Method of preparing levulinic acid via hemicellulose

Abstract

The invention relates to a method of preparing levulinic acid via hemicellulose. The method comprises the steps of screening hemicellulose which is 200-400 mesh, preparing hemicellulose liquid havinga concentration of 15-25% with a dual-water-phase solvent, adding the prepared hemicellulose liquid into a reactor, adding 5-10% of a mixed solution of formic acid, acetic acid and iron chloride, 1-5%of a tin porous carbon-based solid acid catalyst, 0.5-1.0% of Raney nickel-alumina-ZSM5 catalyst, and 0.3-0.8% of Au-ZrO2-SBA15 catalyst, stirring while temperatures are controlled in different periods of time, introducing hydrogen for a period of time, holding the set temperature for a period of time, and preparing to obtain levulinic acid solution. few byproducts occur to the preparation of levulinic acid; subsequent separation and purification are simple; the yield of levulinic acid is increased; one-step preparation of levulinic acid by hemicellulose is achieved.

Description

technical field [0001] The invention relates to a method for preparing levulinic acid from hemicellulose. Background technique [0002] Levulinic acid is one of the important products produced by biomass hydrolysis, and it is also an important platform compound and chemical raw material. In industry, levulinic acid is difficult to be directly produced by organic synthesis, and is usually obtained through biomass conversion. [0003] At present, there are two main production routes of levulinic acid: the first one is the synthetic route of furfuryl alcohol catalytic hydrolysis. Using pentosan as raw material, it is first converted into furfural by cracking, and then furfural is hydrogenated to generate furfuryl alcohol. Under acid catalysis, furfuryl alcohol generates levulinic acid through hydrolysis, ring opening and rearrangement reactions. The second is: biomass direct hydrolysis synthetic approach. Using biomass six-carbon sugar as raw material, levulinic acid is di...

AI Technical Summary

Problems solved by technology

The Chinese patent with the publication number CN108675928A discloses a method for directly preparing levulinate from furfural, by using furfural as raw material and lower alkanol as the reaction medium, the combination of loaded molecular sieve ZrO2 / MCM and ion exchange resin Amberlyst-15 As a catalyst to prepare levulinate, the disadvantage of this technology is that the raw materials used are highly toxic, and there are hidden dangers in terms of safety and environmental protection

The Chinese patent of publication number CN104311411A discloses the method technology of preparing levulinic acid by multi-stage acid hydrolysis, uses inorganic acid as catalyst, adopts multi-stage hydrolysis, hydrolyzes cellulose component, prepares levulinic acid product, the shortcoming of this technology is: preparation There are many by-products in the product, the operation is complicated, the energy consumed by multi-stage hydrolysis is increased, the cost is high, the subsequent products are difficult to separate, and the purity is reduced