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-phenoxybenzyl acetate is partially converted to the S-enantiomer of alpha-cyano-m-phenoxybenzyl alcohol, which is an important synthon for pyrethroid insecticides. 1-Octanol acts as a reaction partner, being transformed to 1-octyl acetate. Binary phase equilibria of each reactant with supercritical carbon dioxide, the solvent for both the reaction and the 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 critical 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 A high-pressure experimental apparatus was used with small samples being withdrawn from a visual equilibrium cell and analyzed online by gas chromatography. The Soave-Redlich-Kwong equation of state with the mixing rules due to Huron and Vidal was applied for correlating the measured equilibria. Deviations of correlated data from experimental results remain, in general, within the estimated accuracy of the measurements.