☆ 4.6 Article

Supported Ziegler-Natta catalyst for ethylene polymerization: Novel data on the effect of polymerization temperature on the number of active centers and propagation rate constant

CATALYSIS COMMUNICATIONS (2014)

Journal

CATALYSIS COMMUNICATIONS

Volume 45, Issue -, Pages 79-82

Publisher

ELSEVIER

DOI: 10.1016/j.catcom.2013.10.041

Keywords

Ethylene polymerization; Ziegler-Natta catalyst; Active centers number; Propagation rate constant; Activation energy

Categories

Chemistry, Physical

Funding

Russian Foundation of Basic Research [12-03-31099]

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Abstract

The number of active centers at ethylene polymerization over highly active supported catalyst TiCl4/MgCl2 + AlEt3 was determined at various polymerization temperatures. It was found that the increase in polymerization temperature in the range of 40-80 degrees C increases the number of active centers. The data on reversible changes in the polymerization rate with temperature in a single experiment give grounds for supposing that alteration of the number of active centers with temperature is a reversible process. The propagation rate constants and the activation energy of the propagation reaction (4.0 kcal mol(-1)) were calculated; the latter value being considerably lower than the effective activation energy of polymerization (16.5 kcal mol(-1)) due to the increase in C-p with rising temperature. (C) 2013 Elsevier B.V. All rights reserved.

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