阅读说明：本技术 采用吡唑啉再循环的制备肼水合物的经改善的方法 (Improved process for making hydrazine hydrate with pyrazoline recycle ) 是由 J-M.萨奇 于 2020-05-12 设计创作，主要内容包括：本发明涉及经改善的方法,该方法用于在活化剂的存在下,通过以过氧化氢对氨进行氧化,从由甲乙酮获得的甲乙酮的吖嗪制备肼水合物,特征在于,该方法包括使吡唑啉族杂环化物的清除物再循环的步骤。(The invention relates to an improved method for producing hydrazine hydrate from azines of methyl ethyl ketone obtained from methyl ethyl ketone by oxidizing ammonia with hydrogen peroxide in the presence of an activating agent, characterized in that it comprises a step of recycling the purge of pyrazoline heterocycles.)

1. a method for preparing hydrazine hydrate comprising the steps of:

(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 an activator; and

-an organic phase comprising the resulting azine and optionally unreacted methyl ethyl ketone;

(c) optionally recycling the aqueous phase to step (a) after optional treatment;

(d) washing the organic phase, preferably in countercurrent;

(e) distilling the washed organic phase to recover the azine;

(f) hydrolyzing azine to obtain hydrazine hydrate and regenerating methyl ethyl ketone, wherein pyrazoline heterocycles are removed;

(g) optionally recycling the methyl ethyl ketone obtained in step (f) to step (a);

(h) recycling the pyrazoline heterocycle purge obtained in step (f) to at least one of steps (a), (b), (c), (d) or (g).

2. The process according to claim 1, wherein the pyrazoline heterocycle purge obtained in step (f) is recycled to at least one of steps (c), (d) or (g).

3. The process according to claim 1 or 2, wherein the pyrazoline-type heterocycle purge obtained in step (f) is recycled to the organic phase washing step (d).

4. The method of claim 3, wherein pyrazoline heterocycle scavenger is sufficient to perform the organic phase wash without adding water.

5. The method according to any one of the preceding claims, wherein pyrazoline-type heterocycle scavenging is carried out by extraction, preferably by continuous lateral withdrawal.

6. The process of any one of the preceding claims, wherein the recycling step (h) is carried out continuously.

7. The method according to any one of the preceding claims, wherein the pyrazoline heterocycles are 3, 5-diethyl-5-methylpyrazoline and 3,4, 5-trimethyl-5-ethylpyrazoline.

8. The process according to any one of the preceding claims, wherein step (f) of azine hydrolysis and methyl ethyl ketone regeneration is carried out in a packed distillation column or a tray distillation column, preferably operating at a pressure of from 2 to 25 bar and having a bottom temperature of from 150 ℃ to 200 ℃.

9. The process as claimed in claim 8, wherein the amount of pyrazoline heterocycles is not more than 5% by weight, more preferably from 1% to 3% by weight, relative to the total weight of the liquid phase on the tray of the column or relative to the total weight of the fraction of the hydrolysis column in which the amount of pyrazoline heterocycles is at its highest.

10. The process of any one of the preceding claims, wherein the activator is acetamide.

Drawings

FIG. 1: the preparation method of hydrazine hydrate according to the invention

Fig. 1 represents an example of an industrial implementation of the process according to the invention.

A shows the synthesis step (a) of MEK azine; stream 1 comprises, for example, ammonia, hydrogen peroxide, and make-up required amounts of acetic acid, ammonium acetate or acetamide or methyl ethyl ketone, as well as various additives used during the synthesis step (e.g., peroxide stabilizers). Stream 13 corresponds to the recycling of the aqueous phase according to step (c) after it has been thermally regenerated and concentrated to remove excess water. Stream 8 corresponds to the recycling of the methyl ethyl ketone regenerated during the hydrolysis step and recovered at the outlet of the hydrolysis column E according to step (g).

B shows a settler (settler) at the outlet of azine synthesis step (a), which receives the reaction mixture 2. It allows an organic phase comprising the crude MEK azine corresponding to stream 3 and an aqueous phase comprising an activator (e.g. acetamide) and corresponding to stream 4 to be separated according to step (b).

C shows a countercurrent washing column according to step (d). The organic phase (stream 3) is introduced at the lower part (foot) of column C and is washed in countercurrent with stream 10 (corresponding to the pyrazoline-type heterocycle purge extracted from the tray of azine hydrolysis column E according to step (h)). Stream 12 (corresponding to the aqueous phase at the outlet of the washing column C) is then sent to section (section) G, corresponding to the step of thermal regeneration and concentration of the aqueous phase using stream 4.

According to step (e), the washed organic phase (stream 5) is sent to a distillation column D for purification. Using this column, a small amount of methyl ethyl ketone recycled at a can be recovered at the top and pyrazoline-type heterocycles present in the azine (not shown) are removed in the bottom.

The organic phase containing the distilled azine (stream 6) is then sent to a hydrolysis column E. The hydrolysis column E is a distillation column operated under pressure. Distilled azine 6 and the water required for hydrolysis (stream 7) are introduced into column E.

After the hydrolysis step (F), at the top, after steam condensation and decantation at F, a stream 8 is obtained comprising mainly methyl ethyl ketone, water and a small amount of azine. This phase is recycled to azine synthesis step a.

The decanted aqueous phase (stream 9) is sent to the top of the hydrolysis column.

Stream 11 corresponds to the hydrazine hydrate solution obtained and recovered at the bottom of the column.

The examples are given for illustrative purposes only and do not limit the invention.

Examples

Example 1: preparation method according to the invention

The method described in figure 1 was used.

Column E was operated under the conditions described below:

after the hydrolysis step (f), at the top, after steam condensation and decantation, about 6500 kg/hour of an organic phase mainly comprising methyl ethyl ketone, water and a small amount of azine is extracted (stream 8). This phase is recycled to azine synthesis step a.

The decanted aqueous phase (stream 9) is returned to the top of the hydrolysis column.

Purging (stream 10) is performed as follows: on the tray of the hydrolysis column, at a rate of 1477 kg/hour, at the position where the pyrazoline-based heterocyclic compound accumulated. The purge is sent to a washing column C in order to wash the organic phase coming from the separator B.

The analyses performed around the scrub column C and the flow rates are reported in table 1:

it is seen that during the washing of the azine stream 3 by the pyrazoline-type heterocycle purge 10, the pyrazoline-type heterocycles contained in the purge 10 are virtually quantitatively transferred to the azine stream 5 at the outlet of the washing column.

It is seen that when stream 3 is washed with pyrazoline-type heterocyclic purge 10, 150 kg/hour of azine is thus recovered in the organic phase (stream 5). Subject to analytical uncertainty, this corresponds to the recovery of 37 and 88kg of azine and hydrazone contained in the purge 10.

During the purification of azines, pyrazoline is removed by distillation of stream 5, giving distilled azine 6 at the bottom of the distillation column, as well as a heavy residue.

Hydrazine hydrate solution obtained at the bottom of the column (found to contain 22.2% hydrazine hydrate or 14.1% hydrazine N)₂H₄) (stream 11) contains only very low concentrations of pyrazoline, which does not cause coloration problems in the final hydrazine hydrate solution obtained after concentration in the process.

Furthermore, a review (audio) was carried out around the hydrolysis column E and reported in table 2: