1'253CHEMICAL CONSTITUTION OF CERTAIN HALOGEN COMPOUNDS. 425t c, . . . . . . . . . . . .K . ............ , . . . . . . . . . .t c, . * . . * . . . . . . .K . . . . . . . . . . . .. . . . . . . . . . . .t ...... 0'000Ct ...0'00K ... -t ...... 0-000 c, ... 0.00K ... -t ... 0'000 1.000C t , . . 0'00 20'00K... - 1.000tcz . . . . . . . . . . . .I<. . , . . . . . . . . ., . . . . . . . . . . .t . . . . . . ct ... 0.00K ...o*ooo-Benzyl Bromide.c.000 0.500 0.667 o m ieooo 1.1670'00 39.55 46'47 50.91 56-11 60.05 - 5.231 5.209 4'9i8 5-022 5.150Mean value of K=5*118.Gin?tumyl Bromide.O*OOO 0.167 0.767 1.917 3.2500'00 1.97 8-27 18'51 27'59- 0.482 0-471 0'475 0.469Mean value of K= 0 '472.Bromoacetic Acid.0'684 1.033 1.333 1'500 1.667 1.8339'00 14-60 15.40 20'00 21-60 24'000'642 0'662 0.676 0'667 0-660 0'688Mean value of K=0*666.Met li yl Bromoace t a t e.1'000 1.500 3'000 3,500 4.000 4.5000'904 0.923 0.930 0-948 0'884 0.91418-43 25.72 41-09 45.30 47-21 50-66Mean valuc of K=0*919.Et h y I BrorrLou c e t a t e .2'000 3.000 4.000 4'500 5.0001'021 1.022 1,021 1.003 0.99133'80 43'40 50.52 53-00 55.32Mean value of K= 1.004.n-Prowl Bromoacetute.0.000 1.500 2.500 3.5840'00 22'07 31.91 40'40- 0.755 0.750 0.757Mean value of K=0.752.isoPropy2 Bromoucetate.20.88 27'97 34.67 39'401.000 1'500 2.000 2.5001.055 1.030 1'060 1'010Mean value of K=l'O48.n-Butyl Bromoacetate.t ...........,... 0-000 1'333 2-000 2.500K ........ .... - 0.754 C.792 0.764Ce .... ........ 0.00 20'09 28.36 32.30Mean value of R= 0.770.5500 6.0000.988 0.98457'60 59'664.5000.74445'603-0001.05344'113.0000.77136-6426 CLARKE : THE RELATION BETWEEN REACTIVITY ANDtert.-Butyl Bronzoacetate.t .. ... . ... ... o*ooo 1'000 1.800 2.250 2.500 ct 9 .. 9 . . ... ... 0.00 19.00 29.90 34'40 36.80K . . . . . . . . . . - 0'938 0'936 0.932 0.932Mean value of K= 0 934.Phenyl Bromoacetate.t ... O*OOO 0.433 0.600 0767 0.934 1.100 1.267 1.433 1.600K ... - 1.929 1.911 1.958 1.936 1-963 1.907 1'915 1.919Mean value of K=1.927.Ct ... 0-00 17-28 22.28 27'28 31.11 34.95 37.67 41.70 43-40Ben& Bromoacetat e.t ......... 0'000 0.784 1.000 1.333 i:5arl 2.350 2.817 3.000 c, ...... o 00 18-71 22-83 28-95 32-60 46-10 47.29K ..... - 1'174 1.180 1'244 1-204 1.268 1'208 1-196Mean value of K=1.211.A Zly2 Bromloacetat e.t ... ... ... ... 0'000 0.834 2-067 3-000 ct ............ 0'00 13.79 28'36 36'36K . . . . . , . . . . . .- 0-769 0.766 0-771Mean value of K=0*768.Ethyl /3-Bromopropionate.t ...... O*OOO 5.250 21.500 24.000 27'500K...... I 0-0313 0.0258 0'0260 0'0264Ct ...... 0.00 3'94 12.20 13'50 15.35Mean value of K= 0.O277.Bromoacetd.t ............ ... 0'000 18-000 21'000 ct .. .. . . . . . . . . ... 0.00 5-21 6'02K , . , , . . . . . . . * . . . - 0'0122 0'0122Mean value of R=0*012.t . . . . . . . . , cr ......K .. ...t c, . . . . . . . . .K . . . . . . . . .. . . . . . . . *Chloroacetanaide.0.000 19.170 21'167 23'5000'00 5'09 5-76 6'14- 0'01120 0.01155 0'01113Mean value of K=0-01115.Chloroacetanilide.0-000 4'600 5'417 6.367 207500.00 2'96 3-55 3'94 12-01Rlcan value of KI-0.0264.- 0,0265 0.0274 0.0258 0.02683.7500'76541.782950016-780.027326*0006 '870.011445'33311 '220.0107024-06613'200'025CHEMICAL CONSTITUTION OF CERTAIN HALOGEN COMPOUNDS.427Bromoacef anilide.t ... .. 0.000 1-000 1.500 1.934 2-834 3.283 3.483 ct ... 0.00 27.65 36-50 41.85 52-80 56-35 57-50K ... - 1,463 1'532 1-485 1-578 1'573 1.665t ...... ... ct ......K ......1 . . . . . . . . . c; ......K ......t ct , . . . . . . .K . . . . . . . . .. . . . . . . . .a'ooo0'00-0'0000.00-o*ooo0.00 -Mean value of K= 1.533.Diphenylch,loroacetamide.10-500 12-000 14'000 15-500 185008-20 9'40 1G-60 11-80 13.400-0340 0.0346 0.0339 0.0345 0.0335Mean value of K= C-0341.Chloroacetorte.3.758 5.550 20.550 22.5006'30 8-66 26.20 27-40Mean value of K= 0'0686.o * o m 0.0683 0.0691 0.0661CMo roac e t o ph enone.5-100 11.550 15-5000.1336 0.1330 0'134614'56 27.75 34'30Mean value of K=0'1339.24-33029.350'068216'33335-450'1345Bromoac e t ophenon e.t .....0.000 0.333 0.500 0.667 0,833 1.000 1.333cl, ... 0.00 37.65 48-00 54.91 60.30 63.75 71.02K ... - '1-252 7.382 7.301 i ~ s s 7.035 7-358Mean value of K=7*269.The following two series of measurements were carried out in25 per cent. aqueous alcohol (by volume) ; temperature 55'6O; initialconcentration N / 8 :Methyl Bromacetate.t ...... 0-0000 o m 6 0-2000 0.2835 0-3667 0.4500 0.5333Ct ...... 0.00 17.60 27-20 34.40 40.00 44'80 48.80K ...... - 14-65 14:95 14-81 14.54 14'43 14-30Mean value of K=14*61.Potassizlm Bromacetate.6 ......0.0000 0*2000 0.3667 0-5333 0.7000 0-8568 1.0333Ct ...... O*OO 18-40 29-60 37-60 44.00 49.60 53'60Y ...... - 9-02 9-18 9-06 8-98 9-10 9-09Mean value of K= 9-07.The following compounds quoted in the foregoing list itre notdescribed in the literature428 REACTIVITY OF HALOGEN COMPOUNDS.Cinna?mjZ Brom.de, CHP h:CH CH,Br.-Cinnamyl alcohol wassaturated with dry hydrogen bromide a t the ordinary temperature,heated to looo for two hours to decoinpose the resulting additiveproduct, washed with dilute alkali and with water, dried, anddistilled under diminished pressure. It is an almost colourless oil,boiling a t 122-123°/10 mm., insoluble in water, and moderatelysoluble in organic solvents :0.1830 gave 0.1752 RgBr.C,H,Br requires Br = 40.62 per cent.n-Bzct yZ Bro moac e tu t e, C€12Br*C02*C,H, .-Equimolecular quan-tities of bromoacetic acid and n-butyl alcohol with a few drops ofconcentrated sulphuric acid were heated to looo for three hours,the product being washed with dilute alkali and with water, dried,.and distilled under diminished pressure.The substance is a colour-less liquid, boiling a t 78O/10 mm., and is insoluble in water, butmiscible with organic solvents; it possesses no sharp odour, thusdiffering from the other aliphatic esters examined :Br = 40.74.0.1085 gave 0.1046 AgBr. Br=41.02.C,H,,O,Br requires Br = 41-02 per cent.tert.-BizttyZ Bromoacetat e, CH2Br*C'0,*CMe3.--tert -Butyl iodidewas treated with a slight excess of dry silver bromoacetate suspendedin ether, the mixture being kept cool.After twelve hours, theethereal soliltion was filtered, and the ether distilled off, the residuebeing fractionated under diminished pressure. A yield of onlyabout 20 per cent. was obtained of a colourless liquid, boiling a t503/ 10 mm., insoluble in water, but miscible with organic solvents ;it possesses a pungent odour, similar to that of methyl bromo-acetate :0.1747 gave 0,1691 AgBr. Br=41*20.CGH,,02Br requires Br = 41-02 per cent.Benzyl Bromsoacetate, CH2Br*C02-CH2Ph.-Benzyl alcohol andbromoacetic acid were esterified in the manner described underr-butyl bromoacetate. The ester is a colourless liquid boiling at143O/10 mm., and insoluble in water, but miscible with organicsolvents; it possesses an odour similar to that of benzyl acetate;the vapour does not attack the mucous membranes a t the ordinarytemperature :0.2136 gave' 0.1746 AgBr.C,H,O,Br requires Br = 34.94 per cent.A ZZyZ Bromoac e tut e, CH2Br* C0,*CH2*CH: CH2.-A11y1 alcoholand bromoacetic acid were esterified in the manner described undern-butyl bromoacetate. The ester is a colourless liquid, boiling a tBr = 34-82VAPOUR PRESSURES OF TWO MISCIBLE SOLIDS. 42973O/10 mm.; it is insoluble in water, but miscible with organicsolvents, and possesses an extremely sharp odour :0.1693 gave 0.1790 AgBr. Br=45.05.C,H70,Br requires Br = 44-69 per cent,.Dipltenylchloroacetamide, CH,Cl*CO*NPh,. - Diphenylamine,dissolved in dry carbon tetrachloride, was treated with excess ofchloroacetyl chloride, the mixture being maintained at atmospherictemperature by immersion in cold water. The precipitated di-phenylamine hydrochloride was separated, and the carbon tetra-chloride removed from the filtrate by distillation. The residue,after being washed with water, was recrystallised from alcohol.The compound forms colourless needles, melting at 116O, and ismoderately soluble in organic solvents :0.1944 gave 0.1163 AgC1. C1= 14.80.CI4H,,ONC1 requires C1= 14.45 per cent.I n conclusion, the author desires to express his thanks toAssistant-Professor Smiles and to Dr. A. W. Stewart for friendlyinterest and valuable advice.CHEMICAL LABORATORY,UNIVEESITY COLLEGE, LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109700416

