Determination of the intrinsic kinetics on biphasic recognition chiral extraction (BRCE) of zopiclone (ZPC) enantiomers was studied. The BREC system was established by adding hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous phase and L-isobutyl tartrate (L-IBTA) in organic phase. Factors affecting the extraction rate such as agitation speed, interfacial area, initial concentration of enantiomers in aqueous phase, concentrations of HP-β-CD and L-IBTA as well as pH of aqueous phase were separately studied. Results show that the kinetics of the extract reaction is fast. The reactions are found to be first order with respect to ZPC enantiomers and second order with respect to L-IBTA with the forward rate constants of 48.74×10^－5 mol^－2•m⁶•s^－1 for S-ZPC and 31.25×10^－5 mol^－2•m⁶•s^－1 for R-ZPC, respectively. The initial extraction rates decrease with the increase of HP-β-CD concentration. These data are very essential for design of the extraction progress.

Key words: biphasic recognition, reactive extraction, kinetic, Lewis cell, zopiclone enantiomers