Production method of dimethyl sebacate

Abstract

The invention discloses a production method of dimethyl sebacate. The production method adopts a solid acid catalyst to catalyze esterification of sebacic acid and methanol to produce dimethyl sebacate. The method comprises the following specific operation processes: melting of sebacic acid, reaction in a primary esterification kettle, and fixed-bed final reaction. The process of the reaction in the primary esterification kettle adopts a methanol fed-batch coupled vaporization dehydration method, the reaction is carried out at a temperature slightly higher than the melting point of sebacic acid, and 95% or more of sebacic acid is converted into methyl sebacate; and the fixed-bed final reaction is carried out at a temperature lower than the boiling point of methanol, a small amount of residual carboxylic acid in a primary reaction product is subjected to a refined reaction, so an esterification rate is increased, the acid value of a product is reduced, and the purity of the product is improved. The method has the advantages of short reaction time, high esterification rate, high product purity, easy separation of the catalyst, long service life, less methanol consumption and low energy consumption.

Description

technical field [0001] The invention belongs to the acid-catalyzed esterification method of fatty acid, in particular to a production method of dimethyl sebacate. Background technique [0002] As a widely used organic chemical product, dimethyl sebacate is often used in the preparation of surfactants, leather additives, textile auxiliaries, etc. At present, the main method for preparing dimethyl sebacate is to esterify sebacic acid and methanol under acid catalysis. The acid catalysts used mainly include homogeneous catalysts such as sulfuric acid and p-toluenesulfonic acid and solid acid catalysts. CN1070395A discloses a kind of concentrated sulfuric acid as the production method of catalyst. Put sebacic acid and methanol into the stirring tank in a certain proportion, add a certain amount of concentrated sulfuric acid, when the sebacic acid is completely dissolved, the temperature drops to the solution to form an interface, and the water phase is separated; continue to a...

AI Technical Summary

Problems solved by technology

The use of solid acid catalysts solves the problem of sulfuric acid as a catalyst, but since the reaction is carried out in a tank-type stirred reactor, the first-stage esterification temperature is between the boiling points of methanol and water, so that part of the added methanol is vaporized, which not only consumes heat energy Moreover, the concentration of methanol in the reaction system is reduced, and the water generated by esterification is not easy to evaporate, so the esterification rate is slow, the esterification time is long, and the esterification rate is low due to the limitation of reversible reactions.

The second-stage esterification temperature is higher than the boiling point of water, which is beneficial to the removal of water, but it will cause a large amount of methanol to distill out, and the amount of methanol remaining in the reaction system is very small, which is not conducive to the second-stage esterification reaction. There is still a high acid value, which needs to be refined by rectification, which further increases energy consumption and equipment investment

Images