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.