CN1733702A

CN1733702A - 3-(2-methoxyethoxy)-propylamine production process

Info

Publication number: CN1733702A
Application number: CN 200510041457
Authority: CN
Inventors: 张存
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2005-08-08
Filing date: 2005-08-08
Publication date: 2006-02-15
Anticipated expiration: 2025-08-08
Also published as: CN100386306C

Abstract

The invention relates to a process for the chemical synthesis of 3-(2-methoxyethoxy)propylamine, which comprises the steps of condensation reaction, distillation and hydrogenation reaction, the end product has good purity, high yield and low depreciation of raw materials.

Description

Production process of 3- (2-methoxyethoxy) -propylamine

Technical Field

The invention relates to a method for chemically synthesizing 3- (2-methoxyethoxy) -propylamine.

Background

3- (2-methoxyethoxy) -propylamine is a primary amine compound with wider application. The product can be used as an important intermediate for synthesizing disperse dyes such as disperse turquoise blue S-GL and the like, and also can be used as a novel corrosion inhibitor and an ionized emulsifier which are introduced abroad and gradually popularized and applied in the petrochemical industry, but at present, no factory is available at home for production. Therefore, the synthesis of 3- (2-methoxyethoxy) -propylamine has important practical significance. After looking up a large amount of literature data, the synthesis method is determined as follows: ethylene glycol monomethyl ether and acrylonitrile are subjected to addition condensation reaction under the action of a catalyst to prepare 3- (2-methoxyethoxy) -propionitrile, and then the nitrile group is reduced by hydrogenation under pressure to obtain the 3- (2-methoxyethoxy) -propylamine. The reaction equation is as follows:

although a design idea is provided for synthesizing the 3- (2-methoxyethoxy) -propylamine, a large amount of work is required for practical production, and parameters such as each process, proportion and the like also need a large amount of creative inventions to be applied to industrial production.

Disclosure of Invention

The invention aims to provide a production process of 3- (2-methoxyethoxy) -propylamine, which has the advantages of simple process, easy operation and high yield.

The invention comprises the following steps:

1) condensation reaction: adding sodium methoxide and hydroquinone into ethylene glycol monomethyl ether, stirring, and then dropwise adding acrylonitrile, wherein the feeding (molar ratio) ratio of the ethylene glycol monomethyl ether to the acrylonitrile is 1: 1-1.1, and the reaction temperature is kept between 25 and 30 ℃; after the dropwise addition is finished, the reaction is continued for 60 minutes +/-10 minutes under heat preservation;

2) and (3) distillation: adding concentrated H into the above reactant₂SO₄Neutralizing until pH is 7 to obtain a brown yellow liquid; distilling the brown yellow liquid at normal pressure, slowly heating to 80 ℃ to evaporate low-boiling fraction; after the atmospheric distillation is finished, carrying out reduced pressure distillation to obtain a colorless liquid of an intermediate product 3- (2-methoxyethoxy) -propionitrile before hydrogenation; the content (more than or equal to 98 percent) is detected by gas chromatography and used for the subsequent hydrogenation reaction. NaSO₄And the residue is left in the distillation still.

3) Hydrogenation reaction: introducing ammonia into a distilled 3- (2-methoxyethoxy) -propionitrile colorless liquid, and carrying out liquid-phase catalytic hydrogenation reaction at 90-100 ℃ under the action of a Raney nickel-cobalt-chromium composite catalyst under the pressure of 3-4 MPa for 4 hours +/-0.5 hours, wherein the weight ratio of the materials of 3- (2-methoxyethoxy) -propionitrile, the catalyst and ammonia is 4000-4500: 20-30: 8500-9000.

In order to improve the purity of the product, the crude product obtained in the step 3) can be further rectified and purified.

The rectification purification method comprises the following steps: and (3) installing a distillation kettle on a rectifying column, distilling a small amount of low-boiling fraction at normal pressure, wherein the middle large-section fraction is a purified product, and the kettle residue is a very small amount of high-boiling fraction such as 3- (2-methoxyethoxy) -propionitrile without hydrogenation.

The process route of the invention has mild operation conditions, good product purity and higher yield, and basically has no other loss except a small amount of distillation kettle residues. Meanwhile, the whole process does not produce any pollution, has remarkable social and economic benefits and can be widely applied to actual production.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

1. The main raw materials are as follows:

industrial ethylene glycol monomethyl ether (the concentration is more than or equal to 95 percent); industrial acrylonitrile (purity is more than or equal to 98%); sodium methoxide, hydroquinone, concentrated H₂SO₄Hydrogen, ammonia

2. Condensation reaction:

adding 410kg of ethylene glycol monomethyl ether, 5kg of sodium methoxide and 0.33kg of hydroquinone into a container, fully stirring, slowly and dropwise adding 284kg of acrylonitrile within 3 hours, wherein the feeding ratio of the ethylene glycol monomethyl ether to the acrylonitrile is 1 mol: 1.05mol, and keeping the reaction temperature between 25 ℃ and 30 ℃. After the dropwise addition, the reaction is continued for 1 hour under heat preservation, and the end point is measured by a gas chromatograph, wherein the end point control index is that the content of acrylonitrile is less than or equal to 1 percent. If the end point is not reached, the heat preservation is continued.

