阅读说明：本技术 一种采用管式反应器制备氧化甲基吗啉的方法 (Method for preparing methyl morpholine oxide by adopting tubular reactor ) 是由 施晓旦 吴国玲 尹东华 于 2021-09-23 设计创作，主要内容包括：本发明公开了一种采用管式反应器制备氧化甲基吗啉的方法,该方法包含：步骤1、将甲基吗啉原料加水稀释,然后与双氧水分别置于不同的原料储罐中；步骤2、通过两个计量输送泵分别从原料储罐中将双氧水和稀释后的甲基吗啉同时泵入管式反应器中；步骤3、在管式反应器内进行反应,反应温度为40-100℃,压力为0.01Mpa-0.1Mpa,反应停留时间为5min-60min；步骤4、反应后将物料转至处理装置中进行除杂处理,得到氧化甲基吗啉。本发明还公开了该方法制备的氧化甲基吗啉。本发明提供的采用管式反应器制备氧化甲基吗啉的方法,能够解决现有技术中合成NMMO反应时间长、副反应多、存在安全隐患等问题。(The invention discloses a method for preparing methyl morpholine oxide by adopting a tubular reactor, which comprises the following steps: step 1, adding water to dilute a methylmorpholine raw material, and then respectively placing the diluted methylmorpholine raw material and hydrogen peroxide in different raw material storage tanks; step 2, pumping hydrogen peroxide and diluted methylmorpholine from a raw material storage tank into a tubular reactor through two metering delivery pumps respectively; step 3, carrying out reaction in a tubular reactor, wherein the reaction temperature is 40-100 ℃, the pressure is 0.01-0.1 Mpa, and the reaction residence time is 5-60 min; and 4, transferring the material after the reaction to a processing device for impurity removal to obtain the methylmorpholine oxide. The invention also discloses the methylmorpholine oxide prepared by the method. The method for preparing the methylmorpholine oxide by adopting the tubular reactor can solve the problems of long reaction time, more side reactions, potential safety hazards and the like in the NMMO synthesis in the prior art.)

1. A method for preparing methyl morpholine oxide by using a tubular reactor, which is characterized by comprising the following steps:

step 1, adding water to dilute a methylmorpholine raw material, and then respectively placing the diluted methylmorpholine raw material and hydrogen peroxide in different raw material storage tanks;

step 2, pumping hydrogen peroxide and diluted methylmorpholine from a raw material storage tank into a tubular reactor through two metering delivery pumps respectively;

step 3, carrying out reaction in a tubular reactor;

and 4, after the reaction, removing impurities from the material to obtain the methylmorpholine oxide.

2. The method for preparing methylmorpholine oxide by using a tubular reactor as claimed in claim 1, wherein in step 1, the mass concentration of methylmorpholine after being diluted by water is 50-99%.

3. The method for preparing methyl morpholine oxide by using a tubular reactor as claimed in claim 1, wherein in the step 2, the molar ratio of hydrogen peroxide to methyl morpholine is (0.9-2): 1.

4. the method for preparing methylmorpholine oxide using a tubular reactor as claimed in claim 3, wherein in step 2, the tubular reactor is model number VTRWSS 05.

5. The method for preparing methyl morpholine oxide by using a tubular reactor as claimed in claim 4, wherein the material of said tubular reactor is silicon carbide, stainless steel or hastelloy.

6. The method according to claim 5, wherein the rotation speed of the tubular reactor is 15-30 Hz.

7. The method for preparing methylmorpholine oxide using a tubular reactor as claimed in claim 1, wherein in step 3, the reaction temperature is 40-100 ℃.

8. The method for preparing methylmorpholine oxide using a tubular reactor as claimed in claim 7, wherein in step 3, the reaction pressure is 0.01MPa to 0.1 MPa.

9. The method for preparing methylmorpholine oxide using a tubular reactor as claimed in claim 8, wherein in step 3, the reaction residence time is 5min-60 min.

10. Methyl morpholine oxide prepared according to the process of any one of claims 1 to 9.

Technical Field

The invention relates to a method for preparing methylmorpholine oxide (NMMO) in the technical field of compound synthesis, in particular to a method for preparing methylmorpholine oxide by adopting a tubular reactor.

Background

The methylmorpholine oxide is NMMO (N-methylmorpholine-N-methylmorpholine oxide), is a heterocyclic tertiary amine oxide, is a crystalline solid or liquid at normal temperature, is nontoxic, weakly alkaline and strong in hygroscopicity, and can be combined with a plurality of water molecules per molecule. The compound is widely used as a solvent in the organic synthesis process; the foaming catalyst for polyester plastics has excellent performance; is a special good solvent with extremely strong solubility to cellulose.

