Azo dicarbonamide powder useful as blowing agents - by reacting molten mixt. of hydrazine salt and urea, and treating prod. with oxidising agent

摘要

Azodicarbonamide is prepd. by (a) reacting a molten mixt. of a hydrazine salt and urea, and (b) oxidising the prod. The process gives good yields, e.g., >90%, of azodicarbonamide. This prod. is obtd. in the form of fine particles having a uniform size, e.g., 10 mu. The particles can be used as blowing agents for rubbers and plastics without additional grinding operations. The hydrazine salt is pref. the sulphate. Stage (b) is effected with an oxidising agent in aq. dispersion, or by treating the dry prod. at 80-100 degrees C with nitrogen peroxide.