Optical Resolution Membranes from Polysulfones Bearing Alanine Derivatives as Chiral Selectors

Polysulfones bearing a derivative of alanyl residue employed as chiral selectors were prepared by polymer modification. The specific rotation ([ α ] D ) of the polysulfone with a derivative of D ‐alanyl residue (PSf‐Ac‐ D ‐Ala) was determined to be 2.87 deg · cm 2  · g −1 (c = 1.00 g · dL −1 in DMF) and that with L ‐alanyl residue (PSf‐Ac‐ L ‐Ala) to be ‐2.36 deg · cm 2  · g −1 (c = 1.00 g · dL −1 in DMF). The membrane from PSf‐Ac‐ D ‐Ala preferentially adsorbed the D ‐isomer of Glu from racemic mixture of Glu and vice versa. Chiral separation ability was studied by applying a potential difference as a driving force for membrane transport. The permselectivity of PSf‐Ac‐ D ‐Ala toward D ‐Glu ( α D/L ) was determined to be 1.40, and that of PSf‐Ac‐ L ‐Ala toward the L ‐isomer ( α L/D ) to be 1.48 at 18.0 V, reflecting their adsorption selectivity.