TABLE XIV.-Heat developed on Mixing Solutions of Magnesium Sulphate or Copper Sulphate with a Solution of Potassium Sulphate. 1 molecule to 400 H2O. Strength of each solution = Quantity taken 307 c.c. of each. A.-Magnesium and Potassium Sulphates Mixed. XXX.-Contributions to the History of Cyanuric Chloride and Cyanuric Acid. By ALFRED SENIER, M.D. RECENT experiments on cyanuric acid and melamine have shown beyond much doubt that these substances are normal, and not iso in their constitution. Nevertheless, it seemed interesting to extend the data upon which this view rests by the preparation and study of other cyanuric derivatives. With this object, I have investigated the action of cyanuric chloride on the salts of various organic acids. Sodium Acetate. If this salt be heated with cyanuric chloride in a closed tube for eight hours at 100°, a reaction takes place, and on opening the tube the characteristic odour of acetyl chloride is perceived. By treating the contents of the tube with cold ether, the acetyl chloride is readily dissolved, whilst any unchanged cyanuric chloride, being but sparingly soluble, remains for the greater part with the residue. By repeated washing with hot ether, the whole of the cyanuric chloride can be removed and a yellow residue is left, mostly sodium cyanurate. This when dissolved in water gives, on the addition of hydrochloric acid, a crystalline precipitate, which readily responds to the cuprammonium test for cyanuric acid. The reaction, therefore, is quite different from what was expected. It was hoped that a triacetyl cyanurate would be formed thus :— C1N ̧CI, +3С2H2O•ONа = C2N3(O°C2H ̧O)3 + 3NaCl, instead of which the following took place : C,N,Cl,+3C2H2O·ONa = C2N, (ONа), + 3С2H2OCI. By converting the acetyl chloride into acetic acid, and finally into silver acetate, the proportion formed was ascertained to be 22.5 per cent. of the theoretical yield. Between silver acetate, in place of sodium acetate, and cyanuric chloride, no reaction was observed, and in the same manner cyanuric acid itself could not be induced to act on acetic anhydride. Sodium Formate.-This salt behaves in a manner similar to the acetate. On opening the tube a gas is evolved, which on examination was found to be carbon monoxide, whilst the residue contains cyanuric acid in abundance. Apparently formyl chloride is produced in the first instance, immediately, however, breaking down into carbon monoxide and hydrochloric acid. The reaction is therefore C3N,Cl,+3CHOONa C,N,(ONa), + 3CO + 3HCl. Sodium Benzoate.-In the benzoyl series, the same general reaction takes place, but whereas in the previous instances it was only partial, here 88 per cent. of the theoretical yield of benzoyl chloride is obtained. The reaction is expressed by the following equation: C ̧Ñ ̧Cl1 + 3C,H2O·ONa = C ̧Ñ ̧(ONa); + 3C,H2OCI. Action of Cyanuric Chloride on Benzamide.—In the hope of obtaining a benzoyl substituted melamine, cyanuric chloride and benzamide were heated in a closed tube for eight to ten hours at 100°. It was thought possible that instead of the desired action melamine and benzoyi chloride might be formed. But on opening the tube, there was a distinct odour of bitter almonds, and treatment with cold ether yielded abundance of an oily liquid having the character of benzonitrile, and easily converted into benzamide by treatment with concentrated sulphuric acid. The residue in the tube was almost pure cyanuric acid. The following action, therefore, had taken place: C ̧Ñ ̧C11 + 3CH ̧·CONH2 = C ̧Ñ(OH), + 3C,H,CN + 3HCl. |