Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

Abstract

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins (SCER). The effects of the mass ratio of methanol to acidified oil, reaction temperature, and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids (FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0, reaction temperature of 65.0 °C, catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including ∆G, ∆S and ∆H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.