Separation of amino-acid enantiomers using micellar-enhanced ultrafiltration.
Micellar-enhanced ultrafiltration (MEUF) is investigated as a large-scale technique for separating amino acid enantiomers. Specifically, L-5-cholesterol glutamate, a chiral ligand-exchange cosurfactant, is used together with a nonionic surfactant to form mixed micelles that preferentially bind D-phenylalanine over L-phenylalanine in the presence of copper(II). Operational selectivities as high as 4.2 are obtained. Potentiometric titrations using a water-soluble model compound similar to the chiral cosurfactant indicate that the ternary copper complex with phenylalanine has a stereoselectivity for the D enantiomer which is significantly smaller than that observed in the MEUF system. Thus, the selectivity of the chiral legend's local solvent and structural environment.
Creagh
A L
AL
Wageningen Agricultural University, Food and Bioprocess Engineering group, Department of Food Science, Biotechnion, PO Box 8129, 6700 EV Wageningen, The Netherlands.
Hasenack
B B
BB
Van der Padt
A
A
Sudhölter
E J
EJ
Van't Riet
K
K