Two sulfated zirconias were synthesized and characterized by X-ray diffraction and infrared spectroscopy. They were used as catalysts in the alcoholysis of soybean oil and in the esterification of oleic acid. Using sulfated zirconia prepared by the solvent-free method (SZrO2) as catalyst, the alcoholysis conversions of soybean oil under optimized conditions (120 degrees C, 1h and 5 wt%, of catalyst) were 98.6% (methanolysis) and 92% (ethanolysis), respectively. The esterification of oleic acid with methanol was complete after 2 h. Zirconia sulfated by standard methods (SZ) had low activity in the methanolysis of soybean oil (conversion of 8.5%,,) and conventional zirconia (NS) was inactive for methanolysis under the conditions optimized for S-ZrO2.(c) 2007 Elsevier Ltd. All rights reserved.