| Post-metallocene Catalyst |
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Information About ™Post-metallocene Catalyst |
| CATEGORIES ABOUT POST-METALLOCENE CATALYST | |
| catalysts | |
| coordination chemistry | |
| polymer chemistry | |
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Most post-metallocene catalysts are Homogeneous single-site systems, so their catalytic properties can be controlled by modification of the structure of the catalyst. A large number of studies have been conducted by academia and industry to construct high-performance post-metallocene catalysts based on new concepts. Most post-metallocene catalysts have been made by using early Transition Metal s. However, late transition metal complexes such as nickel, palladium, and iron complexes have also been reported as good catalysts for olefin polymerization by Maurice S. Brookhart , Robert H. Grubbs , Vernon Gibson and others. A salicylimine catalyst system based on zirconium, developed by Terunori Fujita and Geoff Coates provides extremely high activity for Ethylene polymerization, and can produce some novel Polypropylene structures. Despite intensive research and development of these systems, very few have been successfully commercialised due to their complex synthesis and relative fragility compared to metallocene catalysts. The presence of (highly toxic) aniline units in the majority of active salicylimine species effectively precludes their use in several major markets for polyethylene. REFERENCES 1) L. K. Johnson, C. K. Killian, M. Brookhart, ''J. Am. Chem. Soc.'', 117, 6414 (1995). 2) C. Wang, S. Friedrich, T. R. Younkin, R. T. Li, R. H. Grubbs, D. A. Bansleben, M. W. Day, ''Organometallics'', 17, 3149 (1998). 3) S. Matsui, Y. Tohi, M. Mitani, J. Saito, H. Makio, H. Tanaka, M. Nitabaru, T. Nakano, T, Fujita, ''Chem. Lett.'', 1065 (1999). |
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