| 摘要 |
1,232,310. Production of aqueous solutions of thiocyanates. GLANZSTOFF A.G. 1 Oct., 1968 [21 Oct., 1967 (3)], No. 46488/68. Heading C1A. Aqueous ammonium thiocyanate solutions are obtained by the reaction of ammonia and carbon disulphide in the presence of water, the reaction being carried out on active carbon at elevated temperature. The process is suitably effected in a reaction tube filled with granulated active carbon, a temperature of 60-100‹ C. being maintained in the reaction zone. In one mode of operation, ammonia and carbon disulphide in a molar ratio from 2:1À2 to 2: 2 are introduced between one quarter and one half the way up the reaction tube filled with granulated active carbon which is mounted on a distillation vessel, and simultaneously steam is supplied from the bottom of the reaction tube from a distillation vessel, the control of the heat supply to the distillation vessel being so effected that the major part of the steam condenses below the point at which ammonia and carbon disulphide are fed to the reaction tube, and the ammonium thiocyanate formed is drawn off at the bottom end of the reaction tube and hydrogen sulphide as well as excess carbon disulphide are drawn off from the top of the reaction tube. The ammonium thiocyanate may alternatively be converted to aqueous alkali or alkaline earth metal thiocyanates by providing an aqueous alkali or alkaline earth metal hydroxide solution in the reaction tube between the points of entry of the steam and the ammonia and carbon disulphide for reaction with the ammonium thiocyanate passing therethrough. |
