摘要:

23x1 .- Trunsformation of the Alkylummonium Cyanates into the corresponding Ureus. By JAMES WALKER, D.Sc., Ph.T)., and JAMES R. APPLEYARD, F.C.S., University College, Dundee. IT has been shown by Walker and Hamblg (Trans., 1895, 67, 746) that the production of urea from an aqueous solution of ammonium cyanate is not a case of fiimple transformation of one molecule into another, but that the law regulating the transformation is the law of n bimolecular action, the active molecules being in all prohabilitg ammonium ions and cyanic acid ions. To use Ostwald's notation, the equation which expresses the action is NHa' + CNO' = CO(NH,),. The velocity constant of the transformation is given by them for different temperatures, and in the present paper a comparison is effected between that constant and those obtained when the hydrogen atoms of the ammoilium ion are replaced by alkyl radicles.The experiments were all made with decinormal solutions, which were prepared in the manner described by Walker and Hambly. The alkylammonium chloride was agitated for an hour with excess of silver cyanate and the requisite quantity of water, after which the solution was filtered, and portions tested, with nitric acid and silver nitrate on the one hand, and with nitric acid and potassium chloride on the other, in order to prove the absence of soluble silver salt and soluble chloride respectively. By operating in this way, the solutions obtained were not always precisely decinormal, but in such cases the experimental numbers have been reduced to a uniform value by applying the very slight correction necessary, so that all the numbers given in the tables which follow are comparable with each other.Experiments were made at one temperature only, namely, at 59.6', except when equilibrium points or reverse actions were being determined. Ethy lanzmonizcm Cyanate. A decinormal solution of ethylammouium cyanate was heated at 59*6O, 5 C.C. of it being removed from time to time, and added t o 5 C.C. of a decinormal solution of silver nitrate. After the mixture had cooled, the precipitated silver cyanate was filtered off, and the amount of silver in the filtrate determined by means of a N/50 solution of ammonium thiocyanate. In order to ascertain the point at which the action ceased, a decinormal solution of ethylurea was heated at looo, and the amount of cyanate formed ascertained in the same way as in the direct action.The time which elapsed from the commence- VOL. LXIX. P194 WALKER AND APPLEYARD : TRANSB'ORllATION OF THE rnent of the heating is given in minutes under t, in the following table, the titres being given in the second column, and the actual concentration of the urea in the third. t. 0 30 80 140 200 260 320 Titre. 25.0 24.05 23.6 23.05 22-95 22.8 22.9 Uyes present. 0~1000 0.0962 0.0944 0.0922 0.0918 0-0912 0.0916 Ethylurea differs from urea in giving no perceptible quantit'y of carbonate when heated for a considerable time with water at 100°. After 260 minutes, the solution was fonnd to possess a feeble ammo- niacal smell, and a slight alkaline reaction, but it gave no precipitate with calcium nitrate.We are thus enabled to fix the end-point with accuracy, the concentrations for equilibrium being 0.0912 normal ethylurea, and 0.0088 normal ethylammonium cyanate. Walker and Hambly found, for the direct transformation of ammo- remained constant., E nium cyanate, that the expression - . - being the end-point, and x the titre. This also holds good for ethyl- ammonium cyanate, as may be seen from the following table. 1 x t E-z Ethylammonium Cyanate. E = 22.8. 1 x - . t. k. E - X. t h T * 30 4.95 17-85 0.0093 50 7.35 15.45 0.0096 70 9.1 13.7 0.0065 100 11.2 11.6 0-0097 130 12-6 10.2 0.0095 Mean .. .. .. 0.0095 for ammonium cyanate at 1 z - t 'E-x 59.7'' is 0.0144, the end-point being practically the same, namely, 22.9.It thus appears that the transformation of ethylammonium cyanate into ethylurea proceeds more slowly than the transformation of ammonium cyanate into ordinary urea, as a direct comparison of the titres a t corresponding times will also show. The values of the constants in the above instrance are nearly proportional to the rates at which the actions start, and this arises from the practical ideittity of the end-points. In the calculation, the progress of the reverse action The value of the expression -ALKYLAJIXONIUJI CYANATES INTO URE-IS. 195 (transformation of urea into cyanate) has been neglected, but this neglect does not invalidate the comparisoti of the rates of the diyect actions when the end-points have nearly the same value. When the end-points are widely apart, however, as they are in the case of other alkyl derivatives, the reverse action inlist be taken into account, if the comparison is to be of any value ; indeed, it i8 otherwise impossi- ble to obtain a, constant when tho point of equilibrium is far removed from the urea end.This greatly complicates the calculation, but the expressions obtained give the true velocity const.ants. If A is the original concentration of the cyanate expressed in teyms of a normal solution, the active mass of the ammonium ions will be A, which is also the active mass of the cyanic ions, supposing the ammonium cyanate to be fully dissociated. This is not quite the case,* but as all the ammonium cyanates eonsidered may be assumed to be equally dimocittted in equivalent solutions, the comparison of the numbers obtained is not thereby affected.Let the quantity x hare been transformed into urea a t thu time t ; then the rate a t =hick1 the direct reactmion will proceed is But at the same time we have the reverse reaction proceeding according t o the equation so that for the real progress of the action we have tla - at At the equilibrium point, - - 0, theyefore &(A - E ) Z = k'g, or K - k ' = - (a - El:>" (4). k r ' where Eis the value of a a t the point of equilibrium. H, the ratio of the velocity constants OE the opposed reactions, is thus easily determined by means of the end-point experiment. Substituting kK for k' in (3) we have dz cl t -- - k ( ( A - x)' - Ks), or = kdt. d.c: x:! - (BA + K)x + A' J(; At the dilutions investigated, the degree of dissociation avei*ages 90 per cent., with a variation from the iiieltii of 4 pel.cent. r 2196 WALKER AND APPLEYARD : TRANSFORMATION OF THE Integrating the expression on the left hand side by partial fractions, and bearing in mind that for t = 0, x = 0, we obtain as the \ d u e of I%, or, if we use decadic, instead of natural, logarithms, The expression, although complicated, is sufficiently convenient The value of k' is obtained from I n the case of ethylammonium cyanate, tlie value of A is 0.1, and for calculation in the form given. the equation k' = Kk. of 0.0912; so that from (4) we have If we now write the table for the transformation with the values of x in terms of a normal solution, and calculate the values of k by means of equation (5) we obtain it in the following form.t. Titrr. 8. k. 30 4.95 0.0198 0.08 1 50 7-35 0.0294 0.083 70 9.1 04364 0*082 100 11.2 0.0448 0.081 130 12.6 0.0504 0.079 Mean.. ...... 0.081 The expression given in equation (5) is thus constant, the mean value of k being 0.081. For k' we have 0.081 x 0.00085 = 0.000069. These constants give the aniourits transformed in one minute when the original concentration is normal, and is maintained at that value. Thus 8 per cent. of a normal solution of ethylammonium cyanate would be transformed into ethylurea in one minute at 59*6O, if the concentration did not fall off as the action proceeded ; whilst of a normal solution of ethylurea only 0.007 per cent. would be re- transformed into cyanate under the same conditions. -- 1 % t 33-x The value obtained for - - in decinormnl solution was 0.0095,ALKYLAMJIONIUM CYANATES INTO UREAS.197 and this for a normal solution would become 0.095. It will be seen, therefore, that by neglecting the reverse action, the value of the simple constant, is considerably greater than that of the real constant ; and thia divergence becomes more marked as the rate of the reveriJe action increases, With ammonium cyanate itself, it is difficult to ascertain the actual constant k, hecause not only is there a reverse reaction, but a slow secondary transformation of cyanate into carbonate. Taking t'he " practical " end-point as the basis of calculation (Walker and Hambly, Zoc. cit., 751), the values of the constant C is by the reverse action made greater thafi k, but by the subsidiary transformation it is made less than k. As these two disturbing influences nearly balance each other in amount, the observed value of C, namely 10 x 0.0144 = 0.144, must be very nearly equal to k, so that for the transforma- tion of ammonium cyanate we may put k = 0.144.The real end- point (Zoc. cit., 750) lies at 95 per cent., and so for f we have 0.095, 0.0052 - 0.000263, giving us k' = 0.144 x 0.000265 = and for I(, 0.000038. These results show that whilst the transformation of the ethylammonium cyanate is more rapid than that of the ammonium cyanate, the reverse transformation of the ethylurea proceeds more slowly than is the case with urea itself. 0.0%. - lMeth y lanmozium Cynnnte. When a cleciiiormal solution of methylurea is heated for half an hour at looo, it gives on cooling only a faint turbidity with siiver nitrate solution.The fitre of the filtered solution (see p. 193) after heating for 120 minutes was found to be 23.9, and after 150 minutes, 24.0. The composition of the solution at the equilibrium point is thus 96 per cent. methylurea and 4 per cent. methylammonium cyanate, the ralne of being, therefore, 0.096. For- K, we have o*oo42 = 0.000166. G * G Calculating the value of k from the foi-mnla given in equation (5) we obtain the following table from the experimental numbers for the direct transformation. t . Titre. X. k. 10 3.0 u.0120 0.1 41 20 5.:3 0.0212 0.135 :!J 5 7.7 0.0308 0129 5 0 9.9 0.0396 0.133 80 12.8 0.05 12 0.132 110 14.9 0,0596 0.135 0*1;34 -- Nean.. . . , .1% WALKER ASD APPLEYARD : TRANSFORMATIOX OF TEE The value of k' is 0.134 x 0.000166 = 0.000022.These numbers show that, the direct; transformation proceeds more rapidly in the case of methylammoiiium cyanate than in the case of the ethyl coni- pound, the reverse being the fact for the retransformation of the corresponding tireas. Uiethyla?ianzoniiim1 Cyanate. Unsymmetrical diethylurea, I\? H,*CO*NEt,, when heated at loo", gave the following numbers. f. Tit IT. Urea present. 0 25.0 0~1000 60 19-15 0.0766 90 18*% 0.0734 170 17.7 0.0706 200 16.7 0.0668 260 16.7 0.0668 After three hours heating, the solution had acquired a faint am- moniacal smell and was alkaline to litmus paper. A very slight precipitate mas obtained on the addition of calcium nitrate. The point of equilibrium in this case is much further removed from the urea end than in any of those preriouslj- considered, one-third of the urea, having undergone transformation into diethylammonium 0.0332? cyanate.Cnlcnlating K from = 0.0668 we obtain K = - 0*0668 - 0.0165. For the direct transformation of decinormal diethgla mnionium cyanate at 59.6", the following values were obtained. f. Titre. .i' . k. 20 3.7 0.0148 0.088 35 5.8 0.0252 0.089 5 5 7.8 0.0312 0.08 7 80 9.1 0-0392 0.088 110 21.9 0*0476 0.09i Mean.. .... . . 0.090 -- - The value of k' is Kk = 0.0165 x 0.090 = 0.00148. Whilst the constant for the direct transformation of the cyanate is not greatly different from the constant for the monetliylammoniuni compound, namely 0.081, the constant of the reverse action is twenty times greatey than the corresponding constaiit f u r monethyl urea, in consequence of the very different positions of the points of equili- brium in the two cases.ALKYLAMMONIUM CYANATES INTO UREAS.199 Uinzetl~ylui,nizo?2ia~nt Cyanate. A decinormal solution of unsymmetrical dimethylurea gave the following numbers on heating at 100'. f. 0 30 60 90 150 2 10 270 Titre. 2 5.0 23.8 23.4 22.8 21.6 21.1 21.1 Urea present. 0~1000 0.0952 0.0936 0.0912 0.0864 0.0844 0.0844 After three hours heating, the solution had a feeble ammoniacal smell and gave no precipitate with calcium nitrate; after five hours the nmmoniacal odour had greatly increased in intensity, rind 5t slight turbidity with calcium nitrate was observed. The value of is 0.0844, from which we obtain K = 0.0156' = 0.00288.0.0844 The following table contains the results of the transformation of a decinormal solution of dimethylammonium cyanate at 5906~. f. Titre. z. k. 20 8.2 0.0328 0.242 35 11.8 0.0472 0-260 4 5 13.0 0.0520 0.248 55 14-3 0.05 72 0.253 75 16.2 0.0648 0.262 Mean .......... 0.253 -- For k' we have Klz = 0.00288 x 0.253 = 0.00073. Here the ra,te of the direct transformation is almost double that found for the mononiethyl compound, and is indeed the greatest we have observed. The constant for the reverse action is no less than thirty times greater than that for the transformation of monomethyl- urea, but is still much less than the corresponding constant for un- symmetrical diet hylurea. Isonmyla~izirio~zizcm Cyanate, NH,(CH,*CH2*CHMe,)CN0.The urea prepa,red from this amylammonium cyanate melted at 88-89', the melting point given by Custer (Bey., 1879, 12, 1330) being 89-91'. A decinormal solixtion yielded the following results at 190".%oo WALKER AND APPLEYARD : TRANSFQRXATION OF THE t. Titre. Urea present. 0 '25.0 0.1000 30 24.8 0.0992 90 24.3 0.0972 180 23.65 0.0946 270 23% 0.0944 After five hours heating, the solution of the urea was slightly coloured, but had no ammoniacal smell, and gave no precipitate with calcium nitrate solvtion. The value of F being 0.0944, we have 0*00562 0.0944 K = - = 0*000334. The results obtained for the transformation of the amylammonium cyanate at 59.6' were as follows. t . Ti tre. k. k. 40 7.2 080288 0.090 70 10.5 00420 0.100 100 12.1 0.0484 0.089 130 13.7 0.0.548 0.090 175 15.6 0.0624 0.093 235 17.1 0.0684 0.090 Mean...... .. 0.092 -- For k' we obtain Kk = 0 000334 x 0.092 = 0*000031. The constants in this case resemble more closely those of the monethyl compounds than the confitants of any of the other alkyl derivatives we have investigated. Tertiarg Ainylammoizium Cyanate, NH,( CMe2Et)*CN0. Tertiary amylurea, melting at 155O, exhibited an abnormal be- haviour when heated in decinormnl aqueous solution at 100'. The titre, which at first diminished, after an inte~val oE three hours reached a minimum, and then increased as the heating was prolonged. t. Titre. Urea present. 30 21.1 0.0844 60 17.95 0.0718 90 16.2 0.0648 120 15.5 0.0620 150 14.8 0,0592 180 14.3 0.0572 200 15.1 0.0602 'i 230 15.5 0.0620 ? The solution had acquired a pronounced ammoniacal smell after 90 minutes heating, and, after two hours, gave a very slight pre-ALKYLAMMONILJX CYASATES INTO UREAS.201 cipitate with calcium nitrate. When the minimum titre was reached, a light precipitate consisting of slender interlaced needles was observed to have separated from the solution, and this increased in bulk as the heating was continued. A small quantity of a white sublimate of similar appearance mas also formed in the coldest part of the tube above the solution. Wurtz who first prepared tertiary axuylnrea (pseudo-amyleneurea) states that when tertiary amylammo- nium cyanate is treated with caustic potash it is converted into un- symmetrical tertiary diamylurea (pseudo-diamyleneuren ; AnnaleqL, 1866, 139, 330).This substance he describes as being almost in- soluble in water and extremely volatile, subliming to a network of light delicate needles. Its properties are, therefore, identical with those of the substance observed by us, which was probably formed according to the equations or, 2NH3A*CN0 = NA,*CO*NH, + NH4*CN0. The ammonium cyanate, supposed to be produced in the second equation, might either appear as urea or as ammonium carbonate, more probably as the latter, as the rise in the titre would then be accounted for (compare Walker and Hsmbly, Zoc. cit., 750). The abn~rmal course of the transformation renders the end-point uncertain, but the minimum value 0.0572 may be taken as an approximate value of E, an almostl identical number having been obtained when the urea was tmnsformed a t 79.6'.Tertiary amylammonium chloride was prepared from the corre- sponding urea as follows. The urea was boiled with strong potash solution for several hours i n a flask with condensing tube, so that the ammonia might escape, and the amylamine be returned to the flask. The contents were next distilled iuto hydrochloric acid solution, and the solution of chlorides thus obtained evaporated almost to dryness on the water bath ; the evaporation was completed in an exhausted desiccator over solid potash. Very little ammonium chloride was present, for on the conversion of a portion of the chloride into cyanate in the usual way, by means of silver cyanate, and rapid eva- poration to dryness of the cyanate solution, the urea obtained melted a t 1 5 5 O , the melting point of the original substance.A decinormal solution of the arnylammonium CJ anate, prepared in the manner above indicated, was heated a t 59.6' with the following result. t. Titre. .L' . k. SNHA*CO*NH, + 2HzO = NAz*CO*NH, + (R'H,)2CO,, 100 3.0 (J.0126 0.0137 160 4.1 0.0164 0.01 27 '220 4.4 0.0176 0.0101 404 6.1 0.0244 0.0085 584 7.6 0.0304 0.0082202 WALKER AND APPLEYARD : TRANSFORMATIOX OF THE The magnitude k was calculated with the end-point F = 0.0572, whence K = 0 ' ~ ~ = 0.032. 'It will be seen that the velue does not remain constant, but continually diminishes as the action proceeds ; this is no doubt due to secondary decompositions of the same nature as those undergone by the urea. Wurtz remarks (Zoc. cit., p. 329) that tertiary amylurea exhibits B marked tendency to break up, with the formation of amylene as one of the products of decomposition.At the beginning of the action, the values of k are probably nearest the true value, so that we may adopt k = 0.013 as being approximately correct. A second set of experiments yielded almost identical results, the value of k for the first two determinations being 0.0135. 0.0572 For k' we hare Kk = 0.032 x 0.013 = 0*0004. Although these values fork and 12' are somewhat uncertain, they are sufficiently accurate to show that whilst the direct transformatior] proceeds much more slowly than is the case with any of the other compoiinds examined, the reverse transformation is only exceeded in velocity by the diethJl a i d dimethyl compounds. Cowpn&m of C'onstaiits.In tlte following table the values of the constants for the various cyanrttes axid ureas have been collected, in order to exhibit any regnlarit,ies that might exist amongst them. C ya list e . Ammonium. .............. Met b ylnmmoni uni ......... Dimethylammonium ....... Ethylammonium .......... .Diethy lammoniuni ........ lsoamy larnmonium ........ Tertiary amylanimonium ... 100k.. 14.4 13.4 25.3 8.1 9.0 9.2 1.3 100k'. 0.0038 0.0022 0.073 0.007 0.148 O*i)O31 0.04 The values of the coilstants have all beeii multiplied by 100 to avoid unnecessary ciphers, arid to give the results in percentages. Thus in the case of ammonium cgaaate the numbers indicate that in a. normal solution 14.4 per cent. would 1.w transformed in t'he first minute i f t he concentration were maintained constaut, the correspond- ing amount of retransformation in a normal solution of urea being only 0.0038 per cent.It must be borne in mind, however, that these values of k and k' would not agree exactly with those obtained by actual experiment in normal solutions, for in calculaiing them the change of dissociation effected by dilution has been neglected, and it has been shorn11 by Walker and Hamblj (loc. c i f . , 763) that neglectALKYLBJIMONIUAI CYANATES INTO TIRE AS. 203 of this factor gives greater values for k in dilute solutions tlian it does in more concentrated solutions. A glance at the table suffices to show that there is no pronouiiced regularity in thc values of k. The introduction of a methyl group into ammonium cyanate leaves the velocity constant practically un- affected ; a second methyl group, however, raises it to almost double the original value.Ethyl groups diminish the value of the constant, the diminution beiiig somewhat greater for the introduction of one group than for two. The increase in the constant effected by the second ethyl group is, however, very slight, and not at all comparable with the effect of a second methyl group. Both the amyl radicles lower the constant, the loweiing in the case of tertiary arnyl being very marked. The isomeric ethylammonium cyanat e and dimethyl- ammonium cyanate have very different constants. This might be attributed to the fact that one isomeride is the salt of a primary base whilst the other is a salt of a secondary base, b u t the widely divergent values of the amylammonium cyanate;, where both bases are primaq, show that isomerism within the alkyl group has as marked an influence on the constant as isomerism directly afiecting the nitrogen atom.The values of k' display as little regularity as the values of k. The introduction of one alkyl group into urea sometimes raises and some- times lowers the constant ; the introduction of a second alkyl group increases the value greatly in both cases examined. Isomeric sub- stances again have T-ery different values of the constant. Points of Eqziilibi-i.tcnz. I n calculating k and k' for 59.6', use was made of the end-point f , determined at 100". The calculation thus proceeds on the assumption that the end-point is not appreciably influenced by temperature.This has already been shown to be tbe case for ammonium cyanate (Eoc. cit., 751), but there the circumstances were unfavourable for detecting any small variation. I n the case of diethylurea and ter- tiary amylurea, the reverse action proceeds with considerable rapidity, and the equilibrium point is a t a considerable distance from either end, so that the conditions are favourable for observing any displacement of this point by temperature. Experiments were therefore made at 80" with both of these substances, with the result that, the end-points observed at. that temperature were, within the experimental error, identical with those obtained at 100'. Temperature, then, influences the position of the end-poiiit to so small a degree that it is permis- sible to use the point of eQuilibrium determined at one temperature in calculating the velocity constants for another.The point of equilibrium is gi.eatly influenced by the concentration204 WALKER AND APPLEYARD : TRANSFORMATION OF THE of the solution, as the following consideration will show. The trans- forniation of a cyantlie into the corresponding urea is a bimolecular action; the reverse t'ransformation of urea into cyanate is a uni- molecular action. In the latter case, each molecule is transformed independently of the others, so that the proportion of the whole transformed in a given time is quite independent of the dilution. On the other hand, two ions must meet before a molecule of urea can be formed ; consequently a smaller proportion of cyanate will be con- verted into urea as the dilution increases, for the chance of the ions meeting varies as the inverse square of the dilution.The result is that as the solutions are taken more and more dilute, the greater will be the proportion of ammozlium cyanate present when equilibrium has been attained. It is easy to calculate the dilution at which half the cyanate has been converted into urea when equilibrium has been reached by means of the equation If we express A, the original concentration in terms of a normal solulion, and E in terms of A, we have the following equation for the case of eqnili brium in which the transformation has gone half way, That is, the oi*iginal concentration of cyanate expressed in terms of a normal solution for which the transforniation into urea will stop half way is numerically equal to twice the ratio of the velocity con- stants, K, as determined from any single end-point experiment.The values of the end-points and of 2K for the vnrious cyanates are tabulated below. Cyanute. Ammoniu n I. . . . . . . . . . . . Met,hylaniruonium . . . . . . Dimethylammonium . . . . Ethylammonium. . . . . . . . Diethylammonium ,. . . . . . Isoainylammonium . . . . . Tertiary amylammonium. l0OE. !J5*0 96.0 84.4 91.2 66.8 94.4 5 7.0 2K. 0*00052-normal. 0.00033 0.0057 0.0017 0.033 0*00067 0.064 In the fiisst column the end-points are given in percentages for decinormal solutions ; for example, the conversion of rtminonium c p n a t e into urea ceases when 95 per cent. of the original amount has been transformed.The numbers in the second column give the con- centrations of the solutions in which the transformation will come to an end, when half the cyanate (or half the urea) has disappeared. ItALKTLAJIiMONIUM UY AN t TES INTO UREAS. PO5 should again be remarked that owing to neglect of the influence of dilution on the degree of eletrolytic dissociation, these numbers are somewhat greater than the true values, the error being relatively larger the smaller the number is. The table, therefore, rather under- rates the differences between the various substances. A solution of methylurea has consequently to be diluted more t'han 200 times as far as a solution of tertiary nmylurea in order to get the same amount of urea decomposed in both cases. Trialkyl- afid Tet~a13;yl-a?n?nor;iu?n Cyanates. A1 though trialkyl- and tetralkyl-ammonium cyanates are not sup- posed to be transformed into ureas by heating with water, a few experiments were made with them in decinormal aqueous solution, in order to ascertain their behaviour under conditions similar to those with the inonalkyl- and dialkyl-ammonium cyanatea. Tetramethylammonium cyanate, prepared from the iodide and silver cyanate, did not change in titre after heating for 18 hours at 59.6'. Triethylammonium cyanate, on the other hand, exhibited distinct signs of change, even after one hour's heating, as may be seen from the following table. f. Tit re. 30 0.1 90 0.2 150 0.65 1320 1.00 2700 1-85 When the experiment was interrupted, the solution was found to be strongly ammoniacal, and to give a copious precipitate with calcium nitrate. Five C.C. of the solution at t = 2700 were treated with excess of calcium nitrate, and the precipitate filtered off. To the filtrate 5 C.C. of decinormal silver nitrate solution were added, and the insoluble salt so obtained was then removed by filtration. The titre of the filtrate was now found to be 12.0 C.C. instead of 1.85, the number obtained without treatmeut with calcium nitrate. These figures would seem to indicate that the final product of the trans- formation in this case is mostly acid triethylammonium carbonate, produced from t'he normal carbonate by protracted heating.

