PHASE-EQUILIBRIA WITH SUPERCRITICAL CARBON-DIOXIDE FOR THE ENZYMATIC PRODUCTION OF AN ENANTIOPURE PYRETHROID COMPONENT .1. BINARY-SYSTEMS

In a lipase-catalyzed kinetic resolution, racemic alpha-cyano-m-phenox ybenzyl acetate is partially converted to the S-enantiomer of alpha-cy ano-m-phenoxybenzyl alcohol, which is an important synthon for pyrethr oid insecticides. 1-Octanol acts as a reaction partner, being transfor med to 1-octyl acetate. Binary phase equilibria of each reactant with supercritical carbon dioxide, the solvent for both the reaction and th e subsequent product recovery by supercritical fluid extraction, were measured at a temperature of 313.15 K. The systems CO2 + 1-octanol and CO2 + 1-octyl acetate were investigated up to their respective critic al pressures of about 17 MPa and 8.5 MPa. Maximum pressures of 20 MPa for the binary CO2 + alpha-cyano-m-phenoxybenzyl alcohol and of 28 MPa for CO2 + alpha-cyano-m-phenoxybenzyl acetate were applied. A high-pr essure experimental apparatus was used with small samples being withdr awn from a visual equilibrium cell and analyzed online by gas chromato graphy. The Soave-Redlich-Kwong equation of state with the mixing rule s due to Huron and Vidal was applied for correlating the measured equi libria. Deviations of correlated data from experimental results remain , in general, within the estimated accuracy of the measurements.