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

VAPOUR PRESSURES OF TWO MISCIBLE SOLIDS. 429XLVIL-The Vapour Presswes o f Two PerfectlyMiscible Solids and their Solid Solutions.By ERNEST VANSTONE, B.Sc. (Wales) (1851 Exhibition ResearchScholar University College, Cardiff , formerly '' Isaac Roberts "Research Scholar).IN a former paper (Trans., 1909, 95, 590) it was shown thatcamphor and hydroxycamphor or borneol form a continuous seriesof solid solutions. The vapour pressures of these substances andof their solid solutions have since been measured; the methodsemployed and results obtained form the subject of the presentpaper.The Vapour Pressure of Camphor.Measurements have previously been made by Ramsay and Young(PI&?. Trans., 1884, Part I, 34) and by Allen (Trans., 1900, 77,413). Ramsay and Young determined the vapour pressures fortemperatures from Oo to 180O. The ordinary barometric metho430 VANSTONE: THE VAPOUR PRESSURES OF TWO PERFECTLYwas employed, and also a second method, in which the temperatureaof volatilisation corresponding with different pressures were readon a thermometer the bulb of which was coated with a layer ofcamphor.This method gave good results for liquids, but does notseem satisfactory when used for solids. Concerning the barometricmethod, the authors state: “We think it right t o give details asto the method of operation, as we found it a matter of extremedifficulty to expel all moisture and air.” In spite of the precautionstaken, I think it very probable that the results obtained werevitiated by the presence of a trace of air.The results obtainedby the two methods are not very concordant, thus a t 64Othe barometric method gave 6.4 mm., whereas the second methodgave 7.2 mm. a t 48.9O.H e tookthe precaution to boil the mercury, but passed the camphor up ina small tube, and applied a correction for the air admitted.The air-current method was also employed, the principle of whichis to find the weight of camphor required to saturate a known volumeof air. The saturation limit was, however, obtained by a methodof extrapolation. Allen’s work extended over temperatures fromOo to 80°. The vapour pressures measured were very, small, thegreatest being 9 mm. at 80°. There is considerable discrepancybetween Allen’s results and those of Ramsay and Young, thus at48.9O the latter obtained 7.2 mm., whereas Allen at 50° obtained1.3 mm.I therefore decided to make determinations by both thebarometric and air-current methods for temperatures from 7 8 O to1 60°.The Barometric Method.Allen also used two methods, one being the barometric.The apparatus (Fig. 1) consisted of two tubes about 80 cm. longand 12 mm. internal diameter. One of these tubes was providedwith it trap 20 cm. from the closed end. This tube served as astandard barometer, which was filled as follows :Mercury was poured in until it extended a few cm. past thetrap. The tube was then connected to the water pump, and themercury boiled. After cooling, the tube was nearly filled withmercury, and heated to the boiling point of aniline in the vapour-jacket.By connecting to the pump and repeatedly tapping thetube, most of the air bubbles were removed. After cooling, thetube was completely filled and inverted in the trough. The secondtube served as the experimental tube. A thick-walled capillarytube was sealed on one end, a piece of wider glass tubing a fewmm. diameter next, and then the stopcock.The lower end of the jacket wasclosed by a doubly-bored rubber cork covered with a layer ofBoth tubes were jacketedMISCIBLE SOLIDS AND THEIR SOLID SOLUTIONS. 431mercury; the upper end by an ordinary split cork. An experimentwas conducted as follows. The experimental tube was connectedto the pump by sealed glass joints, and the mercury pumped up.The tube was then heated to the boiling point of the liquid in thebulb, the pump kept at work, and the tube repmtedly tapped toremove bubbles from the side.It was then allowed to cool, andthe camphor introduced as a small pellet under the mercury in thetrough. - The tube was again heated, andthe pump worked. As the upper partof the tube became hot, the camphorvaporised, and some of it passed into thecapillary portion, where it condensed andclosed the tube.When the vapour was condensing wellup in the side-tube, t'he heights of themercury in the barometer and experi-mental tube were read by means of acathetometer, provided with a vernierwhich enabled readings to be made to0.01 mm. The telescope of the catheto-meter was brought into the horizontal byfocussing on the surfaces of the mercuryin the limbs of a wide U-tube clampednear the top of the apparatus. Readingswere taken until the pressure was con-stant.The apparatus was then allowedto cool, and readings again taken at roomtemperature. If the difference in levelwas now greater than 0.1 mm., thecapillary tube was gently heated; thecamphor which had condensed there waaby this means driven back into theexperimental tube or into the upperwider portion, and thus the passage tothe pump was again open. The aboveoperations were then repeated until thedesired result was obtained.This made i t certain that all the airFIG. 1.and moisture had beenremoved, the vapour pressure of camphor a t room temperaturebeing about 0.1 mm.It was found more convenient to makeobservations a t the highest temperature first, as on passing from alower t o a higher temperature air bubbles always appeared on thesides of the tube.In the early experiments a Topler pump was used, but later 432 VANSTONE: THE VAPOUR PRESSURES OF TWO PERFECTLYFleuss pump was placed a t my disposal, and the work became farless tedious. Accurate results at five temperatures were obtained,the temperatures being the boiling points of the following liquidsunder atmospheric pressure : ethyl alcohol, 78O ; propyl alcohol, 9 6 O ;toluene, 1 loo ; chlorobenzene, 130° ; and bromobenzene, 1 5 6 O .The temperatures were read on Anschutz normal thermometers(which had been previously standardised) placed inside the jacket.These could be read to 0.lo.I n some cases the temperatures wereobtained by reading the barometer, from Ramsay and Young'stable of vapour pressures.The following results were obtained :Vapour Pressure of Camphor.Temperature.78.0"96%110'9131 '1131.4152'0157.0Number of readings. Vapour pressure.30 6-40 mm.6 16'15 ,,20 33'00 ,,28 75.37 ,,16 76.00 ,,15 76.61 ,,14 181'50 ,,T h e Vapour Pressure of Borneol.It was determined in the same manner with the following results:The vapour pressure of borneol has not been previously measured.Temperature. Number of readings. Vapour pressure.77.9" 6 2'16 mm.96.8 11 6-65 ,,110'0 9 14.94 ,,131'0 16 40.92 ,,156.0 14 115.16 ,,The Air-Current Method.The apparatus was the same as that used by Perman and Daviesin finding the vapour pressures of naphthalene and dilute solidsolutions of naphthalene and &naphthol (Trans., 1907, 91, 1114).Details are given in that paper.A stopcock replaced the groundglass stopper, and a larger bulb was necessary for condensing thecamphor. The stopcock was sealed on after introducing thecamphor. A thermostat containing water and a toluene regulatorwere used for temperatures below looo; for higher temperaturesolive oil and a mercury regulator were employed. In order that thepressure of the air in the spiral should be the same before andafter the experiment, it was placed in the thermostat and a currentof air drawn through for some time; the stopcock was then closed,the spiral removed, the camphor washed out of the bulb witMlSCIBLE SOLIDS AND THEIR SOLID SOLUTIONS.433alcohol and ether, the spiral cleaned by immersing in lightpetroleum, dried, and weighed. It was again placed in thethermostat, and a known volume of air drawn over, then cleanedand weighed as before.The temperature of the aspirator and the height of the barometerwere observed a t the end of the experiment.Method of CaZcu2ation.