Epoxidation of used cooking oils: Kinetic modeling and reaction optimization

Abstract

This work developed a kinetic model for the epoxidation of used cooking oils (UCOs) via Prileschajew reaction with peracetic acid formed in situ. Such models, that have been not reported, are required for process design to assess feasibility of exploitation of UCOs as feedstock in the production of value-added oleochemical epoxides. The study evaluated the impact of reaction temperature and H2O2 loading on the oxirane yield, under constant loading of acetic acid (5% wt.), using H2SO4 as catalyst (2% wt.). Experiments were monitored by quantifying oxirane oxygen content along reaction, and the assessed conditions were defined based upon a factorial design. Considering a two-phase reactive media, two kinetic models were proposed and the corresponding kinetic parameters were adjusted by regression of the experimental data. It was found that the model that included two oxirane ring opening reactions pathways better described the experimental results, and that it can be further used for process design and scale up. Finally, the validated model was used to optimize a batch UCOs epoxidation by mean of a multi-objective optimization approach. Results indicate that conversions below 88% are required to avoid oxirane ring opening reaction, obtaining a product with an oxirane oxygen content of 4.4% wt.