At present, there are many methods for synthesizing NMMO, and the more mature synthesis methods at home and abroad mainly include two methods, namely a hydrogen peroxide oxidation method and a molecular oxygen-aldehyde catalytic oxidation method. The hydrogen peroxide method is widely applied due to the advantages of mild reaction conditions, high product quality and the like, and the method is widely used for preparing NMMO in China at present. Most of the existing hydrogen peroxide oxidation methods use catalysts to promote forward reaction, the reaction time of kettle type reaction materials in a reaction kettle is long, the stirring and mixing effects are poor, the heat transfer effects are poor, the reaction time is long, byproducts are easily generated, the color and the quality of products are affected, the reaction is severe, the spraying can be generated carelessly slightly, and potential safety hazards exist.

Disclosure of Invention

The invention aims to provide a method for preparing NMMO through a tubular reactor, which is used in the technical field of compound synthesis and solves the problems of long reaction time, more side reactions, potential safety hazards and the like in the prior art for synthesizing NMMO.

In order to achieve the above object, the present invention provides a method for preparing methylmorpholine oxide by using a tubular reactor, wherein the method comprises: step 1, adding water to dilute a methylmorpholine raw material, and then respectively placing the diluted methylmorpholine raw material and hydrogen peroxide in different raw material storage tanks; step 2, pumping hydrogen peroxide and diluted methylmorpholine from a raw material storage tank into a tubular reactor through two metering delivery pumps respectively; step 3, carrying out reaction in a tubular reactor; and 4, after the reaction, removing impurities from the material to obtain the methylmorpholine oxide.

In the above method for preparing methyl morpholine oxide by using a tubular reactor, in step 1, the mass concentration of methyl morpholine after being diluted by water is 50-99%.

In the above method for preparing methyl morpholine oxide by using a tubular reactor, in step 2, the molar ratio of hydrogen peroxide to methyl morpholine is (0.9-2): 1.

the method for preparing methyl morpholine oxide by using the tubular reactor is described above, wherein in the step 2, the model of the tubular reactor is VTRWSS 05.

The method for preparing methyl morpholine oxide by using the tubular reactor is characterized in that the tubular reactor is made of silicon carbide, stainless steel or hastelloy.

The method for preparing the methylmorpholine oxide by using the tubular reactor is characterized in that the rotating speed of the tubular reactor is 15-30 Hz.

In the above method for preparing methyl morpholine oxide by using a tubular reactor, in step 3, the reaction temperature is 40-100 ℃.

In the above method for preparing methyl morpholine oxide by using a tubular reactor, in step 3, the reaction pressure is 0.01Mpa-0.1 Mpa.

In the above method for preparing methyl morpholine oxide by using a tubular reactor, in step 3, the reaction residence time is 5min to 60 min.

The invention also provides the methylmorpholine oxide prepared by the method.

The method for preparing the methylmorpholine oxide by adopting the tubular reactor has the following advantages:

the method of the invention replaces the traditional kettle-type dripping process condition, and greatly shortens the reaction time by adopting the new process of the tubular reactor; the tubular reactor has extremely high heat and mass transfer efficiency, the traditional dropwise addition reaction needs to add a catalyst to accelerate the reaction, and the tubular reactor can achieve higher reaction efficiency without adding a solid catalyst in the preparation process, thereby saving the subsequent catalyst recovery process, greatly shortening the reaction time and realizing the continuous and safe production; the tubular reactor reduces the equipment requirement, is easy to operate, and reduces the occupied area and investment.

Detailed Description

The following further describes embodiments of the present invention.

The invention provides a method for preparing methyl morpholine oxide by adopting a tubular reactor, which comprises the following steps: step 1, adding water to dilute a methylmorpholine raw material, and then respectively placing the diluted methylmorpholine raw material and hydrogen peroxide in different raw material storage tanks; step 2, pumping hydrogen peroxide and diluted methylmorpholine from a raw material storage tank into a tubular reactor through two metering delivery pumps respectively; step 3, carrying out reaction in a tubular reactor; and 4, transferring the material after the reaction to a processing device for impurity removal to obtain the methylmorpholine oxide.

In the step 1, the mass concentration of the methylmorpholine after being diluted by water is 50-99%.

In the step 2, the molar ratio of the hydrogen peroxide to the methyl morpholine is (0.9-2): 1.

in step 2, the tubular reactor was model number VTRWSS 05.

The tubular reactor is a tubular continuous operation reactor with large length-diameter ratio, belonging to a plug flow reactor. The reactor can be very long, the tubular reactor has small back mixing, so the volume efficiency (unit volume production capacity) is high, and the reactor is especially suitable for occasions requiring higher conversion rate or having series side reactions.

The material of the tubular reactor is silicon carbide, stainless steel or hastelloy.

The rotation speed of the tubular reactor is 15-30 Hz.

In step 3, the reaction temperature is 40-100 ℃.

In step 3, the reaction pressure is 0.01MPa-0.1 MPa.

In the step 3, the reaction residence time is 5min-60 min.

The invention also provides the methylmorpholine oxide prepared by the method.

The process for preparing methylmorpholine oxide by using a tubular reactor according to the present invention will be further described with reference to the following examples.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; the reagents and materials used, unless otherwise indicated, are commercially available.

Example 1

A method for preparing NMMO using a tubular reactor, comprising the steps of:

step 1, adding water to dilute the methylmorpholine to 50% of mass concentration.

