Heterogeneous catalytic conversion of rapeseed oil to methyl esters: Optimization and kinetic study

Biodiesel as a cleaner fuel has emerged to prominent attention for its commercialization. Biodiesel has great potential to replace mineral diesel due to its reduction in SOx and CO2 emissions. This study investigated biodiesel derived from rapeseed oil in the presence of impregnated bentonite with sodium hydroxide as a heterogeneous catalyst. The transesterification reaction parametric study and optimization were conducted by response surface methodology. Numerical optimization resulted in methyl esters yield of 96.99 wt. after 4 hours of reaction time, with a bentonite-to-NaOH ratio of 1:20 and 6 wt. of catalyst. Reaction temperatures of 62°C and alcohol-to-oil molar ratio of 6:1 have been used for all the experiments. Reaction kinetics of transesterification was studied at three different temperature intervals at optimized conditions and followed pseudo-first-order reaction. Fuel properties of biodiesel satisfied the criteria of international standards such as ASTM D6751 and EN 14214. © 2019 Elsevier Inc. All rights reserved.