Phase equilibria with supercritical carbon dioxide for the enzymatic production of an enantiopure pyrethroid component .2. Ternary and five-component systems

(S)-alpha-Cyano-m-phenoxybenzyl alcohol is an important synthon for pyrethroid insecticides. It is obtained by the lipase-catalyzed kinetic resolution of racemic alpha-cyano-m-phenoxybenzyl acetate, with 1-octanol acting as an acyl acceptor and thus being converted to 1-octyl acetate. Supercritical carbon dioxide is used as a unique solvent for the reaction and the subsequent product recovery by extraction. Phase equilibria of the ternary systems CO2 + alpha-cyano-m-phenoxybenzyl alcohol + alpha-cyano-m-phenoxybenzyl acetate and CO2 + 1-octanol + 1-octyl acetate were measured at 313.15 K and at respective pressures of 20 MPa and 8 MPa. The latter ternary exhibits alyotropic behavior. Phase equilibria of the ternary CO2 + 1-octanol + alpha-cyano-m-phenoxybenzyl acetate and the five-component system CO2 + 1-octanol + 1-octyl acetate + alpha-cyano-m-phenoxybenzyl alcohol + alpha-cyano-m-phenoxybenzyl acetate were determined at 313.15 K and at various pressures of up to 17 MPa. The Soave-Redlich-Kwong equation of state with the mixing rules due to Huron and Vidal was checked for its ability to reproduce the measured equilibrium data. Whereas model predictions match experimental data of the ternary systems within the estimated accuracy of the measurements, larger deviations exist for the five-component systems.