Optimized Conversion of Waste Cooking Oil to Biodiesel Using Calcium Methoxide as Catalyst under Homogenizer System Conditions

Abstract

Although many types of heterogeneous catalysts have been applied to the transesterification reaction, some of them are unsuitable for industrial applications due to their high price and the extra preparation required to synthesize them. Calcium methoxide is a low cost, strong base with high catalytic activity and is thus commonly used in the biofuels synthesis process during the transesterification reaction. The objective of this study was to determine the optimized conversion in the transesterification reaction of waste cooking oil (WCO) for biodiesel production by using a homogenizer with a calcium methoxide catalyst. It was shown that the optimal reaction conditions are a methanol-to-oil molar ratio of 6:1, 4 wt % Ca(OCH3)2, a reaction temperature of 65 °C, a rotation speed of 7000 rpm, and a reaction time of 90 min. The conversion rate under these conditions reached 90.2%. Ca(OCH3)2 thus has potential as a catalyst for industrial use. In addition, with a homogenizer system, the reaction time for synthesizing calcium methoxide catalyst can be reduced by half compared to that for conventional water-bath heating. In addition, the large amount of waste water required in the oil-water separation step can be reduced by using calcium methoxide instead of a homogeneous catalyst, significantly reducing manufacturing costs.