Enantioseparation of mandelic acid and alpha-cyclohexylmandelic acid using an alcohol/salt-based aqueous two-phase system

摘要

An alcohol/salt-based aqueous two-phase system (ATPS) was employed for enantioseparation of (R,S)-mandelic acid (MA) and (R,S)-alpha-cyclohexylmandelic acid (alpha-CHMA). Sulfonated beta-cyclodextrin (Sf-beta-CD) with different degrees of substitution (DS) was considered as the chiral selector. The ethanol/(NH4)(2)SO4 system showed the optimal chiral recognition ability for MA. To optimize the experimental conditions, Sf-beta-CD concentration, ethanol and salt concentration, temperature, and pH were studied. The recognition ability of enantiomers was mainly dependent on the type of the chiral selector but the ethanol and (NH4)(2)SO4 concentrations also had significant influence on the enantiomeric recognition. The maximum values of alpha and ee (up) of 1.69 and 16.3 % were obtained, respectively, for MA under the optimal conditions. A potential application of this alcohol/salt ATPS is the scale-up of chiral separation of MA.