Kinetic Study of the Epoxidation Intensification of Methyl Oleate by Phase-Transfer Catalysis in a Micellar Medium

Abstract

The aim of this work is to investigate the potential combination of phase-transfer catalysis (PTC) and microemulsions for the rapid epoxidation reaction of the double bonds present in methyl oleate, a monounsaturated vegetable oil. The reaction takes place in the presence of a quaternary ammonium salt, hydrogen peroxide, sodium tungstate, and phosphoric acid without solvents to which a nonionic surfactant is added. Two surfactants were tested: polysorbate 80 and Triton X-100. The results show that the coupling of PTC and micellar catalysis (MC) has reduced the reaction time by almost half of the epoxidation by PTC in the absence of surfactants. This intensification can be attributed to the behavior of the reaction medium formed by micelles playing the role of nanoreactors. The estimation of mass-transfer and chemical kinetic parameters was performed using the thermal power profile measured in a calorimetric reactor RC1-RTCal. Mass balance is evaluated using the main epoxidation reaction and that of the catalyst regeneration, whereas the mass-transfer kinetics between phases is determined by using a double film model. The activation energy of the epoxidation reaction was found to be 44 kJ·mol–1. Safety parameters, maximum temperature of synthesis reaction, and T D24 (temperature at which time to maximum rate is 24 h) were also determined, and their corresponding results demonstrated that this epoxidation process remains thermally safe.