阅读说明：本技术 一种1-乙酰基-2-吡咯烷酮的生产方法 (Production method of 1-acetyl-2-pyrrolidone ) 是由 吴彦彬 闫广学 宋国全 吴正岭 肖强 杨理 梁斌 周淑飞 李清霞 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种1-乙酰基-2-吡咯烷酮的生产方法,包括以下步骤：以1,3-丙二醇、氨水、乙酸甲酯、甲酸甲酯为原料,在铜基催化剂的作用下,在管式固定床反应器内发生胺化、加成、环化反应,得到1-乙酰基-2-吡咯烷酮粗品,然后进一步提纯,即得。本发明催化剂催化活性高,反应条件温和,工艺操作简便,所得产品收率≥98.4%,选择性≥99.0%,纯度≥99.9%,水含量≤40ppm,氨含量≤2ppm,满足下游医药、精细化工中间体等领域的要求。(The invention discloses a production method of 1-acetyl-2-pyrrolidone, which comprises the following steps: the method comprises the steps of taking 1, 3-propylene glycol, ammonia water, methyl acetate and methyl formate as raw materials, carrying out amination, addition and cyclization reactions in a tubular fixed bed reactor under the action of a copper-based catalyst to obtain a 1-acetyl-2-pyrrolidone crude product, and further purifying to obtain the compound. The catalyst has high catalytic activity, mild reaction conditions and simple and convenient process operation, the yield of the obtained product is more than or equal to 98.4 percent, the selectivity is more than or equal to 99.0 percent, the purity is more than or equal to 99.9 percent, the water content is less than or equal to 40ppm, and the ammonia content is less than or equal to 2ppm, thereby meeting the requirements of fields such as downstream medicine, fine chemical intermediates and the like.)

1. A method for producing 1-acetyl-2-pyrrolidone, which is characterized by comprising the following steps:

the method comprises the steps of taking 1, 3-propylene glycol, ammonia water, methyl acetate and methyl formate as raw materials, carrying out amination, addition and cyclization reactions on the 1, 3-propylene glycol, the ammonia, the methyl acetate and the methyl formate in a tubular fixed bed reactor under the action of a copper-based catalyst to generate a 1-acetyl-2-pyrrolidone crude product, and further purifying to obtain a target product 1-acetyl-2-pyrrolidone.

2. A process for the production of 1-acetyl-2-pyrrolidone according to claim 1, comprising the steps of: 1, 3-propylene glycol, ammonia water, methyl acetate and methyl formate are respectively pumped into a pipeline from a feeding buffer tank by a metering pump, mixed by a mixer, sent into a preheating section for preheating, then sent into a tubular fixed bed reactor, and reacted under the action of a catalyst; and (3) after heat exchange and condensation of the mixed material discharged from the reactor, sending the mixed material into a constant pressure tank, releasing the pressure of the mixed material through a flow-limiting orifice plate, then sending the mixed material into an intermediate storage tank to release the surplus ammonia, returning the collected surplus ammonia into the reaction system again, and separating and purifying the crude product in the intermediate storage tank through a three-stage continuous tower to obtain the product.

3. The process for producing 1-acetyl-2-pyrrolidone according to claim 1, wherein the molar ratio of 1, 3-propanediol to ammonia in aqueous ammonia to methyl acetate to methyl formate is 1 (1.0 ~ 1.2.2): 1.0 ~ 1.2.2 ]: 1.0 ~ 1.2.2), the reaction temperature is 220 ~ 260 ℃, the reaction pressure is 0.5 ~ 5MPa, and the liquid hourly space velocity is 1 ~ 10h^-1。

4. A process for producing 1-acetyl-2-pyrrolidone according to claim 1, wherein said tubular fixed bed reactor comprises an upper section and a lower section, the upper section of the reactor is a laminar flow tubular type, the lower section is an auto-thermal countercurrent tubular type, the diameter of the upper section is 100 ~ 150mm, and the diameter of the lower section is 50 ~ 80 mm.

5. A process for producing 1-acetyl-2-pyrrolidone according to claim 1, wherein said copper-based catalyst is prepared by a method comprising the steps of:

(1) dissolving copper nitrate, bismuth nitrate and silver nitrate in deionized water to prepare a solution A of 1 ~ 2mol/L, adding polyethylene glycol with the polymerization degree of 2000 ~ 10000, stirring, transferring to a microwave hydrothermal parallel synthesizer, and reacting at 70 ~ 90 ℃ to obtain the product5 ~ 10h to obtain mixed solution B containing Cu/Bi/Ag, and mixing the mixed solution B with nanoscale Fe₂O₃And TiO₂Dispersing the nano-scale carrier in deionized water by using ultrasonic waves to prepare a solution C, dispersing the nano-scale carrier in the deionized water by using ultrasonic waves to prepare a solution D, cocurrently flowing and mixing the solution B, C, D, stirring for 12 ~ 24h, dropwise adding a precipitator to control the end point pH to be 6.5 ~ 7.0.0, standing, filtering, washing, drying a filter cake in vacuum, and roasting for 8 ~ 12h at 500 ~ 600 ℃ to obtain a catalyst;

