阅读说明：本技术 一种n-甲基氧化吗啉的制备方法 (Preparation method of N-methylmorpholine oxide ) 是由 黄凤翔 杨俊� 袁波 石飞 于 2020-08-12 设计创作，主要内容包括：本发明提供了一种N-甲基氧化吗啉的制备方法,以钼硅中空微球为催化剂,催化N-甲基吗啉和双氧水反应合成N-甲基氧化吗啉；本发明所提供的N-甲基氧化吗啉的制备方法采用钼硅中空微球作为催化剂,在低浓度的H<Sub>2</Sub>O<Sub>2</Sub>溶液中N-甲基吗啉依然能够被氧化,反应过程无需加入过量的H<Sub>2</Sub>O<Sub>2</Sub>,节约了原料的同时减少了多余水的生成,降低了后续减压精馏的压力。(The invention provides a preparation method of N-methylmorpholine oxide, which takes molybdenum-silicon hollow microspheres as a catalyst to catalyze N-methylmorpholine and hydrogen peroxide to react and synthesize the N-methylmorpholine oxide; the preparation method of N-methylmorpholine oxide provided by the invention adopts molybdenum-silicon hollow microspheres as a catalyst and adopts low-concentration H 2 O 2 The N-methylmorpholine in the solution can still be oxidized, and excessive H does not need to be added in the reaction process 2 O 2 The raw materials are saved, the generation of redundant water is reduced, and the pressure of subsequent decompression and rectification is reduced.)

1. The preparation method of N-methylmorpholine oxide is characterized in that molybdenum-silicon hollow microspheres are used as a catalyst to catalyze N-methylmorpholine and hydrogen peroxide to react to synthesize the N-methylmorpholine oxide.

2. The method for preparing N-methylmorpholine-N-oxide according to claim 1, wherein the amount of the molybdenum-silicon hollow microspheres is 0.2-0.4 wt% of the mass of N-methylmorpholine.

3. The method for preparing N-methylmorpholine-N-oxide as claimed in claim 1, wherein the molybdenum-silicon hollow microspheres are prepared by the following steps:

s1, mixing a molybdenum source compound and a sulfur source compound, adding the obtained mixture into ionic liquid, uniformly stirring, putting into a reaction kettle, heating, centrifuging, cleaning and drying the obtained mixture after reaction to obtain MoS₂；

S2, sequentially hydrolyzing and emulsifying the silicon source compound, filtering, washing, drying and roasting to obtain SiO₂Hollow microspheres;

s3, MoS prepared in the step S1₂And SiO obtained in step S2₂Mixing the hollow microspheres in deionized water, and performing ultrasonic treatment, standing, washing, drying and roasting to obtain the molybdenum-silicon hollow microspheres.

4. The method according to claim 3, wherein in step S1, the stirring time is 20min-30min, the reaction kettle heating time is 4h-6h, and the reaction kettle heating temperature is 230 ℃ to 250 ℃.

5. The method according to claim 3, wherein in step S1, the mass ratio of the molybdenum source compound to the sulfur source compound to the ionic liquid is 1: (1-2): (9-11).

6. The method according to claim 5, wherein the molybdenum source compound is: sodium molybdate, potassium molybdate, ammonium molybdate or sodium thiomolybdate;

the sulfur source compound is: thiourea, sulfur, sodium thiosulfate, or sodium sulfide;

the ionic liquid is as follows: 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium tetrafluoroborate or 1-butyl-3-methylimidazolium trichloroacetate.

7. The method according to claim 3, wherein in step S2, the silicon source compound is methyl orthosilicate, ethyl orthosilicate, or tetraethyl orthosilicate, and the emulsifying medium used for emulsification is laureth, isooctyletheth, or fatty alcohol-polyoxyethylene ether.

8. The method for preparing N-methylmorpholine oxide according to claim 3, wherein the hydrolysis is carried out in four stages, the first hydrolysis is carried out at a temperature of 30-40 ℃ for a time of 0.2-0.4 h, the second hydrolysis is carried out at a temperature of 45-55 ℃ for a time of 0.2-0.4 h, the third hydrolysis is carried out at a temperature of 65-75 ℃ for a time of 0.2-0.4 h, and the fourth hydrolysis is carried out at a temperature of 85-95 ℃ for a time of 0.2-0.4 h.

