Enantioselective separation of lambda-cyhalothric acid enantiomers by chiral extraction with tartaric esters

Partition behavior of lambda-cyhalothric acid enantiomers was examined in two phase system of water and 1,2-diochloroethane containing the chiral selector tartaric esters.The influences of pH,the concentrations of tartaric ester,concentrations of phosphate salt,extraction temperature and length of alkyl chain of tartaric esters on the parti- tion coefficients and separation factors were investigated.The results showed that K increased with increasing the con- centration of tartaric ester,but a increased firstly,and then decreased;with the increasing of pH,K decreased,but a increased firstly,and then decreased.When pH was 5.50 and concentration of tartaric esters was 0.30 mol/L,a better result was obtained.With the increase of concentrations of phosphate salt,both K and a decreased.With the increase of extraction temperature,K increaed,a had a little change.The length of alkyl chain of D,L-tartaric esters had a great influence on K and a,too.