3. And (3) distillation:

if the acrylonitrile has been substantially completely reacted, about 2kg of concentrated H are added₂SO₄Neutralizing the feed liquid, and adjusting the pH to 7. The reaction product obtained here is brownish yellow, still liquid and soluble in water. Solid NaSO can be separated out from the product at low temperature₄It must be removed by distillation prior to hydrogenation.

Firstly, atmospheric distillation is carried out, and the temperature is slowly raised to 80 ℃ to distill out low boiling point fraction. And carrying out reduced pressure distillation after atmospheric distillation is finished, thus obtaining an intermediate product 3- (2-methoxyethoxy) -propionitrile before hydrogenation, wherein the intermediate product is colorless liquid, and the content (more than or equal to 98%) is detected by gas chromatography and used for subsequent hydrogenation reaction. NaSO₄And the residue is left in the distillation still.

4. Hydrogenation reaction:

thehydrogenation reaction equipment is a stainless steel pressure kettle, the catalyst is a Raney nickel-cobalt-chromium composite catalyst, the reaction temperature is 90-100 ℃, and liquid-phase catalytic hydrogenation is carried out in an ethanol solvent under the hydrogen pressure of 3-4 MPa (ammonia gas is introduced in the reaction process).

The specific feeding ratio is as follows: about 440kg of intermediate product 3- (2-methoxyethoxy) -propionitrile, 2.5kg of catalyst and 880kg of ammonia gas. The reaction time was about 4 hours. The crude product is obtained.

After the reaction is finished, the ammonia gas is led out through another tower and can be recycled in the next reaction.

5. And (3) purification:

and (3) installing a distillation kettle on a rectifying column, distilling a small amount of low-boiling fraction at normal pressure, wherein the middle large-section fraction is a purified product, and the kettle residue is a very small amount of high-boiling fraction such as 3- (2-methoxyethoxy) -propionitrile without hydrogenation.

The crude product is rectified and purified to obtain a final product 3- (2-methoxyethoxy) -propylamine with the content of more than 99.5 percent, and the total yield is 91 percent.

Claims

1. The production process of 3- (2-methoxyethoxy) -propylamine is characterized by comprising the following steps of:

1) condensation reaction: adding sodium methoxide and hydroquinone into ethylene glycol monomethyl ether, stirring, and then dropwise adding acrylonitrile, wherein the molar ratio of the ethylene glycol monomethyl ether to the acrylonitrile is 1: 1-1.1, and the reaction temperature is kept between 25 and 30 ℃; after the dropwiseaddition is finished, the reaction is continued for 60 minutes +/-10 minutes under heat preservation;

2) and (3) distillation: adding concentrated H into the reaction mass liquid₂SO₄Neutralizing until pH is 7 to obtain a brown yellow liquid; distilling the brown yellow liquid at normal pressure, slowly heating to 80 ℃, and distilling out low-boiling-point fractions; after the atmospheric distillation is finished, carrying out reduced pressure distillation to obtain a colorless liquid of an intermediate product 3- (2-methoxyethoxy) -propionitrile before hydrogenation;

3) hydrogenation reaction: introducing ammonia into 3- (2-methoxyethoxy) -propionitrile colorless liquid, and carrying out liquid-phase catalytic hydrogenation reaction at the reaction temperature of 90-100 ℃ under the action of a Raney nickel-cobalt-chromium composite catalyst and under the pressure of 3-4 MPa for 4 hours +/-0.5 hours, wherein the weight ratio of the 3- (2-methoxyethoxy) -propionitrile to the catalyst to the ammonia is 4000-4500: 20-30: 8500-9000.

2. The process for the production of 3- (2-methoxyethoxy) -propylamine according to claim 1, wherein the catalyst in the step 1) is sodium methoxide.

3. The process for the production of 3- (2-methoxyethoxy) -propylamine according to claim 2, characterized in that the concentration of sodium methoxide in step 1) is 27%.

4. The process for producing 3- (2-methoxyethoxy) -propylamine according to claim 1, wherein the polymerization inhibitor used in the step 1) is hydroquinone.

5. The process for producing 3- (2-methoxyethoxy) -propylamine according to claim 1, wherein the weight ratio of ethylene glycol monomethyl ether to acrylonitrile in step 1) is 410-415: 280-285.

6. The process for producing 3- (2-methoxyethoxy) -propylamine according to claim 1, wherein the crude product obtained in the step 3) is purified by rectification.

7. The process for producing 3- (2-methoxyethoxy) -propylamine according to claim 6, wherein the rectification and purification are carried out by: and (3) installing a distillation kettle on a rectifying column, distilling a small amount of low-boiling fraction at normal pressure, and obtaining a large middle fraction which is a purified product.