Kinetics of ethylene polymerization reactions with chromium oxide catalysts |
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Authors: | Yury V. Kissin Anita J. Brandolini Joyce L. Garlick |
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Affiliation: | 1. Rutgers, The State University of New Jersey, Department of Chemistry and Chemical Biology, 610 Taylor Rd., Piscataway, New Jersey 08854;2. School of Theoretical and Applied Science, Ramapo College of New Jersey, 505 Ramapo Valley Road, Mahwah, New Jersey 07430;3. Edison Research Laboratory, Mobil Chemical Company, P.O. Box 3029, Edison, New Jersey 08818 |
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Abstract: | Principal kinetic data are presented for ethylene homopolymerization and ethylene/1‐hexene copolymerization reactions with two types of chromium oxide catalyst. The reaction rate of the homopolymerization reaction is first order with respect to ethylene concentration (both for gas‐phase and slurry reactions); its effective activation energy is 10.2 kcal/mol (42.8 kJ/mol). The r1 value for ethylene/1‐hexene copolymerization reactions with the catalysts is ~30, which places these catalysts in terms of efficiency of α‐olefin copolymerization with ethylene between metallocene catalysts (r1 ~ 20) and Ti‐based Ziegler‐Natta catalysts (r1 in the 80–120 range). GPC, DSC, and Crystaf data for ethylene/1‐hexene copolymers of different compositions produced with the catalysts show that the reaction products have broad molecular weight and compositional distributions. A combination of kinetic data and structural data for the copolymers provided detailed information about the frequency of chain transfer reactions for several types of active centers present in the catalysts, their copolymerization efficiency, and stability. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5315–5329, 2008 |
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Keywords: | catalysts chromium‐based copolymerization gel permeation chromatography molecular weight distribution polyethylene |
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