Method for preparing sorbitol from cellulose

Abstract

The invention relates to a method for preparing sorbitol through cellulose hydrolysis and hydrogenation. The method comprises that under carbon dioxide pressure of 0.1-3MPa, in the presence of a hydrogen mesoporous ZSM-5 zeolite-loaded Pt-Ni catalyst, under conditions of a temperature of 230-250 DEG C and H2 pressure of 0.5-6 MPa, sorbitol is prepared through cellulose hydrolysis and hydrogenation, wherein a sorbitol yield is 53.2% and a ratio of sorbitol to sorbitol isomer mannitol is greater than 12, and after the reaction, carbon dioxide spontaneously separates from the liquid product. The method is free of a liquid inorganic acid so that acid pollution and equipment corrosion are avoided. The method solves the problem that a sorbitol yield is low at a high reaction temperature of 230-250 DEG C, realizes rapid cellulose conversion and improves a sorbitol yield.

Description

technical field [0001] The invention relates to a method for preparing sorbitol by hydrolysis and hydrogenation of cellulose. It specifically relates to a method for preparing sorbitol by hydrolysis and hydrogenation of cellulose with Pt-Ni supported on mesoporous ZSM-5 zeolite as a catalyst in the presence of compressed carbon dioxide. Background technique [0002] Cellulose is the most abundant biomass resource in nature. The conversion and utilization of cellulose can reduce the dependence of human beings on fossil resources. The "one-pot" hydrolysis and hydrogenation of cellulose in high-temperature water to produce important chemical platform molecules such as sorbitol, mannitol, ethylene glycol, and propylene glycol is one of the green and feasible processes for utilizing cellulose. [0003] Cellulose hydrolysis and hydrogenation products are complex, and the basic reaction process is as follows: cellulose is hydrolyzed to generate glucose, while glucose is hydrogenat...

AI Technical Summary

Problems solved by technology

[0005] At present, there are the following main problems in the preparation of sorbitol by hydrolysis and hydrogenation of cellulose: (1) at a relatively low reaction temperature (such as 150°C), the hydrolysis rate of cellulose is slow, which becomes the rate-controlling step of the reaction, resulting in a slow reaction rate, Long time; (2) At a higher reaction temperature (eg >230°C), the hydrolysis rate of cellulose and the overall reaction rate are significantly increased, but the degree of hydrogenolysis reaction is intensified, resulting in a decrease in the yield of sorbitol

(3) Add copper salt to the reaction system, the reaction process will generate acid, and increase the difficulty of subsequent separation