Ca-Al Hydrotalcites as Catalysts for Methanolysis and Ethanolysis of Soybean Oil

Abstract

The use of heterogeneous catalysts in the transesterification reaction of vegetable oils has getting emphasis in recent years, mainly by the alternative of obtaining clean fuel derived from renewable sources. Metal oxide such as MgO or CaO, supported ones like -; -2 3 2 3 Na / NaOH / Al O KF / Al O γ γ and zeolites are often applied in transesterification process. Among them, hydrotalcite has shown potential as catalysts on this reaction due to their physicochemical properties, such as: thermal stability, porosity, specific surface area, memory effect, basicity, acidity and anion exchange ca-pacity. This work studies the catalytic performance of the calcium and aluminum based hydrotal-cite in the transesterification reaction of soybean oil in methanol and ethanol. The hydrotalcite samples treated at 450˚C were impregnated with KOH. The efficiency of impregnated and non-impregnated samples was compared and the non-impregnated one showed the best performance. This property was attributed to the higher availability of active sites used in the transesterifica-tion process.