--If w = weight in grams of camphorwithdrawn :P = pressure of atmosphere in mm.p = ,, air in aspirator in mm.Y'= absolute temperature of aspirator.P=volume of air aspirated, in litres.22.41M-u, = specific volume of camphor vapour = - ~M = molecular weight of camphor.then, assuming the truth of Dalton's Law of Partial Pressures, thefollowing relationship holds good :Pressure of camphor vapour - Volume of camphor vapourTotal pressure.Total volume. ' -orcorrecting volume V for temperature and pressure we get:wvcTP 760273pVt- 760 wvC2" pc =The following results were obtained :UI.0.41690.34390.25220.34550,33590-33550.25610'2555P (mm.).752-2z65.0r56.5763.6759-8764'9763.6759.9v.7.3055'9154.4395.9155-9155.9154.4394.439P.738.7752.6744'2751.6747.0752.2750-8746.3T. Time (mins.). to.288'9" 540 77'9287.5 370 78'0287'4 325 78.0287'1 480 78.0288.2 350 78-0287.9 330 77.9288'2 285 78.0289'0 555 78-0Pc (mm.1.6.8236.9046.7466-9236.8056.7506-8726.8000-39560.39940.39520-40160.39270.39600'40G50-39080.3959758.7 2-957z59-0 2.957161.2 2.957763'2 2'957765'6 2.957766-1 2.957764-1 2.959766.5 2.959765.4 2.959Mean vapour pressure at 78" ,..........744'9745'3747'3749'1750.2750'4748.4751.7750.8289'2289'1289.3289 -6291'0291'3292'3290-4'290.218018028025022024027025527095.295-195'195.295-195'195-195'195 '16.82815.82015.96115.81216-08315-83515 *98915.98115.71115.896Meaa vapour pressure a t 95" ............15-88434 VANSTONE: THE VAPOUR PRESSURES OF TWO PERFECTLYw0.38630-38700.38750.38751.35001 '33321-30441 -29401-01001.00641 *00900'68590.68920'69980'69281.03521.02481 -03041 *02041 '58301'58721'60142-04102-0154P (mm.).760.3764.3763.3762.2759.5762.0767.1751.6746.3744 '27485758-6759.1759 -5757 -7774'4773-9774'1774.2765.7764.0766 '4758.5764.0l? P .T. Time (mins.) to.1'4764 746.4 289.3 80 109.01'4764 750'8 288.8 80 109.01'4764 749'7 289.0 80 109-21'4764 748.4 289'2 80 109.0Mean vapour pressure a t 109" ............2.959 750-0 283'4 135 120.32.959 752.3 283-9 150 120.22.959 758.1 282.7 150 120'02.959 741.8 284.0 180 120.0Mean vapour pressure a t 120" .. . ... . . . . . .1.4764 736.1 284-6 115 130.41.4764 734'1 284'4 70 130'41'4764 738-7 283-9 70 130.4Mean vapour pressure a t 130 '4". . . . . . . . . . .1.000 744.6 2895 60 131'21.000 745-1 289.4 35 131.31.000 745.5 289'5 35 131.31.000 743'4 289.7 40 131.5Mean vapour pressure a t 131 -3".. . . . . .. . .. .1-000 765.7 282.2 55 139'91'000 764'8 282.9 60 139'91'000 764'8 283-3 50 140.11'000 765.6 282.0 50 139'6Mean vapour pressure a t 140" ... . .. .. ....1-000 756.4 282.9 90 150.01-000 754-6 283.3 60 150.01'000 757-7 282-2 45 150-1Mean vapour pressure at 150" ............1'000 744-3 298'8 60 156.01'000 750'6 288-8 60 156.0Mean vapour pressure at 166" ,...........pc (mm.).30'36630'34730.42030.43530.39050 -1 549'6748'4548-304 8 '3773-0472.7872.T272'8474.78375.09075-2737552875-17104-77104'12104'76103'40__.104.5149.83150.0315056150'13186'43184'34186.4It is seen from the above that for temperatures of 120° andupwards, considerable quantities of camphor were drawn off.Alarger spiral was used in these experiments. At 150° the camphorshowed signs of charring. The rate at which the air was drawnover was varied widely to ensure saturation.The results obtained by the two methods are compared in thefollowing table :Temperature.78.6"96%111'0131'0157.0Barometric (mm.). Temperature. Air ourrent (mm.).7 *09 78.1" 6-8316.15 95-1 15.8833-00 110.9 33.0075'00 131.1 75.20181.5 156.0 185-MISCIBLE SOLIDS AND THEIR SOLlD SOLUTIONS. 435The agreement is very close; the high values given by the air-current method at 150° and 156O are probably due to charring ofthe camphor. The vapour presures at the temperatures of Ramsayand Young's experiments and those of Allen have been obtainedby graphic interpolation.These are given in the table below:Vapour pressure Ramsay and Young AllenTemperature, (mm.).(mm.). (mm. 1.78.4" 6'8 9.5 * 7 '6280'0 7 *l - 9'1592 '4 13.1 15-4 * -100'0 19.5 22.6 -101.0 20.5 27 *2 -109'4 30.8 35 '0 -116.7 42-6 46-0 -127'4 65 -5 66.3 -132.0 76.7 78 '1 -134'2 84.2 88.6 -136.3 91'0 92 '8 -140'3 105.0 105.0 -141-7 110.0 109'4 -147'0 131.0 155'1 -154'3 165.8 197-6 -* These results were obtained by the barometric method.It is seen that the present results are a t nearly all temperaturesThe vapour pressures of borneol were also determined by the air-lower than those of the other investigators.current method, with the foIIowing results :V.p (mm.). 7'. Time(mins.). to. V.P. (mm.).5'021 742'8 285.7" 390 78.0 2.2135.021 745'8 284'5 390 78.0 2.8445'021 749.3 283.6 345 78.1 2'358,la P.0-095 753 -70.1085 755.90-1072 758.80.2912 761.60'2858 758.10'2884 752.30'2908 763.9Mean vapour pressure a t 78" ............ 2.3055.021 751.5 284'5 255 95.0 6.7085-021 747-7 284'9 270 95-1 6.5975'021 741'6 285'4 350 95-3 6'6715'021 753'2 285.4 300 95-3 6.7250.4105 749'70.4095 754'10.5918 751-10 3528 754'10.2039 755.50.2025 765.00'3344 763.30'3330 752'40'3286 764'4Mean vapour pressure a t 95.2" ... ........ , 6.6753'0024 736.8 285.7 180 1105 15.7652-9545 743'2 285.7 180 110.5 15-9204.9180 740.2 285.7 180 109.8 15-4502'6185 742.9 286'0 180 110'4 155081-4825 744.3 286'1 180 110.9 16.8291'4825 752.0 285'8 85 110.4 15.685Mean vapour pressure a t 11 0 -4".. . . . , . . . . . . 15.721.4825 752.1 286'0 60 120.0 25-6661.4825 741'6 285.5 60 120.0 2.5.4631.4825 754'1 284-8 60 120.0 25.045VOL. XCVII.Mean vapour presstire at 120" ......... .. 25.37 1G 436 VANSTONE: TRE VAPOUR PRESSURES OF TWO PERFECTLYW. P. 7. p (mm.). T. Time (mins.). to. V. P. (mm.).0.5470 765.9 1-4825 756-1 284.0 60 130.4 40.6620'5397 767.3 1'4825 757.5 284'0 60 130.0 40-148Mean vapour pressure at 130.2" ..... .... ... 40'400.6016 770.6 1-00 76@9 284'2 45 139.9 64-1810.5988 770.4 1.00 760.4 284.3 45 140'1 63.936Mean vapour pressure a t 140" ............ 64.060.4738 769.9 0*500 759.8 2845 45 150'2 96.5210'4748 769-6 0.600 759.3 284-8 45 150'2 96.814Mean vapour pressure a t 150*2"... ... .. . ... 96-660'6910 7684 0.500 T57.9 285.1 30 159.2 133-310.6560 767.7 0'500 457.2 285-1 30 158'4 127'20These results are compared below with those obtained by thebarometric method :Temperature. Air CUI rent (mm. ). Temperature. Barometric (mm. ).78.0" 3 -30 77'9" 2-1695'2 6.67 96 -8 6 5 5110.5 15-70 110.0 15.00130-2 40'4 131'0 40-92150.2 96'6 156.0 115.16158.4 127-2 - -As in the case of camphor the results agree closely,.Ramsay and Young have shown that the ratio of the boilingpoints expressed as absolute temperatures of closely related liquidsis constant. As the two solids investigated are also very closelyrelated, the ratios of the absolute temperatures corresponding withequal vapour pressures have been calculated :Pressure (nim. ).102030405060708090100110Tc.360'3373.5381-8388.3393 '3398.0401.3405-9409.041193415'3T B .376.0388.4396 4403-0407 *8411.6415-0418-0421 -2423-7426'3TBI T,.1.0431'0401.0381.0381,0571'0341 '0341.0301 *0301.0291 -026The constancy of the ratios is evident.The Vapour Pressures of Solid Solutions.One of the chief difficulties of previous investigators has beento obtain solid solutions having vapour pressures large enough tobe accurately measured. The only work of importance is that ofSperansEy ( Z ~ i t s c l i .phyysikal. Chem., 1903, 46, 70; 1905, 51, 45)MISCIBLE SOLIDS AND THEIR SOLID SOLUTIONS. 