ISSN:0368-1645    

DOI:10.1039/CT8966900193

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

XXII -Lutedin. Part I. HJ- ARTHUR G. PERUS, F.R.S.E. THE yellow dyestuff weld, which contains the colouring inatter luteolin, is the dried herbaceous plant known as Reseda ZziteoZa, a native of Europe, formerly cultiwted in many parts, especially in France and Germany. Although with tin and aluminium rnordants it yields purer and faster yellow shades than those given by quercitron and other well known natural dyestuffs, it is now b u t little employed, chiefly on account of the small amount of colouring matter it con- tains. I n continuation of the study of the action of acids on the natural yellow colouring matters (Trans., 189.5, 67, 644), it was desirable to test the behaviour of luteolin in this respect, and being then struck by the very meagre examinatiori it had received, i t was deemed advisable to subject, it to fui+heer investigation.Luteolin was isolated from weld by Chcvreul (J. Chiin. mLd., 6, 157), and subsequently studied by Moldenhauer (Annulen, 1856, 100, lSO), who assigned to it, the formula CzoH1408. Schiitzeriberger and Paraf (Jahresbenkht, 1861, 707), on the other hand, considered i t to have the formula C12HROI, and describe a lead salt, Pb0,CIzH80b. Somewhat later Hlasiwetz and Pfaundlei- (Annalen, 1859, 112, 107) gave it the formula C,,Hl,06, which is isomeric with paradiscetin, a substance they obtained by the action of fused alkali on quercetin (AnnuZen, 1859, 112, 102). By t.he action of nitric acid on luteolin, Rochleder (Zeit. fiig. Chem., 1886, 602) obtained oxalic acid, and with fused alkali protocatechuic acid and a substance which he con- sidered was in all probability phloroglucin. Accorcling to Clievreul (Zoc.,:it.), luteolin unites with acids. The preliminary experiments on the preparation of luteolin were cai-ried out according to Moldenhauer’a directious (Zoc. cit.), but as the resnlts were somewhat unsatisfactory, a new method was devised. Owing to the small amount of colouring matter which weld contains, the exti-action of luteolin from the plant itself had to be abandoned, a commercial e x h c t of the dyestuff being found preferable. For this purpose, however, it WAS necessary to have ail extract specially prepred for this invesLigation, for experience sliowed that many of the so-called “ meld” extracts in the market ;ire not preparations of weld at a l l ; owing to ignorance of this fact, much time andPERKIN : TAUTEOLIN.207 labour was lost, some of the so-called ‘’ weld ” extracts being found to consist chiefly of extract of Persian berries. Three hundred grams of true weld extract, dissolved in 3 litres of water to which 100 C.C. of hydrochloric acid was added, was digested a t a boiling heat for several hours; the liquid was at first opaquc, b u t as the boiling proceeded, a black, taiary mass gradually separated, and, as soon as this ceased to form, i t was removed by filtration through calico, and the clear filtrate allowed to stand for 12 honrs. The brown amorphous precipitate of impure luteoiin which had then separated was collected, and, after being washed with water, was suspended in the same liquid, and shaken up with a large volume of ether, in which most of it dissolved.As the ethereal liquid did not always readily separate from the mixture, it was found preferable to strain the whole through calico, separation quickly taking place wlien the undissolved product had been removed. The ethereal solu- tion was now extractcd with dilute alkali, t h e alkaline extract lieu- tralised with acid, and the yellow precipitate collected, washed with water, and allowed to drain upon a porous tile until it had the consistency of a thin clay. A saturated solution of this prodnct in boiling alcohol, 011 cooling, deposited a crystalline mass, which was collected and repeatedly recrystallised from dilute alcohol until pure. As the residue left undissolved by the ether during the purification of the crude luteolin still contained some colouring matter, it was dissolved in a little alcohol, the solution treated with a large volume of ether, filtered, and the filtrate washed with water ; from this, by extraction with alkali and treatment as above, pure luteolin could be obtained.The black, tarry matter which separated during the boiling of weld extract with dilute acid contained but a mere trace of colouring matter. An analysis of luteolin dried a t 160’ gave the following result. C = 62.75 ; H = 3.99 p.c. ClZH8OS (Schutzenberger and Paraf) requires C = 62.07 ; H = 3-44 ,, C15H1006 (Hlasiwetz and Pfanndler) C = 62.94 ; H = 3.49 ,? CJT140, (Moldenhauer) ,, C = 62.82; H = 3.66 ,, 0.1149 gave 0.264A CO, and 0.0413 H20. ,, This result, therefore, agrees well with the formule Cl,H,,O6 and CzoH1408, but not with the formula C,,H,O,. I n conjunction with L.Pate (Trans., 1895, 67, 644), I have pre- viously shown that quercetin, fisetin, and various other allied yellow colouring matters, yield peculiar compounds with mineral acids, which as a rule indicate the molecular weight of these substances. The behaviour of luteolin towards these acids was therefore studied. Luteolin. Szdphate.-The addition of sulphuric acid to a saturated solution of luteolin in boiling acetic acid cawed the formation of ap208 PERKIK : LUTEOLIK. orange-coloured liquid, from which crystals gradually deposited on cooling. These were collected, washed with acetic acid, and dried. 0.1229 gave 0.2104 CO, and 0*0:378 H20.C = 46.69 ; H = 3.41. 0.2534 ,, 0.2635 ,, ,) 0.0475 ,, C = 46.84 ; H = 3.44. C15H1006,H2S01 requires c = 46-87; H = 3.12 per cent. C:oHi40p7H2S04 ,, C = 50.00; H = 3-33 ,, The compound consisted of a mass of orange-red needles, insoluble in acetic acid; by treatment with water it is decomposed qnantr- tatively into luteolin and sulphuric acid, as the following result shows. Cl5H1006 = 74.81 ; 0.5225 gave 0.3910 C15H100G and 0,3174 BaS04. S = 8.35. C15H1~06,H2SOI requires C,,Hlo06 = 74-48 ; S = 8.33 per cent. Luteolin Hydrobyomide.-When hydrobromic acid is added to a pasty mixture of luteolin with boiling acetic acid, a clear solution is formed, but crystals are not deposited on cooling, unless a consider- able excess of the acid has been used. The product thus obtained was washed with acetic acid and dried.0.1250 gave 0.2160 C02 and 0.0375 H20. C = 47.12 ; H = 3.33. 0.1331 ,, 0.2298 ,, ,, 0.0435 ,, C = 47.09; H = 3.63. CIbHlo06,HBr requires C = 49.04 ; H = 3.00 per cent. C15H1006,HBr,H20 requires C = 46.75 ; H = 3.37 per cent. It consisted of an ochre-coloured mass of fine needles, which, by contact with water, are somewhat slowly decomposed into luteolin and hydrobromic acid, being much more stable in this respect than the corresponding compounds of quercetin, fisetin, and morin (Zoc. cit.) . 0.4124 gave 0.3081 C15H1006. C15H1006 = 74-70. 0.6267 ,, 0.4690 ,, aiid 0.3040 AgBr. C15H1006 = 74.81 ; Br = 20.63. CI5Hl0o6,HBr,H20 requires C15Hlo0, = 73.93 ; Br = 20.67 per cent. To be certain that the product obtained on decomposing the hydro- bromide by means of water was luteolin, itl was dried a t 160' and analysed, with the following YesuIt. 0.1214 gave 0.2800 CO, and 0.0397 H20.Luteolin hydrochlol-ide wits prepared in the same way as the hydro- 0.1384 gave 0.2675 C02 and 0.0472 H20. C = 62.90; H = 3.63. C15H1006 requires C = 62.94; H = 3.49 per cent. bromide, which it closely resembles. C = 59-71 ; H = 3.79. C15RloOG,HCl requires C = 55.81 ; H = 3.41 per cent. C15H1006,HC1,H20 requires C = 52-56 ; H = 3-81 per cent.PERKIN : LUTZOLIX. 209 Lzcteolin hydriodide crystallises beautifully in orange-coloured glistening prisms. I t was not analysed. The sulphuric acid compound of Zuteolin is of the normal cha- racter, and shows that the true formula of luteolin is C,,H,,O,.The compounds of luteolin with the haloid acids are, however, peculiar, in that they appear to crystallise with lHzO, and differ in this respect from the corresponding compounds of qnercetin, fisetin, and morin, which do not contain water of crystallisation. Attempts to remove the water were ineffectual, the weight of these compounds remaining constant even at the temperature of boiling aniline, but the suppo- sition that they contain water of crystallisation receives weight from their comparative stability towards water, and the fact that they are not formed except in the presence of some quantity of the aqueous acid. Moreover, analysis has shown that the formula of luteolin cannot be c15H100, + H,O (Cl~H&) (C = 59.21 ; H = 3-94> ; and further, luteolin is regenerated from them by prolotiged contact with water.Dibromc~ZuteoZin.--In order to leave not the slightest doubt as t o the molecular weight of luteolin, experiments were carried out with the object of preparing a bromine derivative. Luteolin ground into a thin paste with acetic acid was treated with slightly more than the theoretical amount of bromine necessary for the production of n dibromo-derivative. Hydrogen bromide was evolved, and after the mixture had been left for 48 hours, the product was drained upon a porous tile, and purified by crystallisation from acetic acid. They must. therefore possess the formula assigned to them. 0.1339 gave 0.2000 CO, and 0.0300 H,O. C = 40.73 ; H = 2.48. 0.3061 ,, by Carius’ method 0.2610 AgBr. Br = 36-29. CI,H,Bi;Os requires C = 40.54 ; H = 1-80 ; Br = 36.04 per cent.There can, therefore, be no doubt that the formula of luteolin is correctly represented by C15HlOO6. Dibromoluteolin was obtained as a glistening mass of lemon-yellow needles, melting at 303O, sparinglj soluble in alcohol, and acetic acid. By crystallisation from dilute alcohol, luteolin is obtained as a glistening mass of yellow needles almost identical in appearance with quercetin or fisetin. Examined in Zeisel’s apparatus, it was found to contain no methoxy-group. As previoiisly shown by other workers it melts above 320°, and yields with ferric chloride in alco- bolic solution first a green, and then a brown-red, coloration. TetracetyZZuteo1in.-A solution of one part of luteolin, and one of anhydrous sodium acetate in six parts of acetic anhydride was boiled for one hour, the product poured into water, and after being allowed VOL.LXIX. Q210 PERKIN : LUTEOLIN. t o stand 24 hours, collected and purified by crysfallisation from alcohol. 0.1108 gave 0.2465 GOz and 0.0399 HzO. It forms a silky mass of colourless needles melting a t 813-21Fi0, very sparingly soluble in alcohol. It is insoluble in cold alkaline solutions. In order to determine the number of acetyl groups present, a slight modification of Liebermann’s method was adopted. To a solution of the substance in boiling acetic acid, a few drops of sulphuric acid were added and the whole boiled for about a minute ; a, cousiderable quantity of boiling water was then added, and the crystals of luteolin which separated on cooling, were collected and weighed.C = (30.67 ; H = 4.00. c16H606(~zH30)4 requires C = 60.79 ; H = 3.96 per cent. 0,5283 gave 0.3310 luteolin. C,sE1006 = 62.65. CI,H~O~(C~H,O), requires C15H1006 = 69.41 per cent. Cl5H606(C2H30)4 1) C,5H,,O6 = 62.99 ,, It was, therefore, a tetyacetyl derivative. Dibronzotet~acety ZluteoZin, prepared from dibromoluteolin in a, similar way to the above compound from luteolin, was obtained in the form of fine colourless needles melting a t 218-220°; it is very sparingly soluble in alcohol. 0.1359 gave 0.2220 CO, and 0.0353 H,O. C = 44.62 ; H = 2.88. C15H,0sBrz(C2H,0)4 requires C = 45.09 ; H = 2.61 per cent. TetrabenzoyZZuteolin was prepared from luteolin by the method of Baumann and Schotten, using ;I ten per cent.solution of caustic soda. The colourless sticky product thus formed became solid after some hours ; it was then ground into a paste with water, well washed with dilute alkali, and purified by cry shllisation from benzene. 0.1114 gave 0.2996 COz and 0.0397 HzO. C = 73.33 ; H = 3.95. c,6&06(c7Hso)3 requires C = 72.24; H = 3.65 per cent. C1sHsOe(C7H,O)4 ,, C = 73-50; H = 3.70 ,, It was, therefore, a tetrabenzoyl derivative. From benzene, in Jvhich it is sparingly soluble, it was obtained aa a spongy mass of colonrless needles melhing at 200--20J0. Action of Fused Alkali on Luteo1in.-Rochleder (loc. cit.) has stated that luteolin, when fused with alkali, yields protocatechuic acid, and probably phloroglucin, but as judging from the formula of luteolin the production of the latter seemed somewhat unlikely, experiments lvero made to determine this point.Unfortnnately, however, b u t a small quantity of pure luteolin was available for this purpose, and the results obtained, although sufficient to prove that phloro-PERKlN : LUTEOLIN. 211 glucin is not produced a t the temperature employed, must be con- sidered as but preliminary to an exhaustive study of this reaction. Luteolin was heated a t 170-200' for half an hour with 10 times its weight of potassium hydroxide dissolved in a little water; the melt was dissolved in water, the solution iieutralised with acid, extracted with ether, the extract evaporated, and the crystalline residue dissolved in a little caustic potash. After saturation with carbonic anhydride, the alkaline liquid was extracted with ether, and the residue left on evaporating the ethereal extract was pnrified by crystallisation from water.The mass of almost colourless needles thus obtained, melted a t 210', and when dissolved in water, the solu- tion gave 120 coloration with ferric chloride. It could not, there- fore, be phloroglncin, which gives such a characteristic reaction with this reagent. The further examination of this substance will no doubt throw considerable light on the constitution of luteolin. To isolate the second product of the reaction, the remaining alkaline solution mas neutralised with acid and extracted with et'her ; on evaporating the ethereal extract, a crystalline residue was obtained which after crystallisation horn water, formed colourless needles melting a t 195'; these, when dissolved i n water, gave a strong green coloration with ferric chloride. It had all the properties of p~ofo- catechuic acid and was found to be identical with it.Methglatioiz of LuteoZin.-One part of luteolin dissolved in a solu- tion of 10 parts of caustic potash in methylic alcohol, was treated with excess of methylic iodide, and digested at the boiling heat for 24 hours. After removal of the excess of methylic iodide, and the greater portion of the alcohol by distillation, the residue was poured into water, the precipitated product dissolved in ether, and the resulting solution after being washed with dilute alkali wzs evaporated t o a small bulk. The crystalline mass which separated on cooling, was collected, rinsed with a little ether, and purified by crystallisation from alcohol.0.1078 gave 0.2643 CO, and 0.0555 H,O. C = 66-66 ; H = 5-71, 0.1264 ?, 0.3102 GO, and 0-0635 H,O. C = 66.92; H = 5.58. Cl5H6O6(CH,), requires C = 66.66; H = 5.55 pel- cent. This compound is deposited from alcohol as a spongy mass of needles, of a faintly yellowish tint, insoluble in alkalis, and melting a t 191-192O. A determination of the metboxy-groups present in- dicated that the cornpound contained but three of them, in wliich case it would be a derivative of methylluteolin. Owing, however, to lack of material, this result cannot a t present be confirmed, but it is hoped soon to be able to thoroughly investigate this reaction. If the properties of luteolin be considered, one cannot but be Q 2212 HUTCHINSON AND POLLARD : LEAD TETRACETATE struck with their close similarity to those of fisetin, C15H,,0,, the colouring matter of " Young Fustic " (Rhus Cotims., L.). This sub- stance according to the investigations of Schmid (Bey., 1886, 19, 1739) and Herzig (Bey., 2895, 28, 293) contains four hydroxyl groups, yields a, dibromo-derivative, is readily decomposed irk0 resorcino 1 and protocatechuic acid, and, as I have shown (Zoc. cit.), also unites with mineral acids. Fisetin (Herxig, 106. cit., and Kostanecki, Ber., 1895, 28, 2302) is most probably a tetrahydroxy-P-phenylpheno- "1-pyrone, and it's constitution is as follows. 0 OH Though it is at present too early to speak with certaiuty as to the constitution of luteolin, it is most probable that its further examina- tion will show i t t o differ only from fieetin in the position of the bydroxyl group in the pheno-y -pyrone ring. The study of luteolin will be continued by the author in conjunc- fion with Mr. G. Y. Allen. Clothworkers' Research Laboratory, Dyeing Department, Yorkshire College.

ISSN:0368-1645    

DOI:10.1039/CT8966900206

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

212 HUTCHINSON AND POLLARD : LEAD TETRACETATE XXII1.-Lead Tetracetate and the Plumbic Sults. By A. HUTCH~NSON, M.A., Ph.D., and W. POLLARD, B.A., Ph.D. In trod uc t ~ O T Z . IN a note published in this Journal in September, 1893 (Trans., 1893, 63, 1136), we pointed out that the crystals obtained when iniiiium is dissolved in glacial acetic acid were to be regarded as lead tetracetate, a s a l t of lead dioxide, and that it would in all probability be possible to prepare other salts of quadrivalent lead from t h i s substance. During the past tvo years we have, as opportunity offered, attempted a fuller study of the properties of this compound, and, although some points are still under investigation, we venture now t o lay before the Society the results we have so far obtained.Lead Tetracetnte. Historical.-Since the time of Berzelius, chemists have been aware that miniurn is soluble in acetic acid, and a method of detecting and estimating certain impurities found in the commercial article hasAND THE PLUMBIC SALTS. 213 been based on this fact. Little, howeTer, was known of the proper- ties of this solution till Jacquelain noticed (Comnptes rendus mensuels tles Trnvaulr: Chimipues, 1851, 1 ; Abstr., J. pr. Chem., 1851, 53, 151), as Dumas had done before him, that a solution of miniurn in aqueous acetic acid soon decomposed and deposited lead dioxide ; he found, also, that this decomposition was greatly accelerated by heat or by the addition of water, and further observed that when he employed glacial acetic acid at 40° as the solvent, the solution, on cooling, deposited a crop of slender, colourless, oblique prisms.The formation of these crystals had, Jacquelain tells us, been previously noted by Balard, who did not, however, study them. A few years later, Schonbein (J. pr. Chem., 1858, 74, 315) made similar observations on the behaviour of the solution of miniuni in acetic acid, m d found that sulphuric acid precipitated only a part of the lead from this liquid, leaving in solution the ‘I acetate of lead peroxide ; ” Schonbein does not appear to have been acquainted with Jacquelain’s work, nor to have obtained any crystals from his solu- ttions. On filtering off the crystals of “ acetate de bioxide de plomb,” and attempting to dry them between filter paper, Jacquelain found that they quickly turried brown, decomposing into lead peroxide and acetic acid.On the addition of water, this decomposition became complete, and he was therefore able to determine the percentage of acetic anhydride i n the substance by titrating the aqueous solution with standard alkali. The lead was estimated as chloride in another portion. The results led him to adopt the improbable formula PbO?,3(CdHsO,) [0 = 100, P b = 129.4, H = 12.5, C = 751, which requires lead dioxide = 43.86 and acetic anhydride = 5G.14 per cent. Finding that Jacqnelsin’s improbable formula was based on insufficient data, we determined to submit the substance anew to investigation. Pre~arntion.-Commercial red lead was added little by little to hot glacial acetic acid till no more dissolved and lead peroxide began to separate; the solution was then either filtered hot, or the crystals deposited on cooling were subsequently freed from peroxide by collecting them in a funnel on a porcelain filtering plate, and washing away the finely divided peroxide by cold acetic acid.The crystals mere pnrified by recrystallisation from hot glacial acetic acid, and dried over sulphuric acid in a vacuum. As regards the interaction which takes place, Jacquelain seems to liavc held the view that a compound of minium with acetic acid is first formed, for he speaks of an “acetate of miniurn” which, a s the solution crystallises, splits up, yielding crystals of acetate of214 HUTCHIKSON AXD POLLARD : LEAD TETRACETATE dioxide of lead, and ordinary lead acetate which remains dissolved.Schonbein, on the other hand, believed that wheu minium ciia- solved in acetic acid, the two oxides contained in the former separated, and that both lead acetate and acetate of the peroxide were present i n solution. As, however, lead peroxide is insoluble in acetic acid, Schijnbein adopted the hypothesis that lead peroxide can exist in two conditions, i u one of which it is capable of union with acetic acid and in the other incapable of such combination. We are inclined to think {hat Schonbein’s view is in the main the cori-ect one, for i t is conceivable that the peroxide set free from iiiinium by abstraction of lead monoxide should, at the moment of its foymation, bo capable of combining with acetic acid, although it is iiisoluble when once formed.We have not, home.c.er, so far been able t o obtain fresh direct experimental evidence bearing on this point. The substance can be readily analysed by taking advantage of the extraordinary ease with wbicli water decomposes it ; a weighed portion was treated with hot water, the I’bO, collected on a tared filter, dried a t l l O o , and weighed, the acetic acid being estimated in the filtrate by titration with a standard alkali. The lcad determina- tions were checked by direct conversion of other portions into chloride and sulphate by evaporation with the respective acids. Analyses I, 11, and IV were made on different samples, I1 and 111 on the same. I. 0.8757 gave 0.4735 PbO,, and required 98.4 C.C. of potash 11. 0.8770 gave 0.4755 PbO,, and required i9.9 C.C.of soda soh- solution (1 C.C. = 0.00948 KOH). tion (1 C.C. = 0.00395 NaOH). 111. 0.6403 gave 0.4040 PbCl,. IV. 0-3474 gave 0.3760 PbS04. Cttlculated for I. I I. 111. IV. Yb(C,H,O,),. PbO,. . .. . . .. 54.07 54-22 54.26 54.16 53.93 /,CH,*CO),O.. 45.85 45.83 - - 46.07 99.92 100.10 100~00 c__- - The pure crystals begin to melt at 175”, and decompose at a tern- perstnre a, few degrees higher. The only substance known to us which dissolves the tetracetate without change is glacial acetic acid, -in which it is readily soluble when hot, crystsllising out again 011 cooling. Before using this solvent for the molecular weight deter- minations, we estiiiiated the amount of tetracetate contained in a solution saturated a t lio. Foi- thi-s purpose, two portioiis of tha solution were weighed, and the lead determined in the one case as chloride, and in the othey as sulphate.AND THE PLUMBIC SALTS.215 I. 10.57 grams of solution gave 0.178 of PbC1,. Hence 100 grams of acetic acid dissolve 2.76 grams of lead tetracetate at 17'. Hence 100 grams of acetic acid dissolve 2-77 grams of lead tetr- acetate at 27'. Lead tetracetate is easily soluble in cold chloroform, but, owing to 17artial decomposition, gives a muddy-bmwn solution. If, howevey, the acetate is previously moistened with a small quantity of acetic acid a, clear solution is obtained. Boiling carbon tetrachloride (dried over fused calcium chloride or over phosphoric anhydride) dissolves it slightly, the greater part of the salt crystallising out on cooling. Hot benzene (dried over sodium) dissolves it somewhat more readily ; i n both these cases a small quantity of acetic acid is necessary t o pre- vent the solution turning brown.!Vhe tetracetate is very slightly soluble in ether and light petroleum, and only slowly attacked by these solvents if they are thoroughly dry. The specific gravity was determined in a pyknometer in the ordi- nary way, but, owing to the difficulty of finding any other liquid which would neither dissolve nor act 011 the salt we were obliged to use a saturated solution of the tetracetate in glacial acetic acid. The specific gravity o€ the solution saturated at 16.4 was 1.0692 at 16-4'/4'. A second determination made as a control, in a small pyknometer, on a portion of the solution which had just been used for finding the specific gravity of the solid gave the value 1.0678 at 17*2'/4O.Two determinations of the specific gravity of the solid as compared with the solution gave the values 2.084 at 16.9' and 8.075 at 18.2'. Hence the specific gravity o i the solid, as compared with water at A3, is (A) 2.228 at 16.9' and (B) 2-218 at 18.2' ; of these results, A is probably the more accurate, and was got by using 8.484 grams of' the solid in a 25 C.C. pyknometer, especial care being taken to get rid of all air bubbles. C'ystallography of Lead Tetracetate. 11. 10.57 grams of solution gave G.1947 gram of PbSO,. The crystals are typically monoclinic, colourless, transpareiit prisms, greatly elongated in the direction of the c axis. They are usually 10 to 25 mm. in length, and 1 t o 2 x 1 to 2 mm.in section. The faces nz and b are often about equally developed, their coiitbi- nation giving a nearly hexagonal prism, The form n(210) is not of very frequent occurrence, and is always narrow and subordinate. Cleavage b perfect. The crystals decomposed so easily that no canplete optical exami- nation could be made. The extinction observed through b makes au angle of -16g with216 HUTCHIKSON AKD POLLARD : LEAD TETRACETATE the c axis, and this is the direction of vibration of the ray traversing the plate with the greatest velocity. System : Monoclinic. Ratio of axes : a : b : c = 0.5874 : 1 : 0.4848.5. /3 = 74’ 24’. Forms observed : c b = ( O l O ) , m = (1101, 12 = (2101, q = ( O l I ) . Angle No. oe measwed. measurements. Limits. m 9 ) ~ ~ = 110 : iio 8 59’ 36’- 58” ??lb = 110 : 010 12 60 17- 60 nd” = 210 : 2io 2 31 43- 31 ab = 210 : 010 6 74 20- 74 ?ill2 = 210 : 110 5 13 62- 13 qq’ = 011 : O i l 4 50 14- 49 qb = 011 : 010 11 65 12- G4 p?? = 011 : 410 5 90 20- 90 qm‘ = 011 : 110 1 - 3 4 47 37 2 19 54 45 3 Mean observed.Calculzc ted. 5 9 O 0’ 59O 0’ 60 30 x 31 40 31 36 74 12 74 12 13 38 13 42 50 4 50 4 64 58 f 90 13 * 65 4 65 8 Moleculay Weight of Lead Tetyacetate by Kaoult’s Methods.-The only solvent available for this purpose was glacial acetic acid ; the specimen employed was carefully purified by recrystallisation, and melted at 1 6 . 5 8 O . The freezing-points of solutions of various concentrntions were de- termined in Beckmann’s apparabns (Zeit. physikal. Chem., 1891, 7, 323), and the precautions taken by him to prevent the acid absorbing moisture from the air, were found highly necessary, and were duly observed.The earlier boiling point determinations were made with Beckmann’s original apparatus (Zeit. physikal. (Ihenz., 1889, 4, 543) ; better results were, however, subsequently obt,aiired with the im- proved form described by him in 1891 (Zeit. phySiku1. Chem., 1891,8, 223). Preliminary experiments made by adding successive portions of acetate to the boiling solvent proved unsatisfactory, probably be- cause a slight decomposition of the acetate was brought about either by the long-continued boiling of its solution, by the action of mois- ture, or by organic matter derived from the cork, and we found it advisable to eliminate as far as possible these sources of error by making a separate determination a t each concentration. The con- stants of the acid were taken as 39 and 25.3 respectively.Our results are contained i n the following tables. The molecular weight of Pb(C2ET302)a is 443. W e numbers tabulated on p. 217 leave but little doubt, therefore, that in solution lead tetracetate consists essentially of molecules of the formula Pb(C2H302)4*AND THE PLUMBIC SALTS. 217 Gi*ams of solvent. Freezing Point Method. Grams of substance. Experi- ment.. I ...... 11 ...... 26.2 0.1915 I 0.0'70 0.73 I 407 -0 9 ) 0 -4538 0 *164 3 -73 412 -0 9 9 0.5544 0 *202 2 a 1 1 408 5 7) 0 -6690 0 -24.3 2.55 410 *O 25.9 0 * 3616 0 *138 1.41) 394.5 -------------- 9 9 0-6513 0.238 I 2-52 412 '0 Rise observed. Grams of 1 Grams of 1 Rise 1 Grams of substance solvent.1 substance. observed. in 100 of Advent. Grams of substance in 100 of solvent. Molecular weight. Molecular weight. 111 ......I 25.0 I 0.1250 1 0.049 1 0-50 I 398.0 I Experi - ment. -- I...... I1 ...... III...... IV ...... IT ...... V I . . . . . . VII ...... Boiling Point Method. 21.1 1 0.25'78 50.4 I 0.5620 25.3 I 0.4830 51 '5 0 -9950 1 -2363 1 '4'133 23 *9 2 *0860 0 '087 0 *075 0.132 0 '134 0 -167 0 *377 0.609 1 '02 1-11 1 9 1 1 -93 2 -36 5 -56 8.72 355 376 366 365 357 373 362 It is interesting in this connection to compare these numbers with the value ti9 obtained by Beckmann for the mean molecular weight of sodium acetate dissolved in boiling glacial acetic acid (Zeit. physikal. Chem., 1890, 6, 450). It wilI be noticed that the ratio of the mean molecular weight ob- served (by boiling point method) t o the true molecular weight i 365/443 = 0.824 for lead tetracetatc, and 69/82 = 0.841 for sodium acetate.MoZecuZar Volume of Lend Tetracetate.-The formula Pb ( C2H,02)t obtained some slight additional support from the fact that, taking the specific gravity as 2.228, we find that the molecular volume is 199, a, number which agrees well with that calculated by the aid of the empirical law enunciated by Schroder (Ber., 1881,14, 1607), namely, that for a, large number of anhydrous acetates the molecular volume of the salt is the same as that of the molecules of acetic acid from which it has been derived. This statement is illustrated in the following table.2 18 HUTCHTNSON AND POLLARD : LEAD TETRACETATE Salt.1 MV. I Salt. I 99 *9 99 -5 98 -5 99 -1 97 *9 97 *2 99 *9 Salt. 19.5 199 Action of m.Tater.--Lead tetracetate is extraordinarily sensitive to the presence of water, so much so, indeed, that exposure to the air for a few moments suffices to turn it brown. The interaction repre- sented by the equation Pb(C,H30z)4 + 2HzO = PbOz + ~CZH,OZ, takes place quantitatively, and forms the basis of the method of analysing the salt used by Jacquelain and ourselves. This salt might sometimes be useful for detecting the presence of moisture in gases. Action of Hydyochlol-ic acid.-Lead tetracetate is readily dissolved by concentrated aqueous hydrochloric acid, giving a deep yellow solution, which contains lead tetrachloride, produced in accordance with the equation Pb(CzH30,), + 4HC1 = PbC14 + 4Cz&O2.The lead tetrachloride cannot, however, be directly isolated, and, on standing, or more quickly on warming, the yellow colour disappears, chlorine is given off and lead dicliloride is left, whilst, in all prob- ability, partial chlorination of the acetic acid occurs at the same t#ime. The existence of lead tetrachloride in this liquid may, nevertheless, be readily demonstrated by pouring it into dilute aqueous hydro- chloric acid, saturated with ammonium chloride, when the double salt, PbC14,2NH4CI, at once separates as a yellow precipitate. A salt, of +his nature was isolated in 1885 by Nikoiukiiie (Abstr., 1886, 128 ; from J. Russ. Chem. Xoc., 1885, 207) from the solution of lead dioxide in hydrochloric acid, but he does not appear to have assigned any formula to it.Some years later, Classen and Zahorski (Zeit. niLoq*g. C'liem., 1893, 4, 100) prepared the salt 2PbC14,5NH4CI, by adding con- centrated ammonium chloride solution to the homogeneous liquid obtained when lead dichloride, concentrated hydrochloric acid, and liquid chlorine were digested together for some hours. Substituting quinoline hydrochloride for ammonium chloride, they obtained from the same solution the salt PbC1,,2CSNH,HCI. Wells (Zeit. unorg. Chem., 1893, 4, 335), on the other hand, and Friedrich (Ber., 1893, 26,1434) are both of opinion that the formulaAND THE PLUllBIO SALTS. 219 of the ammonium s a l t is really PbC14,SNH4Cl. The former obtained i t by adding ammonium chloride dissolved in hydrochloric acid to n, solution of lead dioxide in the same acid, and made the correspond- ing yotassinm, rubidium, and cEsium compounds by a similar process.The latter worked with a solution of lead tetrachloride prepared by passing chlorine gas into lead dichloride dissolved in aqueous hydrochloric acid. Goebbels ( B e y . , 1895, 28, 792) has recsiitly sought to explain th;s discrepancy by assuming that two sets of double salts exist, of the types PbC1,,2M'C1 and 2PbC14,5M'C1 respectively, and claims t o have prepared the two corresponding lutidine compounds, and also a 1)icoline salt, 3PbC1,,7C6N€€,,13C1, belonging to a different type. Finding that ammonium chloride was precipitated from its satii- iated aqueous solution on the addition of hydrochIoric acid, me endeavoured, when preparing our salt, to avoid this source of iinpnrity by using, as Wells had done, a solution of amnoninm chloride in hydrochloric acid.The following analyses show that the salt obtained by us under these condilions is identical with those prepared by Wells and Friedrich. I. 0.6888 gave 0.4390 PbSO,. Pb = 45-51. 11. 0.5437 ,, 1.0234 AgC1. C1 = 46.54. 111. 05'905 required 35.1 C.C. of Na,S,O,. C1 (active) = 15-21. (1 C.C. = 0.2396 Na,S,O,). PbC14,2NH,C1 requires Pb = 45.39, C1 = 46.71, C1 (active) = 15.57 per cent. Action of GaseGus Hydrogen Chloride.-This gas, dried by means of mlphuric acid, acts energetically on lead tetracetate in accordance with the equation given abore, a i d in the early part of 1893, we made numerous attempts to separate the acetic acid from the tetrachlo- ride by means of carbon tetrachloride and other liquids.Our efforts in this direction met with no success until we learnt from Friedrich's ljaper (Ber., 1893, 26, 1434) that lead tetrachloride is not acted OH !)y sulphuric acid, when by employing this acid we were able to 1)repare small quantities of lcad tetrachloride direct from the tetr- itcctate. For this purpose, a few grams of the finely powdered salt \yere placed in a test tube and coirercd with concentrated sulphuric acid. The tube was then quickly cooled in ice, and dry hydrogen chloride was passed in ; after a short time, a globule of lead tetra- -chloride collected at the bottom of the tube. The yield was un- forbunately small, the greater portion of the lead being converted into sulphate.A similar result, but a still poorer yield, was obtained220 HUTCHINSON AND POLLARD : LEAD TETRACETATE by passing hydrogen chloride over lead tetracetate kept cool in ice ; on adding cold, concentrated sulphuric acid, the acetic acid was dissolved, and a small globule of lend tetrachloride remained. Action of Hydrobromic and Hydriodic acids.-Lead tetracetate dis- solves in the concentrated acids, but almost immediate separation of the halogen and corresponding halo'id occurs. We have not succeeded in isolating double salts from the solutions, but Classen and Zahorski hare prepared the two quinoline derivatives, PbBr,,BC,NH,,HBr and PbIt,2C9NH,,HI, by decomposing the chloride with potassium bromide and iodide respectively. Action of Hydrofliioric acid.-The aqueous acid (37 per cent.) dissolves lead tetracetate readily, and gives a colourless solution, which, in all pyobability, contains either PbF, or H,PbF,.If excess of acid is present, the solution is stable at the ordinary temperature, but, like the liquid obtained when hydrochloric acid is used, it is entirely broken up on evaporation even in a vacuum ; the decomposi- tion in this case, however, takes a somewhat different course, and results in the quantitative deposition of lead dioxide in accordance with the equation PbF, + 2H,O = PbOz + 4HF. The explanation of this difference in the behaviour of the two hnloxds is most likely to be sought in the small relative affinity of hydroflnoric acid as compared with hydrochloric acid.The hydrofluoric acid solution of the tetracetate may, however, be eTaporated to dryness without separation of lead dioxide if a small quantity of ammonium fluoride is first added to it, and leaves then st residue rich iu quadrivalent lead. This is, doubtless, due to the formation of an ammonium double salt analogous to those derived from lead tetrachloride.* Action of Hydrogen 8trlphide.-In view of the ease with which water and lead tetracetate interact to form lead dioxide, we thought it desirable to see iE a corresponding sulphide, PbS2, could be pre- pared by passing hydrogen snlphide over the salt or into its solutions in glacial acetic acid or chloroform. The product, in all cases, appeared to consist of lead sulphide and free sulphur, and we have been quite unable to obtain any evidence of the existence of t h e Iiisulphide PbS,.* We obtained the above results in the summer of 1893, but were unable t o continue the research till the following spring. In the meantime, several points we had proposed to investigate, were cleared up in An interesting paper by Brauner (Tram., 1894, 65, 393), who, unknown to UP, hadlbeen working on the same lines as ourselves, and who by a similar method to the abore, succeeded in preparing considerable quantities of the salt PbF,, 3KF, HF, isomorphous with the cor- responding tin compound, pink salt, SnF,, 3RF, HF, and Fointed out that after hydrofluoric acid had been expdled by heating at 250°, the residue yielded fluorine on ignition.ASD THE PLUMBIC SALTS. 221 Action of Xulphuric acid.-Lead tetracetate is insoluble in aqueous sulphuric acid, which rapidly converts it into lead dioxide.When treated with the concentrated acid at ordinary temperatures, no change occurs a t first, but after a tinit. the salt turns yellow, slowly gelatinises, and finally decomposes, lead sulphate being deposited, and a small quantity of gas chiefly consisting of carbon dioxide evolved. This change takes place at once if the acid and salt are warmed together on the water bath ; under these conditions, lend tetrasulphate, Pb(SO,), if f ormed, is exceedingly unstable, and me have not been able to obtain any satisfactory proof of its existence Brauner (Zeit. arzorg. Chern., 1594,7, ll), however, found that a clear solution of lead tetrafl uoride in excess of concenhated snlphuric acid deposited yellow crusts, believed by him to be Pb(SO& when it was warmed t o 100' from time to time, during a period of more than two months. Lead Tetraphosp h ate.When a 50 per cent. aqueous solution of orthophosphoric acid is allowed to act on lead tetracetahe, the latter is converted info a pale yellow gelatinous mass, which readily turns brown on adding excess of water, and evolves chlorine when treated with hydrochloric acid. These observations led us to make numerous attempts to pyepare phosphates of quadrivalent lead, and though we Ewe not so far been successful in preparing a pure specimen of such a compound, we believe, nevertheless, that our results warrant the assertion that Pb(HP04)2 is capable of existence, and we attribute our inability to obtain it pure chiefly to the lack of a suitable solvent for lead tetr- acetate, and also to the difficulty of washing away excess of phosphoric acid, without a t the same time decomposing the tetraphosphate formed.In the course of this part of our work, a large number of preparations has been made and analysed ; we only propose, however, to describe a few experiments which either illustrate our methods or give information as to the naturs of the compounds obtained. 1. Lead tetracetate was dissolved in glacial acetic acid, excess of aqueous phosphoric acid added, and the white gelatinous precipitate, after being collected on a filter plate, and washed first with acetic acid and finally with absolute alcohol, was then placed over sulphuric acid in a vacuum till all smell of ace& acid had disappeared.The solid obtained turned brown when treated with water, and contained 7.9 per cent. of quadrivalent lead, PbIV (determined by distillation with hydrochloric acid) 52 per cent. of bivalent lead, Pb" (total lead - Pb'") and 12.54 per cent. of phosphorus. Pb : P = 1 : 1.417. Two orthophosphates of lead Pbs( POJ2 and PbHPO, have been described. They contain Pb and Y in the ratio 1 : 0.666 and 1 : 1 respectively.222 HUTCHINSON AND POLLARD : LEAL) TETRACETXTE Correspouding phosphates of quadrivalent lead would be Pb,( PO,) and Pb(HPO&, with the ratio Pb : P = 1:1.333 and 1: 2. The analysis shows that the sample contains more phosphorus than would be found if all the bivalent lead were present as PbHP04, and t h e quadrivalent lead as Pb(HPO,),; this is doubtless due to imperfect washing, while the explanation of the small amount of quadrivalent lead is to be sought in the reducing action of the absolute alcohol.2. It was subsequently found that niuch better remlts could be obtained by adding a solution of tetracetate in acetic acid to a concen- trated solution of aqneous phosphoric acid, mixed with two or three times its volume of acetic acid. Tbe precipitate which formed was sucked up, washed quickly with acetic acid only, and dried as coin- pletely as possible in a vacuum over sulphuiaic acid and solid caustic soda,. This specimea proved, on analysis, to be entirely free from bivalent lead, whilst quadrivalent lead and phosphorus were present in the ratio 1 : 2.36.Owing to the presence of excess of phosphoric acid as an impurity we have not been able to assign a definite formula to this compound, the fact that all the lead is quadrivalent provesr however, quite conclnsively that tetraphosphates of lead can be pre- pared by precipitation. 3. Lead tetracetate is only slightly soluble in cold glacial acetic acid, and any method involving the use of large quantities of such a solvent is open to so many objections that we resolved to try and precipitate chloroform solutions of the tetracetate by alcoholic phos- phoric acid. Preliminary experiments showed us that the salts obtained in this may contained considerable quantities of quadrivalent lead, and were fairly stable in the presence of alcoholic phosphoric acid.a. Five grams of lead tetracetate were moistened with acetic acid, dissoIved in 75 grams of chloroform, and the solution poured slowly into 14.75 grams of a 30 per cerit. alcoholic solution of H,P04 (4 mols, H,POa : 1 mol. PbAc4), the precipitate a t first redissolved, but became permanent after the greater part of the solution o€ lead tetracetate had been added. On adding ether, a bulky solid came down, which filtered readilg, and was soluble in water, giving a brown liquid from which lead dioxide was precipitated on boiling. Alcohol acted on thc precipitate, dissolving some of it, and converting the rest into a yellow, semi-transparent jelly, which i t was almost impossible to filtcr. After sucking if up as completely as possible with the aid of a piimp, it was placed in a vacuum till i t dried to a whitc mass. The lead in this substance was probably all quadrivalent, for although, owing to the presence of alcohol in the apparently dry mass, I!O satisfactory determination could be made, still, in spite of the reducing action of the alcohol, upwards of 80 per cent.of the totalAND THE PLUMBIC SALTS. 223 lead was found to be present as PbZV. After heating for some time at 150°, a portion of the substance was gently ignited ; the residue contained Pb, 50.45; P, 19.68 per cent. b. Another specimen, prepared in a similar way, gave a salt which, after drying at 150°, was found to contain Pb, 52.9 ; P, 15.63 per cent. It lost, on ignition, 5.07 per cent., and the composition of the residue, calculated from these data, is Pb, 56.2 and P, 16.61 per cent.Pb : P = 1 : 1.99 (mean of three analyses). From these numbers i t will be seen that in this sample the ratio Pb : P is that required by the formula Pb(HPO&. This may be a mere coincidence, but it seems to us highly probable that this substance was actually formed, for its composition, Pb, 51.88 and P, 15.54 per cent., agrees fairly well with that of our preparation. Again, if we grant that such a sub- stance as Pb(HP04), may exist, we may fitirly be allowed to assume that it will give off water and oxygen on ignition, and be converted into the metaphosphate (Pb(P03)2. This change will result in a loss of 7.39 per cent., and the residue will contain Pb, 56.71 and P, 16.98 per cent. The numbers quoted above as representing the actual com- position of the ignited substance agree fairly well with these.It is probable that our preparation while drying at 150' underwent a certain amount of decomposition, and this would account for its containing rather more lead and phosphorus than the formula Pb(HPO,), demands, and also to some extent for the small loss when it was subsequently ignited. It is, perhaps, worth noticing in this connection that the composi- tion of the residue obtained in Experiment 3n may be also fairly satisfactoyily explained if me assume that the substance before ignition consisted of a mixture of Pb(HPO& and H,P04, and that these on heating were converted into Pb(PO,), and HPO, respec- tively, for if we calculate and subtract the weight of HPO,, which corresponds to the excess of phosphorus present, the residue has the composition Yb = 57.81 and P = 17.17 per cent., while Yb(P@,)z requires Pb, 56.71 and P, 16-98 per cent.If all the lead in these two compounds had been present in the quadrivalent state, a strong case would have been made out for assigning the formula Pb(HPO,), to our precipitate. Determinations made by distillations with hydrochloric acid showed, howevela, that of the total lead in 3a, only 80 per cent., and in 3!1, ouly 65 per cent. was present as quadrivalent lead. We are, how- ever, inclined to think that this result was due, partly to reduction of the tetraphosphate during its preparation, and possibly also to the presence of small quantit,ies of alcohol in the apparently dry sub- stance, which, being acted on by the chlorine evolved, vitiated the determination.We believe, however, that th facts we have quoted, P b : P = 1 : 2.605.224 HUTCHINSON AND POLLARD : LEAD TETRAGETATE t,hough insufficient to establish. the formula Pb(HPO,)e, make it es- tremel y probable that this compound was actnally piaecipitated. This point cannot, however, be satisfactorily settled without further experimental work, and we hope to find an early opportunity of sub- mitting this subst.ance to a more thorough examination." Lead Tetrapropionate. This salt resembles the corresponding acetate vcry closely, and was prepared and analysed in a precisely similar way. It crystallioes from it,s solution in propionic acid in thin needles, which melt a t 132O, and decompose at a somewhat higher temperature.The substance can be recrystallised from hot propionic acid, bnf the process is attended with loss, a portion of the tetrapropionate bciug apparently reduced to propionate. The sample analysed was recrystallised twice. 0.6389 gave 0.3077 PbO,, and required 51.7 C.C. of soda solution [l C.C. = 0.00395 gram NaOH], whence PbO, = 48.16 and (C3H5O),0 = 51-94 per cent. The formula Pb(C3H5O2)d requires PbOz = 47.87 and (C3H50)20 = 52-13 per cent. 0.3870 gave 0.2172 PbC12, whence PbO, = 48.26 per cent. Arialogom Salts of othw Xctabs. The existence of a stable crystalline acetate derived from lead dioxide led 11s to enquire i f the higher oxides of other metals afford similar compounds. We find that several such substances have been described, the most interestiug of which are the thallic and manganic acetates.According to Willm (Ann. Chiin. Phys., 1865, [43, 5, 5), the acetate, TI( C2H302),, obtained by dissolving freshly precipitated thallic oxide in strong acetic acid, is the most stable of the thaliic salts. Like lead fetracetate, which it resembles extraordinarily closely, it is quantitatively decomposed, on treatment with water, into T120s and acetic acid. It is soluble in hydrochloric acid, giving thallic chloride ; added to potassium iodide it sets free iodine, thallous iodide being precipitated, whilst phosphoric and arsenic acids give gelatinous precipitates, probably consisting of TiPO$H20 and T1AsOa,2H20 respectively. Thallic chloride and the thallic salts generally are, * By methods somewhat similar to those employed for preparing the lead tetra- phosphate described above, we have recently succeeded in obtaining E lead tetrarse- nate, containing 42.01 per cent.of lead, and 30'89 per cent. of arsenic ; the formula Pb(HAsO,), requires Pb, 42.423 per cent., and As, 30.83 per cent. This substance, together with some otliern made by acting with a hydrofluoric acid solution of lead -teti*acetate on eolutions of phosphoric acid, are still under investigation, and we hope 60011 to make E further communication to the Society on this suhject.AND THE PLUMBIC SALTS. 2.25 however, somewhat more stable than the plumbic salts, and the nitrate, sulphate, and oxalate have been prepared. Like lead dioxide, manganic oxide, Mn203, is not attacked by acetic acid, the oxide Mn,04, however, dissolves readily enough, and on adding a little water, crystals of Mn(C2H302)3,2Hz0 are deposited (Christensen, J.p ~ . Chem., 1883, [S], 28, 1). This salt is apparently the most stable of the manganic compounds, and its behaviour towards reagents is similar t o that of lead tetracetate ; a sulphafe, &In,( S O,),H,S 0 4 , 8H20 ; p hosphat cs, MnP04,H,0, and MnNaP20,, 5 H20, and an arsenate, MnAs04,H20, have been prepared from it. Christensen has also described a fluoride, MnF1,3H20, and numerous double salts of the type 2M'F,MnF3 (J. pr. Chem., 1887, [2], 35, 57). Cobaltic acetate exists in the solution prepared by dissolving hydrated cobaltic oxide in strong acetic acid (Beetz, Ann. Phys. Ohern., 1844, 61, 472). With the exception of the sulphate described by Marshall (Trans., 1891, 59, 767), i t seems to be the most stable of bhe simple cobaltic salts.When the oxide, Cr03, dissolves in glacial acetic acid, an acetate may possibly be found ; we have not, however, been able as yet to obtain any evidence of thie." List of Salts of Quadrivalent Lead. Leaving out of consideration the numerous organo-metallic deriva- tives of lead, and omitting a few compounds whose nature is not yet fully elucidated (Wells, Zeit. unorg. Claem., 1895, 9, 305), the fol- lowing list comprises the salts of quadrivalent lead which have, up to the present, been described by Brauner, Classen and Zahorski, Friedrich, Goebbels, W ells, and ourselves. PbF,? PbCI4. PbF,,3KF,HF. K,PbCl,. Rb2PbCI6. CSzPbCI,.(NH,),PbCI,. (C9NH7)2,H2PbC16, (C,NH,),,H2PbBr6, and 2PbC14,5NHdCI. 2PbC14,5(C5NH5,HCl) (pyridine salt). 2PbCl~,5(C7N€X9,HCl) (lutidine salt). 3PbC1,,7(CoNH,,HCI) (picoline salt). Pb(SO4)z ? Pb(HPO,)z ? Pb(C2H,02)4 Pb(CaH,O,),. Pb(HAsOd),. * Y'he remarkable compound obtained by Tafel (Der., 1894, 27, 816) by acting VOL. LXIX. R with Na202 on acetic wid, does not appear to belong to this alaas of substances.226 LEWES: THE ACETYLENE THEORY OF LUMINOSITY. Brauner, Friedrich, and Wells have pointed out that several of these compounds present analogies not only in composition, but also in behaviour and crjstalline form, with certain of the stannic salts, and the relationship between lead and tin is further exhibited by the existence of plumbates allied to the stannates. Of them the potas- sium, sodium, barium, strontium, and calcium salts have been pre- pared, whilst the two oxides Pb203 and Pb304, may be regarded as derivatives of meta- and ortho-plumbic acids respectively, and may therefore be written Pb@,PbOz and PbO) PbO,. In conclusion, the principal results of o u r work, and our deductioiis from them, may be summed up as follows. 1. The substance obtained by dissolved Pb304 in glacial acetic acid has the molecular formula Pb(C2H302),. It is decomposed quanti- tatively by water into lead dioxide and acetic acid; hydrochloric acid converts i t into lead tetrachloride, and orthophosphoric acid into a phosphate. Its general behaviour is analogous to that of the thallic and manganic acetates, and its molecular volume agrees with that calculated for the acetates by Scliroder’s empirical law. PbO These facts lead us to regard it as a, salt of lead dioxide. 2. A similar propionate exists. 3. When acted on by orthophosphoric acid, the tetrncetate is con- verted into a phosphate, to which in all probability the formula Pb(HPO,), must be assigned. 4. Numerous lead salts exist which bear the same relation to the stannic salts that the ordinary lead compouuds do to the stannous salts. The former should therefore be termed plumbic salts, and the latter plumbous salts. 5 . Like stannic oxide, lead dioxide is capable of playing the part of either an acid or a basic oxide. The appropriate name for it is plumbic oxide, which should be used in preference to the term per- oxide, which in this connection is both unsuitable and misleading. Miqaeralogical Museum, Cam bridge.

