IMPROVED METHOD FOR PRODUCING HYDRAZINE HYDRATE WITH PYRAZOLINE RECYCLING Russian patent published in 2023 - IPC C01B21/16 C07C45/42 

FIELD: chemical industry.

SUBSTANCE: method for producing hydrazine hydrate includes the step of reacting ammonia, hydrogen peroxide and methyl ethyl ketone in the presence of a solution containing at least one activator to produce azine. Then the stages of separation from the resulting reaction mixture of the aqueous phase containing the activator and the organic phase containing azine are carried out. The organic phase is washed. The washed organic phase is distilled to recover the azine. Hydrolysis of azine is carried out to obtain hydrazine hydrate and regenerate methyl ethyl ketone. In this case, by-products (heterocyclic compounds of the pyrazoline family) are purged. The resulting purge stream of heterocyclic compounds of the pyrazoline family is recycled to at least one of the preceding reaction steps, separation of the aqueous and organic phase, or washing of the organic phase. A variant of the method for producing hydrazine hydrate is proposed.

EFFECT: group of inventions makes it possible to eliminate the coloring of hydrazine hydrate by stabilizing the concentration of heterocyclic compounds of the pyrazoline family in the hydrolysis column during stable hydrolysis in a continuous mode.

11 cl, 1 dwg, 2 tbl, 1 ex