Abstract: Biodiesel produced by the transesterification of vegetable oils is a promising alternative fuel to diesel regarding the limited resources of fossil fuel and environmental concerns. An environmentally benign process was developed for the production of biodiesel from jatropha curcas oil using a heterogeneous solid super base catalyst, calcium oxide. The results showed that the base strength of calcium oxide was more than 26.5 after calcination following dipping in an ammonium carbonate solution. A study for optimizing the reaction conditions for the transesterification of jatropha curcas oil was performed. Under the optimum conditions of catalyst calcination temperature of 900 ℃, reaction temperature of 70 ℃, reaction time of 2.5 h, catalyst dosage of 1.5%, and methanol/oil molar ratio of 9, the oil conversion was 93%. The purification of the as-synthesized biodiesel by decalcification agents for eliminating the remaining calcium was investigated. Citric acid showed good performance in decalcification. The properties of the refined biodiesel accord with the domestic and foreign standards.

Key words: solid super base, calcium oxide, heterogeneous catalysis, jatropha curcas oil, biodiesel, refining