(2) filling the catalyst obtained in the step (1) into a tubular fixed bed reactor, replacing the reactor with nitrogen, reducing the catalyst with hydrogen, keeping the pressure less than or equal to 0.5MPa, gradually increasing the temperature from room temperature to 280 ℃ according to the temperature gradient, cooling to 230 ℃ after the reduction of the catalyst is finished, replacing the whole reactor with nitrogen, maintaining the pressure, and keeping the temperature for later use.

6. A process for producing 1-acetyl-2-pyrrolidone according to claim 5, wherein the carrier in step (1) is molecular sieve ZSM-5 and/or HZSM-5.

7. A process for producing 1-acetyl-2-pyrrolidone according to claim 5, wherein the precipitant in step (1) is (NH)₄)₂CO₃、Na₂CO₃、NaOH、NaHCO₃And a urea solution.

8. The method for producing 1-acetyl-2-pyrrolidone of claim 5, wherein the chemical components and weight percentages of the catalyst in step (1) are CuO 25 ~ 35%, TiO₂ 5~10%、Fe₂O₃ 3~5%、Ag₂O 0.5~2%、Bi₂O₃ 3 ~ 5%, the balance being carrier.

9. A process for producing 1-acetyl-2-pyrrolidone according to claim 5, wherein the temperature gradient in step (2) is as follows: the whole reactor is replaced by nitrogen to be qualified at the beginning, and then hydrogen is gradually introduced until the reduction is finished; gradually heating from room temperature to 120 ℃ in 10h, and keeping the temperature for 5 h; heating to 150 ℃ again within 5h, and keeping the temperature for 5 h; heating to 200 ℃ again within 10h, and keeping the temperature for 5 h; heating to 280 ℃ again within 10h, and preserving heat for 10 h; and finally, cooling to 230 ℃ within 5h, replacing the whole reactor with nitrogen, maintaining the pressure and preserving the heat.

10. A process for producing 1-acetyl-2-pyrrolidone according to claim 9, wherein said temperature gradient is such that the hydrogen concentration in the reactor is 2% or less at room temperature of ~ 150 ℃, 5% or less at 150 ~ 200 ℃ and 100% hydrogen concentration at 220 ℃ after completion of the reduction.

Technical Field

The invention belongs to the field of production of fine chemical products, and particularly relates to a production method of 1-acetyl-2-pyrrolidone.

Background

1-acetyl-2-pyrrolidone with a molecular weight of 127.4 and a density of 1.15g/cm³The product has a boiling point of 231 ℃, has special smell and higher biological activity, can be used for synthesizing acetylpyrrolidine, acetylpyrrole and the like, is an important starting material in organic synthesis, and is widely applied to the fields of pharmaceutical and chemical industry, fine chemical industry, pesticide and chemical industry, spices and cosmetic additives.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide a method for producing 1-acetyl-2-pyrrolidone.

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

a method for producing 1-acetyl-2-pyrrolidone, comprising the steps of:

the method comprises the steps of taking 1, 3-propylene glycol, ammonia water, methyl acetate and methyl formate as raw materials, carrying out amination, addition and cyclization reactions on the 1, 3-propylene glycol, the ammonia, the methyl acetate and the methyl formate in a tubular fixed bed reactor under the action of a copper-based catalyst to generate a 1-acetyl-2-pyrrolidone crude product, and further purifying to obtain a target product 1-acetyl-2-pyrrolidone.

Preferably, the production method comprises the following steps: 1, 3-propylene glycol, ammonia water, methyl acetate and methyl formate are respectively pumped into a pipeline from a feeding buffer tank by a metering pump, mixed by a mixer, sent into a preheating section for preheating, then sent into a tubular fixed bed reactor, and reacted under the action of a catalyst; and (3) after heat exchange and condensation of the mixed material discharged from the reactor, sending the mixed material into a constant pressure tank, releasing the pressure of the mixed material through a flow-limiting orifice plate, then sending the mixed material into an intermediate storage tank to release the surplus ammonia, returning the collected surplus ammonia into the reaction system again, and separating and purifying the crude product in the intermediate storage tank through a three-stage continuous tower to obtain the product.

