Kinetic modelling of decyl acetate synthesis by immobilized lipase-catalysed transesterification of vinyl acetate with decanol in supercritical carbon dioxide

The synthesis of decyl acetate, by the transesterification of vinyl acetate with decanol, was studied using supercritical CO2 as solvent and immobilized Candida antarctica lipase B as catalyst (Novozym® 435). The enzymatic content was determined for each particle size of the catalyst, indicating that the enzyme is located in an external shell of the particle, following an “egg-shell” distribution, with an estimated thickness of ca. 60 μm, independent of the particle size. The reaction was enhanced by increasing the enzyme loading, the concentration of vinyl acetate and the temperature; it was inhibited by excess of decanol and by increasing the pressure. A simplified model, based on the Ping-pong bi-bi mechanism with competitive inhibition by the alcohol, was proposed for the transesterification of vinyl acetate with decanol at 35 °C and 100 bar, and it was found to be suitable to represent the kinetic data.