Inclusion Phenomena Between Chiral Selectors And Amino Acids And The Use On Chiral Solid Membranes

The separation of chiral compounds is very important for the chemicaland biological field, meanwhile, the method that shows high efficiencyand low energy consumption is the main point in current research. Thesolid membrane separation process, as a tremendous potential method,has some advantages including high efficiency, low energy consumptionand convenient continuous operation, compared with the traditionalmethods. The process is based on the selective difference of chiral groupof selector immobilized on membrane for the two isomers needed to beseparated, and the driving force of separation contains pressure,concentration and potential difference. Obviously, the selection of chiralselector is very crucial for the process mentioned above. Thus, the aim ofthis work is to explore some noval chiral selectors and preparationmethods of solid membrane.The mono-6-deoxy-6-(3-methylimidazolium)-β-cyclodextrin tosylate(β-CD-IL), a chiral selector, was synthesized by the modification ofβ-cyclodextrin (β-CD) in this work. The Inclusion phenomena of β-CD and β-CD-IL with different amino acids were investigated, and theinclusion ratio and inclusion constant were obtained by UVspectrophotometry method. The inclusion ratio between β-CD andD,L-Tyr was1:1, while the inclusion constant between β-CD and D-Tyror L-Tyr was214.42or220.40. The inclusion ratio between β-CD andD,L-Trp was still unknown.The inclusion compounds between β-CD chiral selectors with aminoacids were prepared using grinding method. The inclusion compoundsprepared were characterized by XRD, FT-IR and NMR, which verifiestheir formation. The saturated solution method was used to investigate theinclusion phenomena between Trp and β-CD based selectors (β-CD andβ-CD-IL), giving the split factor. It was evident that the two selectors hadchiral recognition ability for the enantiomers. Further, the split factorsincreased with the chiral agents concentration increasing. When thereactant ratio of β-CD and D,L-Trp was5:1, the split factor mounted to1.402, while the reactant ratio of β-CD-IL and D,L-Trp was20:1, the splitfactor reached1.558.In the solid membrane separation process, moreover, the PANmembrane and N6membrane were used as the basement membranes,while the β-CD-IL and CS were deemed as the chiral selectors. And aseries of the chiral solid membranes were prepared by immobilizingdifferent chrial selectors on different porous support bodies. The solid membranes prepared showed different species and layers by controlingdifferent concentration and proportion. The resulted membrane werecharacterized by FT-IR and SEM to verify the fact that the chiralcompounds were immobilized on the membranes. The membranesobtained were used to separate and adsorb tryptophan (D,L-Trp) racemate.The s highest split factor using PAN basement membranes was1.12, thepermeate flux reduced with the time proceeding. The highest split factorof N6membranes was1.18. The adsorption capacity of solid membranefor tryptophan increased with growing concentraction of the chiral agents.The maximum adsorption capacity mounted to105.53mg/g membrane.