Critical Role of Catalyst-Dependent Solvent Effect for the Conversion of Xylan to Furfural

The synergistic catalyst-solvent interaction is paramount in dictating the efficiency of xylan catalytic depolymerization. However, the intricate interactions between catalysts and solvent molecules present a significant challenge in the research. By innovatively integrating quantum chemical calculations, molecular dynamics simulations, and experimental validation, this work establishes a comprehensive analytical framework. This strategy thereby uncovers the synergistic interplay between solvent molecules and catalytically active species in xylan depolymerization at the molecular level. A furfural yield of 70.6% was achieved from xylan under optimal conditions in the γ-valerolactone (GVL)/H₂O-Al₂(SO₄)₃ composite catalytic system, leveraging its powerful synergistic effect. Water molecules promote the formation of the catalytic active center and drive its reactive binding with the xylose intermediate. On the other hand, GVL not only stabilizes the catalytic active centers but also forms a protective solvent shell around the furfural product molecules. This work provides a blueprint for the precise and efficient construction of solvent systems in biorefining.