Synthesis of Biodiesel from Vegetable Oil Using Supported Metal Oxide Catalysts

Biodiesel is known for its less polluting, renewable, and biodegradable properties. It is conventionally produced by the alkali-catalyzed transesterification of triglycerides. The use of a heterogeneous catalyst can make the production process cost-effective and environmentally friendly. In this work, we evaluated two catalysts, ZnO/zeolite and PbO/zeolite, for the synthesis of biodiesel using jatropha oil as a feedstock. Both catalysts exhibit reasonably good activity for the reaction of interest and are reusable under the reaction conditions. The leaching of metal ions during the course of the reaction is minimized by using zeolite as a support. The catalysts were characterized by X-ray diffraction, N-2 adsorption, transmission electron microscopy, scanning electron microscopy, and temperature-programmed desorption/temperature-programmed reduction. The PbO/zeolite catalyst performed better than the ZnO/zeolite catalyst when sunflower oil, which is free of fatty acids, was used as the feedstock. However, ZnO/zeolite was more active when jatropha oil, which contains substantial amounts of free fatty acids (>10% w/w), was used as the feedstock.