Synthesis Of Phenoxy-imine Catalyst Ligands And Preparation Of Nano-silica Supporter

The core of polyolefin industry is olefin coordination polymerization catalysts whose development could be divided into tree phases. The third phase is post-metallocene catalysts which are of clear chemical structure, low production costs and can be used for manufacturing diverse polyolefin products. But it also faces enormous challenges in industrial applications. How to improve the applicability of industrial processes and how to solve process issues that may happen in industrial production is the key to let post-metallocene catalyst used widely. According to the development of olefin polymerization catalysts, immobilization can solve these problems. FI catalyst is prominent among post-metallocene catalysts. It can obtain polyethylene and block copolymers with high molecular weight and narrow molecular weigh distribution in a very high activity. So the research on immobilization of FI catalyst is of great value.The research in this article is based on the immobilization of olefin polymerization catalysts. The ligand design-oriented research idea was employed. A series of ortho-F substituted phenoxy-imine ligands were synthesized. The catalysts of high activity and unique polymerization properties were picked out. At the same time, we prepared the nano-SiO2which can disperse stabely in toluene with the method of silane coupling agent modification. This kind of nano-SiO2particles can serve as catalyst supporter.In the first part, according to the relationship of structure with properties of FI catalysts and the need of further research, a series of phenoxy-imine ligands were designed and synthesized. We researched the reaction conditions of2,3,5,6-tetrafluoro-4-styrylaniline synthesis with the analysis method of HPLC. Effects of ratio of raw materials, catalysts amount and the reaction time on yield were considered and the optimal reaction conditions were given. All the complexes were characterized with FTIR-.1H-NMR、13C-NMR and melting point testing.In the second part, we transfer the SiO2gel from the aqueous to1PrOH by azeotropic distillation. Different kinds of silane coupling agent were used to modify nano-SiO2.The effects of type and amount of silane coupling agent on nano-SiO2particle size and surface hydroxyl group number were studied and optimum reaction conditions were given. Besides, FTIR and TGA were employed to characterize the surface grafting of SiO2. Nano-SiO2modified by octyltriethoxysilane and dodecyltriethoxy silane was prepared and transfer to toluene and n-octane.In the third part, several catalysts were prepared by ligands synthesized in the first part and were used to catalyze ethylene polymerization. Structure of bis [N-(3-tertbutylsalicylaldehyde)-2,6-difluoro-4-styrylaniline] titanium dichloride (IV) was characterized by1H-NMR、13C-NMR、elemental analysis and ESI-MS. Other two catalysts were characterized by1H-NMR. We evaluated and compared their activity and polymerization behavior. The corresponding polyethylene was also characterized by GPC and DSC.The ligand design-oriented study method used in the first part was proved to be correct by polymerization experiment in the third part. Olefin polymerization catalysts of high activity and special properties were picked out through a series of experiments. Nano-SiO2prepared in the second part can disperse stably in toluene and serve as catalyst supporter. All the work done in this paper lay the foundation for FI catalysts immobilization researches.