Influence of support on physicochemical properties of ZrO2 based solid acid heterogeneous catalysts for biodiesel production

Environmental pollution control is the challenge area of heterogeneous catalysts to avoid the use of harmful materials in chemical synthesis. So ZrO2 -based solid acid catalysts were prepared and used in environmental applications like production of biodiesel. ZrO2 loading on different supports (Al2O3, Fe2O3, TiO2 and SiO2) prepared by a hybrid sol-gel auto combustion methods. The structural, surface and acidity properties are studied. The catalytic activity was evaluated by production of biodiesel through conversion of stearic acid to ester. ZrO2/SiO2 has the highest conversion rate because of a high surface area and a high number of Lewis acid sites. Under the optimal reaction conditions of alcohol/ acid molar ratio 120:1, mass ratio of catalyst to acid 0.1, reaction time 3 h and reaction temperature 120 degrees C, the conversion rate reached 48.6%. Moreover, the catalysts reused over at least five runs without significant loss of activity.