My attempts to isolate such an intermediate compound have been unsuccessful, and, therefore, it would not be proper to lay too much stress on the above explanation; however, such a compound would, of course, be very unstable, and the above considerations seem sufficient to show that Minunni's objection to the stereochemical representation of the aldoximes cannot be maintained by means of this decomposition. Action of Phosphorus Pentachloride on Benzaldoximes. An excess of phosphorus pentachloride was gradually added to an ethereal solution of benz-antialdoxime kept below -8° by a freezing mixture. A small quantity of a white powder was precipitated, probably benz-antialdoxime hydrochloride. The orange-coloured liquid was poured into ice-cold water and the mixture distilled; in the aqueous portion of the distillate, formic acid was identified, an aliquot portion yielding, with mercuric chloride, a precipitate corresponding to 003 gram on the whole quantity. An oil had also come over which was a mixture of benzaldehyde and benzonitrile; the latter, when hydrolysed with potassium hydroxide, gave a quantity of ammonium chloride corresponding to 21 grams of benzonitrile on the whole quantity. Hydroxylamine and aniline were identified in the residue from the original distillation. Benz-antialdoxime had thus yielded, under the influence of phosphorus pentachloride, the hydrolytic products of formanilide 0·08 gram, and benzonitrile 2-1 grams, and some oxime had been regenerated. Benz-synaldoxime, treated in the same way, gave similar results. 006 gram of formauilide and 2-3 grams of benzonitrile were obtained besides regenerated oxime. The formation of formanilide as a product of the action of phosphorus pentachloride on the oximes of benzaldehyde does not appear to have been noticed by previous workers, but it was, of course, probable considering that the formation of formamide from acetaldoxime had been observed by Dunstan and Dymond (loc. cit.). It is, nevertheless, very difficult to explain this result. In the first place it is quite clear that benz-antialdoxime is not in this experiment converted into benz-synaldoxime by the action of hydrogen chloride, for it has been shown that at these low temperatures the anti-hydrochloride suspended in ether is stable; moreover, the quantity of hydrochloride precipitated is only very small. If, however, in the experiment with benz-antialdoxime, it be assumed that either the hydrogen chloride formed, or the phosphorus pentachloride favours the transformation into the synaldoxime, so that the benzonitrile is formed as the result of the action of the pentachloride on the latter, then it would be necessary to make a further assumption that in the experiments with benz-synaldoxin.c under identical con ditions, the same reagent favoured a transformation of part of the synaldoxime into anti-aldoxime which yielded the formanilide. It seems more reasonable to assume that the action of phosphorus pentachloride in some way removes the cause that makes the stereoisomerism possible. For instance, it may combine in a loose way with the oxime, so that the latter ceases to have a double link between carbon and nitrogen, and the action goes on mainly in the sense of the most favoured (syn) configuration, whilst a small proportion of the molecules are caught in the less favoured configuration, and undergo the Beckmann transposition, yielding formanilide. Action of Phosphorus Trichloride on Benz-antialdoxime. On adding phosphorus trichloride to a cooled ethereal solution of benz-antialdoxime a white precipitate of hydrochloride is thrown down, and the filtrate, having been poured into water and neutra lised with sodium hydroxide, is found to contain much benzonitrile, but to regenerate a certain quantity of the oxime. By reversing the process, and adding the oxime to a large excess of phosphorus trichloride, less of the hydrochloride is precipitated, but still the elements of hydrogen chloride are eliminated from some of the chlorine compound, so that the product of the action consists of a mixture of the very unstable chlorine substitution compound, CH, CHNCI, benzonitrile, and the excess of phosphorus trichloride. From this mixture it is impossible to isolate the new compound, as there is no means of separating it from the benzonitrile. Its presence was, however, proved by decomposing the phosphorus trichloride with the least possible quantity of water, and then, after distilling off the ether under diminished pressure and extracting the residue with light petroleum, in which hydrogen phosphite is insoluble, the solution thus obtained was freed from the last trace of phosphite compound by shaking with a drop of water; on now decomposing it by sodium hydroxide, it was found to contain a considerable quantity of chlorine, evidently from the presence of the chlorine substitution compound CHCH:HO-N. This compound was ultimately obtained as