| 摘要 |
1. Process for the preparation of hydrazine hydrate in which methyl ethyl ketone azine is hydrolyzed in a column having a bottom and a top to obtain hydrazine hydrate at the bottom and methyl ethyl ketone at the top, wherein heterocycles of the pyrazoline family are bled off in an amount sufficient to prevent coloration of the hydrazine hydrate by taking a sidestream of the heterocycles from the hydrolysis column. 2. Process for the preparation of hydrazine hydrate, in which: (a) ammonia, hydrogen peroxide and methyl ethyl ketone (MEK) are reacted in a working solution to form an azine; (b) the working solution is separated from the azine, which optionally comprises unreacted methyl ethyl ketone; (c) the working solution is recycled to the stage (a) after an optional treatment; (d) the azine is hydrolyzed in a column having a bottom and a top to obtain hydrazine hydrate at the bottom and to regenerate the methyl ethyl ketone at the top, wherein heterocycles of the pyrazoline family are bled off by taking a sidestream of the heterocycles from the hydrolysis column; (e) the methyl ethyl ketone is recycled to the stage (a), characterized in that on stage (d) heterocycles of the pyrazoline family are bled off by taking a sidestream of the heterocycles from the hydrolysis column. 3. Process according to claim 1 or 2, in which the heterocycles of the pyrazoline family are 3,4,5-trimethyl-5-ethylpyrazoline and 3,5-diethyl-5-methylpyrazoline.
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