Catalysis of xylose to furfural by metal salts in a methanol–water system

Furfural (FF), an important biomass platform compound, is extensively utilized in the synthesis of high-value-added chemicals, fuels, resins, and pharmaceuticals. To achieve the efficient conversion of xylose into FF, we systematically screened a series of metal salt catalysts in a homogeneous methanol–water system and thoroughly investigated their catalytic performance and reaction mechanisms. The results demonstrated that AlCl 3 exhibited the optimal catalytic activity in this reaction, achieving >99% xylose conversion and a 77.3% FF yield under the conditions of 160 °C and 2 h of reaction. Kinetic studies indicated that the conversion of xylose to intermediates was the rate-determining step, with an apparent activation energy of 42.97 kJ mol −1 . Mechanistic analysis further revealed that AlCl 3 possesses both Lewis and Brønsted acid sites, which synergistically catalyze the multi-step reactions – including isomerization, ring-opening, dehydration, and cyclization – of xylose to form FF. This study develops a green and efficient catalytic system prototype with low cost, which not only clarifies the structure–performance relationship of AlCl 3 and the dual function of the methanol–water system, but also provides a theoretical foundation and technical basis for the sustainable production of biomass-based FF.