Esterification of High Free Fatty Acid Rice Bran Oil: Parametric and Kinetic Study

The esterification of free fatty acids (FFA) in rice bran oil (RBO) with methanol in the presence of sulfuric acid as a homogeneous catalyst was studied. The effects of catalyst concentration (0.15 to 1.0 wt%), reaction temperature (318 K to 333 K), and molar ratio of oil to methanol (1:5 to 1:30) on the conversion of FFA were investigated to optimize the conditions for maximum conversion of FFAs. A detailed kinetic study was carried out using second-order pseudo-homogeneous kinetic model. The kinetic parameters were obtained and activation energy was determined from the Arrhenius plot. The activation energy of 23.21 kJ mol -1 and pre-exponential factor of 32.65 L mol -1 min -1 was obtained under the optimum catalyst concentration of 0.5 wt %, stirring speed of 500 rpm and oil to methanol ratio 1:20.