Continuous kinetic resolution catalysed by cross-linked enzyme aggregates, ‘CLEAs’, in supercritical CO 2

We report the use of cross-linked enzyme aggregates (CLEAs®) to catalyse the kinetic resolution of tetralol and 1-phenylethanol in a continuous supercritical carbon dioxide (scCO2) system. We describe the performance of the CLEA from Candida antarctica lipase B (CALB) and compare this to the catalytic activity of Novozym 435 (CALB immobilised on a macroporous acrylic resin). In addition, we report a two-stage reaction with the kinetic resolution of 1-phenylethanol performed in series with the metal (Pd) catalysed hydrogenation of acetophenone. Reactions performed in series have a potential economic advantage as the second, and subsequent reactions do not require additional expenditure of energy for re-pressurization of solvent.