Method for efficiently producing levulinic acid from cellulose resources

Abstract

The invention discloses a method for efficiently producing levulinic acid from cellulose resources, which specifically comprises the following steps of: preparing a reaction system from a strong acid catalyst, a cellulose raw material and acetic acid or an aqueous solution thereof, carrying out a heating reaction, and after the reaction is finished, carrying out solid-liquid separation on the reaction system, the solid obtained after separation being cellulose or other biomass components which are not completely reacted; adding a precipitant into the solution obtained after separation, and neutralizing and precipitating the acid catalyst in the solution; and carrying out solid-liquid separation again, and distilling the obtained liquid to remove the solvent, thereby obtaining levulinic acid. According to the method, acetic acid is adopted as a catalytic solvent, weak coordination of acetic acid can help to retain high acidity of the strong acid catalyst in the system, the reaction conditions are mild, the catalytic activity is high, acetic acid is wide in source, low in price and low in evaporation heat, the product separation cost is low, and favorable conditions are provided for economic recovery of levulinic acid.

Description

technical field [0001] The invention belongs to the field of biomass catalytic utilization, and in particular relates to a method for efficiently producing levulinic acid from cellulose resources. Background technique [0002] Levulinic acid is an important biomass-based platform compound. It contains a carboxyl group and a ketone carbonyl group. It can undergo various reactions such as esterification, decarboxylation, oxidation, reduction, and carbon-carbon bond coupling to generate a variety of chemicals and energy. substances, and their efficient, economical and green synthesis has received more and more attention. [0003] Levulinic acid is currently mostly synthesized from biomass-based sugars or their derivatives such as furfural and 5-hydroxymethylfurfural through multi-step catalytic conversion. The formation of levulinic acid from furfural is essentially a hydration process. During the reaction, the carbon number of the molecule remains unchanged, the reaction cond...

AI Technical Summary

Problems solved by technology

The formation of levulinic acid from furfural is essentially a hydration process. During the reaction, the carbon number of the molecule remains unchanged, the reaction conditions are mild, and the yield is high. However, furfural itself is an important biomass-based platform compound. It is derived from Biomass-based hemicellulose is produced by acid-catalyzed dehydration, the production cost is high, and the process route of its conversion to levulinic acid is not economical

5-Hydroxymethylfurfural is also a biomass-based platform molecule. Compared with furfural, its raw material sources are wider. It can be synthesized from cellulose or monosaccharides through acid-catalyzed conversion, but 5-Hydroxymethylfurfural The same production cost is high, and the economics of preparing levulinic acid is similar to that of furfural.

However, the key issue in the relevant technological process is not the yield, but the concentration of levulinic acid generated in the reaction process is often very low, mostly around 5%, and some are even lower than 1%, and levulinic acid is miscible with water. It is difficult to separate levulinic acid from the water phase system, and the water in the system can be removed by means of distillation in time, but the separation of levulinic acid and catalysts such as sulfuric acid is also a great difficulty

In addition, due to the low catalytic activity of catalysts in aqueous systems, these processes often require higher reaction temperatures.

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