Liquid-liquid equilibrium during ethanolysis of soybean oil

This study obtained the liquid-liquid equilibrium (LLE) data for systems involved in the stepwise ethanolysis of soybean oil. Experiments were performed in a 1:9 M ratio (soybean oil:ethanol), at a reaction temperature of 303 K, in two different catalyst concentrations (0.02% and 0.5% of NaOH). Data on phase equilibrium allowed analyzing the presence of biphasic and monophasic regions during the ethanolysis and the phase distribution of partial acylglycerols and esters. Two different sets of UNIFAC binary interaction parameters were used to test their ability to predict the data obtained. As expected, the original parameters could not describe well this kind of system. Nevertheless, an alternative set of parameters obtained from the literature, adjusted to the liquid-liquid equilibrium data of systems in biodiesel production, was able to properly predict these LLE experimental data.