阅读说明：本技术 一种甲基吗啉的连续生产方法 (Continuous production method of methyl morpholine ) 是由 薛士林 陈红星 唐毅 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种甲基吗啉的连续生产方法,以二甘醇、一甲胺为原料,将二甘醇、一甲胺通过高压计量泵连续泵入进料,二甘醇和一甲胺的摩尔比为1:1.2～8,二甘醇泵入速度1～3ml/min,一甲胺泵入速度0.6～6ml/min,反应压力为0.5～1.0MPa、反应温度为200～260℃,二甘醇液空速为0.1～1.0h～1,循环泵的循环气量为30～60L/h,经过固定床反应后物料经过冷凝得到N～甲基吗啉粗产品。本发明所述的一种甲基吗啉的连续生产方法,自制的催化剂填充到固定床反应器,能够实现连续进料,较现有技术中采用的釜式反应器,反应选择性高。(The invention discloses a continuous production method of methyl morpholine, which takes diethylene glycol and monomethylamine as raw materials, and the diethylene glycol and the monomethylamine are continuously pumped into the raw materials through a high-pressure metering pump, wherein the molar ratio of diethylene glycol to monomethylamine is 1: 1.2-8, the pumping speed of diethylene glycol is 1-3 ml/min, the pumping speed of monomethylamine is 0.6-6 ml/min, the reaction pressure is 0.5-1.0 MPa, the reaction temperature is 200-260 ℃, the airspeed of diethylene glycol liquid is 0.1-1.0 h-1, the circulating gas flow of the circulating pump is 30-60L/h, and the raw materials are condensed after the reaction of a fixed bed to obtain a crude product of N-methyl morpholine. According to the continuous production method of methyl morpholine, the self-made catalyst is filled in the fixed bed reactor, continuous feeding can be realized, and the reaction selectivity is high compared with a kettle type reactor adopted in the prior art.)

1. A continuous production method of methyl morpholine uses diethylene glycol and monomethylamine as raw materials, and is characterized in that: continuously pumping diethylene glycol and monomethylamine into a feed through a high-pressure metering pump, wherein the molar ratio of diethylene glycol to monomethylamine is 1: 1.2-8, the pumping speed of diethylene glycol is 1-3 ml/min, the pumping speed of monomethylamine is 0.6-6 ml/min, the reaction pressure is 0.5-1.0 MPa, the reaction temperature is 200-260 ℃, the airspeed of diethylene glycol is 0.1-1.0 h-1, the circulating gas flow of the circulating pump is 30-60L/h, the material is condensed after the reaction of a fixed bed to obtain a crude product of N-methylmorpholine, the fixed bed is formed by stacking copper-loaded catalyst particles with the diameter of phi 5 x (4-5) mm, the thickness of the fixed bed is 40-60 cm, and the copper-loaded catalyst comprises the following components: 30-50 wt% of copper and 50-70 wt% of silicon dioxide, and the fixed bed system maintains the concentration of monomethylamine to be 40-60%.

2. The continuous process for the production of methylmorpholine as claimed in claim 1, wherein: the preparation method of the catalyst of the fixed bed reactor comprises the following steps: dissolving Cu (NO3) 2.3H 2O in water, stirring carrier silicon dioxide and water in a kettle into slurry, simultaneously dropwise adding a sodium carbonate aqueous solution (20%) and a copper nitrate solution, finally ensuring that the slurry solution is neutral (PH is 7), aging in a water bath at 50 +/-5 ℃ for 5 +/-1H, centrifuging, adding an extrusion assistant agent sesbania powder into a filter cake, uniformly stirring with a small amount of water, extruding and forming by a strip extruding machine, cutting into cylinders with the diameter of 5mm and 5mm, drying, roasting at 500 ℃ for 10H, and cooling to the normal temperature for later use.

3. A continuous process for the production of methylmorpholine as claimed in claim 2, wherein: the weight ratio of the copper nitrate trihydrate to the silicon dioxide is 500-600: 200 to 400.

4. A continuous process for the production of methylmorpholine as claimed in claim 2, wherein: the weight of the water is 2-3 times of that of the nitrate when the water is dissolved.

