Functionalized assembly of solid membranes for chiral separation using polyelectrolytes and chiral ionic liquid



The successful assembly of a new solid membrane for chiral separation, assembled via the formation of complexes of a polyelectrolyte and β-cyclodextrins chiral ionic liquid (β-CD-IL) is presented. Before the assembly, the β-CD-IL, used as a chiral selector, was synthesized and characterized by 1H NMR. To tune the chiral separation capability of the solid membrane, β-CD-IL was subsequently immobilized on to porous supporting membranes through layer-by-layer assembly of the β-CD-IL and polyelectrolytes. The resulting membrane was used in the chiral separation of D, L-tryptophan racemate enantiomer. The membrane structure and surface morphologies were systematically analyzed by FT-IR, UV–vis, SEM and AFM. The effects of layer number on the chiral separation were investigated. It was found that the more β-CD-IL was immobilized on the membranes; the higher average separation factor could be obtained. The stability of the multilayer membrane was improved by coating with crosslinked polymer layer. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4772–4779, 2013