The Synthesis Of Hyperbranched Polysiloxysilane Modified With β-cyclodextrin And Crown Ether And Application In Chiral Separation By Capillary Electrophoresis

Hyperbranched polymers were regarded as having lower viscosity, better rheology and dissolvability because of their unique molecular structure and performance in comparison with corresponding linear counterparts of the same molar mass. Compared with dendrimers, while the properties of hyperbranched polymers were basically similar to that of dendrimers, they can be synthesized in one-step polymerization process, simple and no purification step by step, also the conditions in the polymerization process was not rigorous as the dendrimers. Naturally, it has been in the scholars'good graces in recent years. The organic siloxane was formed with repeating flexible Si-O bond, which results in both heating and cryogenic resistance in company with excellent thermal and chemical stability. The peripheral reactive groups in outside of polymers made it easy to construct highly branched polymers, and act as a"carrier"if further functionalization was needed on polymers. Based on a quantity of referrances and the productions of our research group, this thesis mainly involves in research of synthetic strategy of hyperbranched polysiloxysilanes, where anhydrous methods was employed to prepare hyperbranched polysiloxysilanes. The prepared hyperbranched polysiloxysilane which was further functionalized was coated to the inner surface of the capillary column, then the study of chiral isomer separation by the capillary electrophoresis was in progress.Particular contents in this paper were summarized as follows:(1) The preparation and characterization of hyperbranched polysiloxysilane: AB3-type monomers, tri(bimethylsiloxy)vinylsilane was synthesized via the hydrolyzation of vinyltrimethoxysilane (VTMS) and chlorosilane catalyzed by anhydrous ferric chloride, then the hyperbranched polysiloxysilane was prepared by polyhydrosilation reaction of monomers using Karstedt as the catalyzer. FTIR, 1H-NMR and elemental analysis were employed to identify the structure of AB3-type monomers and hyperbranched polysiloxysilane. The result indicated that the reaction between alkoxysilane and chlorosilane could be promptly catalyzed by anhydrous ferric chloride, consequently, the hyperbranched polysiloxysilane terminated with Si-H groups was synthesized successfully. (2) The modification of terminal groups of hyperbranched polysiloxysilane: A methylatedβ-cyclodextrin modified with allyl group in 6-location hydroxyl group was grafted onto the outer end of hyperbranched polysiloxysilane through hydrosilylation catalyzed by Karstedt, which resulted the preparation ofβ-cyclodextrin hyperbranched polysiloxysilane chiral and selective(Hp-SiA). Simultaneously, the terminal crown ether hyperbranched polysiloxysilane (Hp-SiB) and the hyperbranched polysiloxysilane terminated withβ-cyclodextrin and crown ether (Hp-SiC) were prepared, respectively.(3) Preparation and evaluation of coated capillaries by chemical-bonded coating: the three kinds of chiral selectors were coated on inner surface of the capillary column with the chemical bonding method, three kinds of capillary column having different chiral selectors were obtained correspondingly. The visible effects of different capillary columns on chiral drugs including lomefloxacin, isoproterenol hydrochloride and norepinephrine bitartrate injection were investaged. The satisfactory results of separation were obtained.(4) Preparation and evaluation of coated capillaries by physical absorption: the prepared three kinds of chiral selectors were coated on inner surface of the capillary column with the physical absorption method, three kinds of capillary column having different chiral selectors were obtained correspondingly. The visible effects of different capillary columns on chiral drugs including lomefloxacin, isoproterenol hydrochloride were investaged. The results showed that the separation effect were satisfying.(5) The evaluation of synergistic effect between the chiral selectors: From the comparition with the different chiral coated colunms in this study, the separation effect of Hp-SiC coated colunm with double chiral selectors was better than Hp-SiA and Hp-SiB with single chiral selector, especially in the capillary column with the chemical bonding. The cause of this phenomenon was due to the synergistic effect existed in the double chiral selectors.