5. A continuous process for the production of methylmorpholine as claimed in claim 2, wherein: the sesbania powder accounts for 2-4% of the weight of the silicon dioxide.

6. A continuous process for the production of methylmorpholine as claimed in claim 2, wherein: the amount of the water used when the water is uniformly mixed with the water is 5-8% of the weight of the silicon dioxide and the extrusion aid.

Technical Field

The invention relates to the field of organic synthesis, in particular to a continuous production method of methylmorpholine.

Background

N-methylmorpholine is an important organic chemical intermediate, and is a colorless to yellow liquid compound with amine smell, and the chemical formula is C5H11 NO. CAS number is 109-02-4, molecular weight is 101.15, the compound has the dual properties of tertiary amine and ether, the compound is widely used as a chemical intermediate, an extracting agent, a corrosion inhibitor, a surfactant and the like, in the polyurethane industry, N-methylmorpholine is used as a catalyst of polyester polyurethane block foam, a solvent (which is an excellent solvent of dye, casomo, wax, shellac and the like), a chlorocarbon stabilizer and an analytical reagent, N-methylmorpholine is also used for synthesizing a rubber accelerator and other fine chemicals, N-methylmorpholine can be synthesized into N-methylmorpholine oxide by oxidizing N-methylmorpholine with hydrogen peroxide, and the N-methylmorpholine oxide is a spinning solvent of Lyocell and Newcell artificial fiber filaments which are called green fibers at present and can also be used as a solvent for producing vegetable intestines.

The synthesis process of N-methylmorpholine is various, and according to the raw material, the morpholine method, the N-methyl diethanol method, the diethanol amine method, the diethylene glycol method and the dichloroethyl ether method are available, wherein the research on methylation by taking morpholine as a raw material is the most, and the method is also an important method for synthesizing N-methylmorpholine. The morpholine methylation method has high price of raw material morpholine, needs a noble metal catalyst, has high generation cost, produces a large amount of industrial wastewater containing formaldehyde and is difficult to treat. Other methods basically adopt concentrated sulfuric acid for dehydration, and have high three wastes and low yield.

Disclosure of Invention

The invention mainly aims to provide a continuous production method of methyl morpholine, which can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for continuously producing methyl morpholine uses diethylene glycol and monomethylamine as raw materials, and comprises the steps of continuously pumping diethylene glycol and monomethylamine into a feed pump through a high-pressure metering pump, wherein the molar ratio of diethylene glycol to monomethylamine is 1: 1.2-8, the pumping speed of diethylene glycol is 1-3 ml/min, the pumping speed of monomethylamine is 0.6-6 ml/min, the reaction pressure is 0.5-1.0 MPa, the reaction temperature is 200-260 ℃, the airspeed of diethylene glycol liquid is 0.1-1.0 h-1, the circulating gas flow of a circulating pump is 30-60L/h, the material is condensed after reaction through a fixed bed to obtain a crude product of N-methyl morpholine, the fixed bed is formed by stacking copper-loaded catalyst particles of phi 5 x (4-5) mm, the thickness of the fixed bed is 40-60 cm, and the copper-loaded catalyst comprises the following components: 30-50 wt% of copper and 50-70 wt% of silicon dioxide, and the fixed bed system maintains the concentration of monomethylamine to be 40-60%.

Preferably, the preparation method of the catalyst of the fixed bed reactor comprises the following steps: dissolving Cu (NO3) 2.3H 2O in water, stirring carrier silicon dioxide and water in a kettle into slurry, simultaneously dropwise adding a sodium carbonate aqueous solution (20%) and a copper nitrate solution, finally ensuring that the slurry solution is neutral (PH is 7), aging in a water bath at 50 +/-5 ℃ for 5 +/-1H, centrifuging, adding an extrusion assistant agent sesbania powder into a filter cake, uniformly stirring with a small amount of water, extruding and forming by a strip extruding machine, cutting into cylinders with the diameter of 5mm and 5mm, drying, roasting at 500 ℃ for 10H, and cooling to the normal temperature for later use.

