Enantioselective extraction of mandelic acid enantiomers using ester alcohol L-tartarate as chiral selector

摘要

Distribution behavior of mandelic acid enantiomers was examined in an aqueous-organic solvent of a two-phase system containing L-tartarate. The influences of pH, length of alkyl chain of L-tartarate, organic solvent, concentration of phosphate salt and time of chiral extraction on partition coefficient (k) and separation factor (α) were investigated, respectively. With the rise of pH, k decreases, but α increases. With the addition of length of alkyl chain of L-tartarate, k and α decrease. The organic solvent and concentration of phosphate salt also have a bigger influence on k and α. A new binary chiral selector system is presented, effective for the enantioselective extraction of racemic mandelic acid. The distribution coefficients of D- and L-mandelic acid as high as 14.9 and 7.0, respectively, and the enantioselectivity value of 2.1 were found.