PRODUCTION OF CHLOROSULFONYL ISOCYANATE

PURPOSE:To obtain the titled compound useful as an intermediate raw material for pharmaceuticals, agricultural chemicals, etc., in high yield and purity on an industrial scale with a simple procedure, by adding and reacting cyanogen chloride to liquid sulfuric anhydride at a specific temperature. CONSTITUTION:Chlorosulfonyl isocyanate is produced by reacting sulfuric anhydride with cyanogen chloride. The reaction is carried out by adding cyanogen chloride to liquid sulfuric anhydride keeping the temperature of the reaction system to 20-50 deg.C, preferably 25-40 deg.C. Any liquid sulfuric anhydride can be used in the reaction, however, the use of gamma-type anhydride is preferable. The cyanogen chloride may be gaseous or liquid state, however, a gaseous cyanogen chloride is more preferable. The amount of cyanogen chloride is 0.8-1.3mol, preferably 0.9-1.1mol per 1mol of the sulfuric anhydride.