And 2, respectively pumping hydrogen peroxide and methyl morpholine with the content of 50% from a raw material storage tank into the tubular reactor simultaneously through two metering delivery pumps, wherein the molar ratio of the hydrogen peroxide to the methyl morpholine is 0.9: 1.

And 3, reacting in a tubular reactor at 40 ℃ and 0.01MPa for 60 min.

And 4, transferring the material to a processing device after reaction for impurity removal treatment to obtain the NMMO.

Wherein the tubular reactor is made of stainless steel; the rotational speed of the tubular reactor was 15 Hz.

Example 2

A method for preparing NMMO using a tubular reactor, comprising the steps of:

step 1, adding water to dilute the methylmorpholine to 70% of mass concentration.

And 2, respectively pumping hydrogen peroxide and methyl morpholine with the content of 70% from a raw material storage tank into the tubular reactor simultaneously through two metering delivery pumps, wherein the molar ratio of the hydrogen peroxide to the methyl morpholine is 1.2: 1.

And 3, reacting in a tubular reactor at the temperature of 60 ℃ and the pressure of 0.02Mpa for 10 min.

And 4, transferring the material to a processing device after reaction for impurity removal treatment to obtain the NMMO.

Wherein the tubular reactor is made of hastelloy; the rotational speed of the tubular reactor was 20 Hz.

Example 3

A method for preparing NMMO using a tubular reactor, comprising the steps of:

step 1, adding water to dilute the methylmorpholine to a mass concentration of 90%.

And 2, respectively pumping hydrogen peroxide and methyl morpholine with the content of 90% from a raw material storage tank into the tubular reactor through two metering delivery pumps, wherein the molar ratio of the hydrogen peroxide to the methyl morpholine is 2: 1.

And 3, reacting in a tubular reactor at the temperature of 80 ℃ and the pressure of 0.05Mpa for 30 min.

And 4, transferring the material to a processing device after reaction for impurity removal treatment to obtain the NMMO.

Wherein the material of the tubular reactor is silicon carbide; the rotational speed of the tubular reactor was 25 Hz.

Example 4

A method for preparing NMMO using a tubular reactor, comprising the steps of:

step 1, adding water to dilute the methylmorpholine to a mass concentration of 99%.

And 2, respectively pumping hydrogen peroxide and methyl morpholine with the content of 99% from a raw material storage tank into the tubular reactor through two metering delivery pumps, wherein the molar ratio of the hydrogen peroxide to the methyl morpholine is 1.5: 1.

And 3, reacting in a tubular reactor at the reaction temperature of 100 ℃, the pressure of 0.1Mpa and the reaction retention time of 5 min.

And 4, transferring the material to a processing device after reaction for impurity removal treatment to obtain the NMMO.

Wherein the tubular reactor is made of hastelloy; the rotational speed of the tubular reactor was 30 Hz.

Comparative example:

a method of synthesizing NMMO, comprising the steps of:

step 1, 202g of methyl morpholine aqueous solution with the mass concentration of 90% is placed in a four-neck flask, 2g of ammonium pyrophosphate is added as a catalyst, and the mixture is heated to 50 ℃ in a water bath.

And 2, putting 272g of hydrogen peroxide with the content of 30% in a constant-pressure funnel, and dropwise adding the hydrogen peroxide into the four-neck flask obtained in the step 1, wherein the reaction temperature is set to be 50 ℃, and the reaction time is 7 hours.

And 3, after the reaction, precipitating and filtering the product to remove the catalyst, and removing impurities to obtain the NMMO aqueous solution.

The methylmorpholine oxide prepared in each example was subjected to a performance test experiment together with a comparative example.

Yield: in terms of input amount.

pH: and a pH meter.

Chroma: a colorimeter.

The results of the measurements are shown in Table 1 below.

Table 1, experimental results table.

Name (R)	Yield%	pH	Color intensity
				Example 1	80.7	8.7	15
Example 2	94.5	9.1	10
				Example 3	87.3	9.4	40
Example 4	80.2	8.9	60
				Comparative example	67	8.5	70

Experimental detection results prove that each index of the NMMO prepared by the method is within the standard requirement range.

The invention provides a method for preparing methylmorpholine oxide (NMMO) by adopting a tubular reactor, which comprises the steps of respectively pumping hydrogen peroxide and methylmorpholine into the tubular reactor through two metering delivery pumps under the condition of normal pressure or micro-positive pressure, and reacting in the tubular reactor, wherein the reaction temperature is 40-100 ℃, the pressure is 0.01-0.1 MPa, and the reaction retention time is 5-60 min. The invention greatly shortens the reaction time by adopting the new process of the tubular reactor; the high reaction efficiency can be achieved without adding a catalyst in the preparation process of the tubular reactor, the subsequent catalyst recovery process is saved, the reaction time is greatly shortened, and the continuous and safe production is realized; the tubular reactor reduces the equipment requirement, is easy to operate, reduces the occupied area and investment, and is suitable for industrial production.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.