However, in both processes (Wimmer, 1992a; Wimmer, 1992b), adding water before removing glycerol could form an emulsion, resulting in losses of esters and glycerol. Usually, transesterification reaction mixtures were allowed to cool to room temperature and the esters were separated with a separatory funnel. Unreacted methanol in the ester layer was removed by distillation or evaporation. The esters were further purified by dissolving in petroleum ether, adding glacial acetic acid or phosphoric acid to adjust the pH to 7, washing three times with water, drying the oil phase over anhydrous magnesium sulfate and filtering and removing solvent by evaporation (Freedman et al., 1984).