Desenvolvimento de catalisadores alternativos para obtenção de ésteres alquílicos por transesterificação ou esterificação

Abstract

Former works of our group have demonstrated the potential of catalytic systems based on titanium and zirconium in esterification of fatty acidy derived from soybean oil, in the presence of methanol. From these results, it arise the interest of evaluate the behavior of these systems in the presence of ethanol in the transesterification of soybean oil and in the esterification of fatty acid derived from this oil. In this context, this study aimed to investigate the catalytic activity of catalysts, exhibiting general formula M(n-butoxide)x (maltolate)4-x where M is titanium or zirconium, on the ethylic esterification and transesterification of soybean oil and soybean fatty acids, for obtaining biodiesel. Six catalysts were synthesized, two based on titanium and ford based on zirconium, in which the amount of the ligand maltolate (3-hydroxi-2-methyl-4-pironate), and n-butoxide. The formation of the complexes was confirmed by infrared spectroscopy. The catalytic activity of these catalysts was evaluated in the ethylic esterification via acid-base titulation, and ethylic transesterification via gas chromatography. The complexes M(n-butoxide)x (maltolate)4-x proved to be active in esterification, with conversions up to 81%, and in the transesterification yields up to 19%. When ethanol is used, the reactivity is lower than that observed when methanol is employed. In addition, complexes of Zr showed catalytic activity higher than the complex Ti.