Preparation And Resolution Mechanism Of Temperature Sensitive Chiral Separation Membrane

With increasing demand for optical chiral drugs,chiral separation technology has developed rapidly.There are many methods to obtain optical pure chiral drugs,but most of them have disadvantages of complicated process and high cost.Recent years,chiral microgels have been widely concerned because of their simple separation process and high separation efficiency.In this study,we prepared thermosensitive chiral microgels and explored the chiral recognition and resolution mechanism of microgels.And we prepared PVDF-g-PNIPAAm/P(NIPAAm-co-AAc-L-PheEt))membrane with chiral recognition and resolution.First,L-phenylalanine ethyl ester hydrochloride and acrylamide(AAc)synthesis the chiral monomers(AAc-L-PheEt).Then,P(NIPAAm-co-AAc-L-PheEt)ware prepared with chiral monomers and N-isopropyl acrylamide(NIPAAm)by free radical copoly-merization.The structure of chiral monomers and microgels ware characterized by FT-IR spectroscopy and NMR spectrometer,and the temperature-sensitive property of P(NIPAAm-co-AAc-L-PheEt)was characterized by turbidity method.The results show that P(NIPAAm-co-AAc-L-PheEt)has good temperature sensitivity,and thermosensi-tive property decreases with increase of chiral monomers content in the copolymeriza-tion ratio.P(NIPAAm-co-AAc-L-PheEt)can specifically recognize and adsorb D-phe-nylalanine,and mass ratio(R = 0.2)of microgels with chiral monomers have the best adsorption ability to D-phenylalanine.By GROMACS molecular simulation software,chiral recognition mechanism of P(NIPAAm-co-AAc-L-PheEt)is studied by analyzing the intermolecular force and con-formation.At the same time,temperature-sensitive property of PNIPAAm molecular chain was characterized by change of molecular chain radius.The results show that the interaction force between P(NIPAAm-co-AAc-L-PheEt)and D-phenylalanine is greater than that of L-phenylalanine.The chiral identification and separation mecha-nism of P(NIPAAm-co-AAc-L-PheEt)were verified theoretically.The membrane of PVDF-g-PNIPAAm/P(NIPAAm-co-AAc-L-PheEt)was prepa red by phase inversion method,and their chemical compositions and property was studied.The results show that microstructure of PVDF-g-NIPAAm membra ne surface is compact and the surface of PVDF-g-PNIPAAm/P(NIPAAm-co-AA c-L-PheEt)membrane is porous.The PVDF-g-NIPAAm membrane and PVDF-g-PNIPAAm/P(NIPAAm-co-AAc-L-PheEt)membrane are temperature-sensitive,an d the temperature sensitivity of PVDF-g-PNIPAAm/P(NIPAAm-co-AAc-L-PheEt)membrane is more obvious.The adsorption of D-phenylalanine at 25℃ is bett er than that at 45℃.