Degradation of the Oxirane Ring of Epoxidized Vegetable Oils in a Liquid-liquid-solid Heterogeneous Reaction System

Abstract

The main oxirane-ring opening reactions that occur during the manufacture of epoxidized vegetable oils using a strongly acidic, gel-type ionexchange resin (IER) (Amberlite IR-120, 8% crosslinking) were analyzed. By using a heterogeneous liquid–liquid–solid model, the reactivity oneach phase was individually assessed, taking into account each transport step as well as the relevant partition equilibria.The combined results on the attack onto the oxirane ring of epoxidized vegetable oils by either hydrogen peroxide (H2O2) or solvated aceticacid (AA) indicate that under ‘regular’ process conditions these attacks proceed in the kinetic regime; that is, they are not mass-transfer controlled.The study indicated that most of the degradation occurs on the catalyst and, also, confirmed that the external surface protons of the IER are themain responsibles of the deleterious degradation of the oxirane ring as, in both cases, the degradation rate was directly proportional to the availableexternal area of the catalyst.