Study on calcium oxide as a solid base catalyst for biodiesel production

摘要

Biodiesel, a mixture of fatty acid methyl esters (FAME) derived from vegetable oils or animal fats, is a promising alternative to fossil fuel oil for diesel engine. However, production of biodiesel is accompanied by environmentally malign effluents, since alkali hydroxide used as the catalyst is soluble in the reactant. In order to solve this problem, the noble process using calcium oxide was studied on the basis of data from transesterification of edible soybean oil (SBO) at reflux of methanol using various solid bases. Calcium oxide gave the above 90% conversion to FAME after 1hour of the reaction, matching sodium hydroxide for the catalytic activity. Although calcium hydroxide, calcium carbonate and magnesium oxide are also commercially available solid bases, they are less active in catalyzing the transesterification than calcium oxide. Alumina supported potassium, used for researches on various chemical reactions catalyzed over solid base, lacked the reusability for further recycling. Further, calcium oxide was anchored on active carbon in the cylindrical mold to compare with anion-exchange resin. The transesterification was more catalyzed over the carbon supported calcium oxide. Data from a set of experiments using the molded catalyst indicated impact of effectiveness factor on the catalytic activity.