Continuous catalytic epoxidation of biodiesel for sustainable production of bio-based plasticizers using molecular oxygen

A continuous catalytic epoxidation process using molecular oxygen and heterogeneous catalysts was evaluated for the first time to produce epoxidized biodiesel. Soybean oil-based biodiesel and 10wt%Mn/Al2O3 were used as the feedstock and catalyst, respectively. The continuous epoxidation process used oxygen gas as an oxidant, instead of hydrogen peroxide, to automatically recycle the oxidant. Over 95% of the unsaturated FAMEs in the feedstock converted their epoxidized compounds at 160 °C and 10 bar with 10 ccm of oxygen gas. The recovery of gas, liquid, and solid phases was successfully achieved by simple liquid-gas separation and 2-stage distillation. An integrated epoxidation process was proposed to produce bio-based plasticizers with continuous separation of the products, solvent, and oxidant for recycling.