Process for production of hydrazine hydrate

A process for preparation of concentrated aqueous solutions of a hydrazine hydrate, the process consisting of:

• (a) reacting a hydrogen peroxide solution, ammonia, and methyl ethyl ketone in the presence of an activator to form a mixture, wherein the activator comprises acetamide and ammonium acetate, and wherein the hydrogen peroxide solution, methyl ethyl ketone, and ammonia are present in a molar ratio of 1:4:3;
• (b) separating the mixture from step (a) into a ketazine layer and an aqueous solution layer;
• (c) concentrating the ketazine layer to obtain ketazine and recovering the methyl ethyl ketone by evaporation;
• (d) purifying the ketazine by vacuum distillation to obtain a purity of more than 95%;
• (e) recovering the acetamide from the aqueous solution layer by dehydration;
• (f) recycling the recovered methyl ethyl ketone and the recovered acetamide to step (a);
• (g) hydrolyzing the ketazine with water in a volume ratio of 1.5:1 to obtain the hydrazine hydrate and regenerating the methyl ethyl ketone;
• (h) recycling the methyl ethyl ketone to the step (a), and
• (i) purifying and concentrating the hydrazine hydrate obtained in step (g) to obtain 80% concentrated hydrazine hydrate in one cycle, and wherein the hydrolysis is catalyst free;
• wherein the acetamide recovered from dehydration step (e) is further purified by centrifugation or filtration under vacuum to get crystalline solid before being recycled in step (f).