Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

In this work, a dual-site heterogeneous catalyst was used to study the kinetics of the transesterification of crude jatropha oil with methanol in batch experiments. Experimental data were obtained between 150 and 182 °C at a constant molar ratio of alcohol to oil (11:1) and at a set catalyst concentration (3.32 wt% based on weight of oil). Kinetic modelling was performed with an assumed pseudo-first order to describe the rate and catalyst deactivation, which suitably fit the experimental data. The model parameters were determined for both the mass transfer controlled and reaction regimes. The triglyceride (TG) conversion, methyl ester (ME) formation, and system thermodynamics were also evaluated. Based on the calculated values, within an acceptable range, the equilibrium constant, Ke = 1.42; activation energy, Ea = 161 kJ/mol; and free energy, ΔG = −1286 J/mol indicate that the developed model adequately described the methanolysis of the oil, which may be useful in reactor design and process simulation. The values that were calculated from the kinetic equations agree well with the experimental values, and the results help to understand and predict the behaviour of dual-site catalysts in practical applications for the production of biodiesel.