Abstract: The reaction activity of catalysts on the synthesis of biodiesel from different oils was studied.By the analysis of GC and chemical method, the best constitution of catalysts was obtained.The results show that the alkaline material was the best catalyst to catalyze the transesterification of oils with acid value below 10 due to their best catalytic result and short reaction time,but for the oils with acid value above 10, neither the acid nor the base, could catalyze the transesterification in a short time.The catalyst NG made in this research, under the condition of temperature 180℃,time 2 h and catalyst dosage 0.1%, had high catalytic activity. The yield of 93% was obtained. The catalyst NG had profound practical significance in subcritical fluid technique.

Key words: natural oils, biodiesel, catalyst