9. The method according to claim 3, wherein in step S3, the MoS is obtained₂With the SiO₂The mass ratio of the hollow microspheres is 1: (4-8).

10. The method for preparing N-methylmorpholine oxide as claimed in claim 3, wherein in step S3, the ultrasonic treatment time is 20min-30min, the standing time is 10h-12h, the calcination time is 8h-10h, and the calcination temperature is 800-1000 ℃.

Technical Field

The invention belongs to the technical field of chemical processes, and particularly relates to a preparation method of N-methylmorpholine oxide.

Background

Morpholine and derivatives thereof are important fine chemical products and are widely applied to the industries of pesticides, medicines, chemical engineering and the like. Wherein, N-methylmorpholine N-oxide (NMMO) is a high-grade tertiary amine oxide, is a special excellent solvent with extremely strong dissolving performance to cellulose, is easy to recover, has a recovery rate of more than 99 percent, and can be used for spinning and manufacturing artificial cotton, cellophane, food casings and the like.

Publication 1 (Liutian. study of Synthesis Process of N-methylmorpholine oxide [ J ]]Shanghai chemical industry 2014,39(08): 16-18) discloses a synthesis process of N-methylmorpholine oxide, wherein self-made N-methylmorpholine is used as a raw material, NaOH is used as a catalyst, and H is used as H₂O₂Preparing N-methylmorpholine oxide by using oxidant, in the process, excessive H is required to be dripped₂O₂The raw materials are wasted, and the time of the subsequent vacuum rectification is prolonged, and the quality of the finally harvested N-methylmorpholine oxide is affected by the increase of the time of the vacuum rectification.

Publication 2 (the study on the synthesis of N-methylmorpholine oxide (NMMO) (sun-juan.,. J.,. proceedings of the national institute of science and technology, 2007(02):33-35+40.) also discloses a process for synthesizing N-methylmorpholine oxide, in which a small amount of manganese dioxide is added after the reaction is completed to decompose unreacted hydrogen peroxide, thus increasing the step of filtering manganese dioxide, and the excess water produced increases the time for subsequent separation and crystallization, resulting in low overall efficiency.

It can be seen that the N-methylmorpholine oxide is mainly prepared by oxidizing N-methylmorpholine, and the preparation process is mature, but the defects of low yield and excessive addition of oxidant are still existed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the preparation method of the N-methylmorpholine oxide, which takes the molybdenum-silicon hollow microspheres as the catalyst, obviously improves the oxidation effect of hydrogen peroxide on the N-methylmorpholine and generates no other byproducts except a small amount of water.

The invention provides a preparation method of N-methylmorpholine oxide, which takes molybdenum-silicon hollow microspheres as a catalyst to catalyze N-methylmorpholine and hydrogen peroxide to react and synthesize the N-methylmorpholine oxide.

In the technical scheme, the transition element molybdenum in the molybdenum-silicon hollow microsphere has the characteristic of multiple adjustable valence states, and is applied to catalytic reaction to improve the reaction efficiency.

Further, the dosage of the molybdenum-silicon hollow microspheres is 0.2-0.4 wt% of the mass of the N-methylmorpholine.

Further, the preparation method of the molybdenum-silicon hollow microsphere comprises the following steps:

s1, mixing the molybdenum source compound solution and the sulfur source compound solution, adding the obtained mixture into ionic liquid, uniformly stirring, putting into a reaction kettle, heating, centrifuging, cleaning and drying the obtained mixture after reaction to obtain MoS₂；

S2, sequentially hydrolyzing and emulsifying the silicon source compound, filtering, washing, drying and roasting to obtain SiO₂Hollow microspheres;

s3, MoS prepared in the step S1₂And SiO obtained in step S2₂Mixing the hollow microspheres in deionized water, and performing ultrasonic treatment, standing, washing, drying and roasting to obtain the molybdenum-silicon hollow microspheres.

