Mitsubishi Gas Chemical Company, Inc.

Nobuhiro Nagata

Kiyoshi Yoshida

Yasuhisa Kuriyama

Chiharu Nishizawa

Toshikiyo Kurai

A method of producing 1,2,4-triazole, comprising a step of subjecting a ketazine, water and formamide to a cyclization reaction. The ketazine and water are added simultaneously to formamide kept at a cyclization temperature. Then, ketone by-produced during the cyclization reaction is distilled off while maintaining the reaction mixture at a cyclization temperature to complete the cyclization reaction, thereby obtaining 1,2,4-triazole. The use of the ketazine in place of hydrazine makes the energy-consuming hydrolysis step in the conventional hydrazine production unnecessary. Therefore, the method of the invention is advantageous over the known methods in energy consumption and production cost.

Method of producing 1,2,4-triazole

A process for continuously and stably synthesizing a ketazine from hydrogen peroxide, ammonia and methyl ethyl ketone in the presence of a solution containing a catalyst. The process comprises removing sec-butyl alcohol by distillation from methyl ethyl ketone, which is reused by circulation. Also a process for preparing a hydrazine hydrate which comprises hydrolyzing the ketazine. By circulating unreacted ketone, accumulation of impurities in the circulated ketone can be prevented to obtain a high yield of the ketazine and the hydrazine hydrate, for a long period of time.

Processes for producing ketazine and hydrazine

A preparation process of hydrazine hydrate is herein disclosed which comprises the step of hydrolyzing a ketazine in a distillation column to obtain hydrazine hydrate, a nonionic surface active agent having a polyoxyethylene group in its molecule and/or silicon dioxide being present in the distillation column. According to this process, in the hydrolytic distillation of the ketazine, flooding can be inhibited and thus a stable operation can be accomplished. As a result, hydrazine hydrate can economically advantageously be prepared.

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Yokkaichi, Japan

Nobuhiro Nagata