IV. On the synthesis of succinic and pyrotartaric acids

Succinic acid bears the same relation to the diatomic alcohol glycol that propionic acid bears to ordinary alcohol. Propionic acid can be obtained by treating the cyanide of the alcohol radical with potash. Can succinic acid be obtained by treating the cyanide of the glycol radical with the same reagent ? or is it an isomeric acid that is formed under those circumstances? C 4 H 5 Cy + O 2 { K H +2HO = O 2 Cyanide of Ethyle. { C 6 H 5 O 2 K + NH 3 Propionate Potash. C 4 H 4 Cy 2 + 2{O 2 { K H + 4HO = O 4 Cyanide of Ethylene. { C 8 H 4 O 4 K 2 + 2NH 3 Succinate of Potash? The following experiments were performed with the view of determining this point. Preparation of Cyanide of Ethylene . As a preliminary step to the formation of succinic acid in this way, it became of course necessary to prepare the cyanide of ethylene. This body I obtained by submitting bromide of ethylene to the action of cyanide of potassium. The process was thus conducted:—A mixture of two equivalents of the cyanide and one of the bromide, together with a considerable quantity of alcohol, was exposed in well-corked soda-water bottles to the temperature of a water-bath for about sixteen hours. To prevent the caking of the salt, it is advisable to have some coarsely-powdered glass in the bottles, and to agitate them occasionally. At the expiration of this time the bottles were opened, and the alcohol separated and distilled. A semifluid residue was thus obtained, which was filtered at 100° Cent. It was very dark in colour, owing to the presence of a considerable quantity of a tarry matter, which embarrassed me for a long time. This I at last succeeded in removing, by exposing the residue to a powerful freezing mixture, and pressing it, while in the mixture, between folds of bibulous paper, as long as the paper was stained. After this treatment there remained a crystalline mass, which was almost white. This was finally washed with a small quantity of ether, and dissolved in the same fluid. The residue obtained on evaporating the etherial solution is the body in question. It was dried at 100° Cent., and analysed. The nunbers obtained agree with the formula of cyanide of ethylene (C 4 H 4 Cy 2 ), as will be seen from the following Table:— Theory. Experiment. per cent. I. II. C 8 . . 48·00 60·00 59·20 —— H 4 . . 4·00 5·00 5·55 —— N 2 . . 28·00 35·00 —— 34·00* ——— ——— 80·00 100·00 This is, I believe, the first example of a diatomic cyanide. It has the following properties:-Below the temperature of 37° Cent, it is a crystalline solid of a light-brown colour, above that temperature it is a fluid oil. It cannot be distilled. Nevertheless it bears a tolerably high temperature without suffering much decomposition. Its specific gravity at 45° Cent, is 1·023. It is very soluble in water and alcohol, and sparingly soluble in ether. It has an acrid disagreeable taste. It is neutral to test-paper. Gently warmed with potassium, it is decomposed, cyanide of potassium being formed in large quantity. Its solution in water is not precipitated by nitrate of silver.