Optical resolution of <img src='/image/spc_char/alpha.gif' border=0>-amino acid derivative through membrane process

Abstract

The present study deals with preparation, characterization and performance of chiral selective composite membrane. The reported membranes are prepared by forming the chiral selective layer on polysulfone (PS) microporous membrane. The chiral selective layer is prepared in-situ on PS membrane by co-polymerization of dibasic amino acid (lysine) and piperazine with trimesoyl chloride. The membranes are characterized by ATR-FTIR spectroscopy and scanning electron microscopy (SEM). The membrane performance is determined by performing optical resolution of racemic lysine monohydrochloride in pressure driven transport. The influence of concentration and ratio of monomers in co-polymerization on the membrane flux, separation and enantioseparation is observed. The observation indicates that membranes perform enantioseparation achieving >95% enantiomeric excess (%ee) for D-lysine hydrochloride in permeate. The composite membrane prepared with equal proportions of L-lysine and piperazine exhibited highest %ee with reasonable flux of D-lysine hydrochloride (4.03 gm^-2h^-1at 1034.21 kPa). High enantiomeric excess is obtained with feed solutions of low concentration.