Statistical optimization for biodiesel production from rapeseed oil via transesterificaion in supercritical methanol

Biodiesel production via transesterification of rapeseed oil in supercritical methanol was performed without catalysts. Response surface methodology (RSM) was used to evaluate the relationships between the content of fatty acid methyl esters (FAMEs) and reaction parameters, such as reaction temperature, reaction pressure, reaction time, and the molar ratio of methanol to oil. A central composite design was employed to fit the available response data to a second order polynomial RS model. The optimal conditions maximizing the content of FAMEs in the biodiesel were investigated. Results showed that the optimum processing conditions were 330°C, 210bar, a reaction time of 16min, and a molar ratio of methanol to oil of 50mol/mol. The predicted response value for these conditions was 93.6% methyl esters and it was in agreement with the experimental value. ► RSM was applied to optimize the supercritical transesterification of rapeseed oil. ► Optimum processing conditions were 330°C, 210bar, 16min, and 50mol/mol. ► The corresponding maximum FAMEs content in biodiesel was 93.7%.