# US 2026/0274786 A1 · Process for preparing azine using reactors in cascade

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- Number: US 2026/0274786 A1
- Document ID: US20260274786A1
- Status: Published application
- Kind: A1
- Application number: 18/875,682
- Filed: 2023-06-23
- Published: 2026-09-17
- Earliest claimed: 2022-06-24
- Applicants: Arkema France
- Inventors: Jean-Marc SAGE; Valérie HENRARD
- Web page: https://patentgrep.com/patent/US20260274786A1

## CPC

- C01B 21/16: Hydrazine; Salts thereof
- C07C 249/16: of hydrazones
- B01J 19/1862: {placed in series}
- C07C 241/02: Preparation of hydrazines
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

The invention relates to a process for continuously preparing azine, comprising a step of reacting ammonia, hydrogen peroxide and a ketone of formula R1R2CO, the groups R1 and R2 denoting, independently of one another, a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl group, in the presence of an aqueous solution comprising at least one activator to form an azine, the reaction being performed in at least 2 reactors arranged in cascade, the agitation of the first reactor being less than the agitation of the following reactor or each of the following reactors, the reactants being injected at the first reactor, the aqueous solution comprising at least one activator and comprising dissolved ammonia in a proportion of between 50% and 100% relative to the saturation of ammonia in pure water at the temperature of the aqueous solution.

## Claims

### Claim 1

Process for continuously preparing azine, comprising a step a) of reacting ammonia, hydrogen peroxide and a ketone of formula R1R2CO, the groups R1 and R2 denoting, independently of one another, a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl group, in the presence of an aqueous solution comprising at least one activator to form an azine,
the reaction being performed in at least 2 reactors arranged in cascade,
the agitation of the first reactor being less than the agitation of the following reactor or each of the following reactors,
the hydrogen peroxide, the ketone and an aqueous solution comprising at least one activator and comprising dissolved ammonia, preferably in a proportion of between 50% and 100% relative to the saturation of ammonia in pure water at the temperature of the aqueous solution, being injected into the first reactor.

### Claim 2 (depends on 1)

Process according to claim 1, characterized in that the aqueous solution comprising at least one activator and dissolved ammonia originates from an absorption column.

### Claim 3 (depends on 1)

Process according to claim 1, characterized in that the agitation within the first reactor is characterized by a Froude number of strictly less than 0.018 and the agitation of the following reactor(s) is characterized by a Froude number of greater than or equal to 0.018.

### Claim 4 (depends on 1)

Process according to claim 1, characterized in that the reaction is carried out in 3, 4 or 5 reactors arranged in cascade.

### Claim 5 (depends on 1)

Process according to claim 1, characterized in that the ketone used in step a) is methyl ethyl ketone.

### Claim 6 (depends on 1)

Process according to claim 1, characterized in that it comprises, after the reaction step a), a step b) of separating the stream formed on conclusion of the reaction step a).

### Claim 7 (depends on 6)

Process according to claim 6, characterized in that it comprises a step c) of regenerating and concentrating the aqueous phase from the separation step b).

### Claim 8 (depends on 7)

Process according to claim 7, characterized in that during step c) of regenerating and concentrating the aqueous phase from the separation step b), the aqueous phase thus regenerated and concentrated is recycled into the ammonia absorption column.

### Claim 9 (depends on 7)

Process according to claim 7, characterized in that during step c) of regenerating and concentrating the aqueous phase from the separation step b), a gaseous ammonia stream is recycled into the ammonia absorption column.

### Claim 10 (depends on 6)

Process according to claim 6, characterized in that it comprises:
a step of washing the organic phase, from the separation step b),
a step of hydrolysing the stream obtained from the preceding step to obtain hydrazine hydrate.