ISSN:0368-1645    

DOI:10.1039/CT8966900212

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

226 LEWES: THE ACETYLENE THEORY OF LUMINOSITY. X X K - T h e Acetylene Theory of Luminosity. By VIVIAN B. LEWES, Royal Naval College, Greenwich. EARLY in 1892 (Trans., 1892, 61, 322), I read a paper before the Chemical Society, in which I showed that in a luminous hydrocarbon flame the baking effect of the outer zone of intense combustion con- verted a very large proportion of the unsaturated hydrocarbonsLEWES: THE ACETYLENE THEORY OF LUMINOSITY. 227 present in the inner zone into acetylene, the maximum production of this compound taking place j u s t before the commencement of lumin- oai ty. I n a second paper, communicated to t,he Royal Society in 1895 (PYOC. Roy. Xoc., 57, 450), I gave experimental reasous for consider- ing that the acetylene so formed on its decomposition by heat into carbon and hydrogen was the main factor in prodiicing luminosity, as the heat developed by this decomposition raised the carbon particles to a temperature above that of the flame.At the time that the latter paper was published, I was unaware that any other work had been done in this direction, but I find that Professors Dewar and Liveing, in their beautiful work on the spectra of carbon and its compounds, had to a great extent forestalled thc conclusions to which I had arrived from a totally different standpoint. I n their paper "On the Origin of the Hydrocarbon Flame Spectrum " (Proc. Roy. Xoc., 1882, 34, 427), they say, when speaking of the flame of cyanogen and acetylene, " Both of these compounds decompose with evolution of heat, in fact they are explosive com- pounds, and the latent energy in the respective bodies is so great that, if kinetic in the separated constituents, it would raise the tem- perature between 3000" and 4000'.The flames of cyanogen and acetylene are peculiar in respect that the temperature of individual decomposing molecules is not dependent entirely on the temperature generated by the combustion, which is a function of the tension of dissociation of the oxidised products, carbonic acid and water. We have no means of defining with any accuracy the temperature which the particles of such a flame may reach. We know, however, that the mean temperature of the flames of carbonic oxide and hydrogen lies between 2000' and 3000', and if to this be added that which can be reached independently by the mere decomposition of cyanogen or acetylene, then we may safely iufer that.the temperature of individual molecules of carbon, nitrogen, and hydrogen iu the respective flames of cyanogen and acetylene, may reach a temperature of from 6000O to 7000". ''A previous estimate of the temperature of the positive pole in the electric arc made by one of us gave something like the same value. # 4F * * * 9 " The formation of acetylene in ordinary combustion seems to be the agent through which a very high local temperature is pro- duced . . . .,' I extremely regret not having known of this most valuable work before, and take this, the first opportunity afforded me, of drawing attention to it. It 3228 LEWES : THE ACETTLESE THEORY OF LUJIINOSITY.I also find tliat M. GuAguen (Cmapte reiidu du Socidtc?‘ Technique de l’hattustrie clu Gaz au France, 18154, 142) pointled out that it was verx probakle that luminosity in hydrocarbon flames is due exclusively t o the production of rays furnished by the molecules O E gas highly heated by chemical changes, ar,d that it must be borne in mind that the heating from exterior sources would not sufficc whatever its power. He also draws attention to the fact that luminous combus- tion is caused by bodies which are cndotherniic, and from which heat is liberated during decomposition. In November, 1895, Professor Smithells read a paper before the Chemical Society in which he criticises somo of the less important points brought forward by me in my previous papers, and without, attenipting to disprove the fact that acetylene undergoes luminous decomposition when heated apart from air or oxygen, the principal fact upon which the acetylene tlheory of the luminosity of hydrocm- bon flames is based, comes to the final conclusion that if the criticism he offers is just “ then tlie acetylene theory of luminosity will share fhe fate of the ‘ dense hydrocarbon ’ theory.” The first portion of his paper is devoted to the measurement of flame temperature by means of the Le Chstelier thermo-couple, and he comes to the conclusion that the experiments show two things.1. The fallacious results that may be obtained by not disposing the couple with due regard t o the conformation of the zone of flame to be measured. 2. The difficulty of ascertaining the increase of tem- perature contributed by the chemical changes occurring in any one The first conclusion is self-evident, and the second I have already warmly endorsed in the paper which Professor Smithells is criticising (Proc.Boy. SOC., 1895, 57, 452). He then proceeds to explore the temperatures existing in a lumi- nous flat flame of coal gas, using for this purpose a No. 4 Bray’s union jet burner at a gas pressure of 2 i in. of water. As Professor Smithells considers the temperature determinations which he made 3s practically valueless, it is not necessary to criticise the pressure used, which should have been 7/10ths rather than 2; in. Consider- ing, however, the nbnormd character of the flame with which he was dealing, his figures accord fairly well with those I have given as representing the gradual rise of temperature in the inner zone of a, laminous flat flame, and this is of interest, as the methods employed were slightly different, and tho coincidence of result goes some way towards establishing the probability of the figures.I n considering the temperature in the flat flame, Professor Smithells says : “ To obtain any useful measurements for this flame i t is o h i o u s that i t can be explored in one way only, namely, by lay- spot.LEWES : THE ACETPLEKE THEORY OF LUUISOSITY. 829 ing the junction and the adjacent wires in a horizontal straight line, arid introdncing it along t’he flat face of the flame so that it may be placed with a considerable length of wires immersed symmetrically in any one sheath nnd passing through parts of the flame in like con- dition.” Having then taken the temperature of the outer and inner zones in this way, he proceeds to say : “ The measurements for the inner parts of the flame above given have only a negative signifi- cance.It is obvious that they cannot be true temperatures as the wires have always to be thrust through the hot outer sheath of flame, and, moreover, the couple would attain by radiation from the outer walls a higher temperature than the rapid strearn of gas in which it is immersed.” With regard to the first objecticn, that the wires have to pass through the outer wall of high temperature, and that this will invali- date t h e reading, I think he is mistaken; there mill be nearly an inch of heated wire between the thermo-couple and the point where the wires pass through the outer zone, and it seems to me that any conduction from thcse bodies will be inore likely to take place out- ward along the cod wire than inwards to the heated zone, YO that if an equal length of wire on each side OE the weld is heated i n order t a 1 revent unequal resistances being introduced, the readings shonld not suffer much from t’his cause.Nor does his second objection appear to me to be i n any way ft fatal one. If the gases in the inner zone had t o pass through a circle or even a belt of high temperature, the objection would be valid, but, inasmuch as the gases are flowing u p within a, sheath of high tem- perature which exists even after the inner zone ceases to exist, and which is fairly constant in temperature, these gases will probably be as much exposed to radiation as the thermo-couple.In taking such readings the thermo-couple is only exposed in the heated zone f o r a very short period, and it has been pointed out by Le Chatelier that the couple takes up the temperature of the locality in which it is placed with astonishing rapidity, whilst Mr. Callendar has pointed out (Trans. Roy. Soc., 1892, 166) that a spiral of plati- num wire is a bad radiator, and is exceedingly sensitive to slight changes in temperature ; i t may be assi-med, therefore, that it will not absorb radiant heat with great rapidity, and that the tempera- tures recorded in the non-luminous zone are not far removed from the truth. Professor Smithclls further accentuates his distrust of these re- corded temperatures hy saying ‘‘ the readings are not even compar- able, as the flame varies in breadth and thickness from point to poiiit in a rei4ical plane.” The inner zone undoubtedly becomes nariwwer in the higher230 LEWES: THE ACETTLENE THEORY OF LUMINOSITY.regions of the flame until ultimately the outer walls meet at the top of the flame, but the rise of temperature due to this cause is one of the factors that aid the generation of light in a flame, and if a gas were flowing up a gradually narrowing tube heated throughout to an even temperature, i t would manifestly become hotter the nearer the walls of the tube approached each other, and 1 cannot understand why, because the tbermo-couple records this fact, the readings are to be discredited.In the determinations which I made of the temperatures existing in the flame from a No. 6 Bray’s union jet burner, I did not attempt to take the temperature of the outer zone, as it was manifest that this would be the hottest part of the flame, and 1 felt that i t would be hopeless to get any accurate readings of it, as it seems clear that close to the inner zone, where there is the maximum of combustible gas meeting with oxygen for its combustion, there will be the hottest part of the flame, whilst the admixture of nitrogen, air, and the eacaping products of combustion will cause a rapid fall in tempera- ture to the outer portion of this zone, which extends much farther than mere observation of the flame would lead one to expect, and that in the outer envelope there are so many gradations of tempera- ture from the hottest to the coolest portion where combustion is finally extinguished, that it would be impossible to obtain even a general idea of its temperature, and the main point which I wished to ascertain was the effect this high temperature layer of combustion had on the gases flowing up through the inner zone.The question of passing; the wires of the thermo-couple through this heated layer before the inner zone could be reached oE course presented itself at the commencement of the experiments, and, after trying several methods, including the one adopted by Professor Smithells, I came to the conclusion that the best way of doing it was to make the twist of the thernio-couple very short, and to bend each wire at right angles three-quarters of an inch on each side of the couple, so that on plunging i t into the flame an equal length of wirc on each side of the twist was equally heated, whilst the portions of the wire passing through the more highly heated zones were equi- distant from the couple, thus ensuriag no unequal resistances being i ti t roduced.In my Inter experiments, I have employed a fixed stand for burner mcl thermo-couple, so that the exact position of the couple could be accurately determined, and in t h i s case the wires come out a t tho ,side of the flame, as in Professor Smithells’ experiments, but the thermo-couple being fixed iminediatelg over the centre of the burner, an equal length of wire is heated on each side of the couple. The use of the Le Chatelier thermo-couple for the determination of:LEWES : THE ACETYLENE THEORY OF LUMINOSITY.231 high temperatures is now becoming so general that a description of the precautions necessary in using it will not be out of place, and in my later experiments these were employed. The thermo-coiiple was connected in series with a dead-beat gal- vanometer-Ayrton and Natthers' pattern-having *a resistance of 304 ohms, and in order to bring the deflections for the high tempera- tures within the limits of the scale, a further resistance of 309 ohms mas included in the circuit. The galvanometer was calibrated by means of a cell of small internal resista.nce and a box of high resistance coils, and, on plotting out the currents and deflections, a straight line was obtained, showing that within the limits of the scale the deflections were directly pro- portional to the currents.The platinum and platinum-rhodium wires used for the thermo- couple were 0.011 inch in diameter, or 0.279 mm., which is the thinnest that can be used without fear of fusion at the highest temperature of the flame. The resistance of the platinum wire per metra was 1-71 ohms, that of the platinum-rhodium wire being 3.6 ohms. In the experiments described by Professor Smithells, the tota resistance of wire and galvanometer was about 4 ohms, which enor- moudy increases the risk of error. The galvanometer and lamp being fixed on a stand, so as to give no possibility of displacement, the couple and galvanometer were cali- brated for temperature, the fixed points selected being the following.Boiling point of sulphuy.. .......... 444.5' C. Melting point of pure silver., ....... 945.0 .. .. copper ........ 1045.0 .. 9 , .. palladium .... 1500.0 .. 9 9 ,, platinum ,. . . 1775.0 ,, 7 9 The melting points of the compounds of the alkalis and alkaline earths vary so widely, as determined by different observers, that they are practically useless for this purpose, and, as there seemed to be some doubt as to whehher the E.M.F. of the thermo-couple is directly proportional to temperatures above 1000°, I made 13 determinations of the fusing point of palladium and 16 of platinum, and, on plotting out a curve for the temperatures, obtained a straight line for all except the palladium, which was above the line. L. Holborn and W.Wein ( A m . Phys. Chew., 1895, 56, 360) find the melting point G f palladium to be 1587O, and, had this figure been taken, it would hare been close t o the same line as the others. From this, I think it is safe to assume that the course of the curve continues in a straight line above 1000°. In continuing his paper, Professor Smi thells proceeds to criticise232 LEWES: THE ACETYLENE THEORY OF LUJIINOSITY. the values which he obtained for the outer envelape of the flame, aud by testiug this portion with a thin platinum mire, wliicli he heats to fusion, comes to the conclusion that his resalts give a temperature slope opposite to that given by the thernio-coupie, Le., that the hottest portion of the outer envelope of the flame is near the bottom, and explains this as being caused by rariations in the thickness of the outer sheath of combustion.I n supposing that this is so, I think Professor Smithells is right as to his facts but wrong as to the causes to which he ascribes them, as the combustion which gives the outer envelope to the flame in the lower half is mainly due to marsh gas and hydrogen diffusing out frow the gas itself, whilst, in the upper portion of the flame, it is due to carbon monoxide and hydrogen produced by the actions in the flame, the combustible gases being diluted by the products o€ the actions taking place, and one would expect, therefore, that the lower portion of the non-luminous envelope would be hotter than the upper, although, in point of fact, the temperature differs but little, as the accumulation of heat from the combustion going on in the lower part of the flame tends to increase the temperature of the upper portion.I am in entire accord with Professor Smithells’ conclusion that there are two separate heat gradients in a luminous coal gas flame: one on the vertical axis, which is, in all probability, a steady decline from the top to the bottom ; the second on a horizontal axis, showing, as we proceed from the centre of the unburnt gas, a steep ascent to the point of contact with the luminous sheath, then a still steeper ascent to the point of contact with the mantle, where the highest point is abruptly attained.” That the temperature gradient on the vertical axis is a steady decline from top to bottom is perfectly clear from both our experiments, whilst that there is a second gradient in a horizontal axis, with the cooleat point in the centre of the flame-which is a t the greatest distance from the source of lieat-is, I think, a foregone conclusion, and I cannot.conceire any othei- condition. The second conclusion is that the temperature of the mantle OE n coal-gas flame is a,bove the melting point of platinum, and caniiot, therefore, be determined by a, thermo.couple in which platinum is one of the elements. Professor Smithells’ own experiments shorn his thermo. couple registered a temperature theile of 1478’ at the bottom of the sheath to 1613” at the top of the flame, and his assumption, therefore, that the temperature exceeds that necessary f o r melting platinum is dependent on the melting in the outer mantle of very fine platinum wire.In my previous paper I have shown the influence which the thick- ness of the platinum and platinum-rhodium wire nsed has on theLEIYES : THE ACETYLENE THEORY OF LUNIKOSITT. 233 temperature recorded, 2nd have clearly pointed out that in all the experiments quoted in that paper, wires having a diameter of 0.011 iiich 01- 0.2i9 mm., were emplojed. Professor Smithells uses wires of newly double this thickness, and obtains a recorded temperature of 1838' before his couple fuses, mhich, if corrected to the thickness of wire I employed, would be over 2000'. This is caiised by tire larger cross section of the wire, which is in the ratio of 3.2 to I, which would lead to a proportion- ately larger amount of lieat being lost by conducticn.I found that during the determinations of tlic deflections corresponding to the fusion of platillurn, great care had to be exercised in raising the temperature of the junction exactly to the melting point. It was, in all cases, the platinum of the junction which fused first, and, in some cases, the platinum-rhodium wire was surrounded by a film of melted platinum. I t was easy, by care full^ heating the junction with a small oxyhydrogen flame, to obtflin readings far above the mean obtained for the melting point of platinum, showing that, although the platinum was in the liquid state, yet a thermo-current was obtained cf greater strength than a t the temperature of the simple fusion of platinum. Professor Smithells makes a strong point of the fact that luminosity does not commence suddenly a t a certain height, but appears as an envelope just below the inner surface of the outer zone, whilst the nor_-lurninous zone continues inside the luminous zone to a consider- able height i n the flame.This mnnifestly must be so, as the decom- position of the diluted acetylene only takes place as particles stray close to the point where the highest temperatures exist, and as the centre of the inner zone is below the necessary temperature, thc de- composition of this compound only takes place close to the point where the two zones coalesce. If flames of various illuminatiiig powers are examined, it will be noticed that the greater the light emitted, that is, the richer the flame is in acetylene, the more marked is the commencement of luminosity, so that although the luminosity begins as a yellow haze with a poor coal-gas flame, it commences almost as a sharp line with a rich acetylene flame.I n concluding this portion of his paper, and i n order to show the untrustworthy nature of the temperatures thus recorded, Professor Sniithells takes two sets of the determinations of temperature existing in flat flames, made a t periods of three years apart, the one with coal gas burning from a 9000 Bray, the other from a No. 6 Bray, and feels snprised that they do not show " parallelism." The tempers- tures given are234 LEWES: THE ACETYLENE THEORY OF LUMINOSITY. 0000 Bray. No. 6 Bray. Non-luminous zone.. .......... 102Y 1014' Commencement of luminosity. .. 1658 1267 Top luminous zone ............2115 1368 Luminosity .............. practically nil. about 13 candles. When a flame of coal gas is spread out in an extremely fine sheet, as when burning from a 0000 Bray, the amount, of air required for the complete combustion of the gas is much more quickly obtained, luminosity is considerably reduced, and tt far higher temperature is attained, whilst the commencement of the feeble band of luminosity is also thrown far nearer the top of the flame, and must, therefore, be a t a higher temperature. Had there been what Professor Smithells is pleased t o call " parallelism," it would have given good grounds for suspecting the worthlessness of the determinations. Moreover, a thicker wire was used in the determinations taken with the No. 6 Bray i n 189.2, and I haye fully poiiited out the result of this.An effectire point is made by pointiug out that one of these tem- peratures is 330' above the melting point of platinum, as determined by Violle. In any determination of the temperature of the luminona zone, the reading bas to be taken with the greatest rapidity, as other- wise the foi-mation of carbon on the couple causes a falling off in the temperature recorded. In the case instanced, the spot of light rapidly rose to the division which had been calibrated as 2116O, and then fell with great oscillations, and on removing the soot from the couple after cooling, it was found that the wires were welded together, and the platinum fused over the surface of the platinum-rhodium, the couple having evidently been only just saved from complete fusion by the deposition of the carbon.The thermo-couple records with great rapidity the temperature attained by the outer surface of the metals, aud it by no means follows that the moment needed to do t h i s should be sufficient to raise the whole mass of metal to the melting point. I n my last paper, several temperatures of between 1800" and 1900' are recorded, and Professor Smithelis fails to call attention to these? I presume, because he found in his own experiments, using wire OE nearly double the thickness, that the couple recorded 1836' before fusion of the platinum in a hydrogen flame, whilst had he employed an oxyhydrogen flame, FO as to very rapidly heat the couple, he would hare found it easy to obtain still higher readings.I can only again repeat tbe statement made in my previous paper, that although flame temperatures taken by the Le Chatelier tliermo-couple may be totally incorrect, they are, a t any rate, comparable when proper pre- cautions are taken i n the methods of using the couple.LEWES : THE ACETYLENE THEORY OF LUYIKOSITY. 235 In the second part of his paper, Professor Smithells deals with other portions of my paper, and summarises his conclusions as f 01 lows. 1. The description of the structure of a flame adopted by Professor Lewes is not in harmony with the facts. I n the paper before referred to on “The Luminosity of Coal Gas Flames,” Chem. Sod:., 1F92, I gave the description of three zones of a luminous flame in the words to which Professor Smithells takes such stmng exception.I n quoting this description, however, he entirely ignores the fact that the seven pages following are devoted to explaining the action of the air in rendering hydrocarbon flames non-luminous, this being done by tracing the action of diluents in destroying the lominosit7 of hydrocarbon gases in the Runsen flame. The results obtained make i t perfect-ly clear that the oater zone of combustion must be the hottest part of the fiame, but i t is also manifest that betweeu the lajer of maximum temperature and the cool air there must be many gradations of temperatme, and althongh I now realise that the outer zone of R flame extends further than I thought at that period, and that, therefore, the amount of products of incomplete combustion are extremely minute, I still believe that infinitesimal traces of carbon monoxide do escape combustion, and make themselves felt by delicate constitutions.All my papers, also, clearly show that I consider it is the baking influence of the heat of combustion, generated in the outer zone of the flame, which leads to the changes taking place in the interior of the flame, and I fail to see why Professor Smithells should desire to hat I look upon the outer zone of the flame as the of-as i t undoubtedly is-the hotiest part of the make it appear coolest, instead flame. 1 should now of two zones, be inclined to describe a coal-gas flame as consisting 1. The outer envelope of combustion. 2. The inner region of non-combustim. The outer zone is tho portion of the flame where the combustible gases present in the original gas or generated by actions taking place in the inner zone meet with the air and undergo combustion, forming an envelope of intensely high temperature b u t no appreciable lu minoeity.Tbe maximum combustion takes place towards the inner aide of the outer zone, a s it is here that the largest proportion of the hot gases meet the oxygen of the ail, the dilution and cooling effect produced by the air and products of combustion rapidly causing the336 LE\FES : TEE ACETYLEYE THEORY OF LUMISOSITY. external portions of this zone to fall in temperature until finally extinguished. The lower portion of the outer zone is chiefly due to hydrogzn a11ct methane which have diffused out from the coal gas undergoing com- bustion, whilst the upper portion of the olrter zone is fed by carbon monoxide and hydrogen, formed by the decompositions and inter- actions taking place in the inner zone.The inner zone is the region into which no oxygen penetibateu, and in it many decompositions take place, due to the baking action of the heat generated in the outer zoce, and to interaction with the products of combustion. This zone may be sub-divided into ihrec parts. A. The non-luminous portion, in which the heavy hydrocarbons flowing upward from the burner rapidly increase in temperature owing to radiant heat from the outer flame walls, and are conrerted thereby into acetylene. B. The luminous portion, which is produced by the acetylene formed in the flame, being heated to a temperature a t which i t is decomposed with such rapidity that the particles of carbon liberated are raised to incandescence by the heat generated by its own decom- position, the carbon particles being afterwards consumed by the carbon dioxide and water vapour diffusing into the flame from the outer zone, yielding carbon monoxide and hydrogen, which, together with the hydiqogen liberated from the acetylene, give, by their com- bust'ion, the upper portion of the outer zone. This portion of the inner zone will only be formed near the point of maximum tem- perature, and therefore forms, in close contact with the outer zone, a sheath or cone which caps the non-luminous part.C. The blue region a t the base of the flame, which has, I believe, been generally ascribed t o the hydrocarbons being consumed without liberation of carbon by the oxygen of the air.I am afraid I am here again at variance with the generally received ideas, as I believe this portion of the flame to be a continuation of the luminous portion in which the carbon dioxide and water vapour from the outer zone burn up the hydrocarbons to carbon monoxide and hydrogen before the temperature has risen sufficiently to decompose them into carbon and hydrogen. If a luminous gas flame is turned down low, i t is seen that as the luminosity disappears the blue region surrounds the inner zone, whilst it is in turn surrounded bp the outer zone-an observation due, I believe, to Hildegard-and the small flame is rendered non- luminous, because there is not a sufficient body of heat to con-i-ert the hydrocarbons into acetylene, or if acetylene is formed, to decompose i t before combustion.It is assumed, with a luminous flame, that. noLEWES : THE ACETYLESE THECRT OF LUMIh’OSII’P. 237 oxygen penetrates through the outer zone, and as the outer zon3 still exists with the small flame, I fail to see why enough oxygen should enter to burn up the hydrocarbons before liberation of free eai-bon. If a flame of acetylene be burnt at the end of an open tube, and carbon dioxide be allowed to gently flow up a fiecond tube into the centre of the flame, the first addition destroys the smoky lurid nature of the flame, and gives a slight increase in luminosity, which gradu- ally dies away as more carbon dioxide is introduced, until a non- luminous flame results, whilst if carbon dioxide, instead of air, be supplied to a Bunsen burner through the air holes, the luminosity is destroyed, and the flame has all the characteristic colour of the blue part zf the inner zone.It is a significant fact that Professor Smithells, in his second objection, considers the amount of acetylene present in a luminous flame insufficient to account for the light emitted, without taking the trouble to perform, or at any rate record, a single experiment in support of his unbelief. The statement made by me, that just before luminosity commences SO per cent. of the unsaturated hydrocarbons present at that spot consist of acetylene, is characterised as “ likely to give a very false impression as to the importance to be attached to the presence of this gas,” 8s Prolessor Smithells is at, a loss to understand how a mixture of 1.5 per cent.of acetylene and 0.5 per cent. of other unsaturated hydrocarbons mixed with 98 per cent. of other gases, four-fifths of which are actually incombustible, could be supposed to have the properties I attribute to it. If he means by this that the liberated carbon particles in the flame axe not derived from the small quantity of acetylene, it seems hardly logical to suppose that they come from the 0.5 per cent. of other unsaturated hydrocarbons, and if they do not come from the nnsatn- sated hydrocarbons at all, perhaps Professor Smithells will be able to explain their source. If a mixture of 1.5 per cent. of acetylene with any combustible gas which gives a xion-luminous flame was burnt from a jet no lumi- nosity would be developed by the flame, and no trace of acetylene found a t the top of the inner zone, it having been all consumed or polymeriscd before the temperature necessary for its decomposition was reached, but i t is, nevertheless, a fact that 1.5 per cent.of acetylene, present at the q o t where luminosity usiinlly commences, will render such a flame luminous. I n an acetylene flame, the nitrogen and products of combustion diffusing into the flame dilute the acetylene present a t the commence- ment of luminosity to 15 per cent. of the gases present a t that point,238 LEWES: THE ACETYLENE THEORY OF LUMINOSITY. and the acetylene flame gives more than 10 times the light of the gas flame with its 1.5 per cent. In an analysis made by me of the gases present in the non- luminous gas flame just before luminosity commences, I found 18.65 per cent.of combustibla gas, whereas Landolt (Pogg. Annalen, 1856, 99, 389), in his experiments on the same portion of the flame, only found 10.01 per cent. Casespresent in the Itzner Zone of Flante just before commencemeut of Luminosity. Lewes. Landolt. Hydrogen ................ 2.35 2.59 Unsaturated hydrocarbons. . 