Resumo

DELGADO, Claudia  e  PASHOVA, Veselina. Enzymatic production of ethyl esters from castor oil. Rev.fac.ing.univ. Antioquia [online]. 2010, n.53, pp.9-19. ISSN 0120-6230.

Biodiesel synthesis through transesterificación of castor oil with ethanol using n-hexane as a solvent and a lipozyme TL IM commercial lipase as a biocatalyst was studied. The effect of ethanol molar relation to oil (3:1-10:1), temperature of reaction (35-65°C), initial enzymatic charge (5-20% p/p) and amount of water (0-10% p/p) was investigated. The maximum percentage of bio-diesel (ethyl-esters) was obtained at a temperature of 35°C, a 5:1 ethanol to oil molar ratio, an initial enzymatic charge of 15 % p/p and an initial water concentration of 2% p/p, both of them based on the castor oil weight. A simplified model was proposed to describe the enzymatic kinetics of castor oil transesterification with ethanol, based on the ping-pong Bi Bi mechanism with competitive inhibition for alcohol. The kinetic parameters of the model were estimated graphically and parametrically; a good approach among the results foreseen by the model and experimental data was found at low ethanol concentration (40-80 mol Kg^-1).

Palavras-chave : Castor oil; biodiesel; transesterification; lipase; Ping- Pong Bi Bi mechanism.

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