Preferably, the weight ratio of the copper nitrate trihydrate to the silicon dioxide is 500-600: 200 to 400.

Preferably, the water is 2 to 3 times the weight of the nitrate when dissolved.

Preferably, the sesbania powder accounts for 2-4% of the weight of the silicon dioxide.

Preferably, the amount of the water used when the water is uniformly mixed with the water is 5-8% of the weight of the silicon dioxide and the extrusion aid.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, continuous feeding can be realized through the fixed bed reactor, the production capacity of the device is obviously improved compared with that of a kettle type reactor adopted in the prior art, and the product content is high (more than 99.5%); in addition, the process route of the raw materials of diethylene glycol and monomethylamine is adopted, the raw material cost is low, the selectivity of N-methylmorpholine is more than 92%, the self-made catalyst is filled in the fixed bed reactor, the continuous feeding can be realized, the reaction selectivity is high compared with a kettle type reactor adopted in the prior art, the production capacity of the device is obviously improved, the process is stable, and the product quality is more stable; in addition, the process route of the raw materials of diethylene glycol and monomethylamine is adopted, so that the cost of the raw materials is low. The obtained crude product is directly used in the rectification step to obtain the product. The excessive monomethylamine can be circularly used, the operation is simple, no corrosive or irritant substances are generated in the production process, and only a small amount of water is generated, so that the production equipment cannot be corroded, the environmental pollution cannot be generated, and the method belongs to clean production.

Drawings

FIG. 1 is a structural formula of N-methylmorpholine in the invention;

FIG. 2 shows the reaction equation in the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

as shown in fig. 1-2, the invention relates to a continuous production method of methyl morpholine, diethylene glycol and monomethylamine are used as raw materials, diethylene glycol and monomethylamine are continuously pumped into the raw materials by a high-pressure metering pump, the molar ratio of diethylene glycol to monomethylamine is 1: 1.2-8, the pumping speed of diethylene glycol is 1-3 ml/min, the pumping speed of monomethylamine is 0.6-6 ml/min, the reaction pressure is 0.5-1.0 MPa, the reaction temperature is 200-260 ℃, the airspeed of diethylene glycol liquid is 0.1-1.0 h-1, the circulating gas quantity of a circulating pump is 30-60L/h, the raw materials after reaction in a fixed bed are condensed to obtain a crude product of N-methyl morpholine, the fixed bed is formed by stacking copper-loaded catalyst particles of phi 5 x (4-5) mm, the thickness of the fixed bed is 40-60 cm, and the copper-loaded catalyst component is as follows: 30-50 wt% of copper and 50-70 wt% of silicon dioxide, and the fixed bed system maintains the concentration of monomethylamine to be 40-60%.

The preparation method of the catalyst of the fixed bed reactor comprises the following steps: dissolving Cu (NO3) 2.3H 2O in water, stirring carrier silicon dioxide and the water in a kettle to form slurry, wherein the weight ratio of copper nitrate trihydrate to silicon dioxide is 500-600: 200-400, adding 2-3 times of water by weight of nitrate, simultaneously dripping a sodium carbonate aqueous solution (20%) and a copper nitrate solution, finally ensuring that the slurry solution is neutral (PH is 7), aging in a water bath at 50 +/-5 ℃ for 5 +/-1 h, centrifuging, adding an extrusion assistant agent sesbania powder into a filter cake, wherein the dosage of the sesbania powder accounts for 2-4% of the weight of silicon dioxide, uniformly mixing a small amount of water, wherein the dosage of the water is 5-8% of the weight of the silicon dioxide and the extrusion assistant agent, extruding and forming on a strip extrusion machine, cutting into 5 mm-5 mm cylinders, drying, roasting at 500 ℃ for 10h, cooling to normal temperature, and reserving for later use.

