Research On Extraction Separation Of Optically Active Mandelic Acid Ester Characteristics

Chiral compounds are widely range of applications, growing importance. In all of the chiral approachs, the extraction separation method is the most valuable. In this paper, zopiclone and ofloxacin enantiomers were separated by chiral extraction with synthesized mandelic acid esters and o-chloro-mandelic esters as chiral selectors.A series of optically pure S-mandelic acid esters and R-o-chloro mandelic acid esters were synthesized. The effect of mole ratio, solvent, the concentration of catalyst, reaction time and other factors on the esterification was investigated. The optimal reaction condition for the development of a reliable synthetic method for mandelic acid ester was determined.Resolution of zopiclone enantiomers by enantioselective extraction with tartaric esters has been studied. Distribution behavior of zopiclone enantiomers was examined in one separation system that the volume of aqueous phase is the same as organic phase. The influence of length of alkvl chain of mandelic esters and o-chloro mandelic esters, the kinds of organic solventon, concentration of chiral selectors, concentration of zopiclone in aqueous phase, pH, and tempreture on the impact of K and a was examined. The preliminary mechanism was study, and the laws of the experiment were analyzed.A similar study was carried about enantiomers of ofloxacin. Distribution behavior of ofloxacin enantiomers was also examined in the same system and in the same way. The results of separation of two enantiomers with two types of esters as chiral selectors was analyzed comprehensively and discussed.