follows. Benz-antialdoxime, dissolved in a very little ether, was gradually added to a large excess of phosphorus trichloride below 0°; the precipitate formed, supposed to be the hydrochloride of the oxime, was filtered off, but after a few minutes it became liquid, and had the characteristic odour of benzonitrile. As it seemed likely that this was the compound which it was desired to isolate, and that had thus evolved its hydrogen chloride on exposure, the experiment was repeated using scarcely any ether at all. The precipitate which was formed was set to drain in a beaker well surrounded by a freezing mixture, but it presently began to evolve hydrogen chloride with almost explosive violence, and after standing in a desiccator for a short time the residnal liquid gave, on hydrolysis, no trace of hydroxylamine, all the oxime having been converted into nitrile. In these experiments, no hydrogen chloride was evolved while the oxime was being added to the phosphorus trichloride, and no hydrochloride of the oxime was formed. The chlorine substitution compound of benz-antialdoxime, C.H, CH:NCI, is therefore a white solid, nearly insoluble in phosphorus trichloride, moderately soluble in ether. In the pure state it decomposes into benzonitrile and hydrogen chloride below 0°, but can be kept for a short time in dilute solution. Action of Phosphorus Trichloride on Benz-synaldoxime. When phosphorus trichloride is added to an ethereal solution of benz-synaldoxime at -10°, half of the oxime is instantly converted into benzonitrile, the other half being converted into the hydrochloride by the hydrogen chloride which is eliminated. If the filtered liquid is poured into water, no oxime is regenerated. Thus the compound formed by the substitution of chlorine for hydroxyl in benz-synaldoxime is so unstable as to be incapable of existence; it instantly decomposes into benzonitrile and hydrogen chloride, and although the latter combines with more oxime, if any is present, to form the hydrochloride, this has no share in effecting the decomposition. This was proved by adding benz-synaldoxime in small portions to a large excess of phosphorus trichloride; hydrogen chloride was freely evolved, and only a comparatively small quantity of hydrochloride was precipitated. This experiment was carried out so as to be strictly comparable with that in which the chlorine substitution compound was obtained from benz-antialdoxime, but no corresponding derivative could be obtained. It evidently breaks up at the moment of its formation. Evidently this difference of behaviour between the two oximes when treated with phosphorus trichloride, confirms the configuration formulæ assigned to them. CH, C.H Benz-antialdoxime, m. p. 34°. C&H, CH N⚫OH This investigation was carried out at the Research Laboratory of the Pharmaceutical Society, and I desire to express my warmest thanks to Professor Dunstan, not only for many valuable suggestions, but also very especially for his kind and unfailing encouragement. 193 XXI.-Transformation of the Alkylammonium Cyanates into the corresponding Ureas. By JAMES WALKER, D.Sc., Ph.D., and JAMES R. APPLEYARD, F.C.S., University College, Dundee. It has been shown by Walker and Hambly (Trans., 1895, 67, 746) that the production of urea from an aqueous solution of ammonium cyanate is not a case of simple transformation of one molecule into another, but that the law regulating the transformation is the law of a bimolecular action, the active molecules being in all probability ammonium ions and cyanic acid ions. To use Ostwald's notation, the equation which expresses the action is NH + 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 ammonium 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 solable 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. Ethylammonium Cyanate. A decinormal solution of ethylammonium cyanate was heated at 59-6°, 5 c.c. of it being removed from time to time, and added to 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 100°, 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. P ment 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. Ethylurea differs from urea in giving no perceptible quantity of carbonate when heated for a considerable time with water at 100°. After 260 minutes, the solution was found to possess a feeble ammoniacal 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 ammo1 x remained constant, E nium cyanate, that the expression t E -x being the end-point, and a the titre. This also holds good for ethylammonium cyanate, as may be seen from the following table. Ethylammonium Cyanate. E = 22.8. 59-7° is 00144, 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 at corresponding times will also show. The values of the constants in the above instance are nearly proportional to the rates at which the actions start, and this arises from the practical identity of the end-points. In the calculation, the progress of the reverse action |