Process for producing 1,6-hexanediol and coproducing epsilon-caprolactone

Abstract

The invention provides a process for preparing 1,6-hexanediol and coproducing epsilon-caprolactone through esterification and hydrogenation of adipic acid. The process comprises the following steps of: performing countercurrent contact of pure adipic acid and methanol steam on a catalyst active ingredient-loaded filler in a reaction catalytic distillation tower, and performing esterification reaction; and purifying dimethyl adipate, and performing hydrogenation purification to obtain the 1,6-hexanediol and coproduce epsilon-caprolactone, wherein polymer generated after product separation is subjected to ester exchange reaction to be recycled. The catalyst has high activity and selectivity, the products are high in yield, energy consumption is low, the equipment investment is small, the catalyst is environment-friendly, and the preparation process is simple, economic and practical.

Description

technical field [0001] The invention relates to a process for producing 1,6-hexanediol and co-producing ε-caprolactone, in particular to a process for preparing 1,6-hexanediol and co-producing ε through esterification and hydrogenation of adipic acid - Process of caprolactone. Background technique [0002] 1,6-Hexanediol is an important fine chemical raw material, widely used in polyurethane, polyester, coil coating, light curing, degradable plastics and other fields. [0003] ε-caprolactone is mainly used in the production of modified polyols and caprolactone acrylic monomers, and is also a strong solvent and a non-reactive solvent for storage and transportation. [0004] Patent CN1212681A discloses a method for preparing 1,6-hexanediol and ε-caprolactone from a carboxylic acid mixture containing adipic acid, 6-hydroxyacetic acid and a small amount of 1,4-cyclohexanediol. The carboxylic acid mixture is obtained from an oxidation reaction of cyclohexane with oxygen to prod...

AI Technical Summary

Problems solved by technology

In this method, the esterification reaction adopts a two-step method, through two processes of pre-esterification and continuous esterification, and the loading method of the catalyst in the continuous esterification process brings about a large bed pressure drop and uneven gas-liquid distribution.

Sulfuric acid in the pre-esterification process has a serious corrosive effect on the production equipment, especially the heater of the reactor. It is difficult to separate the product from the catalyst. There are side reactions such as dehydration, oxidation, and carbonization, and the energy consumption of product separation and purification is relatively high. The production process is basically a batch operation

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