Intermediate product MoS₂Because of the layered structure, the catalyst has larger specific surface area and stronger reaction activity, and is doped in SiO₂In the hollow microspheres, SiO on the one hand₂The hollow microspheres can be used as a micro-reactor to improve the catalytic efficiency, and SiO is used₂The shell of the hollow microsphere is densely distributed with a porous structure and MoS in a layered structure₂The specific surface area of the whole material is increased and the adsorption capacity of the whole material is enhanced by mutual matching, so that the catalytic activity of the material is improved, and the low-concentration H is obtained₂O₂The N-methylmorpholine in the solution can still be oxidized, and excessive H does not need to be added in the reaction process₂O₂。

Further, in step S1, the stirring time is 20min to 30min, the heating time of the reaction kettle is 4h to 6h, and the heating temperature of the reaction kettle is 230 ℃ to 250 ℃.

Further, in step S1, the mass ratio of the molybdenum source compound, the sulfur source compound, and the ionic liquid is 1: (1-2): (9-11).

Further, the molybdenum source compound is: sodium molybdate, potassium molybdate, ammonium molybdate or sodium thiomolybdate, preferably sodium molybdate;

the sulfur source compound is: thiourea, sulphur, sodium thiosulfate or sodium sulfide, preferably sodium sulfide;

the ionic liquid is as follows: 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium tetrafluoroborate or 1-butyl-3-methylimidazolium trichloroacetate, preferably 1-butyl-3-methylimidazolium bromide.

Further, in step S2, the silicon source compound is methyl orthosilicate, ethyl orthosilicate, or tetraethyl orthosilicate, preferably methyl orthosilicate; the emulsifying medium used for emulsification is polyoxyethylene lauryl ether, isooctyl polyoxyethylene ether or fatty alcohol polyoxyethylene ether, preferably polyoxyethylene lauryl ether.

In the technical scheme, sodium molybdate is purchased from urban Keron chemical Co., Ltd, sodium sulfide is purchased from urban Keron chemical Co., Ltd, 1-butyl-3-methylimidazolium bromide is purchased from Shanghai Ethyl chemical Co., Ltd, methyl orthosilicate is purchased from Jiangsu province Haian petrochemical plant, and lauryl polyoxyethylene ether is purchased from Quanzhou City Bixin chemical Co., Ltd.

Furthermore, the hydrolysis is divided into four stages, the temperature of the first hydrolysis is 30-40 ℃, the time is 0.2-0.4 h, the temperature of the second hydrolysis is 45-55 ℃, the time is 0.2-0.4 h, the temperature of the third hydrolysis is 65-75 ℃, the time is 0.2-0.4 h, the temperature of the fourth hydrolysis is 85-95 ℃, and the time is 0.2-0.4 h.

Further, the MoS₂With the SiO₂The mass ratio of the hollow microspheres is 1: (4-8).

Further, in step S3, the ultrasonic time is 20min-30min, the standing time is 10h-12h, the roasting time is 8h-10h, and the roasting temperature is 800 ℃ to 1000 ℃.

The preparation method of the N-methylmorpholine oxide provided by the invention has the beneficial effects that:

(1) the invention adopts molybdenum-silicon hollow microspheres as a catalyst and adopts the method that the catalyst is used for preparing the low-concentration H₂O₂The N-methylmorpholine in the solution can still be oxidized, and excessive H does not need to be added in the reaction process₂O₂The raw materials are saved, the generation of redundant water is reduced, and the subsequent reduced pressure rectification is reducedThe pressure of (a);

(2) the total reserves of molybdenite are in the front of the world, so that compared with other transition elements, the cost of molybdenum selection is lower, and the cost for preparing N-methylmorpholine oxide is lower;

(3)MoS₂in combination with SiO₂The porous structure of the hollow microsphere enables the prepared molybdenum-silicon hollow microsphere to further improve the catalytic effect.

Drawings

FIG. 1 is a TEM image of a molybdenum-silicon hollow microsphere prepared in example 1 of the present invention;

FIG. 2 shows MoS obtained in example 1 of the present invention₂XRD pattern of (a).

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.