Preferably, the molar ratio of the 1, 3-propylene glycol to ammonia in ammonia water to methyl acetate to methyl formate is 1 (1.0 ~ 1.2.2) to (1.0 ~ 1.2.2) to (1.0 ~ 1.2.2), the reaction temperature is 220 ~ 260 ℃, the reaction pressure is 0.5 ~ 5MPa, and the liquid hourly space velocity is 1 ~ 10h^-1。

Preferably, the tubular fixed bed reactor consists of an upper section and a lower section, the upper section of the reactor is a laminar flow tubular type, the lower section of the reactor is an auto-thermal countercurrent tubular type, the diameter of the upper section reaction tube is 100 ~ 150mm, and the diameter of the lower section reaction tube is 50 ~ 80 mm.

Preferably, the preparation method of the copper-based catalyst comprises the following steps:

(1) mixing copper nitrate, bismuth nitrate anddissolving silver nitrate in deionized water to obtain 1 ~ 2mol/L solution A, adding polyethylene glycol with polymerization degree of 2000 ~ 10000, stirring, reacting at 70 ~ 90 deg.C for 5 ~ 10h to obtain mixed solution B containing Cu/Bi/Ag, and adding nanoscale Fe₂O₃And TiO₂Dispersing the nano-scale carrier in deionized water by using ultrasonic waves to prepare a solution C, dispersing the nano-scale carrier in the deionized water by using ultrasonic waves to prepare a solution D, cocurrently flowing and mixing the solution B, C, D, stirring for 12 ~ 24h, dropwise adding a precipitator to control the end point pH to be 6.5 ~ 7.0.0, standing, filtering, washing, drying a filter cake in vacuum, and roasting for 8 ~ 12h at 500 ~ 600 ℃ to obtain a catalyst;

(2) filling the catalyst obtained in the step (1) into a tubular fixed bed reactor, replacing the reactor with nitrogen, reducing the catalyst with hydrogen, keeping the pressure less than or equal to 0.5MPa, gradually increasing the temperature from room temperature to 280 ℃ according to the temperature gradient, cooling to 230 ℃ after the reduction of the catalyst is finished, replacing the whole reactor with nitrogen, maintaining the pressure and preserving the heat.

Preferably, the carrier in the step (1) is molecular sieve ZSM-5 and/or HZSM-5.

Preferably, the precipitating agent in the step (1) is (NH)₄)₂CO₃、Na₂CO₃、NaOH、NaHCO₃And a urea solution.

Preferably, the chemical components and weight percentages of the catalyst in the step (1) are CuO 25 ~ 35%, TiO 25₂ 5~10%、Fe₂O₃ 3~5%、Ag₂O 0.5~2%、Bi₂O₃ 3 ~ 5%, the balance being carrier.

Preferably, the temperature gradient in step (2) is as follows: the whole reactor is replaced by nitrogen to be qualified at the beginning, and then hydrogen is gradually introduced until the reduction is finished; gradually heating from room temperature to 120 ℃ in 10h, and keeping the temperature for 5 h; heating to 150 ℃ again within 5h, and keeping the temperature for 5 h; heating to 200 ℃ again within 10h, and keeping the temperature for 5 h; heating to 280 ℃ again within 10h, and preserving heat for 10 h; and finally, cooling to 230 ℃ within 5h, replacing the whole reactor with nitrogen, maintaining the pressure and preserving the heat.

Preferably, the hydrogen concentration of the reactor is less than or equal to 2% at room temperature of ~ 150 ℃, less than or equal to 5% at 150 ~ 200 ℃, and 100% at 220 ℃ after reduction is finished.

The general formula of the reaction process of the invention is as follows:

the invention has the following positive beneficial effects:

1. CuO and Fe in the catalyst of the invention₂O₃And TiO₂A special crystal interface is formed between the iron oxide and the titanium oxide, electrons of the iron oxide and the titanium oxide migrate to the conduction band of the copper oxide through a space charge region of the heterojunction after migrating to the conduction band, the electrons reduce the copper oxide into low-valence copper, the catalytic activity of the low-valence copper is higher, the migration of the electrons is also beneficial to the chemical adsorption and dissociation of C-H bonds between the metal and a carrier interface, the C-O-H, C-H bonds of intermediate product molecules adsorbed on the surface of the catalyst are broken, and H is generated⁺And combines with the hydroxyl on the surface of the catalyst to generate water. The active components of the elements Bi and Ti can well inhibit atom migration in crystal lattices in the activation process of the catalyst, prevent crystal grains from becoming large and accumulating, enable the active components of the catalyst to be uniformly loaded on a carrier, maintain sufficient pore channels, have good dispersion and prevent agglomeration. Silver in the same main group with copper has the characteristics of mildness and alkalescence, and the addition of Ag element enables Bi to be added₂O₃And TiO₂The crystal in the crystal lattice is refined, the crystallinity of the catalyst is reduced, and the diffraction peak intensity of the catalyst is gradually weakened along with the increase of the doping concentration of Ag, so that the catalyst keeps higher activity. The copper-based catalyst has the advantages that the active ingredients of the copper-based catalyst are synergistic, the yield of the crude 1-acetyl-2-pyrrolidone obtained by the tubular fixed bed reactor is more than or equal to 98.4%, the selectivity is more than or equal to 99.0%, the catalytic activity is high, the reaction time is short, the higher yield is realized without prolonging the reaction time, a plurality of reaction sites in a reaction substrate are inhibited, the side reaction is less, the price is low, the cost is easy to obtain, the toxicity is low, the environment is protected, the efficiency is high, the stability is high, and the large.

