Method for continuously preparing 1,3-propanediol by one-step glycerol conversion

Abstract

The invention relates to a method for continuously preparing 1, 3-propylene glycol by glycerin through one step of conversion. With the presence of metal / solid acid bifunctional catalyst, glycerin water solution and hydrogen are simultaneously and continuously led into a fixed bed reactor and have a catalytic reaction at the temperature of 100-150 DEG C, and a pressure of 2-8MPa, wherein, the volume ratio of hydrogen and glycerin water solution is 600-1200; volume air speed of glycerin water solution is 0.15-1h<-1>; the reaction product is collected and has a gas liquid separation to remove gas hydrogen; the liquid phase is distilled and separated to remove the side product to obtain the 1, 3-propylene glycol product; the metal / solid acid bifunctional catalyst is functioned by zirconia / tungsten oxide complex oxide with attachment of platinum; and weight ratio of each metallic element in the catalyst is: Pt: W: Zr=1-5:5-20:69-55. The process of the reaction is simple; the production can be continuous; high concentration glycerin can be converted under a relatively moderate reaction condition; content of 1, 3-propylene glycol is high, while content of side product is low; and 1, 3-propylene glycol separation and purification cost is low.

Description

technical field [0001] The invention provides a method for continuously preparing 1,3-propanediol by one-step catalytic conversion of glycerin, a by-product of biodiesel, belonging to the field of biomass chemical industry. Background technique [0002] 1,3-propanediol (1,3-PDO), the molecular formula is HO-CH 2 -CH 2 -CH 2 -OH, it is an important raw material in the field of fine chemicals, it can be used in solvents, antifreeze agents, protective agents, lubricants, especially for the production of polyester materials, it and terephthalic acid produce polytrimethylene terephthalate (PTT ), compared to polyesters formed by other diols (such as ethylene glycol, 1,4-butanediol), such as polyethylene terephthalate (abbreviated as PET), polybutylene terephthalate (abbreviated PBT), PTT has more unique properties, such as excellent elasticity, dyeability, stain resistance, good anti-ultraviolet discoloration performance, antistatic, good biodegradability, etc., in carpets, en...

AI Technical Summary

Problems solved by technology

However, the common problem of microbial fermentation is that during the fermentation process, higher concentrations of glycerol and fermentation products will inhibit the activity of enzymes or engineered bacteria. In order to maintain the activity of microorganisms in the fermentation broth, the initial concentration of glycerol generally Very low (maximum concentration cannot exceed 17%)

It can be seen that the separation and purification of the product 1,3-propanediol is complicated and costly, which limits the wider application of the microbial fermentation process

[0007] (4) glycerin is converted into 1 by chemical catalysis, and the method for 3-propanediol, adopts the homogeneous catalyst of tungstic acid and rhodium complex as U.S. Patent US 4642394, and glycerin and pressure are the synthesis gas (CO / H of 31MPa 2 =1 / 2) In the organic amine and amide solution, react at 200°C for 24 hours, but the yield of 1,3-propanediol is less than 20%, and it cannot be reacted with aqueous glycerin

Many reaction steps, long process, high temperature