Separation Of Tryptophane And Phenylalanine Enantiomer Through β-CD To Chiral Membrane

Recently, β-cyclodextrin has received extensive attention since its special molecular structure, and the researches about it focus mainly on the molecular recognition, especially the chiral recognition, inclusion ability of complexation with numerous guest molecules, assembling mechanism, and the construction of novel self-assembly supramolecular architecture. β-Cyclodextrin and its derivatives have been widely used in preparation of separation membrane. The aim of this study is to improve the ability of separation membrane to recognize the substrate and chiral molecules.Chiral resolution membrane was prepared by blending of sodium alginate and cellulose acetate as the membrane material, and the β-cyclodextrin as the chiral selective reagent, and the effect of β-cyclodextrin on resolution was investigated. The membrane properties and the structure were characterized by FTTR, flow check, the potential of Zeta and TGA. At the same time, the properties of Trp adsorption and resolving effect were measured by HPLC. Considering the properties of membrane itself, we choose the cellulose acetate as the membrane material for a deep investigation.Membranes with different CA/β-CD ration were prepared by adding different chiral selective reagent to cellulose acetate, which is used as the base of chiral material. HPLC analysis shows that the resolving rate of the membrane is8.46%for tryptophan, and9.47%for phenylalanine. The property and structure is characterized by circular dichroism spectrum, TGA, the potential of Zeta, SEM and the Flux. The resolving mechanism for Trp and Phe has been investigated deeply.β-CD was modified to give BAN-β-CD, TS-β-CD, HO-β-CD. Alloying membrane is prepared by blending of a-CD,2.4-dimethyl β-cyclodextrins and the modified β-CD. Further, the chemical crosslinking membrane is prepared by the reaction of β-CD with cellulose acetate. The chemical crosslinking membrane shows high resolving effect for Trp and Phe, with the maximum resolving rates up to9.86%and10.89%, respectively, and has a good properties of temperature resistance.The adsorbing kinetics of the membrane for Trp, the effects of temperature on adsorption, and the relationship between maxmuim adsorption and concentration were investigated. The results showed that the adsorbing capacity increased when the substrate concentration increased at the first stage, then the adsorbing capacity decrease at the follow-up stage. The adsorbing capacity increase at beginning and then decrease with the temperature increasing, the adsorption kinetics is fit for Langmuir equation.