Optimization of biodiesel production from palm oil under supercritical ethanol conditions using hexane as co-solvent: A response surface methodology approach

In the present work, response surface methodology (RSM) was used to optimize the biodiesel production from palm oil under supercritical ethanol conditions. Hexane was added as a co-solvent, which in turn accelerated the reaction rate and increased the biodiesel yield. This process enables simultaneous transesterification of triglycerides and ethyl esterification of fatty acids in a shorter reaction time and may reduce the energy consumption due to simplified separation and purification steps. Different process parameters including alcohol to oil molar ratio (25:1–50:1), reaction time (10–30 min), reaction temperature (260–300 °C) and co-solvent ratio (0.1–0.4% v/v) were optimized using response surface methodology. A mathematical model was developed for predicting the fatty acid ethyl ester (FAEE) yield. Fatty acid ethyl esters produced from palm oil were measured and analyzed using FT-IR, GC–MS and thermogravimetric analysis (TGA) methods. The fuel properties of the biodiesel produced were determined and compared to the American society for testing and materials (ASTMs) standards for biodiesel.