Example 2:

in addition to example 1, the compositional fixed bed was formed by stacking silica-supported copper catalyst particles having a particle diameter of Φ 5 × (4 to 5) mm, and a thickness of 40 cm; composition of silica-supported copper catalyst (by weight): 35% of copper and 65% of silicon dioxide, 570g of Cu (NO3) 2.3H 2O is dissolved in 1200g of water, 300g of carrier silicon dioxide and 1000g of water are stirred into slurry in a kettle, simultaneously sodium carbonate aqueous solution (20%) and copper nitrate solution are added dropwise, finally the slurry solution is ensured to be neutral (PH is 7), the slurry solution is aged in a water bath at 50 +/-5 ℃ for 5 +/-1H, the centrifugation is carried out, 9g of extrusion assistant agent sesbania powder and 22g of water are added into a filter cake to be wetted and uniformly stirred, then the mixture is extruded and formed on an extruding machine to be cut into cylinders with 5mm x 5mm, then the cylinders are dried, roasted at 500 ℃ for 10H and then cooled to room temperature for standby.

Example 3:

on the basis of example 2, the compositional fixed bed was formed by stacking silica-supported copper catalyst particles having a particle diameter of Φ 5 × (4 to 5) mmmand a thickness of 60 cm; composition of silica-supported copper catalyst (by weight): 45% of copper and 55% of silicon dioxide.

Example 4:

on the basis of example 2, a fixed bed reactor 1.0 meter long and 25cm in diameter was packed with ceramic balls of 25cm each above and below and with a self-made catalyst in the middle. After the catalyst is 50cm in thickness, 1.0MPa in pressure, the molar ratio of monomethylamine to diethylene glycol is 8:1, the temperature is 220 ℃ and the circulating gas amount is 30L/h, and a fixed bed reactor is filled, the pressure is tested at 1.8-2.0MPa, no obvious gas leakage exists, nitrogen and hydrogen are replaced, mixed gas with the volume ratio of 4:1 of nitrogen to hydrogen passes through a catalyst bed layer, the catalyst bed layer is gradually heated to 280 ℃ and continuously aged for 72 hours, and then the temperature is reduced to 220 ℃ for later use.

Preparation of N-methylmorpholine: filling hydrogen into a fixed bed reactor to 0.4Mpa, stabilizing the temperature of a bed layer at about 220 ℃, continuously pumping monomethylamine (the pump speed is 4ml/min) by a metering pump, starting a circulating pump, circulating reaction gas, adjusting a frequency converter to ensure that the circulating gas amount is 30L/h, sampling after 2 hours, detecting that the concentration of the monomethylamine is more than 40%, starting to continuously pump raw material diethylene glycol into a tubular reactor of the fixed bed reactor containing a copper-filled catalyst bed layer by the metering pump, carrying out gas, liquid and solid three-phase reaction, simultaneously reducing the flow rate of the monomethylamine to 0.6ml/min, reducing the flow rate of the diethylene glycol to 1ml/min, wherein the molar ratio of the diethylene glycol to the monomethylamine is as follows: diethylene glycol is 1.24:1, the reaction temperature is 220 ℃, the reaction pressure is 0.8-0.9 MPa, a high-pressure circulating gas pump circulates reaction gas at 30L/h, the reaction is continuously carried out for 6 hours, materials are cooled by a condenser, a liquid-phase crude product is discharged, the crude product is heated to remove redundant monomethylamine (the monomethylamine is recycled), a small amount of generated water is removed, and 400g of liquid is obtained, and the GC analysis shows that the diethylene glycol is 2.3%, the methylmorpholine is 94.2%, and the morpholine is 2.2%. The crude product was rectified by a 80cm rectification column to obtain 358g of finished product (content: 99.5%) with a yield of 93.5%.

Example 5:

on the basis of example 4, after the fixed bed catalyst is filled, the pressure is tested at 1.8-2.0MPa, no obvious gas leakage exists, and after nitrogen and hydrogen are replaced, the catalyst is replaced by nitrogen: the mixed gas of hydrogen gas 4:1 (volume ratio) is passed through the catalyst bed layer, the catalyst bed layer is gradually heated to 280 deg.C, continuously aged for 72 hr, then cooled to 240 deg.C, and is used for stand-by.

