Preparation Of Cellulose Derivatives, Chromatographic Separation Of Applications And Mechanistic Studies

The chiral chromatography is more attractive and has been developed rapidly in recent years. It is mainly performed by thin-layer chromatography(TLC),gas chromatography(GC),high performance liquid chromatography(HPLC) and high performance capillary electrophoresis(HPCE), etc.The resolution of enantiomers is important to contemporary synthetical chemistry,biological medicine and agricultural chemistry etc.by TLC and HPLC.However,research was concentrated on the chiral analysis and chiral separation,and the study on the chiral recognition mechanism is not enough,The polysaccharide stationary phase of cellulose derivatives has been identified as useful Chiral stationary phase for the separation of enantiomers.The purpose of the study is to investigate the synthesis and application of cellulose derivatives as stationary phase on resolution of enantiomers,and the mechanism of separation is studied.The work can be divided into four parts:In the first chapter,Summarized the chiral resolution method.This review also deals with the development of Prikle brush-type CSP,cellulose derivate type CSP and cyclodextrin type CSP.In addition,we summarized the kinds of chiral stationary phase of cellulose derivatives,the affect of chiral selective factors and the chiral recognition mechanisms.In the second chapter,Cellulose tribenzoyl(CTB) was ultrasonically prepared by the reaction of microcrystalline cellulose with benzoyl chloride,and cellulose 2,3-dibenzoate-6-pchlorobenzoate (mixed ester) was heating and refluxing prepared by the reaction of microcrystalline cellulose with benzoyl chloride and p-chlorobenzoyl chloride.The two kinds of cellulose derivatives were characterized by ~1H NMR spectrometry,IR spectrometry and elemental analysis. The chiral stationary phases were mixed with microcrystalline cellulose and the mixture were used as chiral stationary phase of thin-layer chromatography to seperate three chiral drugs,such as ofloxacin,gatifloxacin and lomefloxacin.Three chiral drugs were completely separated after optimization of mobile phases.In the third chapter,The structures of cellulose derivatives,chiral drugs and their compounds were optimized by the ab initio method at HF/3-21G level.All this calculation was done by Gaussian03W.Theoretical study of their separation mechanism was done at the same level.The calculation results showed that the ofloxacin configuration with large R_f was S-ofloxacin.The results are agreed with the observed results of the chromatographic resolution on CTB and mixed easter.Therefore,theoretical results were credible.It was also identified that the larger R_f value components of lomefloxacin and gatifloxacin were S configuration and R configuration, respectively.In the last chapter,cellulose trisbenzoate and cellulose 6-hydroxyl-2,3-dibenzoate were synthesized by the reaction of microcrystalline cellulose with benzoyl chloride.Two chiral stationary phases were prepared by coating or bonding cellulose derivatives on the 3-aminopropyl silica gel and were investigated by the scanning electron microscope.