Kinetics of the epoxidation of soybean oil with H2O2 catalyzed by phosphotungstic heteropoly acid in the presence of polyethylene glycol

Abstract

In this work, the kinetics of “in situ” epoxidation of soybean oil with H2O2 (30% w/w), catalyzed by phosphotungstic heteropoly acid [π‐C5H5N(CH2)15CH3]3[PW4O16] (PHA) phase transfer catalyst and polyethylene glycol (PEG) as interfacial agent in dichloroethane, were investigated at 40, 50, 60, and 70°C. Assuming that the epoxidation reaction occurred in the pseudo‐homogeneous catalytic system and the side reaction of epoxy ring cleavage was negligible, the results appeared that the epoxidation reaction of soybean oil in the presence of PEG was a second‐order with respect to double bond concentration and a first‐order to the H2O2 concentration. The corresponding apparent activation energy (42.12 kJ/mol) was lower than that of PHA alone (49.23 kJ/mol), indicating that PEG could decrease the activation energy and speed up the epoxidation reaction of soybean oil.Practical applications: An environmentally friendly catalyst is eagerly needed to produce peroxided soybean oil for low yield and to prevent polluting the environment through the epoxidation of soybean oil with peracid. Phosphotungstic heteropoly acid phase transfer catalyst and polyethylene glycol improve the conversion and selectivity of the epoxidation reaction of soybean oil, and enhance its production efficiency.The activation energy of the soybean oil epoxidation reaction with H2O2 catalyzed by phosphotungstic heteropoly acid (PHA) in the presence of polyethylene glycol (PEG) was lower than that of PEG alone, accounting for the results showing that the epoxy group band of the former (PHA + PEG) appeared quicker than the latter (PHA) in IR spectra.