Immobilization And Enantioseparation Performance Of Chiral Stationary Phases Based On Cellulose Ester Bearing Electron-donating Pendants

Cellulose tris(4-methylbenzoate)derivatives with electron donor side groups have excellent chiral separation performance,which can achieve high-efficiency resolution of a variety of chiral compounds.They are one of the most widely used chiral separation materials at present.However,this kind of chiral separation material is mainly prepared by coating method,and some solvents with strong polarity cannot be used as mobile phase components,which greatly limits the application of this kind of chiral stationary phase.In order to break through this limitation,the immobilizing method can be used instead of the traditional coating method to prepare the stationary phase.The obtained immobilizing chiral stationary phase can use any polar solvent,which can not only greatly broaden the scope of use,but also effectively improve the solubility of the analytical substrate,and bring the reverse of the enantiomeric elution sequence.Up to now,there is no report on cellulose tris(4-methylbenzoate)-based immobilizing chiral stationary phase.Based on this situation,this paper intends to study the immobilizing methods of cellulose benzoate chiral stationary phase,and to study the chiral resolution performance and the influencing factors of the stationary phase prepared by different immobilizing methods.Four cellulose tris(4-methylbenzoate)derivatives with different proportions of triethoxysilypropyl were synthesized by esterification with microcrystalline cellulose as the matrix material.Seven new types of immobilized type cellulose tris(4-methylbenzoate)chiral stationary phases were prepared by intermolecular polycondensation and diisocyanate method,and a series of new cellulose esters were prepared by homogenate method`s immobilized type chiral column.The structure of the synthesized cellulose ester derivatives was characterized in detail by FT-IR and ~1H NMR,and the immobilizing efficiency of the prepared immobilized type chiral stationary phase was analyzed by TGA.Eight chiral compounds with typical structural characteristics were separated by HPLC,and the prepared immobilized chiral stationary phase was further evaluated of it`s chiral separation performance factors.The results shows that although the immobilizing efficiency of cellulose ester bonded chiral stationary phase prepared by intermolecular polycondensation is higher than that prepared by diisocyanate method,the chiral resolution performance of the latter is significantly better than that of the former.With the increase of the amount of functional groups,the resolution performance of the two methods decreased.In addition,the two kinds of immobilized type cellulose tris(4-methylbenzoate)chiral stationary phases have unique chiral separation advantages(the separation factors are 2.59 and 3.42 respectively)for tr?ger base(Rac-1).The resolution performance of the chiral compound is much better than that of the commercial chiral column Chiralcel OD(the separation factor is 1.63).