Study On Enantioseparation Of 1,1'-Bi-2-naphthol And Its Derivatives By Capillary Zone Electrophoresis

Chirality widely exists in our world.Chiral compounds(single enantiomers) have comprehensive applications in many fields dealing with pharmaceuticals,natural products, agrochemicals,and ferroelectric liquid crystals etc.For example,anything of optical pure 1,1'-bi-2-naphthol and its derivatives can be used as monomer material in synthesis of chiral macromolecule,but only racemic sample can't be used.So enantioseparation is very important.Capillary electrophoresis(CE) has manifested its versatility and potential in the study on separation and analysis of chiral compound,and was become one of the most commonly used separation techniques,because of its high efficiency,rapid analysis,wide range of separation modes and low consumption of buffer and samples etc.In CE enantioseparation,the chiral selector is dissolved in the running buffer to provide chiral environment.So the two enantiomers can be separated owing to the difference of the interactions between chiral selectors and enantiomers and thus the difference of elecrtophoretic motilities.Cyclodextrins(CDs) are the most widely used chiral selectors. Presently,CE enantioseparation is focused on experimental research between different kinds of cyclodextrins and enantiomers.The thesis is aimed at resolving the problem of separation and analysis of 1,1'-bi-2-naphthol and its derivatives,carrying out studies on capillary zone electrophoresis by using cheaper homemadeβ-CD and its derivatives as chiral selectors.There are four parts in the dissertation:The first chapter briefly summarized the research progresses in the enantioseparation of chiral compounds,and the chiral capillary electrophoresis was emphasized:Theory of chiral resolution,choice of chiral selector and all kinds of effect factors for enantioseparation.At last,the content of the study was briefly shown.The second chapter investigated on chiral capillary zone electrophoresis(CZE) for resolution of 2,2'-binaphthol enantiomers with homemadeβ-cyclodextrins as chiral selectors.1,1'-bi-2-naphthol enantiomers were separated baselinely by choosing optimal conditions of resolution such as the types and concentrations of CDs and buffer. Furthermore,recognition mechanism of chiral resolution was discussed by studding inclusion constant,thermodynamic equilibrium constant and infrared spectrum.It was found that the area ratio of 1,1'-bi-2-naphthol enantiomers isn't 1:1.This will because the absorption spectrum of CD-1,1'-bi-2-naphthol enantiomers inclusion compounds is differrent.The expression of e.e.with CE was proofreaded by comparing with HPLC. This method was used to determination of e.e.of 1,1'-bi-2-naphthol in chemic resolution and photoracemization.The third chapter studied on enantioseparation for racemic 2,2'-dihydroxy-1,1'-binaphthalenyl-3,3'-dicarboxylic acid(HBNC) by CE.The mechanism of resolution was investigated by studying inclusion constant and thermodynamic equilibrium constant. It was found that:Racemic HBNC is separated baselinely with phosphate buffer and SBE-β-CD as a chiral selector;the R-HBNC is eluted first when using neutral CD,but the enantiomer elution order is reversed when using SBE-β-CD;Comparing with the enantioseparation on HPLC,the resolution is better and the migration time is shorter.The fourth chapter studied on enantioseparation for four types of 2- substitute 1,1'-binaphthol derivatives.It was found that:2'-hydroxy-1,1'-binaphthyl-2-yl benzoate was separated well by using HP-β-CD or SBE-β-CD,moreover,the SBE-β-CD is better for the result of resolution,other three derivatives were also separated in the optimal conditions;Furthermore,this part also studied dual cyclodextrin system,due to the enantiomers elution order will be reversed when using HP-β-CD and SBE-β-CD.So the retention time,resolution and elution order can be adjusted by changing the ratio.