Abstract: The silica-supported ferric sulfate [Fe2(SO4)3/SiO2] catalysts were prepared by impregnating SiO2 in ferric sulfate aqueous solution followed by calcination in air at high temperature. The effects of calcination temperature, loading amount of ferric sulfate, the amount of catalyst used, reaction time and reaction temperature on the synthesis of ethyl oleate were investigated. Results showed that Fe2(SO4)3/SiO2 was an efficient solid catalyst for the esterification of oleic acid and ethanol under solvent-free condition. The kinetic study of the reaction was carried out by an integral method and using an equivalent proportion of the reactants under atmospheric pressure. It was also found that the experimental data were in good agreement with the reaction mechanism proposed by Langmuir-Hinshelwood model. The experimental data fitted the pseudo second-order rate equation. The apparent activation energy and the pre-exponential factor were calculated to be 50.40 kJ•mol−1 and 1.22×107(mol/L)-1•h-1, respectively.

Key words: sol-gel, ferric sulfate, solid acid, esterification, kinetics