Optimization and kinetic studies of 12-tungstophosphoric supported mesoporous aluminosilicate through response surface methodology for biodiesel production using green seed canola oil

Abstract

Biodiesel synthesis using a non-edible feedstock obtained from green seeds of canola oil using 12-tungstophosphoric heteropoly acid supported mesoporous aluminosilicate (HPW/MAS) catalyst was conducted. Response surface methodology (RSM) based on central composite design (CCD) approach was implemented to study the effects of catalyst loading, methanol to oil (M/O) molar ratio, and reaction time on biodiesel yield. A polynomial quadratic model was developed as a suitable model to correlate the reaction parameters to the response. M/O molar ratio indicated the most effect on biodiesel yield owing to the reversible nature of this reaction, while catalyst loading had minor effect on it. The highest biodiesel yield of 89 % was obtained at optimum reaction conditions of 5.9 wt% of catalyst loading, 27.2 of M/O molar ratio, at 200 °C and 4 MPa for 8 h. The formation of biodiesel was verified using HPLC, NMR and GC–MS analyses for their functional groups corresponding to esters. Kinetic study was carried out with pseudo first order assumption at various reaction temperatures in the range of 160 to 200 °C. From the Arrhenius equation, the pre-exponential factor and activation energy were found to be 9.1 × 102 min−1 and 36.34 kJ/mol, respectively.