437who measured the vapour pressures of solid solutions of pdichloro-benzene and p-dibromobenzene, and p-chlorobromobenzene andp-dibromobenzene. He concluded that “the regular laws whichhold for liquid solutions also hold for solid solutions.”The Vupour Pressures of Solid Solutions b y the Air-CurrentMethod.The equation given on page 433 for calculating the vapourpressure of camphor, when applied to solid solutions, becomes :whereP8 = vapour pressure of solid solution.pc and p b =partial pressures of camphor and borneol.wc ,, wb=weights in grams of camphor and borneol in the totalweight (V) drawn off;alsowc+wb=w (2).Equations (1) and (2) contain three unknowns, namely, w,, wb,and P,, hence it seems impossible to determine the vapour pressureof a solid solution, in which both constituents have appreciablevapour pressures, by the air-current method alone.I f , however,P8 can be obtained by the barometric method, wc and Wb can becalculated, and pc and pb, the partial pressures of the constituentsobtained.Solving for wc in this way, we get:It is obvious that this involves the difference between the specificvolumes v, and v b , so that the method can only be applied to casesin which these differ fairly widely.For camphor and borneol vc = 0.1 473 and V b = 0.1 454, hence themethod is of no use in the present case; we may, however, writevc=vb in equation (l), which then becomes:WC = vps - v’b(P - Pa)/(v, - vb)(P - pg).wvc P P*=---- v+ WW,’thus the total vapour pressure of a solid solution can be obtainedapproximately by the air-current method.The error involved isabout 1-2 per cent.The difficultieswere now very much greater, as change in concentration had to beavoided as far as possible.The temperature of l l O o was chosen for two reasons: (1) Theweight of substance drawn off by aspirating a litre of air throughA series of experiments was carried out at l l O o .G G 4138 VANSTOKE: THE VAPOUR PRESSURES OF TWO PERFECTLYthe spiral was small, and hence the change in concentration of thesolution would be small; (2) the vapour pressure at that tem-perature was large enough to be accurately measured by thebarometric method, that for camphor being 33 mm.and for borneol15 mm.The solutions were made by fusing the accurately weighed quan-tities of camphor and borneol in sealed tubes. These were thenbroken, the mass removed, cut up in small pieces, dried oversulphuric acid, and introduced into the dry spiral. The spiral wasplaced in the thermostat, and a few C.C. of air drawn through; thestopcock near the condensing bulb was then turned off, the otherend of the spiral closed by means of a small india-rubber stopper,t.he spiral removed, cleaned, and weighed. It was then againplaced in the thermostat, and a known volume of air drawn through,again closed, cleaned, and weighed. It was necessary to clean outthe spiral after each experiment, and refill with a fresh quantityof solution.The following results were obtained :Mols.ofborneolPer100 Qfmixture. W.0.26320'26420'26450'24040.2406 20 {0.233230 { 0'23450'214440 { 0'21540.205450 { 0.20450.26420.2642 60 .(0.2662loo { 09682P.769.8750.6762'4771.1770.7754.2755.8747'1760.9753.7754-8763.5763.5764'3764.8765.3765.1764'3763.8758.7758.7P.765.5737.5749.0758.5757.7740.9742-4734'7747'2740'7740'0750.3750.0750.4750.7751'9750.5749.7749'1744'1744'1V.1'001 -001.001 -001 '00I -001 -001'001 moo1'001-001'48251 *4825iwm1'48251'48251'48251 '48251-48251 '00T.288.8"288'5288'9287.9288.3288.8288-9287'6289'2289'2289.3288'6289'0294.4289-7290.0290-2290'2290.3290'21-00 290'2Time(mins.).7575759075808090110110751001501001051001009010090100to.110.1"110.1110.1110.1110.1110.0110.0110'1110.1110'1110'0110.1110.1110.0110.0110.1110.1110.1110'1110.0110.0PI (mm.1305230-6230.1227'8127.9027-1027.2625'2124'8624-0023-9620.8720'8819 9319'9418 '2418-1717-9017.8115-0016-1MISCIBLE SOLIDS AND THEIR SOLID SOLUTIONS. 439Attempts were made to confirm these results by the barometricmethod. The difficulties were now even greater, and the resultscan only be regarded as approximate.To remove air and moisture, to prevent any change in con-centration by having a large quantity of substance present, andyet not so much as might obscure the mercury meniscus, was indeedextremely difficult.The experimental tube was now provided witha three-way tap in place of the ordinary stopcock previously used.The junction of the tube nearest the capillary wits well groundon the inside. This enabled the tube to be closed by a ground-glass stopper, sealed to a long glass rGd, which passed down thetube beneath the mercury in the trough, being bent at its lowerend so that it could be moved from the outside, One branch ofthe three-way tap communicated with the air pump, the other witha small reservoir of mercury.The plan was to cause the substance to sublime quite near thetop of the tube, keeping the pump at work, then to run in mercuryon the top of the grpund joint closed by the stopper, and soeffectively close the tube.Experiments with solutions containing 20, 40, 60, and 80 mole-cules of borneol per 100 molecules of mixture were made.For theexperiments with the 20 per cent. solution, a three-way tap and acapillary tube alone were used, mercury being run into the capillarytube. There wits some loss by sublimation into the portion outsidethe vapour jacket, whilst it is certain that air and moisture wereremoved.Experiments were made with the same solution at five tem-peratures, a.s in the case of the pure substances.The apparatus had to be taken down and the tube cleaned outbefore proceeding to make observations with a solution of differentconcentration, and often for the same solution as the quantity ofsubstance necessary a t the high temperatures obscured the mercurymeniscus a t the lower temperatures.Vapour Pressures of Solid Solutions of Camphor and Borneol.Barometric Method.Molecules of borneol per 100 of mixture=20.Temperature.78.6"97.097'4110.6131'6131'8156.2Number of readings.54615466Vapour pressure.6'10 mm.15-90 ,,16.04 ),28.13 ,)66'90 ,,67'50 ,,159.40 ,440 VANSTONE: THE VAPOUR PRESSURES OF TWO PERFECTLYMoEecular Concentration = 40 per cent.borneol.Temperature. Number of readings. Vapour pressure.78.4" 5 5-54 mm.97'2 5 13.27 ,,110'0 5 25-60 ),131 -0 5 63'70 ,)156.4 5 150.5 ,,Molecular C o ~ ~ c e ' l ~ t m t ' i w ~ = 60 per cent.Zlor.rLeo2.Temperature. Number of readings. Vapour pressure.78-50 7 4'83 mm.97.1 6 11.40 ) )11 0'2 5 23.05 ,)131.2 5 60-58 ,)156'0 7 140.00 J JMolecular Concentration = 80 per cent. borneol.Temperature.78 '6"96-897 '1110'6110.8131.8156.2Number of readings.64544410Vapour pressure.3'56 mm.8'80 ,,9-10 ),19-70 ) )20.00 ),56.40 ),130'20 ,,These results, as well as those for camphor and borneol, have beenplotted on a temperature-pressure diagram (Fig. 2); it is seen thatthe curves for the solutions lie between those for the pure sub-stances. The vapour pressures obtained by both methods arecompared in the following table :Barometric Air currentConcentration. Temperature.(mm. ). Temperature. (mm. ).20 mols. borneol ......... 110.6" 28-1 110'1" 27 -840 $ 2 ) ) ......... 110'0 25.6 110'1 25.060 ), ) ) ......... 110'2 23.0 110.8 20.880 ,, ,, ......... 110.6 19.7 110'1 18-2The deviations are in the direction expected, since the errors areentirely due to change in concentration. For those solutionsrelatively richer in camphor, the barometric method would give,owing to loss of the more volatile component, results which wouldbe too low, and conversely for solutions relatively richer in borneol.The agreement is as close as can be expected, considering theextreme difficulty of determining the vapour pressure of a solidsolution by the barometric method.Isothermals are shown in Fig. 3. The results given at llOo arethose obtained by the air-current method ; for other temperatures,the barometric results are given.It is seen that the isothermalMISCIBLE SOLIDS AND THEIR SOLlD SOLUTIONS. 