Modeling the Stabilization of Surface Defects by Donors in Ziegler鈥揘atta Catalyst Support
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- 作者：Andrey Bazhenov ; Mikko Linnolahti ; Tapani A. Pakkanen ; Peter Denifl ; Timo Leinonen
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：March 6, 2014
- 年：2014
- 卷：118
- 期：9
- 页码：4791-4796
- 全文大小：322K
- 年卷期：v.118,no.9(March 6, 2014)
- ISSN：1932-7455
文摘
We describe a concept for modeling structural defects in crystalline magnesium dichloride used as a support in the Ziegler鈥揘atta polymerization catalysis. The defects are systematically generated into the catalytically relevant (104) and (110) MgCl2 surfaces and stabilized by methanol, selected as a model electron donor. Periodic quantum chemical calculations indicate a strong effect of surface site coordination on the relative stabilities of both ideal and defect surfaces, favoring sites with five-coordinate magnesiums. Saturation of the surfaces by the donor completely reverses the stability order in comparison to the plain surfaces, ending up favoring four-coordinate magnesium atoms. The approach can be readily expanded to include more complex donors as well as titanium chlorides.