1.98 1-18 Methane ................ 7-80 0.79 Carbon monoxide.. ........ 6.52 5.45 .--- 18.65 10.02 Landolt also uotes the fact that the gae from the lower portion of the flame is free from smell, but that from the higher portions has a feeble empyreurntitic odour. I should have thought that the small proportion of combiistible gases present at this point was an important proof that luminosity must be due to some such action as that to which I have ascribed it, rather than to any ordinary combustion.In order to see if 1.5 per cent. of acetylene injected into fhe upper portion of the non-luminous zone of de-illuminated coal gas restored its luminosity, coal gas was slowly passed through washing flasks containing a solution of bromine in potassic bromide until its illumi- nating power was reduced to 1.7 candles. Two open tubes were then arranged side by side, and ordinary coal gas burnt from one, and de-illuminated coal gas from the other, in flames of equai size, and acetylene was then allowed to flow through a fine platinum tube into the inner zone of the de-illuminated gas flame, at such a rate as to form 1.5 per cent.of the gases present there, the result being that the flame became nearly as luminous as the one used for comparison. Another point insisted upon by Professor Smithells is (3) that " there is no evidence of any local condition of temperature within the flame such as would point to the decomposition of acetylene with the evolution of much heat." In order to see exactly what the increage of sensible heat at the moment of deconiposition of pure acetylene amounted to, I arranged a t.hermo-couple in a small, hard glass tube, passed acetylene through the tube until free from air, and while the gas was burning at the exit of the tube, heated six inches of the tube in such a way that theLEWES: THE ACETTLESE THEORY OF LUMINOSITY. 239 thermo-couple should be a t the spot where the acetylene entered the heated zone.The luminous decomposition commenced, as is usually the case, about two-thirds of the way u p the heated zone, and the glow slowly ran back to the commencemtnt of the heated area, and O n coming in contact with the thermo-couple gave a rise of tempera- ture of 30’ as the mean of three closely concordant experiments. It is evident from this experiment, that no very high local con- dition of temperature would be found in the flame at the spot where the decomposition of the acetylene took place. The fourth coiiclusion has been already fully dealt with. I n liis fifth conclusion Professor Smithells says : “ The conclusion in favour of the acetylene theory, based on t’he comparative luminosity of the ethylene and acetylene flames, is due to a neglect of the coil- sideration that i n the latter there me higher temperatures, and a greater relative amount of carbon.” When acetylene and ethylene are burnt at the same rate of flow from similar burners, a certain portion undergoes non-luminous com- bustion in order to supply the heat necessary to, in the one case, form acetylene and then decompose it, and in the other to decompose it only. That far more ethylene is needed to do this work is manifest from the size of the non-luminous zone, which is many times greater than that of the acetylene flame.The portion of the gas undergoing non-luminous combustion gene- rates heat only, of which but little is radiated ; the portion converted into acetylene and decomposed gives off its energy to a cousiderable extent by radiatiou, hence, although the heat of combustiou of acetylene may be far higher thaii the heat of combustion of ethylme, i t is conceivable that the acetylene flame may develop brit little more heat than a flame of ethylene of the silme size. The figures I gave were for the interior of the flame only, and I quite agree that the outer envelope of the lower portion of an acetj 1- ene flame must be hotter than the same portion of an ethylene flame, but it by no means Pollows that the total heat developed by the acetylene flame is much greater than that developed by the ethylene.Ethylene and acetylene both contain two stoms of carbon in the molecule, and if we do not assume some such theory as the one pro- posed, we might be led into the error of supposing that the luminosity of the ethylene should be only one half that of acetylene, because the carbon is diluted with twice the volume of hjdrogen, whereas experi- ment shows its illuminating value is only one quarter.Professor Smithells argues, that because a platinum wire glows nearly as strongly in the lower portion of the outer envelope of an acetylene flame as the carbon particles within that envelope, that24(’, ZEWES : THE ACETYLENE THEORY OF LUMINOSITY. the hezt of the flame is sufficient to raise them to this high degree of incandescence. This assumption is apparently based on the idea that they both have equal powers of emitting light when heated to the same temperature, which is about as reasonable as snpposing that carbon has the same emissive powers for light as the earths used in n Telstach mantle.I t is also evident that the platinum wire mnst be heated to a higher temperature in the outer envelope of the flame than the carbon particles which are within it. Metals a t a high temperature have been shown to reflect light, and it is quite possible that some of the apparent brightness of the platinum wire is due t o light reflected from its surface. I n arriving a t his sixth conclusion, Professor Smithells has repeated an experiment described by me, and finds that “ t h e in- direct evidence deduced from the behavionr of cyanogen arises from the yellow ammonia flame having been mistaken for one con- taining solid carbon.” When a cyanogen flame issuing from a small jet has hydrogen supplied around it, the inner rose coloured cone becomes luminous, and on examining the light emitted, by means of a spectroscope, a coctinuoiis spectrum is obtained i n which the nitrogen lines are faintly visible.If now the hydrogen be increased i n quantity, the flame enlarges, the luminosity becomes fainter and more spread over the flame, and the light emitted no longer gives a continuous spec- trum, but only the nitrogen lines. If the flame emitting the continuous spectrum be now surrounded with oxygen, the luminous inner zone shrinks in size and emits an intense light, which gives a bright continuous spectrum with flutings which correspond to the cyanogen lines. This experiment is best performed with a burner made of three concentric platinum tubes, cyanogen being supplied t o the central one, hydrogen to the middle, and oxygen to the outer tube.Professor Smithells has repeated this experiment, but apparently has only dealt with the cyanogen flame in presence of a large excess of hydrogen, and, noting that the luminosity was low and of a yellowish colour, he attempted to deposit carbon from it upon a cold porcelain dish. E’ailing t o do this, he then fed a hydrogen flame with ammonia, obtained a similar appearance in the flame produced, and on examining both flames with a spectroscope, got identical lines, which he silys are those of ammonia; and from these facts he argues that in the above experiment an ammonia flame has been mistakeri for one containing solid caybon. If a hydrogen flame be taken, and ethylene be passed into it until it is endowed with These experiments I think are entirely fallacious.LEWES : THE ACETYLENE THEORY OF LUMINOSITY.241 the same or even far higher luminosity than the hydrogen flame fed with cydnogen, it is imp:)ssible t o deposit carbon particles from it by immersing in the flame a cold porcelain surface, because the intense power which the excesq of heated water mpour present in the flame has o€ oxidising the solid carbon particles is so great that no deposi- tion is possible,, and this result is therefore 110 proof G f the absence of carbon particles. The spectra given by the cyanogen and ammonia fed into hydrogen flames are unquestionably identical, and on comparing them with the spectrum of nitrogen give11 by a Geisaler vacuum tube, they were found also to correspond with the spe-trum given by ihis gas.The cvidence adduced by Professor Smithells to show that ammonia and not the carbon particle.. is the cause of liiminosity is therefore of no value, and his asmmption that the increased iuniinosity obtained when the dual flame is fed with oxygen is due to sodiiim vapour from the platinum is also absolutely devoid of foundation. It is evident that in the experiment, properly performed with hjdrogen alone, we are dealing with temperatures only just suficien t t o lead to luminosity, and a piece of cold metal piaced against the inner cone causes i t to again become non-Iumiiloiis, whilst if hydrugeil be replaced by carbon monoxide RO luminosity ensiles, :I fact which miglit be taken to support Professor Smithells' views were i t not that a slight increase of temperature leads to lumimsity, as when the dual flame is surrounded with oxygen j whilst a still further increase in temperature not only again increases the lumi~iosity, but enables one t o obtain a copious deposit of carLon from the flame.This is readily done by burning the cyanogen from the end of a tube and surrounding it with nitric oxide, the decomposit,ion of this endothermic body (the bent of formation of which is -4575') raising the temperature of th? flame to a point a t which the cyanogen burns with a dazzling light, and with the flow of cyanogen and nitric oxide properly regulated i t can be made to deposit soot i n abundaace." The continuous spectrum given by this flame is of a most magnifi- cent character, showing bi-illiant flutings in the red and green, and extending with particulai. brilliancy far into the violet, and when the light is develcped froni a burner of the kind before descrihed, by using quartz lenses and prisms the spectrum may be projected upon a screen.I think there can be no doubt from these experiments that I was perfectly correct in my former statement (PTG 3 0 y Xoc , 1895, 57, 4b5) that the luminosity of a cyanogen flame is purely a question of temperature, whilst I hare no doubt that, given sufficient heat t o In order to obtain a deposit, the cyanogen and nitric oxide inust be p r e . This soot contains a truce of paracyanogen. VOL. L U X . <242 LEWES : THE ACETYLENE THEORY OF LUMIINOSITY.rapidly deoompoae it, as high an illnminating value a3 that of acety- lene would be obtained. The seventh conclusion arrived at by Professor Smithells is that “ the theore tical arguments based on thermochemical cunsiderations are invalid.” I n my paper (Zoc, cit., p. 4-51), I incautiously speak of carbon exist- ing in a molecular state of division, meaning, as the context clearly shows, exccedingly arnsll particles of aolid carbon, but Professor Smithells does not fail to make the most of thiH slip, and supposes that it is R periphrasis for “carbon i n the form of gas,” and that if so i t sounds the key note of much that follows, as, wliilat I con- tinue to speak of solid particles of carbon, my theoi-etical specnlations are applicable only to atoms, I am not aware that when atoms of carhon form molecules, a dis- sppearaiice of heat takes place, a i d m.y gefieral impression was that when gaseous matter assnmed the solid form, heat wap evolved rather than a,bsorbed, and a14 these are the only factors which would invsli- date my argnments, I fail to see whet Professor Smithells means, Moreover, I carefully point out in my paper (Zoc, cit,, p.460) that 1 consider these theoretical calculations of “ no vctlue, except as show- ing that a ratio doea exist betweon heat of foi*mntioii and illuminat’ing value. ” Professor Smithells’ last conclusion is “ tbe phenomena of lurn;nodPi hydrocarbon flames can be adequately explained without the acetylenc theory,” If by this it is meant that because an imperfect explatia- tiori already exists no one is to attempt to render o u r knowledge more exact, it Reems to me so utterly oppcjsed to the whole spirit df scitai- tific iiiquiry that I think j t best to ignore i t, more est~eciallp as I fail to see how such au idea, chii be reconciled with the quotation froni his own work with which Professor Smithells commences his paper, ‘( A problem remaining to be studied concercs the exact course of the decomposition of the hydrocarbon in the flame.’’ I n conclusion, I must protest against tl.e statement made by Pro- fessor Smithells that I adduce measurcmeiit~ of temperature BS t h e chief basis for the acetylene theory. I have clea~ly pointed out in the paper criticised thal at most they are only valu:Lble for comparison under well-defined conditions, I consider the acetylene theoily of lumho&ty iii hydrocai<bon flames to be based ayon the following facts, 1. That the largsst proportion of the nnsaturated hydrocarbons in a gas flame are conr-erted into acetylene before luminosity CoTnrneiices. 2, That acetyleue develops luminosity when heated to a tempem- ture a t which it decomposes, the conditions under which this takes place rendering the presence af atmospheric oxygen irnposjible,SOLUTION AND DIFFUSION OF METALS IN MERCURY. 243 3. That the temperature necessary to decompose acetylene with luminosity is insufficient to.raise the carbon liberated from it to the point at which it emits light. 4. That ir, luminous hydrocarbon flames of sufficiently high tern- perature the luminosity varies directly with the amount of acetylene present where luminosity corn mences. Professor Smithells has not attempted to experimentally refute any one of these points, and until this is done I, at any rate, shall con- sider that the '' acetylene theory '' offers a satisfactory explanation of the most important phenomenon of luminous hSdrocarbon flames. I desire t o express my thanks t o Mr. A. Haddon, Demonstrator oP Physics at the Royal Naval College, for the help he has afforded me in the work entailed by this paper.

ISSN:0368-1645    

DOI:10.1039/CT8966900226

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

SOLUTION AND DIFFUSION OF METALS IN MERCURY. 243 XXV.-Solution and D@.~sion of certain Jletuls in Mer.cury. By W. J. HUNPHREYS. (Communicated by J. W. NALLET.) THE purpose of the investigation described in this paper was to examine quantitatively the solution and diffusion of metals in mer- cury, and thus to obtain some ides of the extent to which these phenomena differ, if at all, from solution and diffusion in the case of non-metallic solids in liquids. Possibly this question bas already been worked upon, and the results published, but if so, I have only to say that both search and inquiry have so far failed to inform me of the fact, and I therefore venture to publish my results, with the hope that, if not entirely new, they may nevertheless be of some value for the purpose of com- parison with results already obtained." * Since this paper was written, my attention has been called to an article by the late Dr.F. Guthric, " On Certain Molecular Constants " (Phil. Mag., Nov., 1883, 16, 321). I n the latter par!, of this paper, pages 329-339, UP. Guthrie treats of the diffusion in mercury of sodium and potassium amalgams, and also of the diffu- sion of the pure metals, lead, tin, and zinc. I n the case of lead, tin, and zinc, he allowed the diffusion to continue 31 days, and in each case made but a single series of analyses. His method of operation (differing entirely froin mine) wae to place the mercury with the metal to be examined in a burette of suitable size, and a t the end of the diffision to draw off siowly from the bottom of the burette the whole of the amalgam in, as nearly a3 possible, 13 equsl portions. The temperature a t which he allowed the diffusion to take place was 16" to 17", from 10" to 12" lower than that a t which I worked, consequently, only a general agreement in OUY results could be expected.However, on examining his table of results (p. 337 of his article), I find VOL. LXIX. ,244 HUMPHRETS : SOLUTION AND DIFF LJSION The method of investigation was to fill an upright vessel of uni- form horizontal cross section with pure mercury, place on its upper surface a piece of the solid metal to be examined (freshly amalga- mated on the surface of contact'), and after allowing it to remain in FIG. 1. that wherever our values for lead are nearly the same, his corresponding values for tin and zinc are approximately the same as the Corresponding values I obtained for zinc and tin respectively.Dr. Guthrie did not make his own analyses, but entrusted this part of the work to others, one of whom furnished the analyses of lead, a second those of tin, and a third those of zinc, and I think it not. impossible that in transferring these analyses to his table of results, those of tin and zinc became interchanged. If so, his results and mine agree quite as closel~ as could be expected. This relation between our results rnakes a repetition of the investigation of the diffusio:i of tin and zinc very desirable.OF CERTAIN METALS IN MERCURY. 245 contact with the mercui-y for a certain length of time in a place free from external disturbances, and of fairly constant temperature, to take, from definite depths below the surface, samples of the mer- cury, and examine them for the foreign metals carried down by diffusion.The method of obtaining samples of the amalgam for analysis may be understood by.reference to Fig. 1. A is a cylindrical glass Tessel, 150 mm. high, and 25 mm. internal diameter, with four tubules T, 10 mm. in diameter. Corks were placed in the tubules, and through the corks were passed the tubes 1, 2, 3, and 4, to the centre of the tank A. The portion of each of these tubes entering the tank was drawn out rather small, so as to interfere as little as possible with the process of diffusion. The inner end of each tube was cut off perpendicularIy to its axis, the opening thus produced being from 0.5-0-75 mm.in diameter; this opening was closed by a small, wooden rod R which could be easily put in place or removed by a slightly rolling motion. The tubes and the tank A were all rigidly bound to suitable framework, amd the distances between the ends of the various tubes, as well as that bet ween the end of the lowest tube and the bottom of the tank care- fully measured. The tank A was then filled to a dsfinite depth with pure mercury, the freshly amalgamated disk D of the metal to be examined put in position, and the whole allowed to remain quietly iin a suitable place until the time came for removing the samples for analysis. The distances from the surface of +,he mercury to the end of the first tube, from the end of the first to the second, from the second to the third, from the third to the fourth, and from the fourth Ito the boktom of the tank, were each usually made equal to 25 mm.The upper surface of the disk D was covered with sealing wax, so a s -to confine the action of the mercury t o a known surface, that is, the under surface of the disk. A small wire W, usually fastened to the sealing wax, though occasionally soldered to the disk (in no case was any of the solder dissolved away), made it convenient to put the disk in position at the beginning of the experiment, and to remove it a t the end. When the diffusion had proceeded as long as desired, the wooden rod in tube 1 was gently removed, and a sufficient amount (about 20 grams) of the amalgam collected in the side biilb I?. This rod was then put back in place, aiid a similar process of drawing off the amalgam and replacing the rod, so as to prevent any further outflaw of the amalgam, was employed i n t)he case of the tubes 2, 3, and 4 respectively, and in the order named.The whole process for all four tubes generally required less than one minute. The mercury was then withdrawn The samples to be analysed were removed as follows. T 2246 HUMPIIREYS : SOLUTION -4ND DIFFUSION from the tank, and the tubes removed and emptied of their samples, which were carefully weighed and analysed. A somewhat different variety of tank was a h used ; it was square, three sides and the bottom being of wood, and the fourth side of glass, In this case, square, instead of circular, pieces of the metal were used.Two tanks of each variety were employed, and altliough no ,difference was foiind in their behaviour, they are, nevertheless, distinguished in the table of results. A and B refer to the wooden tanks of square cross section, whilst C and D refer to the glass ones of circular cross section. The method of analysis adopted in the case of lead amalgam was to volatilise as much of the mercury its possible without loss of lead, dissolve the residue in dilute nitric acid, add an excess of sulphuric acid, and evaporate till fumes of sulphuric acid began t o come off freely ; then add water or dilute sulphuric acid till all the mercuric sulphate was dissolved, the snlphate of lead of coui'se remaining undissolved. This was then collected, the sulphate of mercury removed by washing with dilute sulphuric acid, and the acid in turn by dilute alcohol; the sulphate of lead was then dried and weighed, and the percentage of lead in the amalgam estimated.In the case of tin, zinc, and bismuth amalgams, as much as possible of the mercury was volatilised without loss of the dissolved metal, the residue dissolved in nitric acid, evaporated to dryness, and then fitrongly heated, SO as to reduce the nitrate of tin, zinc, or bismuth to the corresponding oxide, and also to decompose and remove the mercuric nitrate ; the oxide of the metal under investigation was then weighed, and its percentage in the amalgam calculated. All the mercury was volatilised from the copper amalgams, the residue dissolved in nitric acid, evaporated to dryness and heated, and from the oxide thus obtained the copper and its percentage in the amalgam calculated.Although the copper in the amalgam never, with but one exception, amounted to a$s much as three parts in 100,000, nevertheless, as soon a s the mercury began to distil off, the whole surface of the amdlgam assumed fimt one, and then another, brilliant colour, some of these being repeated a second time, until finally it became and remained in appearance like a solid mass of copper. The mercury was also completely distilled from the silver amalgams, and thus the silver obtained pure, and weighed as such. As already stated, the temperature did not change very greatly during any one experiment, still it was not constant; when the time of diffusion was several days, the average temperature, as given in the table, was obtained by taking the average of the temperatnre, as shown by a thermometer kept beside the tank, at 9 A.M., and at Each side measured about 25 mm.inside.OF CERTAIN METALS IN MERCURY. 247 4 p . ~ . When the time of diffusion was less than one day, several i-eadings of the thermometer were taken during the interval and averaged. After preparing a tank for a diffusion experiment, it was put i n place, and the mercury allowed to come to n steady temperature before the amalgamated disk was put on it. The results of the work are all given in the table, mhich needs no explanation, except possibly the statement that the decimals in the column headed ;‘ Percentage of metal ’’ are probably in many cases carried further than the accuracy of the work would warrant.The last figure of course, was certainly never correct, but the third could usually be trusted, and since the work was done with care it was thought best to give the results as they oppear in the table. Two sets of curves (pp. 248 and 249) are plotted for each metal examined. Those to the left have for abscism the depths in milli- metres below t h e surface of the points from which the samples were taken, and for ordinates the percentages of the metals found. These curves consequently represent the conditions of the columns of amalgam from top to bottom, as found after the diffusion had been going on for a definite length of time. The time, in days, of diffusion is marked on each of these curves. The other sets of curves, those to the right, have for ordinates the percentages of the metals found.and for abscism the time, in days, of their diffusion, and conse- quently they represent, the rates of concentration at definite depths, that is, 25, 50, 75, and 100 mm. respectively below the surface. Owing to the small extent t o which silver and copper dissolve, their curves are plotted with ordinates respectively 10 and a 100 times greater than those of the curves of other metals; and their ciirves of concentration, those to the right, mere so nearly coincident that it, seemed best in each case to let a single curve represent all four. A set of comparison curves for the different metals is given just below those of copper (Fig. 3). Those to the left give the conditions of the columns of amalgnm a t the end of 10 days’ diffusion, whilst those t o the right show the rates of concentration at; a depth of 25 mm.From the table and the curves it will be seen that, so far as these experiments go, solution and diffusion in this case are not, essentially different from the same phenomena in the case of non-metallic solids and liquids. Copper and silver are both interesting from the fact that they dis- solve to a very slight extent (at ordinary temperatures), but diffllse very rapidly. Not only did the mercury seem to become saturated with the silver from the fact that very little silver dissolved after the first day, and apparently none a t all after the fifth, but also that, when the248 HUMPHREYS : SOLUTION AXD DIFFUSION amalgam obtained by fire or 10 days’ diffusion was allowed t o coo1 down slowly, small crystals would separate out, b u t dissolve again in the amalgam from which they had separated on slightly warming it.FTG. 2. The extreme rapidity with which silver diffnsed led to the sus- picion that possib1.y some form of amalgam was obtained of great,erO F CERTAIN MKTALS IN MERCURY. 249 density than that of mercury. To test this, a considerable amount (probably from 75 to a 100 grams) of saturated silver amalgam was carefully placed on a column of mercury and allowed t o stand t w o FIG-. 3. hours. depths and analysed. Samples were then taken from the surface and from different The resnlts, as shown by the table, indicated250 HUMPHREYS : SOLUTION AND DIFFUSION the same concentration from top to bottom, which disproved the idea that the rapidity was due to the formation of an amalgam heavier than the mercury ; and, besides, no such silver amalgani has ever been obtained.It seems, therefore, safe to say that, whilst silver dissolves to a comparatively small extent in mercury, it diffuses through it with relatively great velocity, about 20 mm. per minute, which is fully 600 times as great a s the velocity with which zinc diffuses. This work was suggested to me by Dr. J. W. Mallet, F.R.S., of the University of Virginia, and was done there under his supervision uring the months of July, August, and September, 1895, and I wish to thank him for his kindly and helpful assistance whenever any difficulty presented itself. I wish also to thank Professor Dunning- ton for occasional b u t always helpful and kind assistance.Of course, the present paper is in the main simply preliminary, and I hope to be able a t an early date to iuvestigate the influence of tern- perature on the solution and diffusion of metals in mercury, and also t o investigate the diffusion of mercury along solid bars of other me tals. I had hoped t o examine the solution and diffusion in mercury of certain metals not given in the table, but was unable to do so bc- cause my work was interrupted at the end of September by otflier duties. Table of Results. Substance dissolved. Pb 9, Y J Y, 7 1 7, Y 9 7> 71 7 9 >9 Y I 7, 7, 7, 79 Time 3f diffu sion. 10 dayt 9 ) 1 ) 5 Jay6 9, 9 , P9 10 days 9, I 9 9) 5 days J t 9 9 9) Average tempera- ture C.Depth in milli- metres of sample. 25 '0 49 '0 75.0 101 *o 25.0 46 * 5 74 '0 100 '0 25 -0 49 -5 76 *O 102 -5 25 *O 52 -0 76 -5 101 '5 Percent. age of metal. 0 '7717 0 '3192 0 -097 1 0 '0220 0 '5463 0 -14.55 0 '0125 0 '0059 0 -8906 0 - 4 6 1 0 '1258 0 -0292 0 '6832 0 -1506 0 * O l 7 0 0 -0046 Remarks. The method of with- drawing the anial- gem in these two cases was different from that described and used in all the other cases, and as i t was not very eatisfactory, these two sets of results are not plotted.OF CERTAIN METALS IS BLERCURY. 251 Subs tan dissolve Tuble of Results (continued). A-ieragc tempera ture C. Depth in milii. metres c sample. 25 .o 50 .O 75 -0 100 *o 25 -0 48 -5 75 5 99 *5 24 *5 50 *5 76 -0 101 *o 25 '0 50 '0 75-0 100 so 25 *O 51 *5 77 -5 102 '0 25 -0 50 *O 75 -0 100 -0 25 -0 50 '0 75 -0 loo -0 25 0 50 '0 75 -0 100 '0 26'0 50 *O 75 '0 100 -0 23 -3 50 *O '15 -0 100.0 25 -0 50 -0 75 -0 1co '0 25 *o 50 -0 '75 -0 100-0 25 -0 50 -0 73 -0 100'0 Percen age oi metal ? 0 '002( trace 0 &O( 0 -2511 0 -105: 0 -0361 0 *383: 0'113i 0 *0291 0 003E 0 -1061 0 -004: none 0 6 6 6 0 -3000 0 -0943 0 '0195 0 -6855 0 -2019 0.0319 D -0062 D -6902 3 '2081 3 '0416 3 '0028 3 -1384 3 -0019 none 1 .$boo 1'6413 1 -2734 1 -0905 ) '9870 ) -3540 )*094i 1 -0192 -5826 1 -0696 1 -0044 none 1 'OU31 1 - 0022 1 -0025 1 -0024 -0027 -0026 -0027 '0027 1 Remarks.~ Lost by accident.252 SOLUTION AND DIFFUSION OF METALS IN IIERCURY. Time ol diff u- sion. 2 day; 77 JY J J 6 hrs. Y Y J J J ) 30 mins J Y YJ f7 10 day > Y J J J J J Y 7 9 7 9 ,, 5 days Y J JY YJ i day Y Y J 7 9 7 3 hours Y) JY J J 2 hours > J J J J J 10 mins.J Y J 7 JY 5 mins. 9 7 J J J J Y J 11 Y J J ? Table of ResuZts (continued). Average tempera. ture C. --I 29 -4 97 JY 24'3 Y Y Y Y 24'4 Y Y 9 7 2s'l04 J J 9 ) Y J 28 '09 7 9 J ) 27'-',0 9 9 J J JY 26 '47 9 9 YJ 2?)'S6 YJ J J 25':7 2 9 97 9 Y 30 '1 Y ? J J 9 9 27 *15 Y Y Y Y J J 29 *3 Y J J 7 Y Y Depth in milli- metres of eample. 25 *O 50 '0 75 '0 100 '0 25 -0 50 '0 75 '0 100 '0 25 '0 50 '0 75 '0 100'0 25 -0 51 '5 76 '5 102 '5 25 '0 50 '0 76 ' 0 100 '0 25 '0 51 -5 ?7 '5 102 '0 25 0 50 '0 75 '0 100 '0 25 '0 50 '0 75 '0 100 '0 25 '0 50 '0 75-0 100 - 0 25 '0 50 '0 75 '0 100 '0 25 -0 50 *O 75 -0 100 '0 25 '0 50 '0 75'0 100'0 I_- Percent age of metal. 0 '0024 0 '0024 0 0023 0 '0020 0 -0007 0 '0007 0 * 0007 trace none Y Y Y Y 0 .&62 0 *0460 0 -0483 0 %4G1 0 *0424 0 -0439 0 '0433 0 %434 0 *0415 0 '0450 3 -0423 D *0432 D *0349 3 -0344 0 *0335 0 -0332 0 -0165 0 '0161 0 -0162 0 '0163 0 '0060 0 *0052 0 -0074 0 '0061 0 -0026 0 -0010 0 * 0007 0 -0014 0 *0006 0 -0006 0 .OW6 0 -0006 0 -0006 0 '0006 0 %006 trace Tank A " 1 8 " I D { > Y " I :{ Y Y 7 ) Remarks. --- Samples taken out a t temperature 28.80. Samples taken out at temperature 26'4'. Samples taken out a t temperature 26.2'. rime of taking out all four samples, 30 secs. Time of t,aking out samples, 30 secs. Chloride f orined and amount esti- mated by com- parison with stan- dard solution. Time of taking o u t samples, 22 secs. Estimated as above.THE STNMETRICAL DIMETHPLS UCCINIC ACIDS. 253 Perceu t - age of metal. Table of Results (continued). Tank. Arerage tempera- ture C. 30 secs. 7 ) 2 hours Depth in milli- ~ ~ ~ ~ l e ~ f Substance dissolred. ---- of diffu- sion. 7) 25 *7 1 7 9 100 -0 0.0 25 *o 50 .O I- -- 0 0017 0.0028 O*OO2i 0*003.% ,, f ,, ) ,, I ,, J Remarke. ------ The two Raniples drawn off simul- taneously. Time, 5 secs. Not plotted.

