Separation method and system for byproduct 2M2BN in course of producing 3PN by 2M3BN isomerization

Abstract

A separation method and system for a byproduct 2M2BN in a course of producing 3PN by 2M3BN isomerization. The present invention proposes that in the course of producing 3PN by 2M3BN isomerization, a byproduct 2M2BN is produced, and 2M2BN will continuously accumulate in the system to suppress the isomerization reaction. The relative volatility of 2M2BN and 2M3BN is increased by using an extractant of the present invention, and separation of 2M2BN and 2M3BN and recycle of the extractant are completed in one distillation column with a partition plate, so that the equipment cost and difficulty are greatly reduced, and 2M2BN and 2M3BN products with high purity can be obtained.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, and in particular relates to a method and system for separating 2M2BN, a by-product in the process of 2M3BN isomerization to produce 3PN. Background technique [0002] 3-pentenenitrile (3PN) is an intermediate for the preparation of adiponitrile, which can be further hydrocyanated into adiponitrile, and adiponitrile is an intermediate of nylon 66, which is an important chemical product. During the isomerization of 2-methyl-3-butenenitrile (2M3BN) to produce 3-pentenenitrile (3PN), 2-methyl-2-butenenitrile (2M2BN) will be produced by-product, and 2M2BN will continue to react Accumulated in the system, resulting in reduced reaction conversion and selectivity, so it is necessary to continuously separate and extract 2M2BN from the reaction system. However, the normal pressure boiling point difference between 2M2BN and 2M3BN is too small, less than 5°C. Common distillation methods require...

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Problems solved by technology

During the isomerization of 2-methyl-3-butenenitrile (2M3BN) to produce 3-pentenenitrile (3PN), 2-methyl-2-butenenitrile (2M2BN) will be produced by-product, and 2M2BN will continue to react Accumulated in the system, resulting in reduced reaction conversion and selectivity, so it is necessary to continuously separate and extract 2M2BN from the reaction system

[0004] Patent CN201410052751.8 A method of direct isomerization of alkene nitrile mixture to synthesize 2-methyl-2-butenenitrile proposes to add calcium-containing inorganic Alkali, which can undergo isomerization reaction to generate 2M2BN. The patent only shows that the inorganic base can make 2M3BN isomerize to generate 3PN reaction in the direction of side reaction 2M2BN, and does not mention the separation method of 2M3BN and 2M2BN

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