Method for producing dimethyl adipate from adipic acid

Abstract

The invention discloses a method for producing dimethyl adipate by continuous esterification of adipic acid. The method comprises the following steps: feeding adipic acid particles into a pre-esterification reactor in a solid form, contacting methanol steam with adipic acid in the pre-esterification reactor to carry out reactions, introducing generated materials into a double-esterification reactor, carrying out reactions, and separating the double-esterification product to obtain dimethyl adipate. The method overcomes the problems that the existing adipic acid cannot be continuously fed, thepre-esterification is discontinuous, and the pre-esterification product is unstable in composition.

Description

technical field

[0001] The invention relates to a method for producing dimethyl adipate from adipic acid, in particular to a method for continuously esterifying adipic acid to produce dimethyl adipate. Background technique

[0002] Dimethyl adipate is an excellent cold-resistant plasticizer, which can endow products with excellent low-temperature softness. And has a certain light and heat stability and water resistance. It has a wide range of applications in the production of solvents, pharmaceutical fragrances, paper and cellulose resins. In addition, dimethyl adipate is also an intermediate in the synthesis of 1,6-hexanediol. Common synthetic methods generally use adipic acid and methanol as raw materials, under the condition of presence / absence of catalysis, first carry out mono / pre-esterification reaction, and then carry out continuous reaction of monomethyl adipate and methanol to synthesize adipic diacetate Acid dimethyl ester.

[0003] CN 102311342 A discloses a p...

Examples

Embodiment 1

[0041] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 1.08MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves rapidly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the temperature of the solution in the tower kettle is 80°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.25h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 37.3%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed. The reaction temperature is 120°C, the reaction pressure is ...

Embodiment 2

[0043] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 1.0MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves rapidly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the temperature of the solution in the tower kettle is 78°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.2h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 35.2%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed, The reaction temperature is 120°C, the reaction pressure is 4....

Embodiment 3

[0045] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 0.9MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves quickly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the solution temperature in the tower kettle is 75°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.2h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 33.7%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed. The reaction temperature is 120°C, the reaction pressure is 4.0MPa, a...

technical field

[0001] The invention relates to a method for producing dimethyl adipate from adipic acid, in particular to a method for continuously esterifying adipic acid to produce dimethyl adipate. Background technique

[0002] Dimethyl adipate is an excellent cold-resistant plasticizer, which can endow products with excellent low-temperature softness. And has a certain light and heat stability and water resistance. It has a wide range of applications in the production of solvents, pharmaceutical fragrances, paper and cellulose resins. In addition, dimethyl adipate is also an intermediate in the synthesis of 1,6-hexanediol. Common synthetic methods generally use adipic acid and methanol as raw materials, under the condition of presence / absence of catalysis, first carry out mono / pre-esterification reaction, and then carry out continuous reaction of monomethyl adipate and methanol to synthesize adipic diacetate Acid dimethyl ester.

[0003] CN 102311342 A discloses a p...

Examples

Embodiment 1

[0041] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 1.08MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves rapidly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the temperature of the solution in the tower kettle is 80°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.25h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 37.3%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed. The reaction temperature is 120°C, the reaction pressure is ...

Embodiment 2

[0043] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 1.0MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves rapidly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the temperature of the solution in the tower kettle is 78°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.2h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 35.2%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed, The reaction temperature is 120°C, the reaction pressure is 4....

Embodiment 3

[0045] Put 14.6Kg of adipic acid particles in the reaction tower, pass through nitrogen to replace the air, heat methanol into steam at the bottom of the reaction tower, control the steam pressure to 0.9MPa, and purify the adipic acid with methanol through the nozzle. The acid dissolves quickly, and the dissolution rate of adipic acid is controlled by controlling the amount of methanol vapor to ensure that the solution temperature in the tower kettle is 75°C. Pass the tower kettle solution into the heat exchanger for pre-esterification reaction, the reaction temperature is 140°C, and the space velocity is 0.2h -1 , the reaction pressure is the saturated vapor pressure of methanol. After the reaction, the conversion rate of adipic acid is 97.2%, and the content of dimethyl adipate is 33.7%. After entering the double esterification reactor, the double esterification reaction is carried out on the catalyst bed. The reaction temperature is 120°C, the reaction pressure is 4.0MPa, a...

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