ISSN:0368-1645    

DOI:10.1039/CT8966900243

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

THE STNMETRICAL DIMETHPLS UCCINIC ACIDS. 253 XXV1.-The SymmetricaI Dinzethylsuccinic Acids. By WILLTAM ARTHUE BONE, and WILLIAM HENRY PERFIN, Juii.. IKTRODUCTION. IN 1869, Wislicenus (Bey., 1869, 2, 720) described as dimethylsuccinic acid n, substance which he had observed among the products of the reduction of iodopropionic acid by means of zinc dust. The substance itself was a syrup, which only partially crystallised on long standing, but it yielded a highly characteristic lead salt, which, on analysis: gave results corresponding with the empirical formula C,H,P bO,. Five years later, Weidel (Annalen, 1874, 173, l o g ) , by the rednc- tion of pyrocinchonic acid, cH3'f?c0>0, by means of sodium c a,* c * c 0 anialgam, obtained a crystalline acid, melting a t 170°, which could be sublimed, for the most part without change, and which he termed " 11 y d ro pyrocinchon ic acid ." In 1878, v.Hnrdtmuth (Annalen, 192, 142), working under the direction of %-islicenus, studied the action of methylic iodide on the sodium compound of ethyl ic P-methy I ace t osuccinate in beiizen e sol u- tion, and on hydrolysing, by means of alcoholic potrash, tbe ethereal salt' thusformed, obtained a '' dimet,hylsuccinic acid " melting at 170". The reactions involved in this process may be thus written C H,*CO*C*Na--CH*CH, CH,*CO*T(CH,)-YH*CH,. COOEt COOEt + CH3I = bOOEt h00Et. + NaI. CH3*CO*y(CH3)*TH*CH3 HF(CH3) *FH*CHs COOEt COOEt + 3H20 = COOH COOH + CHs*COOH + 2CzHS.OH.254 BONE AND PERKIN: I n 1882, v. Roscr (Bey., 15, 2012) obtained " hydropyrocinchonic acid " by the reduction of pyrocinchonic acid by means of hydrogen iodide, and found that it melted a t 190".A very similar result waq obtained by Weidel and Brix (Moolzatsh., 1882, 3, 612), who, however, used sodium amalgam as the reducing agent ; the acid they obtained crystallised in glistening, triciinic needles, melting a t 189'. Three years later, Otto and Beckurts (Bey., 1885, 18, 823) published the resnlts of a detailed investigation on thc reduction of pyrocinchonic acid. When this acid was reduced by hydrogen iodide in sealed tubes a t 220°, two acids were obtained, which could easily be separated by fractional crystnllisatioii from water; the more insoluble acid melted at 193--194',and seemed tobe identical with the acids obtained byv.Roser and Weidel and Brixrespectively, whilst the other melted a t 118--l2O0. Quite different results were obtained when sodium amalgam was used as the reducing agent; in this case, in addition to the acid melting at 193-194", tbere was produced an isomeric acid which melted witli- out decomposition att 240-241', whilst the acid melting at 118-120' mas not to be lound among the products of reduction. This last experiment gave resulls, therefore, quitc different from that in which hjdrogen iodide was employed as the reducing agent, but, on repeat- ing it, no trace of the acid melting at 240-241' could be detected amongst the products, which, on the other hand, contained acids melting a t 193-194' and 118-120'. An examination of the acid melting at 193-194' showed that when it was heated to 200' it was transformed into an anhydride melting at 186-187", which dissolved in hot water, and yielded, not the original acid, but the acid melting a t 240-241', which they found might be distilled without decomposition.They con- cluded, therefore, that these acids stood to one another in the same relationship as do fumaric and maleic acids, and they termed them dimethylsuccinic and isodimethylsuccinic acids respectively.* They found that when the acid melting a t 118-120' was heated to 160°, it decomposed with evolution of carbonic anhydride, and con- cluded that it was identical with the ethylmethylmalonic acid pre- pared in 1880 by Conrad and Bischoff (Annalen, 204, 143, lSZ), which meIt a t 118'. * Otto and Beckurts published their paper in 1885, two years before Wisliconus put forward his views as to the constitution of fumaric and maleic acids.Prom the views then held as to the constitution of the last-named acids, we may infer that Otto and Beckurts would have assigned the following constitutions to their acids : CH,.CH*COOH CH, CHgCOOH \ ~ . C O O H (See Leuckart, Ber., 18, 2334). CH,-hH-COOH ' CH,/ M. p. 193-194'. M. p. 2M-2413.THE SYMMETRICAL DIMETHTLSUCCINIC ACIDS. 255 I n 1886, Bischoff and Rasch (AnnuZen, 234, 54) prepared a sym- metrical dimethylsuccinic acid synthetically by three methods, which may be briefly described as follows. 1. By the action of methylic iodide on the sodium derivativc of ethylic propenyltricarboxylate, according to the equation CH,*vH*CNa(COOEt), + CHJ = CH,*~H*C(CH,)(COOEt>z + NaI, The oil formed was hydrolysed by means of alcoholic potash, and the tricarboxglic acid thus obtained was heated at l G O o until the evolution of gas had entirely ceased.2. By hydrolysis of ethylic dimethylacetosuccinate (prepared by the action of ethylic a-bromopropionate on the sodium deriva- tive of ethylic methylacetoacetate) by means of alcoholic potash. 3 . By the action of methylic iodide on the disodium derivative of ethylic acetylenetetracarboxylate, according to the equation COOEt COOEt CH3* Q (C 0 OE: t) 2 + 2CH31 = 2NaI + $lNa(COOEt), CNa( C OOE t)z CH3*C (GO OE t) The oil formed was hydrolysed by means of potassium hydr- oxide, and the tetracarboxylic acid obtained was heated at 170' until the evolution of gas had entirely ceased.They found that the dimethylsuccinic acid obtained by either of these methods melted a t 187', and that on being heated to its melting point it lost water, and yielded an anhydride melting at 87". These results were fully confirmed by Leuckhart (Bey., 1885, 18, 2344), who prepared the acid synthetically from ethylic methyl- malonate and ethylic a-bromopropionat,e. He found that i t melted at 188-189", and a t that temperature was converted into an snhy- dride melting a t 78-81", which, with hot water, yielded, besides the original acid melting at 189O, an isomeride melting at 121-122"- The last-named acid, although it resembled in some respects, such a s crystalline form and solubility, the acid melting at 118-UO", obtained by Otto and Beckurts by the reduction of pyrocinchonic acid, differed from i t in that i t might be distilled apparently without change.It will be observed that Leuckhart's results were quite incompatible with those of Otto and Beckurts ; matters were? however, consider- ably cleared up in the following year, when Otto and Rossing pub- lished a remarkable paper (Bey., 1887, 20, 2737), which contained an, ent,ire refutation of the conclusions arrived a t by Obto and Beckurts two years previously. They now found that their dimethylsuccinic: acid melting at 193-194" is not changed, on heating t.0 200°, into an256 BONE AND PERKIN: anhydride melting at 186-1887", which with water yields '' iso- dimethylsuccinic acid " melting at 240-5241', but, on the contrary, like Bischoff's dimethylsuccinic acid, it was converted into an anhydride melting a t 86-87', which with water yielded the original acid again.The acid, when treated with acetyl chloride, was con- verted into a mixture of two anhydrides, one of which melted at 86", and the other at 38', the last-named, with water, again yield- ing the original acid melting a t 195'. Furtlier, they found that the acid melting at 121', which Otto and Beckurts had obtained by the reduction of pyrocinchonic acid, did not decompose at 180" with evolution of carbonic anhydride, and, therefore, could no longer be considered as ethylmethylmalonic acid ; on the contrary, it was converted by acetyl chloride into an anhydride melting at 87', which with water yielded a mixture of two acids melting at 195' and 121' respectively.They concluded, therefore, that both these acids were dimethylsuccinic acids. In 1888, Zelinsky (Rer., 1888, 21, 3L60) prepared two symmetrical dimethylsuccinic acids by the hjdrolysis of aa-diinethylcyanosac- cinate (obtained by the action of potassium cyanide on ethylic a-bro- mopropimate) hy means of concentrated hydrochloric acid. One acid melted at 192', and was almost insoluble in cold water ; the other melted at 123-124', and was fairly soluble in water. Both acids, on distillation, were transformed into the same anhydride, melting at 87', which dissolred in water yielding the lower melting acid. He proposed the following constitutional formuh f o r these acids :- p 3 H-7 *C OOH H*F *C 0 OH H*Y*COOH ? COOH*F*CH, CH3 CH, B-F'umaroYd. M.p. 192". a-Maleino'id. M. p. 123'. I n 1890, Bischoff and Voit (Ber., 1890, 23, 639) reinvestigated t,hese acids, their results in the main confirming those of ZelinskF. The two acids melted at 194' (para-acid) and 120" (anti-acid) respec- tively. At temperatures above 200°, both were converted into the Same anhydride melting a t 87"; this with water yielded a mix- ture of the para- and anti-acids. The para-acid, however, when heated with acetyl chloride, was converted into an anhydride melting at 38' (see Otto and Rossing), which with water yielded the para-acid again. On heating the anti-acid with concentrated hydrochloric acid at 180-190', it was transformed into its isomeride. In 1893, Crum Brown and Walker (Annulen, 274, 41) prepared the symmetrical dimethylsuccinic acids by the electrolysis of potas- sium ethylic methylnialonate. They found that the para-acid meltedTHE SYRIRIETRIOAL DIhIETHYLSUCCINIC ACIDS.257 at 1 9 3 O , and that its dissociation constant was K = 0.0208, whereas the anti-acid melted at 120-121°, and had the dissociation constant I( = 00138. The results of previous workers are given in tabular form on p. 258. As the descriptions of the properties o€ the acids obtained by various experimenters differ so widely, the authors determined to carefully re-investigate the subject, with the results described in this com- munication. They have prepared the symmetrical dimethylsuccinic acids in two ways, namely (l), by the hydrolysis of ethylic cra-dimethylcyanosuc- cinate with concentrated hydrochloric acid (Zelinsky's method), and (2) by the action of ethylic a-bromopropionate on the sodium de- rivative of ethylic methylmalonatc, subsequently hydrolysing the product with alcoholic potash, and then heating the tribasic acid thus obtained at 200" u n t i l the evolution of carbonic anhydride had entirely ceased (Leuckhart's metliod).In both casas, the authors obtained a mixture of two symmetrical dimethylsuccinic acids, which mere separated by fractional cry stallisation from water. The melting points of these acids, especially that of the fumarojid (trans-) acid, differed materially from those assigned to them by previous inresti- gators. When pure, the fumaro'id (trans-) acid melts at 209", and with acetyl chloride yields an anhydride melting a t 43", which by the action of water is reconverted into the trans-acid ; it must, therefore, be the anhydride of this acid ; further, this anhydride, on prolonged heating with acetic anhydride, is transformed into an isomeric an- hydride melting at 8 8 O , which, with watep, yields the cis-acid.The maleinojid (cis-) acid melts a t 129", and with acetyl chloride yields an anhydride melting a t 88", which with water is reconverted into the original acid, and must, therefore, be the anhydride of the cis-acid. Both acids, when heated for a long time a t 210°, or on distillation under atmospheric pressure, are converted into the cis-anhydride melting a t 88'. Each of the anhydrides, when pure, yields with water only one acid (not a mixture of acids as stated by some previous investigators) ; that melting a t 43" yields only the trans-acid melting a t 209", whilst that melting a t 88" yields the cis-acid melting at 129".The authors hare further shown that the cis-acid is almost entirely converted into t'he trans-acid when it is heated with concentrated hydrochloric acid in sealed tubes at 180' ; under similar conditions only a very small part oE the trans-acid is transformed into the cis- modification, by far the greater portion of it being recovered un- changed. Our results may be represented in tabular form as follows (p. 259).Y Date. 1869 1874 1878 1882 1882 1885 -- -- -- -- 1885 - 1887 -- 1888 - 1890 - 1893 - Investigators and References. -4 cids. m. p. of acids. Wislicenus (Ber., 2, 720) .................. - Liquid Weidel (Annulen, 173, 109) .............. Hydropyrocinchonic acid .....v. Hardtmuth (Anvtnlen, 192, 142) ... " Dimethylsuccinic acid" ...... v. Roser (Ber., 15, 2012) ................ " Hydropyrocinchonic acid".. . Weidel and Brix (Monrctrh., 3, 612) ... '' Hydropyrocinchonic acid" ... ----- --_.__ 170O 170' 190' 189' 193-194' ~ - - - ------- - -~------.-_I--__ ---- ----~----___--- -- -------- ---- - Otto and Beckurts (Be)'., 18, 825) ...... " DimethyIsuccinic acid" .... " Isodimethylsuccinic acid" ... 240-241 " Ethylmethylmalonic acid ..... 118--120 ---.._--- ____ ---- 1 ---- Leuckhart (Bey., 1 8 , 2344) ............... Dimcthyleuccinic acid ............ 1 188-189' Otto and Rossing (Bcr., 20, 2737) .... Dinicthylsuccinic acid ......... __------------I-- Zelinsky ( B e y ., 21, 3160) .................. a-maleinoid ......................... ---_1_- ---_.---- I ---- Bischoff and Voit (Ber., 23, 639) ...... Para- ........................... 123' j3-fumaroid ........................... I 192 1920 *-*-*I Anti- .................................. 120 Crum Brown and Walker (Annakn, Para- .................................. I 193' _ _ ~ ~ - - - - - --.---I--- Anti- .................................... I 1%-121' I 274, 41) m. p. of anhydride. Anhydride formation. I---- _------- - - -------- _-_ - - ------- ____ Maintained a t 200' 186-187' ----- -____ At 200' 79-81' ----- _--__ On heating to 200' 86-87' { With acetyl chloride 38' With acetyl chloride a7 } On distillation 87' ( At 200' _-_I_)_------ I a73 7 Acctsl chloride At 200' Anhjdridc + water.-----.,------ -.--_I_--- -- " Isodimethylsuccinic acid," m.p. = 240-241°. - -__I_--- Xixture of acids, m. p. 189' 195' acid. Do. Mixture of acids, m. p. 19.5' and 118--120°. ---__-__- and 1'?l0. ---_--__- Maleinoid acid. Mixture of para- and anti- acids. Para- acid. Mixture of para- and anti- acids. _-______- -THE SPhII\IETRICAL DIMETHYLSUCCINIC ACIDS. 259 FumaroYd (tvass) acid. Maleindid (cis) acid. With cone. HC1 at 180". M. p. = 209". ----- M. p. = 1 2 9 O . Insoluble in cold water. Fairly soluble in cold watcr. Trans-anhydride --- d Cis-anhydrid e. acetic anhydride. M. p. = 43O. On prolonged heating with M. p. - 88". E x P E R I 31 E N T.A L P A R T. PART I.-A. Preparation of the Symmetrical Dimethylsuccink acids from Bthylic ax-Dirnethylcyanosuccinate.The ethylic aa-dimethylcyanosuccinate used in these experiments mas prepared by the action of potassium cyanide on an alcoholic solution of ethylic a-bromopropionate, according to the method described by the authors in a previous paper (Trans., 1895, 67, 420). The first action of potassium cyanide on ef hylic a-bromopropionate consists in a replacement of the bromine by the cyanogen group, resulting in the production of ethylic a-cyanopropionate according to the equation CH,*CHBr*COOEt + KCN = CH,*CH(CN)*COOEt + KBr. Subsequently a part of the ethylic a-cganopropionate thus formed condenses with some of the unchanged ethylic a-bromopropionate, the result being the production of ethylic aa-dii72ethylcyunosuccilzsrttr, as follows. CH,*CH(CN)*COOEt + CH,*CHBr.COOEto = COOEt*C(CH,)(CN)*CH(CH,)*COOEt + HBr.The product, after distilling off the alcohol and extracting with ether in the usual manner, consists of a mixture of unchanged ethylic a-bromopropionate, ethylic a-cyanopropionate, and aa-di- methylcyanosuccinate, which are separated by careful fractiona- tion under reduced pressure (30-40 mm.). T'he ethylic a-bromo- propionate distils over between 77" and 85", and the ethylic a-cyaaopropionate between 103' and l l O o , whilst the dark-cdoured residue in the distilling flask consists for the most part of ethylic ax-dimethylcyanosuccinate. If the distillation be continued further, VOL. LXIX. U260 BONE AND PERKIN: a large quantity of a pale yellow oil passes over between 170" and 200"; this oil %as t.wice iractionated under a pressure of 80 mm., and the portion distilling between 195" and 200' was employed for the preparat io 1 1 of the symmetrical dimet hy lsuccinic acids.Hydrotysis of the OiZ.--The oil was mixed with about five or six times its bulk of concentrated hydrochloric acid in a large, round- bottomed flask, and to the mixture glacial acetic acid was added, until the oil j u s t dissolved. The whole was then heated on a sand bath in a flask fitted with a long glass tube, ground into the neck to serve as a reflus condenser; when a sample of the liquid no longer deposited an oil on being diluted with water, it was allowed to cool, wheii a large crop of white crystals separated, consisting for the most part of ammonium chloride. The liquid was then poured into a large basin, and evaporated nearly to dryness, first over a bare flame, and finally cn a water bath ; water was added to the residue, and the solution again evaporated down in the water bath, this time com- pletely to dryneas.In this way, a11 the acetic acid and the ethylic acetate formed during the hydrolysis was got rid of. The residue was finally dissolved i n hot water, when, on cooling, the solution deposited a greyish-white, crystalline mass of the crude acids ; this WAS separated from the mother liquor by filtration a t the pump, thoroughly washed with cold water, redissolved in hot water, boiled with animal charcoal, and filtered while hot. Tho filtrate, on standing, deposited a, crop of white crystals, which, after drying, melted at 207-208". After another recrystallisation from hot water, the substance melted a t 209'.On concentrating the filtrate on the water bath, a further quantity of an acid was obtained on cooliiig ; this acid, separated from the solution by filtration, and recrystallised, also melted at 209". The filtrate WAS repeaLedly extracted with pure ethei-, the ethereal solution dried over calcium chloride, and the ether distilled off. The thick, oils residue, which solidified on standing, was dissolved in hot benzene; the solution 011 cooliiig deposited crystals melting between 115" and 125". These were once more crjstallised from hot benzene, but no alteration i n the melting point occurred ; the acid was then dissolved i n hot, concentrated, hydrochloric acid, and 011 cooling this solution crystals separated melting a t 128 -130" ; after a second crystallisa- tion from hot, concentrated hydrochloric acid, the substance melted a t 129". The Acid melting a t 209" (Trans-dinzethylsuccinic a c i d ) .This acid was analysed, with the following results, which agree well with the empirical formula C6H,,04.THE SYMMETRICAL DI\IETHTLSUCCISIC ACIDS. 261 Found. r---h-- 7 I. 11. Calculated. Carbon.. .... 49'21 49.49 49.32 Hydrogen.. .. 7.12 6.73 6.85 Trans-dime thy Zszbccir~ic acid is only very sparingly soluble in cold, but readily in boiling water. It is almost insoluble in benzene or chloroform, either hot or cold, but is fairly soluble in alcohol or ether. Salts of the Acid.-To a neutral solution of the ammonium salt was added (a.) Ferric chloride. A reddish-brown precipitate of the ferric salt was immediately thrown down.( b . ) Copper suZphate. A greenish-blue and very gelatinous pre- cipitate was formed. (c.) Lead nitrate. A heavy, crystalline precipitate of the lead salt was produced; this was fairly soluble in hot water, and crystnllised out again on cooling. ( d . ) Silver ?Litrate. A white precipitate of the silver salt was formed, fairly soluble in cold water. (e.) Calcium chloride. When calcium chloride was added to a dilute solution of the ammonium salt, no precipitate was produced either in the cold, or even on boiling for a con- siderable time. When, however, a fairly strong solution of the ammonium salt was used, the calcium salt was immediately precipitated, even in the cold. We may here remark that the lead, silver, and calcium salts of the trans-acid, and especially the last-named, are decidedly more soluble than the corresponding salts of the cis-acid. The Acid melting at 129' (Cis-dimethylsuccirhic acid).This acid was analysed, with the following results. Found. Calculated for CsH1,,04. Carbon.. ........ 49.38 49-32 Hydrogen ....... 6.88 6.85 Cis-dimethylsucciiiic acid is fairly soluble in cold and readily in warm water, alcohol, or ether, separating rapidly from its aqueous solution when this is saturated with gaseous hydrogen chloride. It is more soluble in warm benzene and chloroform than the isomeric trans-acid. Its salts are very similar to those of the trans-acid, but the calciuw, lead, and silver salts are much less soluble in water than the corre- sponding salts of the trans-acid.u 2262 BONE AND PERKIN: Separation of the Dinzethylsuccinic Acids by means of their Calcium Salts. The marked difference in the solubilities of the calcium salts of tEc cis- and trans-dimethylsuccinic acids affords a, very convenient method of separating them, and of obtaining them readily in a state of purity. The method employed by the authors may be briefly described as follows. Calcium chloride was added to a cold dilute solution of the am- monium salts of the two acids, when, after a short time, a white precipitate of the calcium salt of the cis-acid was formed ; the whole was then gently warmed, and the precipitate collected with the aid of the pump, washed with a little hot water, and dissolved in hot con- centrated hydrochloric acid.On cooling, crystals of the cis-acid, melting sharply a t 1 2 9 O , were deposited. The filtrate from the first crude precipitate was then concentrated on the water bath, and the smalI precipitat,e which separated during the operation, consisting of a mixture of the calcium salts, removed by filtration. On proceeding further with the concentration, a very bulky precipitate came down ; this was separated from the mother-liquor with the aid of the pump and after washing with cold water, was dissolved in hot concentrated hydrochloric acid, On cooling, colourless crystals of the trans-acid meltiag at 204-209' were deposited ; after recrystallisation from water they melted at 209O. B.-Preparation of the Sy?nrnetrical Dirnethytsucci?zic acids from Ethylic Methylma lonate and Ethylic a- Bromopropionate.Forty-four grams of ethylic methylmaloiiate were mixed with a cold solution of 6 grams of sodium in 75 grams of absolute alcohol contained in a flask, and 45 grams of ethylic a-hromopropionate were carefully added. The mixture at once became hot, and sodium bromide began to separate. On heating the mixture in a water bath in a reflux apparatus for two hours, it became quite neutral; and on pouring the contents of the flask into water, a heavy oil separated. This was extracted with ether, the ethereal solution washed with dilute sodium carbonate solution and with water, dried over calcium chloride, the ether distilled off, and the dark-yellow, oily residue (60 grams) hydrolysed without further purification.Hydrolysis of the Oil.-The oil was slowly added to about twice its weight of pot.assium hydroxide dissolved in alcohol, and contained in a large flask ; there was a considerable development of heat, so that i t was necessary to cool the flask well to prevent loss by frothing ; the whole Fas then heated for six hours in a reflux apparatus on the water bath. A potassium salt soon separated, and after the conclusion of the hydrolysis, water was added to the liquid until this had dissolved,THE SYMMETRICAL DIMETHY LSUCCINIC ACIDS. 263 the solution was poured into a n evaporating basin, and concentrated on a water bath until all t.he alcohol had been driven off. The alka- line liquid YJRS then cooled, carefully acidified with dilute hydro- chloric acid, and repeatedly extracted with pure ether ; the ethereal solution was dried over calcium chloride, the ether driven off, and the oil which was left heated in an oil bath at 200" until the evolution of carbonic anhydride entirely ceased.The oily residue was then dissolved in hot water, the solution boiled with animal charcoal, and filtered whilst hot ; on cooling, the filtrate deposited a mass of white crystals, which mere separated from the mother liquor by filtration, and washed well with cold water. On recrystallising these from hot concentrated hydrochIoric acid, they melted a t 209"; a second re- crystallisation from concentrated hydrochloric acid did not alter the melting point. This acid on analysis yielded the following results. Found. 7 r--'h-, I. 11.Calculated for C6111004. Carbon.. ...... 49*2:3 49.55 49-32 Hydrogen.. .... 6.75 6.92 6.85 and was identical in all its properties with the tmm-acid melting at the same temperature obtained from ethylic aa-dimethylcyano- succinate as described in the preceding section. The filtrate, after removal of the acid melting at 209' was con- centrated somewhat, and then repeatedly extracted with pure ether, t,he ethereal solution dried over calcium chloride, and the ether dis- tilled off; a small quant,ity of a viscous oil was left, which, on standing, solidified almost entirely. This solid mass was ground up and washed with cold benzene to remove any oily matter, and the residue recrystallised from hot concentrated hydrochloric acid ; in this way an acid was obtained melting at 125-127', which, after a second recrystallisation, melted at 129', and was identical iu all its properties with the cis-acid melting at 130" obtained from ethylic as-dimethylcyanosuccinate.This acid on analysis yielded the follow- ing results. Found. Calculated. Carbon .............. 49.30 49.32 Hjdrogen ............ 6.67 6-85 The amonnt of cis-dimethylsuccinic acid obtained by the method above described is comparatively small, not more than about one- fourth of the weight of the trans-acid formed at the same time. Behaciozcr of t h e Dimethylsuccinic Acids on Prolonged Heating with Concentrated Hgdrochloric acid in Sealed Tubes at 180". 1. About 5 grams of the tmns-dimethylsuccinic acid (m. p. 309") were sealed up in a tube with about 40-C.C. of concentrated hydro-264 BONE AXD PERKIN: chloric acid, and heated at 180" for eight hours.On cooling, the crystals: which had separated were collected, well washed with water, and dried a t 100" ; they melted a t %00-204', and, after recry- stallisation from water, a t 208". The mother liquor was extracted with ether, the ethereal solution dried over calcium chloride, and the ether distilled off, when a very small quantity of an oily substance was left; this partially solidified on long standing, and the solid, after drying on a porous plate, was found to melt a t 117-124'. It probably consisted of the cis-acid (m. p. 129O), but the amount was exceedingly small, nearly the whole of the trans-acid being recovered unchanged. 2. The cis-dimethylsuccinic acid (m. p.129') was heated in a tube with concentrated hydrochloric acid under pressure, as described in the previous experiment ; the crystals which separated on cooling were collected, washed with water, and dried at 100". They con- sisted of crude trans-dimethylsuccinic acid and melted between 190" and NO', and, after recrjstallisation from water, a t 201-205°. The mother liquor was extracted with pure ether, and, as iii the case of the previous experiment, a very small amount of the unchanged cis- acid was obtained. Thus it is evident that, on heating the trans-acid under pressure with concentrated hydrochloric acid a t 180", it is only partially trans- formed into the cis-acid, the greater part of i t being unchanged, and that when the cis-acid is subjected to the same treatment, it is for the most part converted into the trans-niodification.PART II.-THE ANHYDRIDES OF cis- AND Tran,S-DIMETHYLSUCCINIC ACIDS. A. Behatiiour of the Dimethylsuccinic Acids on Prolonged Heating at 210-215O. 1. One gram of the tmns-acid (ni. p. 209") was heated i n a test- tube immersed in an oil bath, tLe temperature of which was raised fairly rapidly to about l i O o , and afterwards gradually to 210'. At about 205O, the substance began to sublime without melting, and con- densed on the upper and cooler portion of the tube in beautiful, asjmmetric needles, which, after being spread on a porous plate, melted a t 195-198'. When the temperature of the bath had risen to 210-211', the substance melted, and water was given off; the bath was now kept at 210-215" for half an hour, when the evolution of steam seemed to have ceased entirely.As the contents of the test- tube solidified on cooling, i t was broken, and the solid mass spread on a porous plate ; it was found to melt roughly between 6 5 O and 85'. When treated in the cold with a dilute solution of sodium carbonate,THE SY MMETRTCAL DIMETHY LSUCCINIC ACIDS. 2 65 no effervescence could be detected, showing, therefore, that the aeid had been completely converted into an anhydride. It was then dis- solved in pure ether, and the ether allowed to gradually evaporate, when beautiful, colourless crystals were deposited melting at 86-86", and identical with the anhydride prepared from the cis-acid by treat- ment with acetyl chloride. It dissolved readily in hot water, and after the solution had been cooled and saturated with gaseons hydrogen chloride, the cis-acid separated in crystals melting a t 2.One gram of the cis-acid was subjected to the same treatment as has been described in the previous experiment ; at a temperature rather above 200°, water was readily given off; the crude product solidified on cooling, arid then melted between 70' and 80'. When treated with a cold, dilute solutioii of sodium carbonate, there was no evolution of carbonic anhydride, indicating that the t,ransformatio ti into anhydride was complete. The solid mass, which, after recrys- tallisatiun from absolute ether melted at 87", was dissolved in hot water, the solution cooled, and saturated with gaseous hydrogen chloride, when the cis-acid separated in crystals melting at 128-129".Both the dimethylsuccinic acids, therefore, when heated a t 810-215°, are converted into the sawie anhydride, which must be the anhydride of the cis-acid, as it yields this acid when treated with water. 126-1 28'. B. Beliauiour of the Dimethylsuccinic acids o n Distillation a t the Ordinary Atnzospheiic P1-esswe. 1. Two grams of the tram-acid were distilled in a small flask into which a thermometer was inserted; a heavy liquid came over be- tween 230' and 235O, which solidified on cooling. The solid mass melted gradually between 70' and 82", aid when treated in the cold with a dilute solution of sodium carbonate, a small portion dissolved with egervescence, and from this solution a small quantity of an acid melting a t about 195' was obtained.The anliydricle, after t,reatinent with sodium carbonate, and drying on a porous plate, melted a t 83-86", which was raised to 88' by recrystallisation from absolute ether. This anhydride, with water, yielded the cis-acid melting a t 2. On distilling the cis-acid in the manner described iu the pre- vious experiment, a liquid passed over between 230' and 235', which completely solidified on standing. The solid mass, which melted be- tween 78' and 85", showed no signs of effervescence when treated. in the cold with a dilute solution of sodium carbonate, and, after re- crystallisation from absolute ether, melted a t 88' When heated with water, i t yielded the original cz's-acid again. 12 7-1 29'.266 BONE AND PERKIN: Thus, on distillation under ordinary pressure, both acids are con- verted into the cis-anhydride ; in the case of the twmzs-acid, however, t.he conversion is incomplet,e, a portion OE the acid distilling over apparently unchanged.C. Distillation of the Trans-acid wder Reduced Pfressure. This experiment was undertaken with a view of ascertaining IT' hether the trans-acid on distillation under reduced pressure would yield the same anhydride as it did when distilled under ordinary pressure; it was found, however, that it sublimed very readily under reduced pressure, and apparently for the most part unchanged. The sublimate dissolved very readily in dilute sodium carbonate with effervescence, but it had no constant melting point ; a small portion melted at a temperature as low as 40°, but by far the greater part of it showed no signs of melting until the temperature had risen to 190°, when it gradually melted between 190° and 198'.It seems probable, therefore, that when the acid is sublimed under these con- ditions it is to a small extent converted into an anhydride, dthougb I\ e were unable to isolate a pure anhydride from the sublimate. 1). Behaviour of the Acids on ?ieatiitg with Acetyl Chloride or Acetic An h ydyid e. 1. About 5 grams of the tyans-acid were mixed with about 7 C.C. of acetyl chloride, and the whole gently heated in a small reflux appa- ratus for 10 minutes, until the whole of the acid had just dissolved ; it was then placed in a vacuum over solid potash, when tlie excess of acetyl chloride rapidly rolatilised, leaving a yellowish-white crystal- line mass, which was then dried on a porous plate in a vacuum.The crude product had no constant melting point, part meltsd between 30' and 40°, but quite half of it did not melt until the tempera- ture had risen to 160°, indicating that a considerable portion of the original acid had remained unchanged. It was accordingly mixed with more acetyl chloride, and heated gently in a reflux apparatus on a sand bath for half an hour ; the product, isolated as described above, now melted sharply at 43', The substance was then heated for about 20 minutes in a reflux apparatus on a sand bath with acetic anhydride, the excess of acetic anhydride distilled off under reduced pressure, and the liquid residue placed in a vacuum over solid potash, where, after standing several days, it solidified to a pure white mass ; this was spread out on a porous plate and left in a vacuum over solid potash, after which it melted very sharply at 43'.The substance was analysed with the following results,THE SYBIMETRICAL DIMETHYLSUCCINZC ACIDS. 267 Found. Calculated for C6H,0,. Carbon .......... 55.82 56.25 Hydrogeu ........ 6.41 6-25 On dissolving this anhydride in hot water, and cooliiig the solu- tion, white crystals separated, which, after drying on a porous plate, melted a t 208O, and were in all respects identical with trans-dimethyl- succinic acid. The substance melting a t 43" is, therefore, the anhy- dride of trans-diniethylsuccinic acid. 2. Five grams of the trans-acid were mixed with 15 grams of acetic anhydride, the whole heated on the sand bath for three hours in a reflux apparatus, and then frationally distilled under a pressure of 30 mm.; after the greater part of the acetic anhydride had come over, the temperatnre rose rapidly to 160°, when the receiver was changed, and the portion distilling over between 160" and 180' col- lected separately, and placed in a vacuiim over solid potash. After the substance had become solid, the crystals were dried on a porous plate in it vacuum, when they melted between 40" and 50", mostly, however, in the neighbourhood of 43'. A. portion of the substance was treated in the cold with a dilute solution of sodium carbonate, but not, the slightest effervescence could be detected, showing that no free acid was present. This anhydride was again heated with acetic anhydride for three hours, and the treatment described above re- peated.Finally we obtained the cis-anhydride melting a t 88", which with water yielded the cis-acid melting at 129'. From this experiment, it seemed probable that the ti-ans-acid, when heated with acetic anhydride, yields first of all its own anhydride (m. p. = 43O), but that on prolonged heating withaceticanhydride this is converted into the cis-anhydride melting at 88". This conclusion was confirmed as follows : A small portion of the trans-anhydride melting a t 43O, obtained in D 1, was heated for several hours with acetic anhydride in a reflux apparatus, the excess of acetic anhydride distilled off under reduced pressure, and the residual liquid placed in n vacuum over solid potash. After several days, the liquid de- posited crystals, which when dried in a vacuum on a poroua plate, were found to melt a t 87-88', and with water yielded the cis-acid. Thus the tram-anhydride, on prolonged heating with acetic anhydride, is converted into the cis-anhydride. 3. Fire grams of the cis-acid mere heated with acetic anhydride for three hours on a sand bath in a reflux apparatus, the excess of acetic anhydride distilled off under reduced pressure, and the residual liquid placed in a vacuum over solid potash. On long standing, the liquid crystallised, and the crystals, after drying on a porous plate, melted at 87", and on being dissolved in hot water yielded the cis-acid melting a t 128-129'.268 BONE AND PERKIN: The c;s.anhydride (m. p. 88') was analysed with the follo~virig re su 1 ts. Found. Calculated for C6H803. Carbon . , .. ,.. . . . 55.99 56 25 6-85 Hydrogen . . . . . . . . 6.60 4. The cis-acid was dissolved in a slight excess of acetyl chloride, the solution gently warmed on the sand bath in a reflus apparatus for 20 minutes, and placed over solid potash in a desiccator, which was then exhausted ; the acetyl chloride was thus rapidly volatilised, and the residue crystallised on standing. The crystals, after drying in a vacuum on a porous plate, were found to consist of the cis-anhydride melting at 88'. Owens College, Hunchester.

