Biodiesel is a biofuel obtained from vegetable or animal oils and fats. These are mainly composed of triglycerides but can contain significant amounts of water and free fatty acids, depending on their origin. Biodiesel is generally produced by transesterification, with or without catalyst, by enzymatic interesterification, by microemulsification, or by pyrolysis. Transesterification (with acid, basic, or enzymatic homogeneous or heterogeneous catalysts) is the most frequently used reaction. The operating parameters, including the types and concentrations of alcohol and catalyst, the reaction temperature and duration as well as the agitation intensity, must be optimized for successful application. In general, biodiesel is characterized by a higher viscosity and a lower heating value than those of petrodiesel. To improve these physical properties, petrodiesel or additives can be added to biodiesel.
Heterogeneous Catalysts Based on H3PW12O40 Heteropolyacid for Free Fatty Acids Esterification