Produção de biodiesel a partir da alcoólise do óleo de palma

Abstract

The production of biodiesel from the alcoholysis of palm oil catalyzed by commercial immobilized lipase was investigated. The effect of alcohol:oil molar ratio, addition of alcohol (single and stepwise), reaction temperature, concentration of enzyme, type of alcohol (ethanol and methanol), type of enzyme, and reuse of enzyme on reaction yield was evaluated. The reactions carried out using ethanol showed yields higher than those obtained when methanol was used. This behavior is related to the deactivation of lipase caused by an alcohol with small number of carbon atoms. The highest yield on biodiesel (54%) was obtained using an alcohol:oil molar ratio of 3:1, with stepwise addition of ethanol (0, 30 and 60 minutes), 9 wt.% of Lipozyme TL IM at 50°C. The recovery of lipase was not possible at the end of the reaction, because the lipase support has solubilized in the reaction medium. In addition, for comparison, the use of commercial immobilized lipase Lipozyme RM IM and Novozymes 435 and of chemical catalysts KOH, MgO, and La2O3 have been investigated. The yield on biodiesel using lipases as catalysts was higher than those obtained using chemical catalysts. The lower efficiency of chemical catalysts can be justified by the high acidity of palm oil (6,26 mg KOH.g-1) which promotes the consumption of the catalyst (KOH), due to the neutralization of free fatty acids in the oil, and the blockage of the active sites of solid chemical catalysts by adsorption of fatty acids on these sites