阅读说明：本技术 采用肟再循环的制备肼水合物的经改善的方法 (Improved process for making hydrazine hydrate with oxime 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,该方法包括使经清除的甲乙酮的肟再循环的步骤。(The present invention relates to an improved process for the preparation of hydrazine hydrate from azines of methyl ethyl ketone obtained from methyl ethyl ketone by oxidation of ammonia with hydrogen peroxide in the presence of an activating agent, characterized in that it comprises a step of recycling the oxime of the methyl ethyl ketone that has been purged.)

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

-reacting ammonia, hydrogen peroxide and methyl ethyl ketone in the presence of a solution comprising at least one activator to form an azine;

-hydrolyzing the resulting azine of methyl ethyl ketone to obtain hydrazine hydrate, wherein during the hydrolysis step the oxime of methyl ethyl ketone is purged;

the process is characterized in that the methyl ethyl ketoxime scavenger is recycled upstream of the hydrolysis step.

2. A process for the preparation of hydrazine hydrate as claimed in claim 1 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 oxime of methyl ethyl ketone 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) optionally, distilling the washed organic phase to recover the azine;

(f) hydrolyzing the azine to obtain hydrazine hydrate and regenerating methyl ethyl ketone, wherein the methyl ethyl ketone is purged of oxime;

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

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

3. The process of claim 2, wherein the methyl ethyl ketoxime purge obtained in step (f) is recycled to at least one of steps (c), (d) or (g).

4. The process as claimed in claim 2, wherein the methyl ethyl ketoxime purge obtained in step (f) is recycled to the organic phase washing step (d).

5. The process of claim 4, wherein the methyl ethyl ketoxime scavenger is sufficient to effect the organic phase wash without the addition of water.

6. The process of any one of the preceding claims, wherein methyl ethyl ketoxime removal is carried out by extraction, preferably by continuous lateral withdrawal.

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

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. Process as claimed in claim 8, wherein the amount of methyl ethyl ketoxime does not exceed 20% by weight, preferably between 5% and 13% by weight, relative to the total weight of the liquid phase on the trays or relative to the total weight in the fraction of the column having the highest concentration of methyl ethyl ketoxime.

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) corresponding to stream 4 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 methyl ethyl ketoxime 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 the heavy impurities present in the azine removed in the bottom (not shown).

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.

At the top, the decanted aqueous phase (stream 9) is returned to 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 point where the methyl ethyl ketoxime 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 when stream 3 is washed with oxime 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. In addition, the oxime contained in the purge 10 is transferred close to quantitatively into the stream of azine 5 at the outlet of the washing column.

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

it is seen that when the process is operated according to the invention with recycling of the purge 10, the oxime is mainly consumed during the hydrolysis of the azine in column E.

Stream 3 (Table 1) represents 154 kg/hour of oxime produced upstream of the hydrolysis by the synthesis step A of azine and the thermal regeneration step G of the aqueous phase. This production is well compensated by the loss of oxime observed between the washing step C and the hydrolysis E, and therefore the recycling of oxime at 171 kg/hour between stream 5(318 kg/hour of oxime) and stream 10 corresponds to the consumption of oxime at 318-.

It was observed that the oxime was not increased in this process, maintaining a concentration of 11% on the tray of the hydrolysis column E.