On the study of KF/Zn(Al)O catalyst for biodiesel production from vegetable oil

A KF/Zn(Al)O catalyst was prepared by doping KF on calcined Zn–Al hydrotalcite-like compounds and tested for transesterification of vegetable oil with methanol to biodiesel. The obtained catalyst was characterized using techniques of nitrogen physisorption, Hammett indicator, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Its catalytic activity was compared with that of Zn–Al hydrotalcite-like compounds, Zn(Al)O, KF, KF/γ-Al2O3 and KF/ZnO. It was found that the prepared KF/Zn(Al)O catalyst showed the highest activity. This catalyst was particularly effective since, for a methanol to oil molar ratio of 6:1, an addition of 3 wt.% KF/Zn(Al)O catalysts, at 65 °C reaction temperatures, the biodiesel yield exceeded 95% at a reaction time of 3 h. Its high activity was ascribed to the formation of new phases KF and KOH and effect of Zn(Al)O support.

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