Method for preparing L-glucan through catalytic pyrolysis of cellulose

Abstract

The invention discloses a method for preparing L-glucan through catalytic pyrolysis of cellulose. The preparation method comprises the following steps: adding zinc oxide into a sodium carboxymethyl cellulose solution to form a mixed solution, adding the mixed solution into a ferric sulfate solution, chelating to generate a precipitate, filtering and collecting the precipitate, washing with deionized water, drying, and calcining in an inert atmosphere to obtain the magnetic solid acid-base amphoteric catalyst. The method comprises the following steps: mechanically mixing a magnetic solid acid-base amphoteric catalyst Znn-coated Fe-CT with cellulose powder, then carrying out rapid pyrolysis at 200-600 DEG C, and condensing pyrolysis gas to obtain a liquid product rich in levodextran. The magnetic solid acid-base amphoteric catalyst Znn-coated Fe-CT can efficiently promote directional pyrolysis of cellulose at a low temperature, the yield of L-glucan in a product is high, and the catalyst can be very conveniently recovered from a solid product by adopting a permanent magnet and can be recycled for multiple times.

Description

Technical field: [0001] The invention belongs to the technical field of environmentally friendly new energy production, and in particular relates to a method for preparing levoglucosan by catalytic pyrolysis of cellulose. Background technique: [0002] Cellulose is reacted at around 500°C for a very short time (about 2 seconds), and rapid pyrolysis occurs to produce levoglucosan (1,6-anhydro-β-D-glucopyranose). Levoglucosan is an important monomer for the synthesis of stereo compounds, and can be used as a chiral synthon to synthesize oligosaccharides, polymers, resins, drugs and related products. Microorganisms can directly or indirectly use levoglucosan as a substrate to produce itaconic acid, citric acid, lipids and ethanol. The rapid pyrolysis of biomass to prepare levoglucosan is a method with great advantages and development potential. [0003] Biomass is usually impregnated and loaded with liquid acid for catalytic pyrolysis. The liquid acids currently used for cat...

AI Technical Summary

Problems solved by technology

Although liquid acid can significantly change the distribution of biomass pyrolysis products and obtain dehydrated sugar products, liquid acid impregnation tends to generate a large amount of waste liquid, which is difficult to handle, and liquid acid is easy to corrode equipment during the experiment, and cannot be recycled after the experiment , high experimental cost and cumbersome experimental operation are not conducive to large-scale application

Compared with liquid acids, solid acid catalysts have the advantages of recyclability and low pollution. Although many solid acids have achieved good results in catalyzing biomass pyrolysis, the production of target products in the pyrolysis products obtained by these solid acids rate is still low

However, the acidity of the liquid acid and solid acid used in related research is difficult to control, and the catalyst with a slightly stronger acidity will lead to further dehydration of levoglucosan and promote the formation of levoglucosone and other by-products