Kinetics of soybean oil hydrolysis in subcritical water

A kinetic model was developed for the hydrolysis of soybean oil in subcritical water in the temperature range of 250–300 °C. The empirical model includes reversible hydrolysis reactions for the production of fatty acids from soybean oil and additional reactions for autocatalysis by fatty acid reaction products. The experimental yield of fatty acids over the time course of the batch reactions was compared to the model prediction and the sum of squared errors was minimized to estimate the kinetic parameters. The kinetic model prediction of fatty acid yield displays good agreement with experimental data. The autocatalytic phenomenon was assessed experimentally by addition of fatty acids to initial reaction mixtures to test the robustness of the kinetic model. The model predicts the increase in the fatty acid yields experimentally observed with acid addition.