Preparation of N-methylmorpholine: filling hydrogen into a fixed bed reactor to 0.4Mpa, stabilizing the temperature of a bed layer at about 220 ℃, continuously pumping monomethylamine (the pump speed is 4ml/min) by a metering pump, starting a circulating pump, circulating reaction gas, adjusting a frequency converter to enable the circulating gas flow to be 50L/h, sampling after 2 hours, detecting that the concentration of the monomethylamine is more than 40%, starting to continuously pump raw material diethylene glycol into a tubular reactor of the fixed bed reactor containing a copper-filled catalyst bed layer by the metering pump, carrying out gas, liquid and solid three-phase reaction, simultaneously reducing the flow rate of the monomethylamine to 1ml/min, reducing the flow rate of the diethylene glycol to 1ml/min, wherein the molar ratio of the diethylene glycol to the monomethylamine is as follows: the method comprises the following steps of 1: 2 of diethylene glycol, reacting at 240 ℃, reacting at 0.5-0.6 MPa, circulating reaction gas at 50L/h by a high-pressure circulating gas pump, continuously reacting for 6 hours, cooling materials by a condenser, discharging a liquid-phase crude product, heating the crude product to remove redundant monomethylamine (recovering and utilizing monomethylamine), and removing a small amount of generated water to obtain 398g of liquid, wherein the liquid is analyzed by GC, and the diethylene glycol, the methylmorpholine and the morpholine are 1.4%, 95.4% and 2.2%. The crude product was rectified by a 80cm rectification column to obtain 360g of finished product (content: 99.6%) with a yield of 94%.

Example 6:

on the basis of example 4, after the fixed bed catalyst is filled, the pressure is tested at 1.8-2.0MPa, no obvious gas leakage exists, and after nitrogen and hydrogen are replaced, the catalyst is replaced by nitrogen: the mixed gas of hydrogen gas 4:1 (volume ratio) passes through the catalyst bed layer, the temperature of the catalyst bed layer is gradually raised to 280 ℃ and aging is continued for 72 hours, and then the temperature is lowered to 260 ℃ for standby.

Preparation of N-methylmorpholine: filling hydrogen into a fixed bed reactor to 0.4Mpa, stabilizing the temperature of a bed layer at about 240 ℃, continuously pumping monomethylamine (the pump speed is 4ml/min) by a metering pump, starting a circulating pump, circulating reaction gas, adjusting a frequency converter to ensure that the circulating gas amount is 60L/h, sampling after 2 hours, detecting that the concentration of the monomethylamine is more than 40%, starting to continuously pump raw material diethylene glycol into a tubular reactor of the fixed bed reactor containing a copper-filled catalyst bed layer by the metering pump, carrying out gas, liquid and solid three-phase reaction, simultaneously reducing the flow rate of the monomethylamine to 3ml/min, reducing the flow rate of the diethylene glycol to 1ml/min, and leading the molar ratio of the diethylene glycol to the monomethylamine: diethylene glycol 6.1:1, the reaction temperature is 260 ℃, the reaction pressure is 0.7-0.8 MPa, a high-pressure circulating gas pump circulates reaction gas at 60L/h, the reaction is continuously carried out for 6 hours, materials are cooled by a condenser, a liquid-phase crude product is discharged, the crude product is heated to remove redundant monomethylamine (monomethylamine is recycled), a small amount of generated water is removed, and 401g of liquid is obtained, wherein the content of diethylene glycol is 0.4%, methylmorpholine is 95.9%, and morpholine is 1.2% by GC analysis. The crude product was rectified by a rectifying column of 80cm to obtain 365g of finished product (content: 99.6%) with a yield of 95.3%.

Example 7:

on the basis of example 4, the GC analysis conditions included instruments including a gas chromatograph, a chromatographic column, a chromatographic workstation, a hydrogen flame ionization detector, a 10 μ L microsyringe, and chromatographic conditions including) column temperature: the initial temperature is 100 ℃, the heating rate is 10 ℃/min, the final temperature is 280 ℃, the pressure before the column, the temperature of the vaporization chamber, the temperature of the detector, the flow rate of carrier gas, the flow rate of fuel gas and the flow rate of combustion-supporting gas.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.