Transesterification of soybean oil with methanol catalyzed by basic solids

The fatty acid methyl esters prepared by transesterification of vegetable oils with methanol are products of commercial interest due to their use as raw materials for chemical, pharmaceutical and food industries and also as biodiesel. Biodiesel is a non-polluting alternative fuel produced from renewable resources whose chemical and physical properties closely resemble those of the petroleum diesel fuel. This work studied the transesterification of soybean oil with methanol over basic solid catalysts such as: MgO, ZnO, Al2O3, and mixed oxides derived from hydrotalcite-like compounds (Mg/Al and Zn/Mg/Al). The influence of the catalyst basicity on their catalytic performance was also evaluated. The results indicated that both MgO and mixed oxides were efficient to catalyze the reaction under study with a fatty acid methyl esters yield higher than 60% at 130 °C. The influence of chemical composition on catalytic performance was closely related to the density of basic sites of the samples. The fatty acid methyl esters yield was favored by the increase on reaction temperature.