Production of isoamyl acetate by enzymatic reactions in batch and packed bed reactors with supercritical CO2

Abstract

Batch reactors (BRs) are probably the most widely used reactor designs for biocatalysis in supercritical fluids, but for industrial scale applications packed bed reactors (PBRs) are frequently preferred. The objective of this work was to investigate and compare BR and PBR in the synthesis of isoamyl acetate through enzymatic reactions in SCCO2 media. Experiments were performed to determine the kinetic parameters and to evaluate the internal and external mass transfer effects. The results indicate that the reaction is kinetically controlled, independently of particle diameter and agitation, therefore intra-particle diffusion and external mass transfer resistance are unimportant. The kinetic Ping-Pong Bi–Bi model described well the esterification of isoamyl alcohol with acetic anhydride at the evaluated conditions, indicating that the affinity of the enzyme to acetic anhydride is larger than to isoamyl alcohol. The PBR achieved the highest productivity of isoamyl acetate, although its conversion was lower than that obtained by the BR. In summary, PBR is the best option to synthesize isoamyl acetate in SC-CO2 media.