Glycerin is an important by-product in biodiesel production. To increase its qual- ity to be suitable for use it in other operations, e.g., the pharmaceutical industry, it needs to be purified. Therefore, the purification of glycerin by liquid-liquid extrac- tion of methanol using different solvents was investigated. It was shown that, in terms of separation, petroleum ether was more effective than toluene and toluene was more effective than n-butanol. In addition to the experimental investigations, the NRTL and UNIQUAC thermodynamic models were used to predict the com- positions of ternary mixtures of glycerin + methanol + organic solvent in glycer- in-rich and organic solvent-rich phases. The results showed the high accuracy of the presented models and their consistency with the measured data.
