Research Of Chiral Stationary Phases Of Chitin Ether Derivatives On High Performance Liquid Chromatography

Chiral stationary phase(CSP)high performance liquid chromatography(HPLC)is one of the effective methods for separation and purification of chiral compounds Coating-type CSPs based on polysaccharide isocyanate derivatives,such as cellulose and amylose derivatives,are well known owing to their high chiral resolving capability towards a wide range of chiral compounds.However,isocyanate raw materials are toxic as well as expensive and have strong stimulating effects on the respiratory tract which limits the development of chiral materials for polysaccharide ester derivatives to some extents.Chitin is an important polysaccharide similar in structure to cellulose,the etherifying agents of chitin ether derivatives are general organic reagents,which are rich in source,cheap,and have much lower toxicity and pollution.Three kinds of chitin ether chiral stationary phases successfully were prepared in this thesis.The main contents are as follows:(1)The research progress of chiral separation materials was reviewed and chiral resolution methods were systematically summarized in this thesis.(2)A series of hydroxyethyl chitin was successfully homogeneously prepared with ethylene oxide as the etherifying agent in the NaOH/urea-water solvent system,including hydroxyethyl chitin with different degree of substitution and different molecular weight.The products were characterized by infrared spectroscopy,nuclear magnetic resonance spectroscopy and gel permeation chromatography.The HPLC CSPs of hydroxyethyl chitin were successfully prepared.The resolution properties of16 racemates including alcohols,amines,amino acids and phenols were preliminarily discussed.Two factors for chiral resolution performance was further analyzed.The results showed that 5 racemates were resolved with n-hexane/ isopropanol(90:10,V/V)as the mobile phase,including two amines and two phenols.Eight racemates were resolved after the change of the flow rate.The influence of the preparation process on the chiral separation performance of the CSP is not obvious.It shows that the CSP has good chiral recognition ability.(3)The 2-Hydroxypropyl chitin was successfully homogeneously prepared with propylene oxide as the etherifying agent in the NaOH/urea-water solvent system.Thestructure and analysis were carried out by infrared spectroscopy.The CSP hydroxypropyl chitin was prepared by uniformly coating hydroxypropyl chitin on the surface of 3-aminopropyl silica gel by coating method.The separation performance of seven racemates including alcohols,amines and esters was discussed.The results showed that two amine racemates were successfully separated by using n-hexane/isopropanol(90:10,V/V)as the mobile phase,which indicated that the CSPs had better chiral recognition ability of the chiral amine compound.(4)Carboxymethyl chitin was successfully synthesized by using chloroacetic acid as the etherifying agent in the NaOH/urea-water solvent system.The structure and analysis were carried out by infrared spectroscopy and nuclear magnetic resonance spectroscopy.Carboxymethyl chitin HPLC CSP was prepared by uniformly coating carboxymethyl chitin on the surface of 3-aminopropyl silica gel by coating method.The separation performance of 12 racemates including alcohols,amines,ethers,amino acids and phenols was discussed.The results showed that five racemates were successfully separated by using n-hexane/isopropanol(90:10,V/V)as the mobile phase,including two alcohols,two amines and one phenol,which indicates that the CSP has better chiral recognition ability for amines and partial alcohol chiral compounds.