ISSN:0368-1645    

DOI:10.1039/CT8966900253

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

268 BONE AND PERKIN: XXVII. -Note o n the act1 -Dimethylgluta?ic acids. By WILLIAM ARTHUR BONE and W r L L I m HENRY PERKIN, Jun. IN a paper published last yeay (Trans., 1895, 67, 416), the authors described as aa,-dimethylglutaric acids two acids meltinq a t 127" and 105-107" respectively, obtained, together with trirnethylsuccinic acid (m. p. 152O), by the hydrolysis of the product of the action of ethylic a-bromisobutyrate on the sodium derivative of ethylic a-cyano- propionatc, in alcoholic solution. I n the same communication, they stated that Auwers and Thorpe (Be?.., 1895, 28, 623) had shown that the acid melting at 105-107" was not a homDgeneous substance, but a mixture in molecular proportion of cis- and Iraizs-xa,-dimethyl- glutaric acids, melting at 127' and 140-141' respectively, but up to the time of the publication of their results the authors have uot been able to confirm this opinion.Since that time, however, Auwers and Thorpe have published fuller details of their work (Annulen, 1893, 285, 31Oj, and the authors have accordingly subjected the acid i n question to a further examination, with the result that they are able to substantiate the conclusions of these investigators. The acid meltiiig at 105-107O is in many respects a remarkable substance ; it may be recrystdlised from various solvents, such as ben- zene or concentrated hjdrochloric acid, without any change in its melting point,. The authors fractionally crystallised the no]-ma1 calcium salt, obtained by adding excess of calcium chloride to a dilute solu- tion of the ammonium salt, and on regenerating the acids from the successive fractioris by separately diseol ving them in concentrated hydrochloric acid, they were found to melt within 2" of the originalTHE a~,-DIMETHYLGLUTARIC ACIDS. 269 acid.Auwers and Thorpe found, however, that if the acid calcium salt, prepared by adding the calculated quantity of calcium carbonate to an aqueous solution of the acid, was fractionally crystallised, two calcium salts could be obtained, one being 1-ery much less soluble than the other. On regener- ating the acids, the more insoluble salt yielded t~a.~~.~-dirnethyl~luta~ic acid, melting at 140--241°, and the other cis-dimethylglutaric acid, melting at 127". The authors are able to confirm this result, and have resolved the acid, melting a t 105- 107", into its two constituents, by the following method, also due to Auwers and Thorpe ; it depends on the fact that cis-dimethylglutaric acid readily yields an a n bydride on treatment pith acetyl chloride, whilst the trans-acid remains unchanged.The acid, melting at 105--107O, was mixed with half its weight of acetyl chloride in a test-tube, the mixture gently warmed for about 10 minutes, until the evolution of hydrogen chloride had ceased, and the substance had completely dissolved, and the solution was then left in a vacuum over solid potassium hydroxide, until the whole of the acetyl chloride had volatilised. The solid residue thus obtained was quickly washed with benzene, whereby the anhydride of the cis- acid was completely removed, leaving behind the unchanged trans- acid, which, after recrystallisation from hot, hydrochloric acid, was found to melt a t 140-141'.On leaving the filtrate in a warm place until the benzene had evaporated, an oily liquid was left, which, on long standing, becanie semi-solid ; it dissolved readily in hot, concentrated hydrochloric acid, and on cooling the solution crystals of cis-dimethylglutaric acid, melting a t 125-127", separated. The mother liquor was extracted with pure ether, and after drying the ethereal solution over calcium chloride and distilling off the ether, a residue was left, which was recrystallised from benzene ; in this way a small quantity of ail acid, melting between 100' and l l O o , was obtained. On grinding together equal portions of cis- and trans-dimethylglutaric acids in a mortar, a substance was obtained which had an almost constant melting point, namely, 104-108', resembling in every way the acid melting a t 105-107", which the authors described in their former paper. No separation could be effected by this method. Owens College, Manchesta-.

