Transesterification reaction of vegetable oils, using superacid sulfated TiO2–base catalysts Original Research Article

Superacid sulfated titania catalyst, TiO2/SO4 (TS-series), have been prepared via the sol–gel technique, with different sulfate concentrations. The relation of structure and catalytic activity of the prepared material have been evaluated. The obtained material was characterized by several techniques, as infrared and Raman absorption spectroscopy, pyridine-adsorption infrared spectroscopy, thermogravimetric analyses and obtention of N2 adsorption–desorption isotherms. The catalyst that exhibits the highest catalytic activity in the methanolysis of soybean and castor oils at 120 °C, for 60 min (40% and 25%, respectively) was that which displayed the highest specific surface area, average pores diameter and pore volume, and highest percentage in sulfate groups (TS-5).