441FIa. 2.I78" 98" 118" 138" 158"Temperature.FIG. 3.6000% bornaol 20 40 60 80 100% borneol100% camphor 0% camphorMols. of borneoZ per 100 of mixture442 VANBTONE: THE VAYOUR PRESSURES OF TWO PERFECTLYare straight lines. This leads to the important conclusion “ t h a tthe vapour pressure of a solid solution is a linear function of themolecular concentration, and can be calculated from the equation :p100- ’ 8 -where n=nurnber of mols. of borneol per 100 mols. of mixture.table :The calculated and observed results are given in the followingV a p o w Pressure of Solid Solutions at l l O o .Concentration.102030405060708090Cal c u I a t ed .30.3 nun.28.6 ,,26‘9 ,,25-2 ,,23.5 ),21-8 ,)20’1 ),16.7 ,,18-4 ,,Observed(air-current method).30.4 mm.57.8 ,I27’1 ,,25.0 ,,24’0 ,,20.9 ),19.9 ,,18.2 ,)17’9 ,,Speransky (ibid.), for solid solutions of p-chlorobromobenzene andy-dibromobenzene, obtained fairly good agreement between calcu-lated and observed vapour pressures.The pressures were measuredin mm. of paraffin oil in a differential tensimeter. Young (Trans.,1902, 81, 768) has shown that the equation given above holds formixtures of liquids which are chemically closely related, hence thepresent work is strong evidence in support of the van’t Hoff theoryof solid solutions, that they follow the same laws as liquid solutions.It is seen also from the curves in Pig.2 that the vapour pressuresof solid solutions of camphor and borneol are always greater thanthe vapour pressure of borneol. Precisely the same may be saidof the freezing points, hence, when the substance of lower freezingpoint and vapour pressure is considered, the addition of a substancewith which it forms solid solutions produces a change in theseproperties opposite to that expected, and directly contrary to thatwhich usually occurs with solutions which obey Raoult’s law. Itseems therefore futile to apply such laws to determine the molecularweight of solids.Summary and Conclusion.1. The vapour pressures of camphor and borneol have beendetermined for temperatures from 7 8 O to 156O.The resultsobtained for camphor are generally lower than those of formerinvestigators. The vapour pressure of borneol has not been pre-viously determined.2. The ratio of the absolute temperatures corresponding witMISCIBLE SOLIDS AND THEIR SOLID SOLUTIONS. 483equal vapour pressures is constant, thus Ramsay and Young’s rulefor closely related liquids also holds for closely related solids.3. The air-current method of determining vapour pressures hasbeen extensively used, and it has been shown that the resultsobtained agree closely with those obtained by the barometricmethod.4. The vapour pressures of a complete series of solid solutionshave been determined. It has been shown that the vapourpressures of solid solutions, like other physical properties, followthe ordinary mixture law :where %=number of mols. of R per 100 of mixture.5. Approximate results for solid solutions have been obtainedby the barometric method, more accurate results by the air-currentmethod.6. A method of determining the partial pressures of solutionsby combining the data obtained from barometric and air-currentmethods has been indicated.7, Since the vapour pressures of solid solutions of camphor andborneol follow the mixture law, it is highly probable that themolecular weights of the solid components are normal.8. The agreement between the results obtained by the twomethods leads t o the conclusion that the densities of the vapours ofcamphor and borneol at the temperatures employed are normal.I n conclusion, I wish to express my thanks to the Principal ofUniversity College, Cardiff, and the st& of the chemical depart-ment, for the interest taken in the work and the facilities affordedme. I am especially grateful to Dr. E. P. Perman for suggestingthe work, and for his advice and assistance in carrying it out.The expenses of the work have been defrayed by grants from theGlamorgan County Council and the College Council, to whom alsoI wish to express my thanks.UNIVERHITY COLLEGE,LONDON, W.

ISSN:0368-1645    

DOI:10.1039/CT9109700429

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

444 MELDOLA AND KUNTZEIN: SALTS AND ETHERS OFXLVIII.--Salts und Ethers oj' 2 : 3 ;5-li.initro-$-acetyl-amino ph e n o 1.By RAPHAEL MELDOLA, F.R.S., and HAROLD KUNTZEN.THE marked acid character of the above compound, which was firstdescribed by one of the authors in 1906 (Trans., 89, 1935), is shownby the readiness with which it forms metallic and organic salts.At the same time, the extreme mobility of one of the nitro-groupstends to bring about decomposition of the salts, especially inpresence of excess of base. With organic bases of the nature ofprimary amines, the trinitro-compound, as stated in former papers,readily forms salts, but these pass rapidly into catenation productsand finally into iminazoles, so that the intermediate productgenerally consists of a mixture of the salts of the trinitro-compoundwith those of the catenation product, or of the iminazole, or ofboth.With respect to metallic salts, it was pointed out in a recentcommunication (Trans., 1909, 95, 1381) that these could be safelyprepared by the interaction of the trinitro-compound and salts ofmetals with weak acids. This principle has now been successfullyapplied for the preparation of a number of metallic and organicsalts from the acetates, carbonates, etc., of the respective metals oralkaloids. Details of the mode of preparation of the various saltsare given in the experimental part of this paper, the series describedcomprising those which are sufficiently insoluble in water tocrystallise from the hot concentrated solution on cooling.Thisseries is, however, quite typical, and the research has not beenextended to those more soluble salts (lithium, calcium, etc.) whichcould not be directly isolated in the manner described, but whichcould no doubt be obtained if wanted by the evaporation of theirsolutions in a vacuum at the ordinary temperature.Generat Churucters of the Salts.The metallic salts of trinitroadetylaminophenol are all highlycoloured, red substances, the parent compound being pale yellow.*It is for this, among other reasons, that these salts have been con-sidered of sufficient interest to form the subject of a special studyin view of the large amount of work which has of late years beenbestowed upon the subject of colour in relation to chemical con-stitution. It has already been pointed out that the trinitro-compound is capable of a double '' isonitro- " isomerism (Trans.,* The lead salt alone approaches the free trinitro-compound in colour2 : 3 : 5-TRINITRO-4-ACETYLAMINOPHEh’OL. 4451908, 93, 1662), so that a change in constitution in passing fromthe free compound to the salt might reasonably be postulated.Assatisfactory evidence of such change was most likely to be furnishedby a study of the absorption spectra, and as Dr. J. T. Hewitt hasrecently been dealing with this subject (Trans., 1909, 95, 1755),he has, a t our request, been good enough to photograph the absorp-tion spectra of the free compound and its salts, and his observationsare appended to the present paper.As will be seen from theseresults, there is justification for the belief that in forming a saltthe isonitro-constitution is acquired, and he has further obtainedevidence of the transitory existence of a disodium salt in presenceof excess of alkali. I n connexion with these results, it is of interestto note that the methyl ether described in this paper (2: 3 : 5-tri-nitro-4-acetylaminoanisole) is, to the eye, a colourless substance,and therefore may be presumed to have the same constitution asthe free trinitro-compound.All the metallic salts of trinitroacetylaminophenol now madeknown are very soluble in water. They are beautifully crysta.lline,and contain water of crystallisation which in most cases cannot beexpelled at looo, and at higher temperatures decomposition takesplace.They all deflagrate on heating in the dry state, but notexplosively, the only exception being the cobalt salt, whichdeflagrates more sharply than any of the others.I n forming salts with natural alkalaids, the trinitro-compoundshows marked preferential characters. With brucine and guanidinevery stable insoluble salts separate a t once on mixing solutionsof the trinitro-compound and the base, or by the action of thetrinitro-compound on the acetate of the base. Narcotine forms aless stable salt, whilst carbamide, theobromine, quinine, st’rychnine,cinchonine, and