ISSN:0368-1645    

DOI:10.1039/CT8966900268

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

270 XXVITL-Cis- and trans-M:thyZisoii.,.oz~ylsv,ccilzic acid. By WTLLIABI HENRY BENTLEY, WILLIAM HENRY PERKIN, jnn., and JOCELYN FIELD THORPE. THE action of the ethereal salts of a-bromo-acids of the fatty series on the sodium compounds of ethylic malonate and its derivatives may take place in two different w a p . 1. The action may proceed direct'ly with the simple separation of sodium bromide, thus :- R*CHz*CHBr*COOCzH6 + XCNa(COOC2H5)2 = R*CH2*CH*(COOC2H5)*CX(COOC2H,), + NaBr, forming an ethereal salt of EL tribasic acid, which, on hydrolysis and subsequent elimination of COz, yields a derivative of succinic acid, thus :- R*CHz*CH* (CO 0 H) .CX( CO OH)? = ROC H2*C H ( C 0 OH) C HX* CO 0 H + C 0,- 2. The reaction is an indirect one. I n this case an unsaturated ethereal salt is first poduced by the removal of hydrogen bromide, R*CH,*CHBI=*COOC,H, = R*CH:CH*COOC2H5 + HBr, and thia unsaturated etherea'l salt then condenses with the sodium derirative employed, as follows, (COOCzH5)zCXNa + ItCH:CH*COOC2H, = (CO 0 C,H5)zCX*C HR*CHNWCOO C2H.5, yieldinga sodium derivative of an ethereal salt from which the corre- sponding tribasic acid may be isolated by hydrolysis. This tribasic acid then readily decomposes on heating with formatioa of a deriva- tive of glutaric acid, (COOH)zCX*CHR.CH,*COOH = COZ + C 0 0 H* CHX* C HR*CHP* C 00 H.The direction in which the action proceeds depends generally on the conditions of the experiment# ; thus, when ethylic a-bromisobu- tyrate is digested with ethFlic methyl malonnte in alcoholic solution (Bischoff and Mintz, Ber., 1890, 23, 649)) an ethereal salt of the formula (COOCzH,)zC (CH,l*CH,*CH( CH,) *COOC2H5 is produced, from which, by hydrolysis and elimination or" COP, the two sym- metrical dimethylglutaric acids are obtained ; whereas if the experi- meut be performed in xylene solution at 200", the action proceeds directly with separation of sodium bromide and formation of ethylic tri- met hg lethane tricarbox ylate, (C 0 0 C2H5) ?C ( CH3)*C (C H3) z*C 0 0 C2H5,CIS- AND TRASS-METHPLISOPROPrLSUCCINIC ACID.27 1 from which trimethylsuccinic acid is readily produced (Bischoff, Ber., 1891, 24,1078; Bredt and Helle, Inaugural Dissert., Bonn, 1893, 31 ; Auwers, Annalen, 1895, 285, 260 and 301). During some experiments on the action of ethylic bromomethyliso- propylacetate, (CH3),CH-CBr(CH3)*COOC2H6, on the sodium deriva- tive of ethylic malonate, on which one of us has been engaged for some time, it was tound to be exceedingly dif€icult to decide whether the substances obtained were derivatives of succinic, or of glutaric acid,* and, in order to throw some light on this point, a seriesof experiments on the action of the next lower homologue, namely, ethyIic brornisopropylacetate (ethylic a-bromisovalerate) on the sodium derivative of ethylic methylmalonate were instituted, with the results described in this commnnicatioo.If this decomposition proceed as indicated in equation I, the end product would be methylisopropylsuccinic acid, (CH,) ,CH*CH ( C 00 H) *C H ( CH,).C 0 OH ; if, however, hydrogen bromide were eliminated, and subsequent con- densation took place, hhe end product would be trimethylglutaric acid, COOH*CH2*C(CH,)2*CH(CH3)*COOH, and i t would be easy to dis- tinguish between these substances, since, in the former case, the acid would contain two asymmetric carbon atoms, and be capable, there- fore, according to the Le Bel-van't Roff theory, of existing in two C3H,*yH*COOH CH3*CHGOOH' and distinct inactive modifications, namely, cis, , methylisopropylsucciniu acid ; whereas the C,H,* H C 0 0 H COOH*CH*CH, t runs, above trimethylglutaric acid, containing only one asymmetric carbon atom, is capable, according t,o the same theory, of existing in one inactive modification only.The action of ethylic a-bromisovalerate on the sodium derivative of ebhylic methylmalonate was first carried out in boiling xylene s o h - trion in the usual manner, the purified ethereal salt obtained was hydrolysed, and the acid produced heated at 200" until all evolution oE carbonic anhydride had ceased.From the product, two well charncterised acids melting a t 174-175O and 124--125', were isolated, which, from the study of their behaviour, were clearly shown to be stereoisomeric ; tbese acids, therefore, are evidently the cis- and tl.u.ns-methylisopropylsucoinic acids, which are formed by the direct action of ethylic a-bromisovalerate on the sodium derivative of ethylic methylmalonate, according to equation 1. Cis-Meth?/liisoprop?llszicciizic acid diff em from the trans-acid in being * It is hoped that the Peaults of these experiments, which are complete, will be ready for publication shortly.2 72 BBNTLEY, PELZKIN, AND THORPE : readily volatile with steam when heated with a 50 per cent.solution of sulphuric acid. It melts a t 125-12fi0, and, when treated with hydrochloric acid, is partially converted into the trans-modification melting at 174-175'. When heated with acetic anhydride, or when distilled, the cis-acid yields a liquid anhydride, and this, on treatment with water, is reconverted into the original acid. (?), melts a t 160°, (C H3) H* C 0 0 H C H3-CH*C 0 *N H* CsH, The cis-anilic acid, and is different from the anilic acid of the tram-acid, although both yield the same m i l when heated at 800'. Trans-methylisopropylsszccciraic acid is much less soluble in water than the cis-acid ; i t melts at 174-175', and when heated with hydrochloric acid at 180°, is partially converted into the cis-acid.When distilled under reduced pressure, or heated with acetic anhydride, the trans-acid yields a solid anhydride melting a t 46O, which by treatment with water is reconverted into the same :wid. If, however, this anhydride be boiled in a reflux apparatus for some time under ordinary pressure, and then distilled, the distillate is found to consist of the cis-anhydride ; the conversion of the trans- into the cis- acid being complete under these circumstances. The trans-anhydride, 011 treatment with aniline, gives the anilic acid of the trans-acid, and this, when heated a t 200°, yields the anil of the cis-acid. We next studied the action of ethylic a-bromisovalerate on the sodium derivative of ethylic methylualonate in alcoholic solution, and in this case again, curiously enough, working up the product in the way described in the body of the paper, we were only able to isolate c is-methylisopropylsuccinic acid, the trans-modification which should have been formed being apparently converted in50 the cis-acid under the conditions of hydrolysis employed in tlhis particular instance.Lastly, i n order that there might be no doubt as to the constitution O F these acids, we have pi*epared them in the following way. I n the first place, the sodium derivative of ethylic malonate was digested with ethylic a-bromisovalerats, when a good yield of an ethereal salt was obtained, which has already been described by Roser (Annalen, 1883, 220,2771, and which is undoubtedly e13iylic isopropyl- ethane tricarbox yla te, (CH,) ,CH* CH (C 0 0 C,H,)*C H (C 0 0 CzH5) 2.I n order to be certain of the constitution of this ethereal salt, it was hydrolysed, and the tribasic acid formed heated a t 200°, whereby i t was converted into isopropylsuccinic acid, ( C H3) C H C H ( C 0 0 H ) C H C 0 0 H , r2 result which confirms Roser's experiments. sodium and methglio iodide in alcoholic solution, The ethylic isopropylethanetricarboxylate was now treated withCIS- ASD TRANS-METHYLlSOPROPYLSUCGINIC ACID. 273 (COOEt)2CNn*CH(COOEt)*CH(CH3)2 + CHJ = (COOEt),C (CHJ *CH( COOE tl)*C H(CH,) + NaT. The ethereal salt thus formed mas identical with that obtained in the previous experiments, since, on liydrolysis and subsequent elimination of carbon dioxide, a mixture of acids was obtained from which cis- and trans-methylisopropylsnccinic acid, melting a t 174- 1 7 5 O and 124-125' respectively, were readily isolated.These acids differec! in no respect from those produced in the manner previously described. The latter method gives by far the best yield of these acids ; it is therefore placed first in t,bis paper, and described i n most detail. E X P E 1: I M E K T A L PA R 1'. I, Et h y 1 ic l ~ o p ~ o p y let hanetricarboxy late, CH, COOC,H, c H? H < ~ H (COO c , H ~ ) ,- In preparing this substance, 23 grams of sodium were dissolved in 250 grams of absolute alcohol and 160 grams of ethylic malonate added, when the sodium derivative separated as a white, gelatinous precipitate.The flask containing the mixture was then connected with a reflux condenser, heated on the water bath, and 209 grams of ethylic a-bromisovalerate added in small portions a t a time t o the boiling solution. The action was not violent, although sodium bromide separated immediately on adding the bromisovalerate ; the boiling was continued for three hours, after which the product was neutral. The alcohol was, as far as possible, distilled off, this being most quickly and completely effected by placing the flask in the boiling water bath, bumping being prevented by suspending a piece of string from the neck of the flask, SO as t o hang in the boiling liquid. When the alcohol had ceased to come over, the residue in the flask was mixed with water, the oil separated, the aqueous liquor extracted four times with ether, tIhe ethereal solution dried over calcium chloride, and the ether distilled off.The oily product was then fractionated under reduced pressure (37 mm.) ; a small portion boiled below 20O0, but the chief portion came orer between 180' and 182'. The weight of this fraction was 186 grams, or 66 per cent. of the theoretical yield of ethylic isopropylethanetricarboxylate. 0.1510 gave 0.3209 CO, and 0,1155 H20. C = 57.96 ; H = 8-49. C,,H,,O, requires C = 58.33.; H = 8.33 per cent. I n order to prove that this ethereal salt has the constitution repre- sented by the formula at the head of this section, 20 grams of the274 BENTLEY, PERKIN, AND THORPE : pure substance were hyclrolysed by boiling with an alcoholic solution of potash for two hours, evaporating the product three times with water, acidifying, and extracting several times with ether ; after dry- i n g over calcium chloride and evaporating the ether, the oily acid was heated at 200' until the evolution of gas had ceased, and the pro- duct, which rapidly solidified and melted indefinitely at 90-llO", was recry stallised from hydrochloric acid un ti1 the melting point became constant at 116-117".02297 gave 0.4408 CO, and 0.1555 H,O. C,H,,O, requires C = 52.52 ; H = 7.52 per cent. A careful examination of this acid proved conclusively that i t is identical with the isopropylsuccinic acid obtained by Hlasiwetz and Grabowski (Anitaleit, 1868, 145, 207), from the fusion of cnmphoric acid with potash, and which Roser (Annulen, 1883, 220, 272) has shown to be identical with the acid obtained by the hydrolysis of e t hylic isopropylace tosuccinate with potash, C = 52-33 ; H = 7.53.C,H,*C(C,H30) (COoc,H,)'CH,.COOC,Ha + 3KOH = C3H7*CK(COOK).CH2*COOK + 2C,H5*OH + CH3*COOK. Not only do the melting points of these acids coincide, but on com- paring the anilic acid produced from the acid obtained by us with that prepared from a sample of isopropylsuccinic acid, which had been obtained by fusing camphoric acid with potash, they both melted at 145O, and were identical in all respects. This anilic acid, which does not appear to have been previously prepared, is readily obtained by mixing isopropylsucciiiic anhydride with aniline in benzene solution; i t crystallises from a mixture of light petroleum and ethylic acetate i n large, glistening plates melting at 145O.N = 6.00. A nitrogen determination gave the following figures. 0.1991 gave 9.9 C.C. moist nitrogen at 12' and 760 mm. On heating this anilic acid in a sulphuric acid bath at 200' for half an hour, it loses water, and is converted i n t o the anil. This compound crystallises from light petroleum (80-looo) in microscopic needles melting at 213'. The same substance was obtained both from the anilic acid prepared from the synthetically produced isopropylsuccinic acid, and from that prepared from the isopropylsuccinic acid from camphoric acid. C,,H,,N03 requires N = 5.96 per cent. Et 12 ylic Isoprop yl methylsthanet m'curbox y 1 cite, 9H3> CH.C B <coo C'*E CH3 C(CH3) (COOC,H,),* This was prepared as follows.13.3 grains of sodium were dis- solved in 133 grams of absolute alcohol, and 166 grams of ethylicCIS- AND TRANS-METHY LISOPROPY LSUCCINIC ACID. 275 isopropylethanetricarboxylate added ; the mass became yellow, but no separation of the sodium derivative was observed. The flask was fitted with a reflux condenser, the solution cooled, and 95 grams (an excess) of methylic iodide added in small portions at a time through the condenser tube ; tlie action was very violent, the tem- perature rising rapidly until the liquid boiled vigorously. I n order to complete the action, the mixture was heated on the water bath for two hours, when i t was found to be neutral ; the product was then heated as usual, the alcohol being distilled off, water added, and the oil extracted with ether.This oil, which was deep red, owing to the presence of free iodine, was fractionated under reduced pi'essure (80 mm.), when the principal portion distilled between 200" and 210" ; the weight of this fraction wa8 144 grams, or 83 per cent. of the theoretical quantity. An analysis gave the following results. 0,2197 gave 0.4818 CO, and 0.1707 H,O. C = 59.81; H = 8.63. C,,H,,O, reqnires C = 59-60; H = 8.60 per cent. a j r d d y s i s of Ethylic Isopropylmethylethanet~ica~boxylate by means of A1 coh o 1 ic Pot ash. The pure ethereal salt (144 grams) was boiled in a reflux apparatus with an alcoholic solution of one and a half times the calculated quantity of potash for four hours, the product diluted with water, and evaporated on a water bath to a small bulk until quite free from alcohol.On acidifying this potassium salt with hydrochloric acid, it was noticed that there was a marked evolution of carbon dioxide, which indicated that the tribasic acid, which should result from tlie direct hydrolysis of the ethereal salt, had either during the hydrolysis or on acidifying with hydrochloric acid, been at least partially decom- posed into dibasic acids with loss of carbon dioxide, and this was afterwards found to be the case. On standing, an oil, which rapidly solidified, separated on the surface of the strongly acid liquid. The whole was then transferred to a separating funnel and extracted Peven times with pure ether, the ethereal solution dried over calcium chloride, filtered, and evaporated, when a slightly yellowish oil remained, which partially solidified on standing.This product was heated in an oil bath at 200°, but only a, small quantity of carbon dioxide was evolved, confirming the conclusion arrived at above, that the tribasic acid had been for the most part already decomposed. The light brownish residue which contained cis- and trans-methyl- isopropylsuccinic acids was then treated by the method described in the next paragraph. Sepnration of cis- and trans-Meth~ Eisoivropylsuccinic acid. Method 1.-The method used by us for the separation of these VOL. LXIX. X276 BENTLEY, PERKIN, AND TI-IORPE : acids is similar to that employed by Hell (Bey.: 1877, 10, 2229) f o r the isolation OE diisopropylsuccinic acid and of tetrftmethylsuccinic acid, namely, distillation in steam from a 50 per cent.solution of sulphuric acid. The mixed acids were placed in a conveiiiently large flask, together with a 50 per cent. solution of snlphuric acid, and distilled in a current of steam, when a large quantity of an oil heavier than water passed over; at the end of two hours, as no more oil passed over and the dist'illate was only slightly acid, the distillation was stopped. (a.) Treatment of the Residue in the Distilling Zi'lask.--On cooling, a large quantity of a crystalline substance separated from the dark brown sulphuric acid solution ; this was collected, and after being washed with water, it melted roughly a t 13O-l6O0 ; crystallisation from water, however, at once raised the melting point t o 160-170°, and subsequently to 174-175", where it remained constant; the quantity of this substance was 18 grams.The filtrate from the cryRtals was extracted four times with ethei-, and the ethereal solution dried and evaporated ; the thick, syrupy residue had only partially solidified after standing over sulphuric acid for two days in n vacuum ; on treatmelit with cold benzene, this was readily separated into two parts. 1. An insoluble, white, crystalline mass melting roughly at 2. A soluble portion which was deposited as an oil on evaporating the benzene; the quantity of this was, however, small, and as all attempts to obtain a crystalline substance from i t wore unsuccessful, i t was not further investigated. It is worthy of remark, however, that on dissolving this oil in water and saturating the solution with gaseous hydrogen chloride, the substance was reprecipitated as an oil, :l,ud not, in a crystalline condition.111 order to purify the crystalline substance insoluble i n cold ben- xeiie, it was treated with boiling benzene and filtered from a small iuantity oE insoluble inorgaiiic matter ; 011 cooling, needle-shaped crystals separated which, after being washed with benzene, melted a t 95--ll(i0, but, on repented recry stallisation from water, the melting point rose t o 117-118", where it remained constant. The quantity of this acid, which was evidently isopropylsuccinic acid, was only about 1 gram. (L.) Trentmwt of the Substance Volatile with Steam.-The steam distillate consisted of a large volume of licpid containing oily drops at the bottom, which dissolved on the addition of excess of potash and warming ; the clear solution thus obtained was evaporated in a porcelain dish t o a small bulk, acidified with hrdroohloric acid, 89-104O.CIS- ASD TRANS-NETHY LISOPROPYLSUCCIKEC ACID.27 7 extracted six times with ether, and the ethereal solution dried over calcium chloride and evaporated, when a very small quantity only of an oil was left which solidified on standing; on recrystallisation from water, an acid was obtained melting at 174"-175", evidently identical with the acid of the same melting point already obtained as described above ; the quantity mas, however, very small and hardly sufficient for a melting point determination. Considering the large quantity of original acid employed, only small amounts of pure substance had been extrscied by ether, and i t seemed likely, therefore, that an acid was contained in the steam dis- tillate, which, owicg to its great solubility i n water, was not capable of being easily extracted by agitation with ether ; this proved to be the case, for on evaporating the mother liquor (which had previously been made alkaline by the addition OF potash) t o dryness on the water bath, adding excess of cmcentrated hydrochloric acid, and again extracting six times with ether, a large quantity of a solid sub- stance was obtained melting a t about 110-120". This could not be recrystallised in the ordinary way owing to its great solubility ; but when i t was dissolved in a little water, and the solution saturated with hydrogen chloride, the pure substance, on standing, separated almost completely in microscopic needles melting at 125-126".The yield of this acid was 30 grams from the 144 grams of ethylic methyl- isopropylethanetricarboxjlate ixsed. The products of the hydrolysis of the 144 grams of this ethereal salt may therefore be tabulated as follows. I. An acid (18 grams) melting a t 174-175", only very slightly volatile with steam," insoluble i n hot benzene. 2. An acid (1 gram) meltling at 117-118°, not readily volatile with steam," but easily soluble in hot benzene. 3. An acid (30 grams) melting at 125-126', volatile with steam,* and readily soluble in hot benzene. In the following sections, we give a detailed account of the pro- perties of the tn-o acids melting at 273' and 126' respectively, showing that the former is the trans-, the latter the cis-methyliso- 1)i opylsuccinic acid.Metltod 11.-Although as a method for the rough separation of large quantities of the crude mixed acids, distillation with steam from a 50 per cent. solution of sulphwic acid serves admirably, and yields tile cis- and trans-acids in a tolerably pure form, yet it cannot be advantageously applied when smaller quantities have to be dealt with. Repeated recrystallisation of the crude mixture of acids from water fails to produce an acid of higher melting point than 170-173', # From a 50 per cent. solution of sulphuric acid. r 2278 BENTLEP, PERKIN, AND THORPE : and it is therefore almost impossible by these means to obtain a pure trans-acid; if, however, the recrystallised producf be boiled for a few minutes with benzene, in which i t is almost insoluble, filtered while hot, washed with warm benzene, and the product thus obtained sub- sequently recrystallised from water, long, flat needles of constant melting point, 174-175', are readily obtained.Owing to the marked difference in the solubility of the cis- and trans-acids in water, the cis-acid is obtained in a very fair degree of purity on saturating the mother liquors with hydrogen chloride ; the product, however, still contains traces of the trans-modification, b u t can easily be purified by treating with cold benzene, filtering, evaporating the filtrate to dryness, and recrystallising the vesidue thus obtained from hydrochloric acid, as above described.H@ 00 H. CO 0H.C.H Trans-2l.lethylisopropylsuccinic acid (m. p. 174-1 75O), This acid crystallises from water in long, flat needles, which melt at 174-175", and decompose at 190" with formation of the anhydride. The following results were obtained on analysis. C8H1404 requires C = 55.17. 0.2272 gave 0.4587 C02 and 0.1640 H20. Trans-methylisopropylsuccinic acid is readily soluble in hot water, ether, and ethylic acetate, but only sparingly in light petroleum and chloroform, almost insoluble in cold water and benzene. The solubility in water was determined by Victor Meyer's method, when i t was found that at 1 8 O , 2.6146 grams of water dissolve 0.170 gram of the acid, or 100 parts of water dissolve 0.64 part of the acid at 18". This acid is, tberefore, very sparingly soluble in cold water.The silver salt, C8H1204Ag2, prepared by neutralising a 10 per cent. solution of the acid with a slight excess of ammonia, boiling for some time, concentrating, adding a little water, and then the requisite quantity of silver nitrate solution, gave the following result on analysis. C = 55-00 ; H = 8.02. H = 8.04 per cent. 0.2122 gave, on ignition, 0.1181 Ag. C8H12Ag20a requires Ag = 55-67 per cent. Action of Heat on tr~ns-~ethylisop9.op?lEszcccinic acicl.-When gently boiled for a, few minutes under slightly diminished pressure, and then distilled, trans-methglisopropylsuccinic acid is converted into an anhydride which, on boiling with water, yields an acid melting from 120--165O, and from which a small quantity of tram-acid can Ag = 55.65.CIS- AND TRANS-I\lETHYLISOPROP'ZiLSUCCINIC ACID.279 be isolated by crystallisation from water. The mother liquor, when concentrated and saturated with hydrogen chloride, yields a considerable quantity of cis-methylisopropylsuccinic acid melting at 12.5-126°. The presence of the trans-acid i n this product was at first thought to be due to its having distilled nnchanged, but as no carbon dioxide was evolved on heat'ing the distillate with a solution of sodium carbonate, this did not seem probable. Subse- quently it was proved, however, that anhydrides of both acids exist, the trans-anhydride being only completely converted into t,he cis- modification after repeated distillation under ordinary or slightly reduced pressure, Behaviour of trans- Netl~ylisoprcYpylszLccinic acid o n heating with Hydrochlol-ic arid at 1&Oo.-h order to investigate this important point, 3 grams of the pure acid mere heated with concentrated hydro- chloric acid in a closed tube, at B O O , for eight hours ; the crystals which separated on cooling, melted a t 120-150°, but on recrystal- lising and extracting with hot benzene, R quantity of the trans-acid, melting at 174-175', was readily obtained, whilst the mother liquor, on saturation with hydrogen chloride, yielded the cis-acid, the two acids being in, apparently, about equal proportions. As, on subse- quent investigation, the cis-acid, when heated in like manner with liydrochloric acid, yielded a mixture of the two acids, it was inferred that here, as in the cases of the sjmmetrical aa-dimethylglutaric acids, the hexahydroisophthalic acids, and other similarly constituted acids, a state of equilibrium exists.It is interesting to note that in this case it is quite easy to separate the mixture of the cis- and trans- acids obtained into its components by means of benzene; and that i t does not behave like the mixture of cis- and trans-dimethglglutaric acids, which can oiily be separated with very great difficulty (AnnuZen, 1895, 285, 332). C/HS H*$I*COOH I'I*C*COOH C i s - ~ ~ ~ t 7 ~ y l ~ ~ s o p r o p ~ l ~ ~ i c c i n i c acid, m. p. 125-126", I c H( c H3)2 On saturating the aqueous solution of the acidwith hydrogen chloride and allowing i t to cool, microscopic needles separate, which melt a t 125-12Go, and decompose a t 140°, with formation of the anhydride.The analysis gare the following figures. 0.1135 gave 0.2282 CO, and 0.0794 HzO. C8HI4O4 requires C = 55.17 ; H = 8.04 per cent. Cis-~Iethylisopi.opylszLccinic acid is readily soluble in all the usual solvents, with the exception of light petroleum, in which it is only C: = 54.83 ; H = 7-77,280 BENTLEY, PERKIN, AND THORPE : sparingly solable in tho cold; i t also dissolves readily in acetyI chloride. The solnbility i n water, determincd by Victor Meyer's method, yielded the followiiig result at 18'. 2.1046 grams of water dissolve 0.0934 gram of the acid, or 100 parts of water dissolve 4413 parts of the cis-acid at 18", i t is, therefore, much more soluble thaii the trans-acid, of which 100 parts of water dissolve only 0.64 part a t this temperature.The silver salt, C8H12Ag,0J, prepared by the same method as t h a t employed in the case of the trans-acid, gave the following result on analysis. 0.2210, on ignition, gave 0.1232 Ag. CsHlzOaAg2 requires Ag = 55-67 per cent. Action of Heat on cis-MethyEisoproplJlsziccinic acid.-When gently boiled under reduced or ordinary pressure for a few minutes, or when slowly distilled, the acid readily loses water, and is converted into its own anhydride, and this, on boiling with watey, again yields the cis-acid in a very pure condition. On treating a drop of this anhydride with a solution of sodium carbonate, on a watch glass, there is no evolution of carbon dioxide, so that the conversion is complete. Ag = 55-74. The An h y d s d e s of cis- a rbd trans- Me t h y 1 isoprop y lsucc inic acids.Anhydride of trans-Met7,ytiso~ro~y2succinic acid.-The simplest method of preparing this anhydride seemed to be the following. Five grams of the pure trarzs-acid were boiled with acetic anhydride for about two hours in a reflcx apparatus, the solution poured into a glass dish, and the acetic anhydride evaporated as far as possible in a vacuum over potash. As no crystals separated after the lapse of five days, the product was distilled under reduced pressure (20 mm.), the anhydride passed ovey at 140-145' as a colourless oil, which, on standing, gradually solidified ; i t was pressed on a porous plate, and recrystallised from light petroleum (b. p. 80-100°), when it gave long, silky needles melting at 46O.0.2010 gave 0*4520 CO, and 0.1534 H,O. CsHl,Os requires C = 61.54 ; H = 7.69 per cent. On boiling with water for half an hour, this anhydride dissolves, and, on cooling, the trans-acid separates in a very pure form, showing that tho anhydride is in reality that of the trans-acid. The anhy- dride is not changed on distillation under reduced pressure, and even when rapidIy distilled at the ordinary pressure it is only par- tially converted into the cis-modification. If, however, it be heated for a few minutes in a reflnx apparatna and then distilled, it is converted C = 61-33 ; H = i.70.CIS- AND TRANS-METHYLISOPROPYLSUCCINIC ACID. 28 I into the anhydride of the cis-acid, as shown by its yielding this acid on boiling with water, as also by its giving no precipitate with n benzene solution of aniline (see below).The An 1~ yd ride of ci s-Meth y lisopropy lsucc inic acid .-This anhydride was prepared in the following manner. Five grams of the cis-acid were heated with acetic anhydride for two hours, and the sohfion placed over potash in a vacuum. As sooii as the smell of acetic anhydride was no longer perceptible, the product was distilled under reduced pressure (25 mm.) when the anhydride passed over at 138-140' as a colourless oil ; this, however, showed no signs of solidification, even when kept for a considerable time, and a11 subsequent efforts to pro- cuye it in a crystalline form proved fruitless. This anhydride, there- fore, appears to be liquid at the ordinary temperature. An analysis OE a sample which has been distilled under reduced pressure gave the following results.0.1902 gave 0.4273 CO,, and 0.1333 H,O. C,H,,Os requires C = 61-54 ; H = 7-69 per cent. On boiling with water for half an hour, this anhydride dissolves, and on saturating the solution with hydrogen cbloride, the cis-acid melting at 125-126° is obtained in IL pure state. Conversion of the Anhjdde of the trans-acid i n t o that of the cis-acid. Three grams of the traibs-anhydride were heated to boiling for three minutes under ordinary pressure in a flask shaped as shown in C = 61.27 ; H = 7.78. the figure, the flask being inclined, so that the liquid could constantly run Sack ; t h e flask was then placed in a horizontal position, and the anhydride distilled into the re- ceiver A under reduced pressure.The liquid thus obtained showed no signs of solidification after pro- longed standing, and, a s it yielded the pure cis-acid on boiling with water, it is evident that a trans- formati.on of the tram- into t<he cis- modification had actually taken place under the conditions of the experiment. The Aitilic acids and the A d of cis- aiid trans-Melhy lisopropylsuccinic acids. (1 j TheAction of A&!ine ON the trans-Anhydride.-Two grams of this anhydride were dissolved in benzene, and a molecular proportion of282 BENTLEY, PERKIN, AND THORPE : aniline, also dissolved in benzene, added ; a thick, white precipitate separated immediatelj-, the contents of the beaker becoming solid. The product was then collected, mashed with benzene, dried, and rrcrystnllised twice from dilute alcohol ; the slender silky needles thus obtained melted at 160", and decomposed at 170" with evolution of bubbles of steam.The substance dissolves readily in sodiulri caxbonate solution. A nitrogen determination of this compound and its behaviour on hydrolysis proved that it consisted of the anilic acid of tmns-methyl- ( C H3) ,QH C 0 OH CsH,*NH* C0.CH.C H3 ('I' isopropylsuccinie acid of the formula 0.2590 gnve 12.3 C.C. moist nitrogen at 17" and 753 mm. N = 5.45. CI,HK,NO~ requires N = 5.62 per cent. H?jdroEysis with AlcohoLic Potush.-Abont 1 gram of this anilic acid was heated with alcoholic potash for 12 hours on a water bath ; on evaporating, acidifying, and extracting with ether, an acid was obtained which melted at 160-170°, rising to 174-175c after treat- ment with hot benzene. It consisted, therefore, of the trans-acid, the formation of which proves conclusively that the substance described above is in reality the tmm-anilic acid.(2) The action of Aniline on the cis-Anhydride.-On mixing a solu- tion of 1 gram of the &anhydride dissolved in benzene with a benzene solution of a molecular proportion of aniline, no precipitate of the anilic acid was formed as in the case of the trans-anhydride, so that this difference in behaviour towards a benzene solution of aniline may be used as a ready means of identifying these anhydrides, On evaporating t o dryness on the water bath, an oil was left which only solidified after standing two days in a vacuum, and repeatedly stirring ; on grinding this up with cold benzene, filter- ing and washing with benzene, a white powder was left which crjstallised from dilute alcohol in large, prismatic needles melting sharply a t 153" and decomposing at 160".Thinking that perhaps this might be the same substance as the anilic acid obtained from the trans-anhydride (m. p. 160°), it was again rec:rystallised, but the melting point remained constant. A nitrogen estimation yielded the following figures. 0-2410 gave 11.9 C.C. moist nitrogen at 16" and 750 mrn. N = 5.71. CIaH,,NO3 requires N = 5.62 per cent. On hydrolysis with alcoholic potrash, this substance yielded again the pure cis-acid, showing that it is in reality the anilide of the cis- acid.CIS- ASD TRAKS-~JIET~TL~SOPROP~LSUCC~~IC ACID. 283 The two anilic acids described above, when heated abore their melting points, yield the snme anil.Thee Aizil obtained f m n the trans-Anilic mid.-The tmiu-anilic acid was heated in a small test-tube in a siilphuric acid bath a t 200°, until water ceased to be given off. On cooling, the a d remained ns n thick, oily substance, which did not solidify on stirring, but i t did so immediately on boiling wilh dilute :immonia. The insoluble matter was collected, washed with hot ammonia, and recrystallised from dilute alcohol, with the aid of animal charcoal. It is iiecessarj- to use a large quantity of the solvent, and to promote crystallisation by adding a crystal of the substance, otherwise owing to its low melting point and the higher temperature of the solvent, i t frequently separates as an oil.This anilide crjstnllises in glistening plates melting a t 85'; it is insoluble in soda. T h e And obtair~ed fi'ona the cis-Anilic acid.-On heating this acid in the manner described, an anil mas obtained, identical in melting point and cr-ystalline form with that prepared from the fivus-acid. A nitro- gen estimation was made. 0.1136 gave 5.5 C.C. moist nitrogen at 16' and 759 mm. N = 5-74. C,rH,7N0, requires N = 6.06 per cent. S a l t s of cis- trizcl trans-~eihylisopl.opylsiccciizic acids. In each case a 10 per cent. solution of the inoi*ganic salt was added to a 10 per cent. solution of the ammonium salt of the acid. 1%" cis- CuS04. Cold, no precipitate ............ ing, the copper salt separates in flakes ..................... Pb(NOs),. Colt?, white crystalline precipitate.. Hg2( NO,)!. Cold, white precipitate ......... ,, Hot, soluble in excess .......... 9 , H o t , no precipitate; but on cool- 99 Hot7 7, 7, HgCI,. Cold, no precipitate ............ 7 9 Hot, ,I ............ CnCI,. Cold, no precipitate ............ $rot, ............. 9 ) Hot, 7 7 3 , I' 9 , 9 9 Fe,CI,. Cold, flocculent red-brown precipitate 1'75" tmi2.s. The same. 3 , White crystalline prccipitate. ?, 7 , 7 7 7 7 x :3284 BENTLEY, PERKIN, AND THORPE : The Actiou of Ethylic a-Bromisoralerate O:L the Sodilcm Com3301md of lilt h y 1 ic Met h y lmnlo 11 ate A1 coh 01 ic Sol u tio n . The action of ethylic a-bromisovalerate on the sodium compound of ethylic methylmalonate was next investigated, in order to determine whether by this means the acids described above, or, perhaps, different ones, would be formed. Six grams OE sodium were dissolved in 60 grams of absoluto alcohol, the solution mixed with 43 grams of et-hylic methylmalonate, and 53 grams of ethylic a-bromisovalerate added in small quan- tities a t a time to the hot solution ; a tolerably energetic action set in, and after three hours' heating on a water bath, the mass was found to be neutral.The alcohol was then distilled off, the product mixed with water, the oil which was deposited separated, and the nqueons liquid extracted six times with ether; after drying over calcium chloride, the ether was distilled off, and the residual oil fractionated under dimiiiished pressure (67 mrn.), when the chief fraction distilled between 190" and 210" ; the quantity was, however, only 10 grams, or not more than 15 per cent.of the theoretical yield. Hpdrolysis of this Ethylic Salt.-The ethereal salt was hydrolysed by boiling with a 50 per cent. solution of sulphuric acid in a round- bottomed flask, connected with Bischoff's reflux 4 apparatus, and heated on a sand bath. As i during the operation an acid oil distilled over 1 with the alcohol, and collected in the receiver, i a short Liebig's condenser was placed on the i shorter arm of the apparatus, as shown in the figure, so as t o ensure complete condensation, and from time to time the oil which had dis- tilled was separated and returned to the flask. , After three hours' boiling, all the oil had dis- appeared, and as, on adding water to the i liquid, it dissolved without the separation of i oily drops, the hydrolysis was considered as i complete.The product. was now distilled with 3. steam, and, as in the previous experiment (p. 276), it wa8s noticed that an oily substance distilled over first,, and sank to the bottom of the receiver; a t the end of two hours the oil ceased to come over, and as the distillate was only faintly acid, the distillation was stopped. As no crystalline substance separated from the sulphuric acid solution 011 cooling, it was extracted with pure ether, and the ex.CIS- AND TRANS-METHYLTSOPROPSLSLJCCIhTIC ACID. 285 tract, after drying, evaporated. The oil which was left did not solidify even when left in a vacuum over sulphuric acid for five days; it was therefore dissolved in water and tbe solution saturated with hydrogen chloride, but the substance was reprecipitated as an oil, no crystals being formed.The steam distillate, which contained, a s stated above, an insolable oil, was made strongly alkaline, evapo- rated to dryness on the water bath, mixed with excess of concentrated hydrochloric acid, and extracted with ether. The oily product, which solidified partially on standing, was dissolved in water and saturated with hydrogen chloride ; the crgst alline substance which separated melted at 113-l17°, but after repeated recrystallisations it had a constant melting point of 12.5-126". An analysis gave the following figures. 0.2303 gave 0.4639 CO, and 0.1643 H,O. C = 54.94 ; H = 7.93. CsH,,O4 requires = 55-17 ; H = 8-04! per cent. The substance is therefore mithont doubt cis-methylisopropylFluccinic3 acid.I t is remarkable that in this reaction the cis-acid alone should be produced ; no trace of the trans-acid could be isolated, and it could hardly have been overlooked, as it usually separates with great ease, and is readily purified. Action of Ethylic u-Bromisovalerate on the Sodium Derivative of Ethylic Meth ylmalonatc in Xylene Sohtion. As explained in the introduction, the object of this experiment was to determine whether, in xylene solution, the condensation be- tween ethylic bromovnlerate and ethglic methylmalonate might not proceed in a different manner from that in alcoholic solution, yielding derivatives of glntaric acid. Fifteen grams of sodium in the form of powderX (molecular sodium) were suspended in about 400 C.C.of xylene and 117 grams of ethylic methylmalonate added ; a t the ordinary temperature t h e sodium dissolved only slowly, but, on slightly warming, a violent evo- lution of hydrogen took place, and the sodium derivative of ethylic methylmalonate separated as a pasty mass, in fact, the contents of the flask became so thick that more xylene had to he odded. Ethylic x-bromisovalerate (141 grams), ~ f a s then poured into the cooled solution, but no perceptible action occurred, although the sodium derivatlive dissolved in the mixture ; the flask was therefore con- nected with a reflux condenser and heated t o boiling on a sand bath for five hours, when sodium bromide separated in large quantities. * As obtained by melting the sodium under the xplene in a corked flaek and sliaking vigorously.286 CIS- AND TRANS-METEYLISOPKOPTLSUCCI~IC ACID. When cold, the product was mixed with water, the sylene solntion separated, and the aqueous liquid extracted three times with smdl quantities of xylene. The combined extracts were dried with cnlciuni chloride, and the xylene distilled off' as far as possible under tlic ordinary pressure ; as soon, however, as the thermomet8er began to i*isc rapidly, the residue was transferred to a smallw flask, and the frac- tionation continued under diminished pressure (80 mm.) ; the chief fraction distilled at 300--210°, and weighed 71 grams, or 35 per cent.of the theoretical yield of pure ethylic salt. Hyd~07ysis of the Ethylic Xa2t.-This ethereal sal t was hyclrolysetl by means of a, 50 per cent. solution of sulphuric acid in the manner described in the previous instance (p. 284) ; after Id hours, alf oil having disappeared, the product was distilled with steam. The szdphzc~ic acid solution, on cooling, deposited a large quantity 0:' crystals, which melted indefinitely at 160-170°, but on twice recqs- tallising from water, the melting point rose to 174--175', and remained constant. The following figures were obtained on analysis, showing that the substance was trans-methylisopropyls?~cci?zic acid. 0.2102 gave 0.4327 CO, and 0.1512 H,O. C,H,,04 requires C = 55.17 ; H = 8.04 per cent. The filtrate from these crystals, on extraction with ether, &c., gave an oily residue, which, on standing, partially solidified ; it was then spread on a porous plate, and the solid residue recrystallised from concentrated hydrochloric acid, when an acid was obtained melti~~g sharply at 115-116O. This was evidently isopropylsuccinic acid,* since, on analysis, it yielded the following result. C: = 53.07 ; H = 7.70. C: = 54-97 ; H = 7-99. 0.2403 gave 0.4657 CO, and 0.1667 H20. C7H,,04 requires C = 52.52 ; H = 7*S2 per cent. The Xtea?n Distillate.-As in the previous experiment (p. 285) this was made strongly alkaline with potash, evaporated to dryness, concentrated hydrochloric acid then added in large excess, and the whole extracted with ether ; in this way, a solid substance WRS ob- tained which melted roughly at 110-120", and on recrystallisiiig four times from concentrated hydrochloric acid, gave cis-rnet1tyZi.w- propylszl,ccinic acid melting constantly at 125-126O. 0.1926 gave 0.3905 CO, and 0.1388 HzO. The quantities of these two acids melting a t ld6O and 175" respec- C = 55.29 ; H = 8.01. C,H,,O, rcquires c' = 55.17 ; H = 8.04 per cent. tively were about equal. * The formation of this substance is obviously due to the presence of traces of ethjlic malonate in tha ethylic methylma,lonate used.AVAILABLE POTASH AND PHOSPHORIC ACID IN SOILS. 287 Cis- and tmns-methylisopropylsucciuic acids are therefore formed in about equal proportion by the action of ethylic a-broinisoralei~ate on the sodium compound of ethylic methylmalonate in xylene solu- tion, whereas the same condensation conducted in alcoholic solution yields the cis-modification only.

ISSN:0368-1645    

DOI:10.1039/CT8966900270

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

AVAILABLE POTASH AND PHOSPHORIC ACID IN SOILS. 287 XXVIIL-Available Potccsh aml Phosphoric acid i i L Soils. By T. B. WOOD, M.A., Secretary to Cambridge and Counties A gi*icultui.al E clucntion Scheme. Is a, paper by Dr. Bernard Dyer (Trans., 1894, 115-167) a colt- venient method is given for deterinining the available minerals in soils. Dr. Dyer determined the sap-acidity of the sinaller roots of a great number of plants, and found that on the average the sap-acidity might be taken as equivalent to that of a citric acid solut,ion con- taining,l per cent. of the crystallised acid. He then determined, in different samples of soil, the percentage3 of potash and phosphoric acid soluble in a citric acid solution of the strength above mentioned. The samples were taken from the various plots in the permauent barley field at Rothamsted, and the analjses, thus conducted, in- dicated very satisfactorily the relative amounts of available potash and phosphoric acid in each plot, as evidenced by the known yield and manuring.A determination OE the percentage of potash and phosphoric acid soluble in a 1 per cent. citric acid solution, would thus appear to give a trustworthy and rapid indication of the amount of available potash or phosphoric acid in any soil. For the last four years, I have taken part in the management of the experimental plots of the Norfolk Chamber of Agriculture, and of the Suffolk County Councils, and during that time I have come across most striking variations in the effects of potash arid phosphatic manures on the different soils.It seemed t o me that an examination of these soils by Djer’s method might give important evidence as to its technical usefulness. The crops grown on the plots have included most of the ordinary agricultural crops, but for the purpose of this paper I quote only the results obtained with barley, in order that they may be more strictly coniparable with those tabulated in Dr. Dyer’s paper. The annexed cable shows the average yield of several years’ crops.288 WOOD : AVAILABLE POTASH AND Table shoioing Yield of Barley i n Bzcshelsper Acre. Warham. Higliam, Bramford. I-- ----- No manure.. . . . . . . . . ------- 25 Potassium salts , . . . . . - ---- Superphosphate.. . . Potassium salts . . . . } } Nitrate of sodium , . Potassium salts . . . . Nitrate of sodium . .Superphosphate.. . . } Nitrate of sodium . . . . ------- ------- ------- ---- 30 38 41 40 29 1 38 40 I 55 33 I 37 -- 37 1 52 I- -- /-- -_- A - I &timatities of 2Clauwes. In each case the quantities used were as follows. Superphosphate., . . . . . . . . Potassium salts,. .. .. . . .. 1 cwt. per acre, as sulphate or’ Nitrate of sodium .. .. .. , . 1 cwt., and in some cases 2 cmt- 3 cwt. per acre. chloride. per acre. E f e c t of Potash Manzwes. From this point of view these soils may be divided into two I. Those to which the addition of potash produces only a small gl’o ups. increase in the yield of corn- Higham, Walaham, Bramford . . . . . . . 11. Those to which an equal addition of potash produces a very Average. 1: bushel per acre. great increase in the yield of corn- Flitcham I.Flitcham 11. Average. 45 bushels 22 bushels 33i bushels per acre. The soils of Group I must evidently contain an abundance of readily available potash, whilst those of Group I1 must be deficient in this constituent in an available condition. Accordingly the soils of the first group should contain much potash soluble in 1 per cent.PHOSPHORIC ACID IN SOILS. 289 Increase bushels per acre. Q 1 2 I t 45 33& 22 citric acid, whilst those of the second group should contain but little potash soluble in that solvent. I have obtained samples of all the soils through the kindness of members of the Norfolk Chamber and of the East and West Suffolk Technical Education Committees, t o whom I now tender my best thanks. The soils are all very similar, being light soils on chalk subsoil.Analysis of the Xoil. The samples were air-dried, sifted, &c., and the moisture deter- mined in the air-dried fine soil, which was then used for all the other determinations, the results being thus calculated on the dry soil. Nitrogen, organic matter, phosphoric acid, lime, potash soluble i n hydl-ochloric acid were all determined by the ordinary methods; thc hydrcjchloric acid used was a mixture of the strong acid with its own volume of water, 10 grams of the soil being boiled with 50 C.C. of the dilute acid for half an hour, evaporated nearly to dryness, and extracted with water. The potash soluble in 1 per cent. citric acid mas determined exactly as directed in Dyer's paper. The results are appended in the annexed tables.~~ Available potash by 1 1x1- cent. citric acid. ------- 0 -013 0.012 0 *019 0 '0147 0 0063 0 '0084 0.00735 Higham, ZMoisture ........... Organic matter ...... Nitrogen. ........... Phosphoric acid.. .... Lime .............. Total potash., ....... Yotash soluble in HC1 Potash soluble in 1 per cent. citric acid 7 #5 4 -63 0 -134 0 -218 5 -86 0.83 0 *171 0 -013 Warhnm. Brnmford. i-- -- 0 -87 1.97 0 -130 0'11 0 -76 0 -185 0 '012 - 1 '8 2 -51 0 -130 0.23 1.96 0.180 0 -019 - Flitcham I. Flitcham 11. 1 -6 5 -5 0 -18 0 '20 0'65 0.14 0 *0063 17 -1 1 *9 4 '12 0 *l9 0 -15 5 '6 0 '136 0 'OOM - Table showing Increase produced by Soluble Potash Manure side hy side with the amount of atiailable Potash as s1iozc.n by Solubility in 1 ye?. cent. Citric acid.Higham. ..................... Wnrham. .................... Bramford .................... Average Group I ............. Flitcha,m I . . ................. Flitcham I1 .................. Average Group I1 ............290 WOOD: AVAILABLE POTASH AISD Potash soluble in 1 per cent. citric acid. . . Potash soluble in 1 per cent. citric acid -t- - enough to neutrnlise all the chalk . . . . . From the above table, it will be seen that Dyer’s method shows twice as much available potash i n the Group I soils as in the Group 11, and this result agrees well with the results of the manurial experiments, which showed so clearly that Group I soils coritained much more available potmh than Group 11. The agreement would have been still more striking had not the occupier of the land a t Flitcham applied two dressings of chloride of potassium, between the times when the field experiments were made there and the samples of soil were taken for analysis.Dyer’s method thus shows clearly the very different amounts of available potash in the two groups of soils; indeed, had i t been applied to the Flitcham soils in the first instance,*it would have indi- cated, more rapidly, and more economically than the field experiments did, the necessity of applying soluble potash manures in order to grow a profitable crop. At the end of Dr. Dyer’s paper, there is a suggestion that, in order to make the results strictly comparable for all soils, suficient citric acid should be added to neutralise all the chalk in the soil and leave 1 per cent. over. As several of the above soils contained large amounts of chalk, I acted on this suggestion, but found that, under these experimeutar conditions, the amount of potash dissolved was nearly equal in the case of each of the three soils tried.The numbers are annexed. 0 -013 0 -0063 0‘0084 --- --- 0 *017 0.018 o ,015 ~ I Higham. I E’litcham I. 1 Flitcham 11. In adding the extra citric acid, the following method of procedure mas adopted. The soil was put into a Winchester quart, with 1 per cent. acid, as detailed in Dr. Dyer’s paper, and the amount of citric acid required to neutralise the chalk was weighed out and added a t the rate of about 1 gram per hour, with frequent shaking. When most of the axtra acid had been added, the solution was titrated, and found to be nearly 1 per cent.i n st.rength. I t was then left until the sixth day and titrated again, and a further small amount of acid added to make the strength 1 per cent. On the seventh day, the liquid was separated, and the dissolved potash deter- mined as before. As will be seen by the above numbers, this method gave no indi- cation of the much greater amount of available potash in thePHOSPHORIC ACID IN SOILS. 29 I ?So inanure.. .......... Superphosphate, 4 cwt.. . Nitrate of soda, 2 uwt,. .. Higlmm soil than in the two soils from Flitcham. and I venture t o suggest that the uleawst indication of the amount of available potash is obtained by extractiiig the soil with 1 pel. cent. citric acid, without r e g a d to the amount of chalk contained in it. I t seems to me, also, that by doing so one is imitating more nearly the conditions under which the plant obtains its potash, for there is no evidence to show that the acidity of the root juice is greater when the soil is more calctweous. Available Phosphoric acid.Among the i*esults of the Norfolk and Suffolk experiments arc man>- numbers 1-eferring to the growth o€ swede turnips with dif- ferent manures, and I have picked out the following as giving a graduated series in which the effect of superphosphate is practically nil, very great, and intermediate between these two. Tons. Cwt. -__. -- 8 7 8 9 10 11 --.-- ---- ---A Brain ford. I Nitrate of soda, 2 cwt. Superphosphate, 4 cwt.. Warham. I Higliain. It will be seen that the effect of superphosphate is practically nil: at Bramford, while a t Higham it is considerable, and a t Warham greatel- still. Z hare estimated the phosphoric :wid in these three soils by Dyer’s method, both with and without t,he addition of extra citric acid to iieutralise the chalk, the extra acid being added in the manner described above.The results are given in the followiug tahle. Warham. I H igha ui . I Rramford. I I 1 I J,ime (CaO) .................. 1 -96 0 -76 Phosphoric acid (Y,C),) I.. ..... 0 -218 .. ...... 7 ) I1 9 7 .. 111.. ... 0’085 I being phosphoric acid soluble in strong nitric acid on boiling ;292 AVAILABLE POTASH ANU PHOSPHORIC ACID IN SOILS. 11, phosphoric acid soluble in 1 per cent. cit,ric acid ; IIT, phosphoric acid soluble in 1 per cent. citric acid using extra acid to neutralise the chalk.The analytical numbers obtained with the 1 per cent. acid show very clearly the much greater amount of available phosphoric acid in the Bramford soil thanin either of the others, and the much smaller and more nearly equal amounts in tho soils from Higham and Warham. This agrees perfectly with the results obtained in the field experiments with swedes quoted nhore, and the method appears t o give even better results for phosphoric acid than it did with potash. When the extra citric acid was added, in the case of the Bramford soil with only 1.97 per cent. of lime, a slightly greater amount of phosphoric acid was dissolved ; in tho Higham soil, containing 5.88 per cent. lime, nearly five times as much P,05 was dissolved as with 1 per cent. acid only. The Wnrham soil contained so little lime that no determination with extra acid was thought necessary. Comparing the results obtained with and without the extra acid, it appears that the 1 per cent,. acid only, the chalk being neglected, gives numbers more nearly proportional to those ascertained by field experiment; and again I think that this is only to be expected, for thus we imitate most nearly the solvent action of the plant juices. In the case of tho 1 per cent. acid :tiid a soil rich in chalk, the large amount of carbonic acid evolved must have an appreciable solvent action on the potash and phosphates present. 100 grams of the Higham soil suspended in 1 litre of water through which purified carbonic anhydride was passed for 48 hours yielded the following numbers. K20 dissolved by water saturated with GO,. . . . K20 soluble in 1 per cent. citric acid . . . . . . , . My thanks are dne to Dr. T. H. Easterfield for many valuable 0.008 per cent. 0.013 p205 9 , 9 , .. .. 0.011 ,, P A ........ .... 0.012 ,, ,, 19 ,, suggestions given in the course of the work. Agricii ltural Departin ent, University Chemical Laboratory, Cambridge.