2. In the reduction process of the copper-based catalyst, once the reaction starts, water vapor does not play a role in retardation, the concentration of hydrogen and copper oxide mainly influences the reduction speed, the reduction reaction of a precursor of the copper-based catalyst is a strong heat release reaction, temperature runaway is easily generated, the temperature is increased to be not beneficial to proper reduction, the reduction temperature is too high, the crystallite size is increased, the specific surface area is reduced, but the reduction speed of the catalyst can be increased, the reaction time is shortened, the temperature is too low, the reduction speed is slow, the production period of the reactor is influenced, the time of exposing the reduced catalyst in water vapor is prolonged, the repeated opportunity of oxidation-reduction is increased, the activity of the catalyst is reduced, the temperature rise speed, the temperature gradient and the hydrogen concentration are strictly controlled, the temperature rise speed, the temperature gradient and the hydrogen concentration are qualified at the beginning, hydrogen is gradually introduced until the reduction is completed, the temperature rises from room temperature to 120 ℃ gradually, the temperature is kept for 5h, the temperature rises to 150 ℃ again within 5h, the temperature is kept for 5h, the temperature is kept at the temperature to 200 ℃ again, the temperature is kept for 5h, the temperature is kept for 10 ℃ to 280 ℃ again, the temperature to the temperature of 200 ℃ for the temperature, the temperature of 200 ℃ of the temperature of the reactor is kept for 5h, the temperature of the reactor again, the temperature of the reactor is kept for the reactor again, the temperature of the reactor is kept for 5h, the temperature of the reactor is kept for the temperature of the reactor for 5h, the reactor for.

3. According to the invention, the starting raw materials of methyl acetate and methyl formate are reacted, the by-products in the reaction process are methanol and water, the difference between the boiling point of an azeotrope formed by the methanol and the water and the boiling point of the methyl acetate is large, the separation and purification are easy, and the burden on the environment is small; the methanol generated in the reaction process can play a role of a solvent, and the methanol can also take away a part of ammonia in the separation process, so that the content of ammonia in the wastewater is reduced, and the difficulty of subsequent wastewater treatment is reduced.

4. The fixed bed reactor consists of an upper section and a lower section, and the reactorThe upper section of the reactor is a laminar flow tube type, the lower section of the reactor is a self-heating counter-flow type, the upper section of the reactor is a high-pressure tube with a jacket, heat is provided by heat conducting oil, the diameter of the upper section reaction tube is 100 ~ mm, meanwhile, the upper section reaction tube of the reactor is also the jacket of the lower section material of the reactor (the lower section reaction tube is positioned in the upper section reaction tube and is the lower section, see the specific figure 2), the temperature required by the lower section reaction of the reactor is provided by the material coming out of the upper section of the reactor, the self-heating is realized to provide energy required by the reaction, the diameter of the lower section reaction tube is 50 ~ mm, the change of the upper and lower tube diameters improves the flow speed of the lower section, the heat transfer coefficient is increased, the heat exchange area is enlarged, the reaction heat is timely removed, the side reaction in the reaction process is reduced, and the selectivity of the product is improved^-1The reaction condition is mild, and the process operation is simple and convenient.

The material from the upper section of the reactor passes through the lower section reaction tube and the upper section reaction tube, the material enters a catalyst bed layer from the bottom of the lower section reaction tube of the reactor in a countercurrent manner, the material flows out of the reactor after reaction, the mixed material from the reactor is sent into a constant pressure tank after heat exchange and condensation, the pressure of the whole system is stabilized by the constant pressure tank, the mixed material enters an intermediate storage tank after being decompressed by a flow-limiting pore plate, the surplus ammonia is discharged, the collected surplus ammonia returns to the reactor again, and the crude product in the intermediate storage tank is separated and purified by a three-stage continuous tower to obtain the product, wherein the purity of the obtained product is more than or equal to 99.9 percent, the water content is less than or equal to 40ppm, the ammonia content is less than or equal to 2ppm, and the product hardly contains free amine.

Drawings

FIG. 1 is a schematic of the temperature gradient of the present invention;

FIG. 2 is a schematic view of the structure of a tubular fixed-bed reactor according to the present invention.

Detailed Description

The invention will be further illustrated with reference to some specific embodiments.