The invention relates to a process for preparing hydrazine hydrate, comprising a step of hydrolyzing an azine in a distillation column in the presence of at least one silicone of the polydialkylsiloxane, polydiarylsiloxane or polyalkyl-arylsiloxane formula.

The invention also relates to the use of at least one silicone of the polydialkylsiloxane formula as an anti-foaming agent in a process for preparing azine hydrate.

The invention relates to a process for preparing hydrazine hydrate, comprising a step of hydrolyzing an azine in a distillation column in the presence of at least one silicone of the polydialkylsiloxane, polydiarylsiloxane or polyalkyl-arylsiloxane formula.

The invention also relates to the use of at least one silicone of the polydialkylsiloxane formula as an anti-foaming agent in a process for preparing azine hydrate.

The invention relates to a process for preparing hydrazine hydrate, comprising the following successive steps: a) preparation by means of an absorption column of an aqueous solution comprising dissolved ammonia and comprising at least one activator, by introduction into the absorption column of an aqueous solution comprising at least one activator and of fresh ammonia, then b) reaction within at least one reactor of the aqueous ammonia solution comprising at least one activator obtained in the preceding step with hydrogen peroxide and a ketone, then c) separation of the organic phase containing the azine from the aqueous phase from the stream formed on conclusion of the preceding step, then d) hydrolysis of the organic phase obtained in the preceding step to obtain hydrazine hydrate.

The invention relates to a process for preparing hydrazine hydrate, comprising the following successive steps: a) preparation by means of an absorption column of an aqueous solution comprising dissolved ammonia and comprising at least one activator, by introduction into the absorption column of an aqueous solution comprising at least one activator and of fresh ammonia, then b) reaction within at least one reactor of the aqueous ammonia solution comprising at least one activator obtained in the preceding step with hydrogen peroxide and a ketone, then c) separation of the organic phase containing the azine from the aqueous phase from the stream formed on conclusion of the preceding step, then d) hydrolysis of the organic phase obtained in the preceding step to obtain hydrazine hydrate.