Transition Metal Catalysts for Ethylene Polymerization

As previously mentioned, in addition to free radical initiation, ethylene may be polymerized by use of transition metal catalysts. To place the importance of these catalysts in proper perspective, one must recognize that transition metal catalysts were used to produce about 73% of the global industrial output of polyethylenes in 2008 or about 56 million tons (124 billion pounds). 

All transition metal catalysts must fulfill several key criteria  

Additional details will be provided in subsequent chapters on the composition and functioning of transition metal catalysts. 

Transition metal catalysts are crucial to the production of polyethylene. Indeed, it would not be practical to produce linear versions of polyethylene without these catalysts. It is difficult to imagine a world without products made from these versatile polymers in our homes, vehicles and workplaces. Ziegler-Natta and supported chromium catalysts will continue to be the dominant catalysts for LLDPE and HOPE for the foreseeable future. However, as single-site catalyst 

A = Initial high rate of polymerization followed by deactivation 

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Xu R, Liu D, Wang S, Mao B (2006) Preparation of spherical MgCl2-supported late-transition metal catalysts for ethylene polymerization. Macromol Chem Phys 207 779-786. doi 10.1002/ macp.200500582... 

Camacho, D.H., Salo, E.V., Ziller, J.W., and Guan, Z.B. (2004) Cyclophane-based highly active late-transition-metal catalysts for ethylene polymerization. Angewandte Chemie-Intemational Edition, 43,1821—1825. 

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