| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for high-purity chlorosulfonyl isocyanate production in a high yield efficiently and safely. SOLUTION: Cyanogen chloride A and sulfuric anhydrite B are subjected to condensation reaction (a first process) to give a reaction solution 4 containing crude chlorosulfonyl isocyanate. When chlorosulfonyl isocyanate 9 is separated by distillation (second and third processes) from the obtained reaction solution, decomposition treatment (a fourth process) of a residue 7 is carried out. Low- boiling fractions (5, 8, 10 and 11) obtained by the separation of chlorosulfonyl isocyanate by distillation and the decomposition treatment of the residue are recovered and reused for the condensation reaction between cyanogen chloride and sulfuric anhydrite.
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