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Please use this identifier to cite or link to this item: http://hdl.handle.net/10119/11452

Title: Coadsorption Model for First-Principle Description of Roles of Donors in Heterogeneous Ziegler-Natta Propylene Polymerization
Authors: Taniike, Toshiaki
Terano, Minoru
Keywords: Ziegler–Natta propylene polymerization
Density functional theory
Donor
Mechanism
Coadsorption
Active site
Issue Date: 2012-07-04
Publisher: Elsevier
Magazine name: Journal of Catalysis
Volume: 293
Start page: 39
End page: 50
DOI: 10.1016/j.jcat.2012.06.001
Abstract: Systematic periodic density functional calculations were conducted to clarify the mechanism for donors to exert steric and electronics influences on propylene polymerization using heterogeneous Ziegler–Natta catalysts. It was concluded that TiCl_4 preferentially adsorbs as mononuclear species on the MgCl_2 (1 1 0) surface, and the coadsorption of donors with it is energetically viable. The coadsorption of donors on the (1 1 0) surface reinforces the electron density of the Ti mononuclear species, and sterically transfers the underlying C_2 symmetry to convert the originally aspecific mononuclear species into isospecific one. The nearest coadsorption of ethylbenzoate (EB) not only sterically induces the isospecificity of the Ti mononuclear species but also electrostatically improves the regiospecificity in propylene insertion. In addition, EB prevents sterically-demanding chain transfer to propylene, increasing the molecular weight of the produced polypropylene. Thus theoretically derived “coadsorption model” is highly consistent with a variety of experimentally known facts and believed to be useful for the ab initio prediction of new donor structures.
Rights: NOTICE: This is the author's version of a work accepted for publication by Elsevier. Toshiaki Taniike, Minoru Terano, Journal of Catalysis, 293, 2012, 39-50, http://dx.doi.org/10.1016/j.jcat.2012.06.001
URI: http://hdl.handle.net/10119/11452
Material Type: author
Appears in Collections:c10-1. 雑誌掲載論文 (Journal Articles)

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