JPS631303B

In the preparation of perchloro-2,5-diaza-1,5-hexadiene by chlorination of N,N-dimethylaminoacetonitrile, the improvement which comprises in a first stage (a) chlorinating N,N-dimethylaminoacetonitrile or its hydrochloride at about 70 DEG to 80 DEG C. in a solvent, removing the solvent by distillation under chlorinating conditions until a bottom temperature of about 120 DEG to 160 DEG is reached, and after-treating the residual reaction at this temperature with chlorine, and in a second stage (b) chlorinating the resulting reaction mixture at a temperature from about 150 DEG to 220 DEG C. Advantageously the solvent in stage (a) is phosphorus oxychloride, the weight ratio of nitrile to solvent is about 1:3, the after-chlorination in stage (a) is carried out at a temperature from about 120 DEG to 140 DEG C., and stage (b) is carried out at a temperature from about 180 DEG to 210 DEG C. in a multi-stage bubble column cascade reactor operated with gas and liquid in counter-current.