Protonated and layered transition metal oxides as solid acids for dehydration of biomass-based fructose into 5-hydroxymethylfurfural

A serial of protonated and layered transition metal oxides , including layered HTaWO 6 , HNbMoO 6 as well as HNbWO 6 , were synthesized by solid-state reaction and ion-exchange. The layered HTaWO 6 has been systematically studied as a solid acid to realize the dehydration of fructose to 5-hydroxymethylfurfural (HMF). The transition metal oxide samples were characterized with ICP-OES, EDS, XRD , XPS , SEM, TGA, FT-IR, N 2 adsorption–desorption and NH 3 -TPD. The influential factors such as reaction temperature, reaction time, solvent, catalyst amount and substrate concentration were deeply investigated. The optimized fructose conversion rate of 99% with HMF yield of 67% were achieved after 30   min at 140   °C in dimethylsulfoxide.