morphine do not give readily isolable salts.Caffeine forms a salt which is interesting as being dissociable inalcoholic solution. If equirnolecular weights of the base and thetrinitro-compound are dissolved in a small quantity of boilingalcohol, the solution, on cooling, deposits at first crystals ofcaffeine, and subsequently a mixture of caffeine and the caffeinesalt, the latter crystallising in yellow, nodular aggregates.Furthercrystallisation of the mixed .crystals leads to the same result, evenwhen excess of trinitro-compound is intentionally added, so thatthe pure caffeine salt could not be isolated. In alcoholic solutionthere appears to be an equilibrium mixture, varying in compositionwith temperature and concentration, of free caffeine, free trinitro-compound, and caffeine salt446 MELDOLA AND KUNTZEN: SALTS AND ETHERS OFAttempt to Prepare an Optically Active Compound Containing anAsymmetric Tervalent Nitrogen. Atom.The main object in studying the salts formed by the trinitro-compound with natural alkaloids was to test a, somewhat plausiblehypothesis which had suggested itself with respect to the possibleasymmetry of the nitrogen atom in the trinitro-compound itself.From the formula of this compound,C,H,O C,H(NO,),*OH-NH-C,H,O\/it will be seen that the nitrogen atom is combined with two acidradicles (acetyl and the substituted trinitro-phenol residue) andone positive atom (hydrogen).I n most of the attempts that havehitherto been made to resolve tervalent nitrogen compounds, thenitrogen atom has been combined with positive radicles, and themolecule as a whole has been basic in character." The negativeresults have in these cases been attributed t o racemisation due tohydrolytic dissociation of the salt or to the temporary assumptionof quinquevalent function by the nitrogen atom.The trinitro-compound under investigation is certainly free from the latterobjection, as it is strongly acid in character, and does not formsalts with acids. On the other hand, disregarding for the presentthe possibility of hydrolytic dissociation, if there is any weightattaching to the hypothesis of mutual attfactions and repulsionsbetween the radicles in a molecule, it might be considered thatthree positive radicles attached to a nitrogen atom would bymutual repulsion f avour the configuration sometimes assigned tosuch compounds (No. I), the " bonds '' being in one plane:CGNc b(1.) (11- 1When two strongly acid radicles and one positive atom are presentit seemed, on this view, that every chance for displacement of the" bonds " would be given, and the asymmehic configuration (No.11)assumed. At any rate, the hypothesis seemed sufficiently plausibleto be worth submitting to the test of experiment. The result, as* By way of exception to this general statement, the attempt by Jones andMillington to resolve methylethylanilinesulphonic acid may be referred to (Proc.Canib. Phil. Soc., 1904, 12, 489).IN/\c bf i ' uIn this w e , also, the result was negative2 : 3 : 5-TRINITRO-~-ACETYLAMINOPHENOL. 447in former cases, was, however, negative. A specimen of the brucinesalt, was prepared by precipitating the trinitro-compound in alcoholicsolution with a semi-molecular proportion of the base.The trinitro-compound recovered from the filtrate and from the salt by decom-position by acid was examined for us by Dr. T. Martin Lowry, butin neither specimen was there any trace of optical activity.Dr. Lowry reports that he made his observations with the acetonesolution of the compound (4 grams per 100 C.C. in 2-dcm. tubes)by means of red (lithium) light. We desire to take this oppor-tunity of expressing our thanks to Dr. Lowry for the assistancethus rendered.Although the result is in this case negative, we propose continuingthe investigation, as there still remains th'e possibility that theasymmetry may exist only while the trinitro-compound and thebase are in combination." To test this point, it will be necessaryto prepare some salt more soluble than the brucine salt, and tocompare its optical activity in some non-hydrolysing solvent withthat of the base with which the trinitro-compound is combined.EXPERIMENTALArnmomim Sdt, C8H,08N4=NH,.Prepared by dissolving the trinitro-compound in a hot con-centrated solution of ammonium acetate and allowing to crystallise.Bright red, spherical aggregates of slender needles.The salt isanhydrous, and undergoes decomposition at about 203O when heatedin a capillary tube:0.0434 gave 8.6 C.C. N, (moist) at 12O and 761.3. N=23.56.C8HQOaNS requires N = 23.10 per cent.Sodium Salt, C8H,08N4Na,3H20.Prepared by dissolving the trinitro-compound in a hot con-centrated solution of sodium carbonate.The salt separates slowlyon cooling in long, transparent, ruby-red prisms. Professor W. J.Pope, who has been good enough t o examine these crystals for us,reports that they "probably belong to the anorthic system. Theacute bisectrix of a large axial angle emerges through the smallend faces; the optic axial dispersion is marked, and the angle forblue is larger than that for red light ":0.1336 gave 17.55 C.C. N, (moist) at 12'2O and 747 mm. N=15*31.0.1132 ,, 0.0220 N%SO,. Na=6-31.C&&OsN4Na,3H20 requires N = 15.47 ; Na = 6-36 per cent.* As bearing on this point, see a paper by Pope and Harvey (Trans., 1901, 79,837)448 MELDOLA AND KUNTZEN: SALTS AND ETHERS OFOn heating in the water-oven, the salt becomes opaque and brick-red in colour, and loses weight owing to dehydration and (possibly)partial decomposition, the loss of weight being somewhat in excessof that required by the 3H,O indicated by the above analyses:0.5486, heated in the water-oven, lost 0*0930 = 16.95 per cent.0.0506 (dried as above) gave 7-75 C.C.N, (moist) at 12O and0.1036 (dried as above) gave 0.0238 Na,S04.C,H,O,N,Na requires N=18.19; Na=7*48 per cent.750.1 mm. N=18*01.Na= 7.45.A lossof 3HiO requires 14.9, and of 3$H,O 17.43 per cent.POtaSSkTh Salt, C&,O8N,I(.This salt has already been described (Trans., 1909, 95, 1381).To the former description we are now enabled to add that ananhydrous salt is formed on long exposure to the air a t the ordinarytemperature :N=17.31.0-0678 gave 10.2 C.C. N, (moist) at 17O and 755.5 mm.0.0928 ,, 0.0244 E2S04. K=ll.81.C,H,O,N,E( requires N = 17-28 ; I( = 12.07 per cent.Barium Salt, (C,H,08N4),Ba,3H,0.This salt was prepared by two methods, first by dissolving thetrinitro-compound in a hot solution of barium acetate, andsecondly, by boiling the trinitro-compound with barium carbonateand water and filtering from excess of barium carbonate. In bothcases the solution deposits the salt on cooling as flat needles of adeep red colour and having a slight metallic reflex in the motherliquor when viewed at an angle. The analyses of the specimensprepared by the barium acetate method were somewhat irregular,and indicate that a more definite salt is given by the other method :0.0550 gave 7.15 C.C.N, (moist) at 19O and 758.5 mm. N'=14*9.0.1099 ,, 13.9 C.C. N,,(moist) at 11'5O and 754.1 mm. N=14.92.0-0770 ,, 0.0238 BaSO,. Ba=18*19.Cl,H,,01,N~Ba,3H20 requires N = 14.71 ; Ba = 18.0 per cent.The salt does not lose weight on drying at looo.Magnesium Salt, (C8H508N4),Mg,6H20.Prepared as above from the trinitro-compound and magnesiumacetate. Bright red prisms. The specimen analysed was twicecrystallised from water :0.1292 gave 17.85 C.C. N, (moist) at 18*5O and 753.4: mm.N = 15.782 3 : 5-TRINITRO-4-ACETYLAMINOPHENOL. 4490-1122 gave 0.0161 Mg,P,O,.The salt does not lose water at looo.Mg = 3.21.C,,H,,,0,,N8Mg,6H,0 requires N = 15-95 ; Mg = 3-03 per cent.Prepared as above from the trinitro-compound and zinc acetate.0.1633 gave 21.1 C.C.N, (moist) at 18O and 760 mm.0.3240 ,, 0.0352 ZnO. Zn=8.73.The salt does not lose weight at looo.Bright red prisms, resembling the magnesium sa,lt :N=14*92.C,,H,,0,,N8Zn,6H20 requires N = 15-05 ; Zn = 8.8 per cent.Cadmzhrn SaZ6, (C,H,O,N4),Cd,6H,O.Prepared by boiling the trinitro-compound with water andcadmium carbonate, filtering from excess of carbonate, and allowingto cool, when the salt crystallises out in red scales:N=14*15. 