Thesis (M.Eng.)--Chulalongkorn University, 2009

To study the production of biodiesel fuel from palm stearin and methanol with transesterification carried out in a batch reactor by using 6:1 methanol/ oil molar ratio, 1wt% potassium hydroxide as homogeneous catalyst and various cosolvent such as tetrahydrofuran (THF), MTBE and dimethyl ether (DEE). Cosolvents were used to reduce the reaction time and costs in biodiesel production. It has been found that the suitable condition for biodiesel production were 60 oC reaction temperature, 250 rpm stirring rate, 10 minutes reaction time with tetrahydrofuran as cosolvent (THF/methanol molar ratio 0.2). At these conditions, the maximum methyl ester content in the product was 97.6% by weight. In the same condition but absence of cosolvent case methyl ester concentration was 93.5 wt%. Therefore addition of cosolvent in the biodiesel production can reduce energy and reaction time.