Glycerol and oleic acid are mutually immiscible components. Their rigorous reaction produces glycerol esters and water. Such mutual immiscibility of glycerol and free fatty acids limits glycerolysis, a reaction capable of upgrading waste-derived oils. The glycerol solubility in the fatty phase increases when glycerol esters are added to the immiscible mixture of glycerol and oleic acid.

Abstract

The mutual immiscibility of glycerol and free fatty acids limits glycerolysis, a reaction capable of upgrading waste-derived oils. In the present work, the liquid-liquid phase equilibrium data for the glycerol-water-oleic acid and glycerol-monoolein-oleic acid ternary systems were determined experimentally and compared with predictions of the UNIFAC-LLE and COSMO-SAC models. Monoolein was found to affect the glycerol solubility in oleic acid strongly. None of the models investigated adequately determined phase equilibria for the glycerol-monoolein-oleic acid system. COSMO-SAC predictions showed the best trend for glycerol solubility in the fatty phase. For the glycerol-water-oleic acid system, UNIFAC-LLE predictions were in good agreement with experimental data.