Kinetics of transesterification of soybean oil

TLDR

Transesterification of soybean oil with methanol is thought to proceed via three stepwise reversible reactions. The study investigates transesterification of soybean oil with methanol and proposes a two‑region mechanism comprising an initial mass‑transfer‑controlled stage followed by a kinetically controlled stage. The authors examined how mixing intensity (Reynolds number 3,100–12,400) and temperature (30–70 °C) influence the reaction rate under a fixed 6:1 alcohol‑to‑triglyceride ratio and 0.20 wt % catalyst, proposed the two‑region mechanism, and determined rate constants and activation energies for all forward and reverse reactions. Mixing intensity and temperature exert parallel effects on the reaction rate, and the kinetic region follows a second‑order kinetic model.

Abstract

Abstract Transesterification of soybean oil with methanol was investigated. Three stepwise and reversible reactions are believed to occur. The effect of variations in mixing intensity (Reynolds number=3,100 to 12,400) and temperature (30 to 70°C) on the rate of reaction were studied while the molar ratio of alcohol to triglycerol (6:1) and the concentration of catalyst (0.20 wt% based on soybean oil) were held constant. The variations in mixing intensity appear to effect the reaction parallel to the variations in temperature. A reaction mechanism consisting of an initial mass transfer‐controlled region followed by a kinetically controlled region is proposed. The experimental data for the latter region appear to be a good fit into a second‐order kinetic mechanism. The reaction rate constants and the activation energies were determined for all the forward and reverse reactions.