Transesterification of sunflower oil to biodiesel on ZrO2 supported La2O3 catalyst

ZrO2 supported La2O3 catalyst prepared by impregnation method was examined in the transesterification reaction of sunflower oil with methanol to produce biodiesel. It was found that the catalyst with 21 wt% loaded La2O3 and calcined at 600 °C showed the optimum activity. The basic property of the catalyst was studied by CO2-TPD, and the results showed that the fatty acid methyl ester (FAME) yield was related to their basicity. The catalyst was also characterized by TG–DTA, XRD, FTIR, SEM and TEM, and the mechanism for the formation of basic sites was discussed. It was also found that the crystallite size of support ZrO2 decreased by loading of La2O3, and the model of the solid-state reaction on the surface of La2O3/ZrO2 catalyst was proposed. Besides, the influence of various reaction variables on the conversion was investigated.