Lattice-water-induced acid sites in tungsten oxide hydrate for catalyzing fructose dehydration

Herein, hydrated WO 3 was synthesized by hydrothermal method, and the relationship between its structure and acidity was explored. The numbers of Brønsted acid sites (BAS) and Lewis acid sites (LAS) can be modulated by adjusting the lattice water content of WO 3 ·nH 2 O. Mechanism studies shown that the density of BAS and diffusion effect have a synergistic effect on the activity of dehydration reaction. The optimized WO 3 ·0.5H 2 O catalyst in the presence of both high BAS density and high BAS accessibility afforded 73% 5-hydroxymethylfurfural (HMF) yield, and almost no deactivation appeared after five cycles. Nearly twice higher turnover frequency (TOF) and 50% higher HMF selectivity were observed in comparison to anhydrous WO 3 .