Microwave assisted rapid conversion of fructose into 5-HMF over solid acid catalysts

Abstract

In this work, we investigated the dehydration of fructose into 5-hydroxymethylfurfural using solid catalysts with microwave assistance in dimethyl sulfoxide. Five kinds of solid catalyst ZrO₂, WO_x/ZrO₂, MoO_x/ZrO₂, SO₄²⁻/WO_x–ZrO₂ and SO₄²⁻/MoO_x–ZrO₂ were prepared and characterized by XRD, UV-DRS, FTIR, XPS, TEM, TPD, BET, and Raman and the surface acid amount was obtained by combining pyridine adsorption and UV spectrometry. The SO₄²⁻/WO_x–ZrO₂ catalyst was found be the most active catalyst, and a fructose conversion of 95.80% with 83.90% 5-HMF yield was obtained at 150 °C in a relatively short reaction time of 5 min. The value of the activation energy was comparable with previous values reported in the literature, implying that SO₄²⁻/WO_x–ZrO₂ was efficient for the dehydration of fructose to 5-HMF and that microwave radiation heating had a remarkable accelerating effect on the fructose conversion.