0.1422 gave 16.9 C.C. N, (moist) at 13O and 765.3 mm.0.1602 ,, 0*0262 CdO. Cd=14.32.C,,H,,0,,N,Cd,6H20 requires N = 14.17 ; Cd = 14.22 per cent.The salt darkens in colour and shows signs of fusion and decom-position when heated in the water-oven.Prepared as above from the trinitro-compound and nickelcarbonate.The salt separates as dark brick-red prisms :0.160 gave 22.3 C.C. N, (moist) at 14O and 745.8 mm. N=16*08.0.2460 ,, 0.0260 NiO. Ni=8*31.The salt undergoes no change a t looo.C,,H,o0,GN,Ni,4H,0 requires N = 15-99 ; Ni = 8.37 per cent.It deflagrate; somewhatsharply when heated in the dry state.Prepared as above from the trinitro-compound and cobalt0.1899 gave 24.2 N, (moist) a t 1l0 and 764.3 mm.0.1714 ,, 0.0135 Co. C0=7.88 per cent.C,,H,,0,,N8Co,6H20 requires N = 15.2 ; Co = 8.1 per cent.This salfi differs from the nickel salt, not only in the quantity ofwater of crystallisation with which it combines, but also in thereadiness with which it parts with this water. When heated inthe water-oven, the salt becomes of a dark brick-red colour, andcarbonate.Crystallises in bright red prisms :N=15.24450 MELDOLA AND KUNTZEN: SALTS AND ETHERS OFloses practically all its water. The anhydrous salt becomeshydrated, and changes to a bright red colour on moistening withwater :0.5032, dried in water-oven, lost 0.071.0.0529 (dried as above) gave 7-85 C.C. N, (moist) at 9O and0.0446 (dried as above) gave 0-0042 Co.This salt, on heating, deflagrates more sharply than the nickelR,O = 14.11.C16H10016NsCo,6H,0 requires H,O = 14.66 per cent.749.6 mm. N=17.6.Co=9.44.C16H,,016N8Co requires N = 17-82 ; Co = 9.38 per cent.salt.Manganese Sat t , (C8H,'08N,),Mn,4H20.Prepared m before from the trinitro-compound and manganese0.2152 gave 29.2 C.C.N, (moist) at 12.3O and 749.9 mm. N= 15.9.0.1266 ,, 0.0132 Mn304. Mn=7.51.C16H,,0,,N8Mn,4H,0 requires N = 16.08 ; Mn = 7.89 per cent.The salt darkens and shows signs of fusion and decompositioncarbonate. Dull red, rhombohedral prisms :when heated in the water-oven.Copper Salt, (C8H;08N4)2Cu,4H,0.Dull brick-red, transparent, rhombohedral prisms :Prepared from the trinitro-compound and copper carbonate aa0.1273 gave 17.1 C.C. N, (moistj at 12O and 745.1 mm. N=15*63.0.1709 ,, 0.0190 CUO. Cu=8.89.The salt becomes light brown and opaque on heating in theComplete dehydration couldbefore.C16HloO16NsCu,4H20 requires N = 15-88 ; Cu = 9.0 per cent.water-oven, and partly loses its water.not be effected without decomposition :0'5247 lost 0.0528.H20 = 10.06.C,,H,,O,,N8C'u,4H,O requires H,O = 12 per cent.The salt thus dried gave the following results on analysis:0.0874 gave 13.1 C.C. N, (moist) at 12O and 755 mm.0.0844 ,, 0.0104 CuO. Cu=9.84.N = 17-68.C,6~,,0,,N8Cu requires N = 17-69 ; c u = 10.03 per cent.Lead S d t , (CsH,0sN,),Pb,3H20.Prepared from lead carbonate and the trinitro-compound asabove. Flat, orange needles 2 : 3 : 5-TRINITRO-4-ACETYLAMINOPHENOL. 4510-0948 gave 10.75 C.C. N, (moist) a t 11'5O and 752.2 mm. N = 13.36.0.1428 ,, 0.0525 PbSO,. Pb=25*16.This salt does not lose water at looo.C,,H,,0,,N,Pb,3H20 requires N = 13-48 ; P b = 24.89 per cent.Thtalk6m Salt, C8H;O&?*T1.From the trinitro-compound and thallium carbonate by the same0.0779 gave 7.6 C.C.N, (moist) at 7'7O and 741.4 mm.method. Brick-red, fern-like leaflets :N = 11.52.0.1577 ,, 0.0770 TlCI. T1=41.60.C,H$O,N,Tl requires N;= 11.46 ; T1= 41.72 per cent.The salt undergoes no change a t looo.Silver S d t , C8H,~,N,Ag,3H2O.The salt was prepared from the trinitro-compound and silvercarbonate by the method described above. It generally crystallisesin red prisms, but sometimes separates as orange-red scales. Theanalysis of the salt offered considerable difficulty, as the free trinitro-compound appears to interfere with the precipitation of the silverchloride. Good results were only obtained when the organic matterwas destroyed by heating the salt in a sealed tube with fumingnitric acid for three hours at 190°.The water could not be com-pletely expelled by heating in the water-oven; at this temperaturethe salt darkens, and, on long heating, shows signs of decomposition.About 102O the salt deflagrates :0.0622 (air dried) gave 6.8 C.C. N, (moist) a t 14O and 744.2 mm.0.2996 (air dried) gave 31 C.C. N, (moist) a t 12O and 768 mm.0.2570 gave 0.0820 AgCI. Ag = 24.02.C8E;08N,Ag,3H,0 requires N = 12.53 ; Ag = 24.14 per cent.A specimen dried in the water-oven gave the following results :0.0682 gave 8.2 C.C. N, (moist) at 14O and 730.5 mm.0.0564 ,, 0.0201 AgCl. Ag=26*82.C,H;O,N,Ag requires N = 14-26 ; Ag = 27.46 per cent.The salt is not only readily soluble in water, but also in methyland ethyl alcohols, and by its means the methyl ether has beenprepared, and is described in the present paper.N = 12'59.N = 12.38.N=13*58.This salt was prepared by adding to a hot saturated solution ofthe alkaloid in absolute alcohol an equimolecular proportion of theVOL. XCVII.H 452 MELDOLA AND KUNTZEN: SALTS AND ETHERS OFtrinitro-compound dissolved in the same solvent. It was alsoobtained by dissolving the trinitro-compound in a hot aqueoussolution of brucine acetate and allowing to cool. I n both cases thesame salt is obtained. It is practically insoluble in alcohol, so thatthe trinitro-compound might be used as a precipitant for the base.It can be best purified by dissolving in hot glacial acetic acid,which does not appear to decompose the salt, diluting the solutionwith water, and allowing to crystallise.It separates, on cooling,in rosettes of deep reddish-brown needles, which appear ruby-red bytransmitted light. The salt melts with decomposition at 222-224O :0.2180 gave 0.4366 CO, and 0.0906 33,O. C = 54.62 ; H = 4.89.0.1322 ,, 0.2648 CO, ,, 0.0572 H,O. C=54.62; H=4*80.0.1268C31H32012N6 requires C = 54.68 ; H =4*74 ; N = 12.36 per cent.I n connexion with this salt it is of interest to note that brucine,, 13.7 C.C. N, (moist) at 21° and 75'7.5 mm. N=12.26.also forms a very insoluble picrate.This salt was prepared by dissolving guanidine carbonate indilute acetic acid and saturating the hot solution with the trinitro-compound, the latter being added in small portions in the solidstate. The salt crystallises out on cooling in dark brown needles,appearing ruby-red by transmitted light, and having a bronzy lustrewhen seen by reflected light.Purification was effected bycrystallisation from hot water, in which the salt dissolves withan orange colour:0.1781 gave 44.55 C.C. N, (moist) a t 20'5O and 754.1 mm. N=28.32.0.2170 ,, 0.2502 CO, and 0.0650 H,O. C=31*44; H=3.32.C9H,,0,N, requires C = 31.29 ; H = 3-21 ; N = 28.41 per cent.The salt is quite stable; the melting point is 227O, and no lossof weight takes place a t looo.Nar co tine Sat t , C,H@,N,, C22H,307N.This salt was prepared from the trinitro-compound and the acetateof the base, or by mixing alcoholic solutions of the components inthe usual way. Some difliculty was experienced in obtaining a pureproduct owing to the tendency of the salt to dissociate whencrystallised from alcohol. The most satisfactory results on analysiswere given by specimens crystallised from alcohol in the presence ofa slight excess of the base:0.0988 gave 0.1860 CO, and 0.0378 H,O.C = 51-34 ; H = 4.35.0.1348 ,, 0.2552 CO, ,, 0.0504 H20. C=51*63; H=4.162 : 3 : 5-TRINITRO-4-ACETYLAMINOPHENOL. 