Pakamas Chetpattananondh and Chakrit Tongurai

pp. 515 - 521

Abstract

The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process were found to be a reaction temperature of 200°C with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction time of 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared with the glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glycerol and crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed by adding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved by using isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35°C. A purity not exceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.