Optimization of levulinic acid esterification via surface response methodology using single metal oxide nanoparticle as heterogeneous catalyst

Increasing energy demands have led to the depletion of fossil fuels, instigating the need for alternative and greener energy sources. The present study focuses on the esterification of levulinic acid into value-added products like butyl Levulinate using heterogeneous sulfated-Al2O3 nanocatalyst. The synthesis method used is very simple and robust and the catalyst possesses high catalytic activity. Its physicochemical properties were studied using various characterization techniques, which indicated its nanocrystalline morphology and the presence of sulfonated active sites. The esterification reaction parameters such as mole ratio, catalyst loading, and time were optimized using JMP PRO 17 focused on the Box-Behnken design. The optimum values were found to be 1:8 (LA: BOH), 1.32 wt.% catalyst loading, and 6 h with 81.04% levulinic acid conversion for the reaction with sulfated-Al2O3 catalyst. Response surface plots were used for evaluating the experimental data, which was subsequently plugged into a complete quadratic regression model. After conducting kinetic investigations, the results of the experiment were found to suit the pseudo-second-order power law model, yielding an activation energy of 26.24 +/- 1.1 kJ/mol.