ISSN:0368-1645    

DOI:10.1039/CT8966900287

出版商:RSC    

年代:1896

数据来源: RSC

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293 XXX.-The Production of Nuphthalene and of Iso- puinolim Deritutives from Deh ydmcetic mid. By J. NORNAN COLLIE, Ph.D., F.R.S.E., and N. T. M. WILSMORE, hf.Sc. (Melbourne). IN a former paper by one of us (Trans., 1893, 63, 329 et Sep.), it was shown that under certain conditions diacetylace tone condenses with loss of wat,er, forming a yellow, crystalline compound, melting a t 108-109°, and this compound condenses further t o a second yellow substance, which melts at 183-184", and proved to be a naphthalene derirative. All the work then done with this second substance indicated, with considerable probability, that its constitution was 3 : 3'-dimethyl-2-acetyl-l : 1'-dihydroxynaphthalene. The present communication is an account of further research on these compounds, in which it was sought to elucidate the mechanism of the reactions taking place in their formation, and to obtain further evidence as to their constitution. It would appear from what follows that, of the possible tautomeric forms of diacetylacetone, one is comparatively stable and incapable of condensation to the above compound, whilst another is unstable- readily changing into the stable form, or condensing by union of 2 mols.with loss of water; It is interesting to note in this connection t'hat W. H. Perkin (Trans., 1892, 61, 827) has shown, from the mag- netic rotation, that a t a temperature of 60-4', two double linkings are present in the diacetylacetone molecule, whilst a t lower tempera- tures, it tends to pass into the trihydroxy-derivative. The condensation occurs most readily when the diacetylacetone- which acts as a dibasic acid to strong bases-is combined with only half its equivalent of barium.Possibly 2 mols. are here united by an atom of barium in the form of an acid salt, this being a first step to the more complete union. Cert,ainly a univalent metal, such as sodium or potassium, cannot be substituted for barium; but, on the other hand, the fcrnmtion of the yellow substance wili take place, even if the whole of the barium be removed as carbonate by a current of carbonic anhydride. I n all other cases, the barium hydroxide liberated by the condensation hydrolyses some of the remaining diacetylacetone, forming barium acetate. The condenscz- tion is, however, not complete in any case ; and at most, only half of the theoretical yield has been obtained.I n accordance with the foregoing, we would suggest that the normal barium salt of diacetylacetone should also be written double, VOL. LXIX. T254 COLLIE ,4ND WILSXORE : THE PRODUCTION O F 0.C (CH,) :CH*CO*CH:C*(CH,) O>Ba 0 - C (CH,):CH*GO*CH:C*(CH,)O having the constitution Ba< instead of that suggested by Feist (Annuleu, 11390, 257; 276). Owing to the difficulty with which the yellow compounds react, comparatively little progress has been made with them. From the second, dirnethyIacebyldihydroxynaphthalene-a dimethylnaphthn- lene has been prepared, which, on oxidation, yields 1 : 3 : 4-methyl- phthalic acid. Also, by the action of strong sulphuric acid, the acetyl group appears to have been removed, leaving a colourless snb- stance.Very little direct experimental evidence as t o the constitution of the first substance, m. p. 108-109°, has been obtained. I n all proba- bility, it is a benzeno'id compound, having long side-chains which unite t o form dimethylacetyldihydroxynaphthalene. The condensa- tion of diacetylacetone, therefore, takes place in two stages. CH,-C:CH C:CH*CO*CH3 H C I-' C; H : C OH* CEC 0.C H2*C 0 CH, H H c c &\ /\/\ \/ \ A 4 C c c 0 13 OH OH - CH3.y $*CH2*CO*CH, - - CH3*y 8 7*cH3 + HzO HC CaCO*CH2*CO*CH3 HC C C*CO*CH3 - First yellow compound. Dimethylacetyldihydroxynaphthalene. The probability of the benzenoyd character of the first compound is heightened by its peculiar behaviour with ammonia, resulting in the formation of what appears to be a derivative of isoquinoline. The reaction seems to be H C H H c c /\ k\/\ CH3y # y*Crr3 + 2H20 HC C N - y\c/ \/ C OH CH,*CO*CH, on a-acetonyl-/3-3-dimethyl-l-hydroxy- isoquinoline. By heating this new base with strong sulphuric acid, part of the side-chain is removed, leaving aa'-3-trimethyl-l-h~droxyisoquinoline (1' : 3' : 3-trimethyl-l-bydroxyisoquinoline),NAPBTHALESE, ETC., FROM DEHYDRACETIC ACID. 2 95 H €1 c c \/\N c c OH CH, aa'-3-trimethyl-l-hydroxy-isoquincline.This second base, on oxidation, gives a pyridinecarboxylic acid, which is probably ola'-dimethylpyridine-P~pdicarboxylic acid (2 : 6- dime thylpyridine-4 : 5-d icarbosy lic acid), CH Hence one more example is to hand of the generalisation empha- sised in the former communication above referred to, respecting the tendency of the aldehydic and ketonic derivatives to produce com- plex compounds by reactions similar to those occurring in nature.Condensation of Diacetylacetone. The immediate starting point in most of these experiments was t,he yellow bayium salt of diacetylacetone, first described by Feist (Annulen, 1890, 257, 276 j. This was prepared from dehydracetic acid by boiling it wit,li strong hydrochloric acid until the evolution of carbonic anhydride ceased, and then eraporating the solation to dryness in a vacuum; the compound, C,H,,03CI, thus obt.ained (Trans., 1891, 59, 619) was dissolved in water, and the strongly acid soiution neutralised with solid sodium carbonate t o produce a solu- tion of dimethylpyrone. It was found convenient to dilute this so that 4 C.C.corresponded with 1 gram of t,he dehydracetic acid taken. On heating t o boiling and adding excess of hot, strong solution of barium hydroxide (2.4 grams of barium hydroxide to 1 gram of the original dehydracetic acid), the sparingly soluble barium salt of diacetylacetone was precipitated. This was washed rapidly with hot water on the filter pump, and used as soon as cold. The weight of barium salt, dried on the pump, was about equal t o the weight of barium hydroxide taken. A sample of the salt, free from barium carbonate, washed with hot water, and then with alcohol and ether, and dried in a vacuum ovei- sulphuric acid, was found to contain 49-32 per cent. of barium, which agrees with Feist's determination. Baz(C7H80& requires 49.46 per cent.Y 2296 COLLIE AND WILSMORE: THE PRODUCTION OF The moist salt has a strongly alkaline reaction, readily absorbing carbonic anhydride from the air, and turning reddish, dimethylpyroue and other products being formed. The original method of bringing about the condensation was a s follows. The barium salt, made into a thin paste with water, was nearly dissolved in hydrochloric acid of about 15 per cent., leaving the solution faintly alkaline, and the solution was filtered from traces of barium carbonate, &c. ; on standing, the fwst yellozo c o m p o z d , melting at 10S-109°, crystallised out, and on concentrating t8he mother liquor under diminished pressure, it further crop of crystals was obtained, consisting, however, of the second szcbstaizce-dinaeth~l- a c e t y l d ~ h y d r o x y i z a ~ ~ t l ~ ~ l e ~ e .The residue obtained on evaporation to dryness contained barium chloride and acetate (the latter apparently formed by hydrolysis of some of the diacetylacetone), mixed with a considerable quantity of resinous matter. The distillate contained, among other things, acetylacetone. The barium saltt dissolved, and the solution became neutral when hydrocbIoric acid equivalent only to half the barium present had been added. If acid stronger trhan that mentioned were used, there was a tendency for free diacetyl- acetone t o be formed. The yield of the yellow substances averaged about 22 per cent. of the weight of dehydracetic acid taken. Several modifications of this method were tried. I. The solution of dimethylpyrone was divided into two equal parts.One part was conmrted into barium salt, and this was then mixed with the other part, in which it dissolved. A very poor yield was obt'ained, owing, probably, to the solution being too alkaline from the excess of barium hydrate, which cannot be completely washed out of a large precipitpke of the barium salt of diacetylacetone without serious loss oE the latter. 11. Acetic acid was substituted for hydrochloric acid as a solvent f o r the barium salt. The latter substance, from 4.5 grams of de- hydracetic acid, was treated with 16 C.C. of acetic acid of sp. gr. 1.05, which neutralised it. Diacetylacetone was the only product. I n another case, however, where acetic acid equivalent to the barium was added, diacetylncetone was again precipitated ; but the filtrate, on standing, deposited Considerable quantities of the first yellow substance.By using only half the amount of acetic acid necessary to neutralise the barium, the reaction went as with hydrochloric acid. I n one case, from 12.5 grams of dehydracetic acid, 2.4 grams of the first yellow compound were obtained, or about 19 per cent. I n another, from 4.5 grams of dehydracetic acid, using 20 per cent. acetic acid for neutralisiag, 2 grams of the yellow substance were obtained, or 44 per cent. In t h i s case, the solution of the barium salt in acetic acid was warmed, and dimethylacetyldih~droxyaaph-XBPHTHALENE, ETC., FROM DEHYDRACETIC AClD. 297 thalene was the chief product. The nietliod witah acetic acid appeared too uncertain in its results to warrant an experiment On a larger scale. 111, The barium salt, from 4.5 grams of dehydracetic acid, was suspended in water, and the barium was neutralised with a current of carbouic acid.The barium carbonate was filtered off, and the solution eraporated rapidly under diminished pressure to 30 C.C. 1-5 grams of the first yellow compound, in a pure condition, crystal- lised out, being a yield of 33 per cent. The distillate contained diacetylacetone. The solution was free from barium, so that di- acetylacetone, in an unstable, tautomeric form, that is, in a nasceut state, must have been present. The method is, therefore, of interest, but is inconvenient owing t o the large bulk of solution which has to be evaporated. This means serious loss hF hydrolysis of the di- acetylacetone to acetylacetone, acetic acid, &c., together with resinous substance8, when dealing with any but smali quantities.IV. A modification, which gave fairly good results, even on a pretty large scale, consisted mainly in the use of oxalic acid for neutralising the barium salt. A 20 per cent. solution of (crystallice) oxalic acid, warm enough to keep the acid dissolved, was used. The mixture became neutral when oxalic acid, equivalent to half the barium present, had been added. The barium oxalate was filtered off rapidly, preferably first with linen, and the filtrate allowed to stand over night, when very pure crystals of the first yellow substance were obtained. It was found better not to con- centrate the filtrate from these, but to precipitate again with barinm hydrate, and treat the barium salt of diacetylacetone thus recovered with oxalic acid as above, when a further, though much smaller, quantity of the yellow substance could be obtained.It did not appear to signify if oxalic acid were added until the reaction was acid. In one case, from 200 grams of dehydracetic acid, 63 grams of the pure first yellow compound was obtained, being a yield of 51.5 per cent. The latter yield was probably due to the smaller amount of mineral salt left in solution. V. The barium salt of diacetylacetone, from nearly 3 grams of dehydracetic acid, was treated with a dilute alcoholic solution of diacetylacetone ; when about 4 grams of the latter had been added, thp_ barium salt had entirely disappeared. On filtering to remove traces of barium carbonate, and concentrating to 30 c.c., no precipi- tate was formed ; but, on standing for several days, about 1 gram of the first yellow substance was deposited.The filtrate from this was made alkaline with ammonium carbonate, aud filtered ; on evapora- tion, a semi-crystalline mass was left, which yielded a further small quantity.298 COLLIE AND WILSMORE: THE PRODUCTION OF VI. An experiment with diacetylacetone alone was next tried. The barium salt, from 50 grams of dehydracetic acid, was treated with excess of hydrochloric acid, and the diacetylacetone formed extracted with chlorofoi-ni ; on evaporating the latter, 33 grams of diacetylacetone were left. This was heated for several days at 100' in a sealed tiibe ; water gradually separated, and the whole finally set to a mass of crystals of dirnethylpyrone, no yellow compound being formed.Experiments V and V I seem to lend further support to the hypothesis that the formation of an acid barium salt of diacetyl- acetone, or of the latter substance in a " nascent " state, are import- ant steps towards the condensation. VII. Dimethylpyrone was treated with strong potash, and the potassium salt which separated was collected ; on adding hydro- chloric acid until the reaction was only faintly alkaline, the salt dissolved, bui no yollow coloration appeared on standing. Ulti- mately, a white, crystalline precipitate of dimethylpyrone was thrown down. The theoretical yield from dehydraaetic acid, supposing all the diacetylacetone to condense, would be 73.8 per cent.of the first yellow compound, or 68.5 per cent. of dimethylacetyldihydroxynaph- thalene. Hence in all the methods tried, there was serious loss, which occurred almost entirely in the process of Condensation of the diacetylacetone, since the preliminary reactioiis were nearly quanti- tat ive. Dirnethylacet y 1dihydroxynaphthaEene. It was mentioned in the foimer paper that, by distilling the di- acetate over heated zinc dust, a naphthalene hydromrbon, melting at 92--93O, was obtained, which appeared to be 2 : 3 : 3-trimethylnaph- thalene. This experiment was repeated, as i t seemed somewhat curious that a trimetbyl derivative should be formed. 50 grams of the diacetate were decomposed by zinc dust at the lowest tempera- ture which would give the naphthalene hydrocarbon; but only a very small yield, in all less than 2 grams of the hydrocarbon, was obtained.This was purified by sublimation between watch glasses, and was finally found to melt at 67-69' ; i t could also be sublimed at the same temperature. On analysis, numbers which agreed with hose required by a dimethylnapht lialene, were obtained. Found. C,,H, (CH,!,. Calculated for C.. .... .. 91.4 91.3 H . .. .. .. 8.7 8.7NAPHTHALENE, ETC., FRO31 DEHYDRACETIC ACID. 299 It mas hardly attacked by boiling with chromic acid; but, by heating under pressure, or boiling with dilute nitric acid for a long time, it ultimately yielded an acid as a flocculent precipitate. This acid was soluble in water, but was removed from its aqueous solution by agitation with ether. On heating alone, it yielded a crystalline sublimate, and i t gave the fluoresce'in reaction.The melting point of a few crystals was somewhere about 115-120' (?), whilst Young (Bey., 1892, 25, 2108) gives for 1 : 3 : 4-methylbenzenedicarboxylic acid the melting point 124O. The silver salt, on analysis, gave Fj5.5 per cent. of silver. The acid was, therefore, in all probability 1 : 3 : 4-methylbenzenedicarboxylic C,H,04Ag, requires Ag = 54.8. CH .A CHS.7 G.COOH acid, HC C-COOH' \/ CH The action of strong snlphuric acid on dimethylacetyldihydrosy- naphthalene was studied with a view of removing the side-chains. On dissolving 7 grams of the substance in about 30 C.C. of 98 per cent. sulphuric acid, a solution was obtained exactly the colour of chromic acid ; but, on warming to 60--80", the colour disappeared ; it was now poured into water, when a white emulsion was formed, which finally changed to a granular niitss of crystals. These were dissolved in cold alcohol, and boiled with animal charcoal ; on adding water, an oil was precipitated, which crystallised on standing.By again dissolving in alcohol and precipitating with water, a white, crystalline precipitate was obtained, which was dried over sulphuric acid and analysed. The results were, however, nnsatisfsctory, Found, C = 74.3 ; H = 6.8. C,,H,,O, requires C = 76.6 ; H = 6.3. The crystals had a very low melting point ; they were soluble in cold soda, but reprecipitated by acids. With chlorine or bromine water, they gave a brilliant purple coloration, but there was no reaction with ferric chloride.On warming with snlphuric acid, violet vapours were given off, but on adding water to the solution, nothing but a black residue, was obtained. On fusion with potash, dimethylacetyldihydroxynaphthalene yielded only a charred mass. With fuming nitric acid, a nitro-com- pound may have been formed, but in quantity too small for investi- gation. The action of hydroxylamine and of aniline was again tried, but the results were as described in the last paper, With ammonia, nothing but a tarry mass mas produced.300 COLLIE AXD WILSMORE: THE PRODUCTION OF CH /\ C H3*$ 8 *CH2*CO* CH, The Fiwt Yellow (Benzenoid ?) Compozmd, HC C.CO-CH,*CO.CH, \/ C*OH Owing to the great readiness with which this substance changes into dimethylacetyldihydroxynaphthalene, very little could be done with it ; this occurs even if its solution in strong or aqueous alcohol is boiled for some time, or concentrated.I n the latter case, the change usually takes place suddenly, the less soluble product crystal- lising out. With hydroxylamine, however, it forms a dioxirne. C14H,,N20a requires 10.0. Nitrogen found, 9.9, It is soluble in alkalis, more easily in potash than in soda ; and if the solution is acidified a t once, the original- substance is reprecipi- tated, but if the alkaline solution is allowed to stand, or is waymed, the corresponding salt of dimethylacetyldihydroxynaphthalene is formed, the solution changing colour from lemon-yellow to deep orange. With ammonia, the action was different ; the compound dissolved easily in aqueous ammonia, and, on evaporation over sulphuric acid in a vacuum, a yellow substance was left,, easily solnbl6 in alcohol and, to some extent, in water, giving intensely yellow solutions, which were neutral to litmus.In one preparation, an attempt mas made to boil off the excess of ammonia, but decomposition ensued, a strong smell of pyridine bases being apparent. On adding hydro- chloric acid to the solutions of the new substance, no precipitate was formed; but,, in the case of the aqueous solution, the colour disap- peared almost entirely. On evaporating its solutions, the substance crysLallised out in minute, yellow needles, which contained nitrogen. It was soluble in warm, dilute soda solution, but insoluble in strong, although it, decomposed to some extent.I n neither case, however, was ammonia evolved. In some cases, the solution of the benzeuojid com- pound in ammonia deposited the new substance on merely standing, indicating that probably an ammonium salt of the former was first formed. The new compound is believed to be a derivative of isoquiuoline. It crystnllises with $ mol. of water, which if retains on drying over sul- phuric acid, but loses a t B O O , leaving a yellow, amorphous powder. 0.2937 gave 0.7679 GO, and 0.1733 HZO. C = 71.31 ; H = 6-56. 0.3152 ,, 0.8251 ,, 0.1921 ,, C = 71.39; H = 6-77. 0.2507 ,, 13.3 C.C. moist nitrogen at 19’and 766 mm. N = 6-00. 0.7778 lost 0.0193 HzO at 130’. C,,H,,R’02,+H20 requires C = 71.49 ; H = 6.64 ; N = 5.96 ; H,O = 2.55 per cent.Zeace salts of the first compound could not be isolated. HzO = 2.48.NAPHTHALENE, ETC., FROM DEKYDRACETIC ACID. 301 The molecular weight of the crystallised base was taken by Raoult's method, using glacial acetic acid as the solvent. A mean of two determinations gave the molecular weight 203, or, allowing for the water of crystallisation, 272. Calculated, for the anhydrous base, CI,H,,NO,, 229, or for the c~ystalline substance, 235. a- Aceton y 1-a' : 3-clinaeth y 1 - l-h@oqisog ziinol ine, H H c c \/\/ c c OH CH2*CO*CH3 The base, when pure, crystallises from alcohol in bright yellow, minute, silky needles, melting at 164-165' (uncorr.). It is easily soluble in alcohol or acetic acid, but only sparingly in water ; these solutions are deep yellow. The free base oxidises readily in solution, particularly in presence of alkalis and on warming ; hence in its pre- paration the temperature must be kept low, and the ammonia evapo- rated in a vacuum.It dissolves readily in dilute acids, yielding 5: nearly colourless solution, from which the corresponding salts may be crpstallised. The hydrochloride crystallises from dilute hydro- chloric acid in beautiful, pale yellow needles, melting a t about 242" with decomposition ; it is slightly hydrolysed in dilute aqueous solu- tion, the latter becoming yellow. The reaction of the aqueous solu- tion is therefore acid. 0.1177 gave 0.0656 AgCl. 0.101 ,, 5.2 C.C. moist nitrogen at 21' and 750 mm. N = 5.7. C14H16N02Cl requires C1 = 13-:34; N = 5.3 per cent. With platinic chloride, a brow nish-yellow platinochloride is pre- cipitated as an amorphous (?) powder. On heating, a strong smell of quinoline was evolved, and oily drops formed on the lid of the crucible.Ct = 13.76. 0.2198 of the dry salt gave 0.0495 Pt. The base is not acted on by phosphorus trichloride, and with the pentachloride it merely chars. It decomposes on heating with acetic anhydride, but no acetate could be isolated. It does not appear to form an oxime when treated with hjdi-oxylamine, although it seems t o give a crystalline, but very iinstable, compound with sodium hydrogen sulphite. On distilling over zinc dust, neither pyridine nor quinoline derivatives could be detected. Pt = 22-52, ( CI,H~,NO,)~,H,P~C!~ requires Pt = 22.55 per cent.302 COLLIE -4ND WILSMORE : THE PRODUCTION 03' On oxidation with potassium permatiganate, an acid was obtained in very small quantity as an amorphous powder, sparingly soluble in water; this acid formed an insoluble lead salt, but could not be purified.By heating with solid soda or with zinc dust, a substance, resembling lutidine, was given off, and condensed as oily drops, which fumed when brought near strong hydrochloric acid, and gave a crys- talline platinocliloride on treatment with platinic chloride. On warming with strong sulphuric acid, the acetyl-derivative described in the last section, part of the side chain appeal-ed to be removed, leaving a methyl group ; 10 grams of the base were treated with 30 grams of strong sulphuric acid, which dissolved it, forming an intensely yellow solhion; on warming to 60--80°, acetic acid was gken off, and the solution became darker, but had far less colouring power.The whole was then poured into about 300 C.C. of water, and, on standing, a nearly white, amorphous substance separated, which was filtered off; the filtrate contained acetic acid, but no trace of an atnmonium salt. When the precipitate, which was nearly insoluble in water or alcohol, was warmed with barium carbonate made into a paste with water, a second base was liberated, and could be extracted with alcohol ; it did not contain sulphur. After being recrystallised five times from alcohol, it began to blacken sliglitly at 225", and melted at 247-280" (uncorr.). 0.1225 gave 0.346 CO, and 0.0813 H,O. C = 77.03, H = 7.37. 0.26'73 ,, 0.7558 C02 and 0.174 H,O.C = 77.12, H = 7.23. 0.2838 ,, 18.8 C.C. moist nitrogen at 18.5Oand 755 mm. N = 7.74. 0.2503 ,, 16.4 C.C. N at 19" and 765.5 mm. N = 7.57. C,2H,3N0 requires C = 77.00; H = 6.95, N = 7.49 percent. H H c c A/\ \A/ ad : 3-T~-i~~iethyl-l-hydrozyiso~i~inoline, CH3*F 9 $I*CH3 (1' : 3' : 3-Trimethyl-l-bydroxyisoquinoline), B c c: N c c OH CH3 aa' : 3-Trimethyl-1-hydroxyisoquinoline crystallises from alcohol in miuute, lemon-yellow needles, but much less readily than the first base ; and the colour, whether in the solid state or in solution, is far less intense than that of the latter. It dissolves to some extent in water, yielding a yellow solution with neutral reaction. The salts are amorphous or very difficult to crystallise, and are colonrless, or nearly so ; they are slightly hydrolysed by water, and have, conse- quently, an acid reaction.The hydrochloride, when pure, is colour- less. It crystallises with difficulty from dilute slcohol, and containsNAPHTHALENE, ETC., FROM DEHPDRACETIC ACID. 303 water of crystallisation ; it does not appear to form a platinocbloride. Owing to lack of material, an estimation of chlorine alone could be made. The base is not acted on by phospliorus trichloride, and chars on heating with the pentachloride. On heating with excess of acetic- anhydride at 150---160' in a sealed tube it appeared merely to dis- solve, for the unchanged base mas recovered on evaporating t h e anhydride. A very small amount of a white substance was, however, formed, which may hare been an acetate, but was insoluble in all the usual solvents.It did not appear to be crystalline, and on heating it charred without melting. The base does not give off pyridine OP quinoline derivatives when distilled over heated zinc dust, or when heated with solid soda. During one preparation of this substance, a bright yellow powder was left on dissolving the crude product in alcohol, and, as it con- tained sulphur and nitrogen, was probably a snlphonic acid; the amount, however, was too small for analysis. This substance charred at 270-280' withont melting. It wits nearly insoluble in water o r alcohol, but dissolved in alkalis, forming a colourless solution which became brilliantly yellow on exactly neuirnlising with acids, although the colour of this yellow powder was again discharged by a slight excess of the latter. On oxidising the trimethylhydroxyisoquinoline with potassium per- manganate, an acid was obtained which, on distilling with solid soda.gave off a substance resembling lutidine, but in quantities too small for investigation. This acid was soluble with difficulty in water, but could not be crystnllised from that solvent, and it was insoluble in all the other usual solvents. The ammonium salt, however, was very soluble in water, and crystallised on evaporation in a vacuum over sulphuric acid ; but, unfortunately, it contained water of crystallisa- tion which could not be driven off without loss of ammonia, and it:. therefore, could not be analysed. I t was pre- cipitated as the lead salt, and the precipitate was warmed with acetic acid, which left any oxalate undissolved ; the filtrate was then boiled several times with sugar cha,rcoal (animal charcoal was found to remove the acid itself), and the acid again precipitated as lead salt, which was decomposed with sulphuretted hydrogen. On evaporating t'be filtrate from the lead sulphide, the acid was left as a white powder which decomposed at about 250' without melting. An analysis was made, but was not 'satisfactory. 0.091 gave 0.180 COz and 0,0451 gram H20. C = 53-96, H = 5.51. 0.13 ,, 8.4 C.C. moist nitrogen at 20° and 754 mm. N = 7.32. CSH,NOa requires C = 55.39; H = 4.62 ; N = 7.18 per cent. An attempt was made to purify the acid as follows.304 LAPWORTH AND KTPPIKG : The acid is believed to be aa’-climethylpyridine-~~~-dica~boxylic C*COOK /\ C o o H w ~ f?H (2 : 6-dimethylpjridine-4: 5-dicai~boxylic acid). CH3*C OCH, The inability to obtain it pure and in quantity is the more to be regretted, as it is the only one of the possible lutidinedicarboxylic acids hi kherto unprepared.

ISSN:0368-1645    

DOI:10.1039/CT8966900293

出版商:RSC    

年代:1896

数据来源: RSC