Method for preparing 1,6-hexandiol by hydrogenation of 1,6-adipic acid dimethyl ester

Abstract

The invention relates to a hydrogenated preparation method of 1, 6-hexanediol by 1, 6 dimethylene adipate. The raw material of 1, 6-hexanediol is injected to a mixer and mixed with hydrogen and the mole proportion of the hydrogen and the 1, 6-hexanediol is 50-150 : 1; the mixed materials put in a reactor is hydrogenated after being contacted with catalyst; the loading of the catalyst is 0.1-0.5 kg ester / H.kg, the bedding temperature is 150-300 DEG C while the reacting pressure is 4-7MPa; mixed reacting matters enters gas and liquid separator after going through a heat exchanger and a condenser and then 1, 6 dimethylene adipate is obtained. The weight proportion of each component of the catalyst is that: 25-60 percent copper oxide, 25-60 percent zinc oxide and 10-30 percent aluminum oxide. The invention adopts comparatively low ratio of hydrogen and ester under comparatively low temperature and pressure, realizes the hydrogenated preparation method of 1, 6-hexanediol by 1, 6 dimethylene adipate with a transforming rate of the 1, 6 dimethylene adipate above 99 percent and option of the 1, 6-hexanediol above 96 percent.

Description

Technical field [0001] The invention relates to a method for preparing 1,6-hexanediol by hydrogenating dimethyl 1,6-adipate. Background technique [0002] 1,6-Hexanediol is a solid at room temperature, with a melting point of 42°C, a molecular weight of 118.18, and a density of 0.965g / cm 3 . 1,6-Hexanediol is mainly used as a raw material for coatings, adhesives, new polyesters, sealants and plasticizers. The polyester polyol prepared from 1,6-hexanediol can be used in the production of polyurethane elastomers, and its products have excellent mechanical strength, heat resistance, water resistance and oxidation resistance. Polyurethane elastomer has a wide range of applications in synthetic rubber, synthetic fiber, synthetic leather and other fields. With the improvement of living standards, people's requirements for the environment are getting higher and higher, and the requirements for environmentally friendly products will increase. Therefore, the coating and adhesive industry ...

AI Technical Summary

Problems solved by technology

Due to the large molar ratio of hydrogen to ester in this preparation method (150:1-300:1), a large amount of hydrogen circulation is caused, the equipment requirements are high, and the hydrogenation catalyst load is low resulting in higher energy consumption.

[0004] World patent WO97 / 31882 discloses a mixture of dimethyl adipate and 6-hydroxyhexanoate in the liquid phase in the presence of a hydrogenation catalyst at 220 ° C / 220 bar, by adding Hydrogen reaction to produce 1,6-hexanediol. The disadvantage of this liquid-phase hydrogenation reaction is that the reaction pressure is as high as 220 bar, and the requirements for hydrogenation reaction equipment are high and the investment is large.

[0005] Chinese Patent Publication No. CN 1594252A reports the hydrogenation raw material is 1, the method for the mixture hydrogenation of dimethyl adipate and methanol to prepare 1,6-hexanediol, the mixture ratio is 1: 2 (weight ratio), The flow rate of the mixture is 0.6 kg / hour, the reactor is controlled at 210°C, the reaction pressure is 2.5MPa, and the hydrogen flow rate is 20 cubic meters / hour. Using methanol as a solvent in the raw materials in the above method actually reduces the load on the catalyst, and at the same time It also complicates the process