4530.0358 gave 3.1 C.C. N, (moist) a t 1 2 O and 761.3 mm.The salt crystallises in flat, yellow needles, melting a t 193-194O.N=10*30.C30H29015N5 requires C =51*48 ; H = 4.19 ; N = 10.02 per cent.Although, for reasons stated in the introductory portion of thispaper, the pure salt could not be isolated, the analytical resultsall pointed to the above formula. The salt, freed as far as possiblefrom admixed caffeine, crystallises in rosettes of yellow needles,melting at about 177O.Dr.J . T . Hewitt's Observations o n the Absorption S p e c t w m ofTriicitroace t ylaminoph en0 I and i t s Salts.The pale yellow trinitro-compound dissolves both in water and96 per cent. alcohol, with an intense yellow colour, inclining toorange. Whilst this orange shade is deepened by the addition ofdilute sodium hydroxide or sodium acetate, the colour in the lattercase soon reaching a maximum, hydrogen chloride has an oppositeeffect, comparatively small quantities causing the solution to assumea pale yellow tint comparable with that of the solid compound. Thisresult is quite in accordance with the fact that trinitroacetylamino-phenol is a fairly strong acid, and necessitates the addition of ahighly ionised acid, such as hydrogen chloride, to the alcoholicsolution if the spectrum of the non-ionised nitrophenol is to beobserved (compare Buttle and Hewitt, Trans., 1909, 95, 1755,e t seq.).*In these circumstances the principal feature of theabsorption spectrum was a band having its head at an oscillationfrequency of about 2800, and not differing very markedly in thisrespect or in its persistency from that observed by Hartley andHuntington in the case of o-nitrophenol (see the curves plotted on alogarithmic scale by Baly, Edwards, and Stewart, Trans., 1906,89, 519).When an alcoholic solution to which a dilute alcoholic solutionof sodium acetate has been added until no further intensificationof the orange shade is noticeable (solution of the monosodium salt),a spectrum is obtained which in one respect shows markedsimilarity to that observed by Baly and his co-workers (Zoc.cit.) inthe case of the sodium salt of o-nitrophenol, and by Buttle andHewitt (Zoc. cit., p. 1756) with that of 2 : 6-dinitrophenol, the bandof slowest vibration having its head a t an oscillation frequency of2250. Hence it seems justifiable to conclude that, as in the caseof o-nitro- and 2 : 6-dinitro-pheno1sy formation of the sodium salt isaccompanied by an alteration in structure, the trinitroacetylamino-aH H 454 MELDOLA AND KUNTZEN: SALTS AND ETHERS OFphenol and its sodium salt being related in the sense of thef ormuk :OH 0jq:NO,Nn {yo2 and NO/[ [NO2NHAc NH- AcNO2\/NO2 \/On the physical side there seems but little doubt that a radicalalteration in absorption on formation of a derivative is accompaniedby a radical alteration in structure, although it is well to keep inmind that the only direct chemical evidence bearing on the assumedchange of structure on salt formation (or ionisation) in the caseof the nitrophenols depends on the isolation of highly colouredaci-esters by Hantzsch and Gorke (Ber., 1906, 39, 1073).If to a solution (aqueous or alcoholic) of the trinitro-compound,alkali be added in excess, a deep purple-red colour is produced;such solutions are, however, unstable, the decomposition makingitself manifest by a.deposition of sodium salt ( 1 nitrite) when asolution in 96 per cent.alcohol is examined, and a, change of colourtowards yellow. Despite this inconvenience, an attempt was madeto photograph the absorption spectrum of a freshly prepared solu-tion, which very possibly contains a disodium salt: the persistencyof the colour band was very similar to that found for a, monosodiumsalt, but the head lies at an oscillation frequency of about 2040.The curves in the figure were obtained with solutions made upin the following manner.TrinitroacetyZaminophenoZ (full curve).-A N / 1000-solution wasprepared from 0.0286 gram and 5 C.C. of fuming hydrochloric acid,made up to 100 C.C. with 96 per cent. alcohol. A N/lO,OOO-solutionwas prepared by diluting 10 C.C. of the N/lOOO-solution and 5 C.C.of fuming hydrochloric acid to 100 C.C. with 96 per cent.alcohol.Monosodium Salt (dotted curve).-O*0286 Gram of the phenol witsdissolved in alcohol, a solution of sodium acetate added in at leasttwice the excess of that necessary to produce any further intensifica-tion of the orange shade, and then made up to 100 C.C. with alcohol.5 111111. of this N/lOOO-solution gave the same absorption as 50 mm.of the solution obtained on tenfold dilution (N/lO,OOO). This showsthat any hydrolysis of the salt is inappreciable, as might have beenexpected.Excess of A Zkali.-The solution photographed was obtained bydissolving 0.0286 gram of trinitroacetylaminophenol in alcohol,adding alcoholic sodium hydroxide in excess of that required formaximum development of the purple shade, and making up to100 C.C.with 96 per cent. alcohol. As 5 mm. of such a solution di2 : 3 : 5-TRINITRO-4-ACETYLAMINOPHENOL. 455not give the same absorption as 50 mm. of a N/lO,OOO-solution, onlythe stronger solution was used. The salt containing more than oneatom of metal is evidently strongly hydrolysed on dilution.Methyl Ether = 2 : 3 : 5-Trinitro-4-acety~am~noa?zisole,0- CH,( y o 2NO,, /NO2NH*CO*CH,Attempts to methylate the trinitro-compound by silver oxide andThe methyl iodide led to negative results (Trans., 1909, 95, 1379).Oscillation freqGencies.18 200022 24 26 28 3000 32 34 36 38 4000 42 44 46T?.in~troc6cetnminophenol i?t alcohol, HCl i n excessY Y ,, , , NaC,H,O, in cxcess¶, ,, ,) NaOH in excess..._.._.._._...__...~.....---___________isolation of the silver salt described in this paper has, however,rendered possible the preparation of the above methyl ether and thecorresponding trinitroanisidine. The silver salt in methyl-alcoholicsolution is rapidly decomposed by methyl iodide, even at theordinary temperature, the separation of silver iodide commencingsoon after mixing the solutions and being complete after about halfan hour's heating on the water-bath.Only about 15 per cent. ofthe trinitro-compound undergoes methylation in this process. Thealcoholic solution, after filtration, is evaporated to a small volume,diluted with water, and extracted with an aqueous solution o456 2 : 3 : 5-Tl~INITItO 4-ACETYLAMINOPHENOL.sodium acetate to remove the unmethylated portion.The residue,after crystallisation from alcohol, consists of white needles, meltingat 194O:0.0566 gave 8.9 C.C. N, (moist) at 13.5O and 762.8 mm. N=18*61.C,H80,N, requires N = 18.67 per cent.That the compound has the above constitution is proved byboiling its alcoholic solution for a short time with a little aniline,removing the excess of aniline by dilute hydrochloric acid,anhydridising the dry product by heating with a little aceticanhydride, and purifying the iminazole thus obtained bycrystallisation from alcohol. The compound was identified as themethyl ether (m. p. 205-206O) of dinitrohydroxy-l-phenylmethyl-benziminazole described in a former paper (Trans., 1908,93, 1672) :0.1074 gave 15.9 C.C. N, (moist) a t 1 2 O and 743 mm.C15Hl,0,N, requires N = 17.07 per cent.As the melting point of the acetyl derivative of the trinitro-anisidine recently obtained by Reverdin (Arch. Sci. phys. nut., 1909,27, 396; 28, 381) is quite different from ours, namely, 242O,Reverdin’s compound is no doubt a derivative of the isomeric2 : 3 : 6-trinitroanisidine. This conclusion is confirmed by a com-parison of the trinitroanisidines, which, by the kindness ofM. Reverdin, who has sent us a specimen of his preparation, wehave been enabled to make. Our acetyl derivative is easilyhydrolysed by heating with excess of concentrated sulphuric acidfor a few minutes to about 105O. The solution, when cold, is pouredinto water, and the trinitroanisidine allowed to separate. Aftercrystallisation from alcohol it consists of dull red, glistening scales,melting at 138-139O :N=21*90.C,H,O,N, requires N = 21-71 per cent.The products ofdiazotisation of the new trinitroanisidine will be of special interest,and we propose extending the research in this direction.N=17.17.0.0632 gave 12 C.C. N, (moist) at 14’7O and 747.8 mm.M. Reverdin’s trinitroanisidine melts at 127O.We have much plea,sure, in conclusion, in expressing our thanksto Mr. Arthur S. Wilson, who has rendered us much assistance inthe course of the work.CITY AND GUILDS TECHNICAL COLLEGE, FINSBURY

ISSN:0368-1645    

DOI:10.1039/CT9109700444

出版商:RSC    

年代:1910

数据来源: RSC