Kinetic modeling of canola oil transesterification catalyzed by quicklime

Abstract

This work aimed to study and model the kinetics of transesterification of canola oil with methanol catalyzed by calcined quicklime (CaO + MgO). The influence of three main variables was studied at 328 K: reagents order addition (has a negligible effect on the reaction), methanol-oil molar ratio (has minor effect on reaction rate after 1.5 h of reaction) and catalyst loading (high effect on reaction rate) to achieve at least a triglycerides conversion of 96.5% in concordance with norm EN 14103. A kinetic model based on an Eley-Rideal mechanism was found to well fit (R2 = 0.9886) the experimental data. Thus, it was concluded that for the quicklime catalyzed transesterification of canola oil with methanol to occur, first the methanol must be chemisorbed and the resulting methoxy species react with triglycerides in the interface liquid-solid. The whole process is limited by this step since methanol readily adsorbs onto the catalytic surface.