Enantioselective Solvent Extraction of Neutral DL-Amino Acids in Two-Phase Systems Containing N-n-Alkyl-L-proline Derivatives and Copper(II) Ion
Distribution behavior of neutral amino acid enantiomers was examined in the aqueous and organic solvent of a two-phase system containing cupric ion and N-n-dodecyl-L-proline or N-n-alkyl-L-hydroxyproline.Significant enentioselectivity was observed when n-butyl, n-amyl, or n-octyl alcohol was used as the organic solvent.Equilibrium constants of ligand exchange reaction for several amino acid enantiomers were estimated for the n-butyl alcohol-water system.The enantioselectivity seems to depend primarily on the difference of the stability of mixed ligand complexes in the organic phase.