Epoxidation of soybean oil in toluene with peroxoacetic and peroxoformic acids - Kinetics and side reactions

Abstract

The kinetics of the epoxidation of soybean oil and the extent of side reactions were studied at 40, 60 and 80°C. Epoxidation was carried out in toluene with "in situ" formed peroxoacetic and peroxoformic acid and in the presence of an ion exchange resin as the catalyst. The reaction was found to be first-order with respect to the double bond concentration. At higher temperatures and at higher conversions a deviation from the first-order kinetics was observed. The rate constants for the epoxidation with peroxoacetic acid were 0.118 (h-1) at 40°C, 0.451 (h-1) at 60°C and 1.278 (h-1) at 80°C, while those for peroxoformic acid were 0.264, 0.734, and 1.250 (h-1). The activation energy was found to be 54.7 kJ/mol for the epoxidation with peroxoacetic acid and 35.9 kJ/mol for that with peroxoformic acid. Three factors indicated that side reactions did not occur on a large scale: The absence of an OH band in the IR spectra, the formation of less than 2% of higher molecular weight products from gel permeation chromatography and the selectivity values between 0.9 and 1.