This study reviews transesterification reaction, an advanced technology for the synthesis of biodiesel, and compares heterogeneous and homogeneous catalysts to highlight their unique properties. Homogeneous catalysts provide a higher yield with a faster reaction rate and operate under mild conditions. However, they can dissolve in the final product, making separation difficult. Heterogeneous catalysts, on the other hand, can utilize raw feedstock from daily waste, making them more environmentally friendly, easier to recycle, and more active. While homogeneous catalysts are better suited for biodiesel made from feedstock with low free fatty acid content and water, heterogeneous catalysts can have their adjusted by controlling the calcination temperature. This article also discusses other factors related to metal oxide catalysts, and identifies the optimal conditions for transesterification as a temperature of 65 degrees, an alcohol-to-oil ratio of 1:8, a catalysts concertration above 1 mg/L, and a reaction time of around 90 minutes. If metal oxide catalysts are used, the ideal calcination temperature ranges from 700 to 900 degrees. However, for other catalysts, their operating conditions might vary, but the overall relationships among the factors remain consistent.
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