Novel Approach on Developing TiO2-Supported Heteropolyacids Catalyst for the Efficient Conversion of Xylose to Furfural

The conversion of biomass-derived monosaccharides to value-added platform compounds, regarded as the alternative biofuels precursors, has attracted increasing attention. This work provides a novel approach on developing efficient and recyclable catalyst for biorefining. Herein, a titania-supported tungstophosphoric acid (TPA-TiO2) nanocomposite catalyst with advantages in acidity flexibility and catalytic stability was proposed for the efficient dehydration of xylose to furfural. The loading of the active component of TPA played an important role in the acidity and Lewis/Brønsted acids distribution of the catalyst. The structure characterization of the catalyst showed that the TPA particles were distributed well in TiO2 support. After the optimization of catalytic reaction conditions, the xylose conversion could approach to 96.12% while the furfural yield of 76.71% was obtained at 190 °C for 60 min catalyzed by TiO2-TPA-3 in a methyl isobutyl ketone (MIBK)–water biphasic solvent system. It was still about 80% of the initial yield after the fifth recycling of the TiO2-supported heteropolyacids catalyst. Furthermore, the reaction kinetics of xylose dehydration to furfural was investigated. The catalytic system in this work had a lower activation energy for xylose dehydration, and the decrease in furfural yield was mainly caused by the side reaction of furfural with intermediates. This work provides a novel approach on developing efficient and recyclable catalyst for biorefining.