| 摘要 |
1,191,493. Methylene bis (thiocyanate). NALCO CHEMICAL Ltd. 4 Sept., 1967 [23 Dec., 1966], No. 40334/67. Heading C2C. Methylene bis(thiocyanate) is prepared by reacting a dihalomethane with an alkaline earth or alkali-metal thiocyanate at a temperature below 85‹ C. in an aqueous medium for a time sufficient to produce said methylene bis- (thiocyanate), the ratio of moles of thiocyanate radical to moles of dihalomethane being at least 2: 1. The dihalomethane preferably has at least one bromine or iodine atom, methylene bromide and chlorobromomethane being particularly preferred. An alkali metal thiocyanate such as NaSCN or KSCN is most suitably used. The impure product obtained from CH 2 ClBr may be purified by treating the crystals with a warm solution of a water-miscible organic solvent, e.g. isopropanol, and water to dissolve the pure methylene bis(thiocyanate) and crystallizing the pure product from this solution. |
