Solid Acid Catalyst for Biodiesel Production from Waste Used Cooking Oils

This paper presents a study of the methanol based transesterification of waste used cooking oil (WCO, 15% free fatty acid content) with the synthesized solid acid catalyst at different temperatures and reaction times. The optimized conditions for fatty acid methyl ester (FAME) yield were investigated using methanol/WCO weight ratios of 0.15−0.35 and catalyst/WCO ratios of 0.25−1.25%. The results show that the methanol/WCO ratio of 0.3 and the catalyst/WCO ratio of 1.0% give the highest yield of 97.5% FAME at 383 K in 2 h. In addition, the capacity of porous supports for WOx synthesized catalysts, based on FAME yield was in the following order: Al2O3 > SiO2 > SnO2 > ZnO. The WOx/Al2O3 catalyst was found to be readily reusable and exhibited consistency in activity upon reuse for three times without loss of selectivity.