US 12,134,558 B2
Process for preparing hydrazine hydrate with pyrazoline recycling
Jean-Marc Sage, Pierre-Benite (FR)
Assigned to Arkema France, Colombes (FR)
Appl. No. 17/611,443
Filed by Arkema France, Colombes (FR)
PCT Filed May 12, 2020, PCT No. PCT/FR2020/050789
§ 371(c)(1), (2) Date Nov. 15, 2021,
PCT Pub. No. WO2020/229774, PCT Pub. Date Nov. 19, 2020.
Claims priority of application No. 1905110 (FR), filed on May 16, 2019.
Prior Publication US 2022/0227627 A1, Jul. 21, 2022
Int. Cl. C07C 45/42 (2006.01); C01B 21/16 (2006.01)
CPC C01B 21/16 (2013.01) [C07C 45/42 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A process for preparing hydrazine hydrate, comprising the following steps:
(a) reacting ammonia, hydrogen peroxide and methyl ethyl ketone in the presence of a solution comprising at least one activator to form an azine;
(b) treating the reaction mixture from step (a) to isolate:
an aqueous phase comprising the at least one activator; and
an organic phase comprising the azine and optionally unreacted methyl ethyl ketone;
(c) optionally recycling the aqueous phase to step (a) after optional treatment;
(d) washing the organic phase;
(e) distilling the washed organic phase to recover the azine;
(f) hydrolyzing the azine to give hydrazine hydrate and regenerated methyl ethyl ketone, with pyrazoline-class heterocycles being purged;
(g) optionally recycling the methyl ethyl ketone obtained in step (f) to step (a); and
(h) recycling the pyrazoline-class heterocycles purge obtained in step (f) to one at least of steps (a), (b), (c), (d) or (g).