Nanosized TiO2—A promising catalyst for the aldol condensation of furfural with acetone in biomass upgrading

Nanosized TiO2 catalyst was successfully prepared by a simple green procedure and used in liquid phase aldol condensation of furfural with acetone, a key step in bio-fuel processing. In order to determine the effect of calcination temperature on catalytic properties of TiO2, the as-prepared TiO2 and calcined TiO2 (150–900 °C) were studied by XRD, BET, TPD-CO2/NH3, TGA/DTG and FTIR evaluation. The catalytic performance of TiO2 samples in aldol condensation of furfural with acetone was evaluated and compared with that of Mg–Al hydrotalcites and a BEA zeolite. These experiments showed that uncalcined TiO2 possessed reasonable activity in aldol condensation of furfural to acetone and resulted in commonly produced condensation products. The observed catalytic behavior of TiO2 could be competitive with that reported for other inorganic solids. The calcination of TiO2 resulted, however, in a decrease in its catalytic activity due to extensive dehydration and surface dehydroxylation as well as due to changes of textural properties resulting in a decrease in the amount of accessible active sites. Thanks to its advanced properties, nanosized TiO2 is a promising catalyst for aldol condensation of furfural with acetone and could broaden possibilities for optimizing conditions for bio-fuel production.