5-Hydroxymethylfurfural and levulinic acid derived from monosaccharides dehydration promoted by InCl 3 in aqueous medium

Controlling the Reaction Networks for Efficient Conversion of Glucose into 5-Hydroxymethylfurfural

Biomass-derived hexose constitutes the main component of lignocellulosic biomass for producing value-added chemicals and biofuels. However, the reaction network of hexose is complicated, which makes the highly selective synthesis of one particular product challenging in biorefinery. This Review focuses on the selective production of 5-hydroxymethylfurfural (HMF) from glucose on account of its potential significance as an important platform molecule. The complex reaction network involved in glucose-to-HMF transformations is briefly summarized. Special emphasis is placed on analyzing the complexities of feedstocks, intermediates, (side-) products, catalysts, solvents, and their impacts on the reaction network. The strategies and representative examples for adjusting the reaction pathway toward HMF by developing multifunctional catalysts and promoters, taking advantage of solvent effects and process intensification, and synergizing all measures are comprehensively discussed. An outlook is provided to highlight the challenges and opportunities faced in this promising field. It is expected to provide guidance to design practical catalytic processes for advancing HMF biorefinery.

Niobium phosphotungstates: excellent solid acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions

A 5-HMF yield of 96.7% was obtained over an excellent heterogeneous catalyst NbPW-06 in DMSO at 80 °C.

Valorization of an underused sugar derived from hemicellulose: efficient synthesis of 5-hydroxymethylfurfural from mannose with aluminum salt catalyst in dimethyl sulfoxide/water mixed solvent

Mannose, an underused sugar derived from hemicellulose, can be effectively converted into 5-hydroxymethylfurfural (5-HMF) with aluminum chloride catalyst under mild conditions, offering useful reference for the refinery of biomass in the future.

Heterogeneous Nb-containing catalyst/N,N-dimethylacetamide–salt mixtures: novel and efficient catalytic systems for the dehydration of fructose

Heterogeneous Nb-containing catalyst/N,N-dimethylacetamide–salt mixtures could be used as an efficient catalytic system for the dehydration of fructose to produce 5-hydroxymethylfurfural.

Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems

Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization.

Glucose dehydration to 5-hydroxymethylfurfural in ionic liquid over Cr3+-modified ion exchange resin

Cr³⁺-D001-cc resin shows excellent catalytic performance for the dehydration of glucose to 5-hydromethylfurfural, which is prepared by a simple ion-exchange method.

One-step method to produce methyl-d-glucoside from lignocellulosic biomass

One-step acid-catalyzed methanolysis of bamboo biomass for the preparation of methyl-d-glucoside as high value-added chemicals.