Geranyl Acetate Synthesis in a Packed-Bed Reactor Catalyzed by Novozym in Supercritical Carbon Dioxide and in Supercritical Ethane

Abstract

The esterification reaction of geraniol with acetic acid (100 mM/100 mM) catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was studied in supercritical carbon dioxide (sc-CO2) and in sc-ethane in a packed-bed reactor (PBR). In sc-CO2 it was easy to adjust the water activity (aw) in the reaction mixture to levels leading to good enzyme performance. Enzyme stability was high and steady-state conversions could be achieved that exceeded the largest conversions measured in batch stirred-tank reactors (BSTRs), which is probably due to the lower aw levels achieved in the PBR. In sc-ethane, where the solubility of water is lower, high steady-state conversions could be attained only by preventing the accumulation on the enzyme bed of the water produced during reaction. The kinetic parameters for the reaction in sc-CO2 were determined using previously published data obtained in a BSTR, and a model was developed for the PBR that included those kinetic parameters. This model was able to predict with ...