文献类型：期刊文献

中文题名：ADSORPTION OF TiCl_4 AND ELECTRON DONOR ON DEFECTIVE MgCl_2 SURFACES AND PROPYLENE POLYMERIZATION OVER ZIEGLER-NATTA CATALYST: A DFT STUDY

英文题名：ADSORPTION OF TiCl_4 AND ELECTRON DONOR ON DEFECTIVE MgCl_2 SURFACES AND PROPYLENE POLYMERIZATION OVER ZIEGLER-NATTA CATALYST: A DFT STUDY

作者：Rui-hua Cheng[1];Jun Luo[1];Zhen Liu[1];Jing-wen Sun[1];Wei-huan Huang[2];Ming-ge Zhang[2];Jian-jun Yi[2];刘柏平[1]

机构：[1]State Key Laboratory of Chemical Engineering,East China University of Science and Technology;[2]Petrochemical Research Institute,China National Petroleum Corporation

年份：2013

卷号：31

期号：4

起止页码：591

中文期刊名：Chinese Journal of Polymer Science

外文期刊名：高分子科学（英文版）

收录：CSTPCD;;Scopus;CSCD:【CSCD2013_2014】；

基金：supported by the Program of Introducing Talents of Discipline to Universities (B08021);Fundamental Research Funds for the Central Universities

语种：中文

中文关键词：Supported Ziegler-Natta catalyst; Propylene polymerization; Defective MgC12 surfaces; Electron donor; Densityfunctional theory.

外文关键词：Supported Ziegler-Natta catalyst; Propylene polymerization; Defective MgC12 surfaces; Electron donor; Densityfunctional theory.

摘要：The formations of defective MgC12 surfaces, and subsequent adsorption of Ti species and electron donor, as well as propylene polymerization over the Ziegler-Natta catalyst have been investigated using density functional theory （DFT） method. Twelve possible support models of regular and defective MgC12 （110） and （100） surfaces were built. The individual adsorptions of titanium chlorides as mononuclear or dinuclear, and ethyl benzoate （EB） as electron donor, on these models were evaluated. The analysis of energies presented the cases of EB adsorption were generally more stable than titanium chlorides on both surfaces. Thus, EB as internal electron donor mainly prevented TIC14 from coordinating on the MgC12 surfaces where mostly non-stereospecific active sites could be formed. Exceptionally, A5 the site model with terminal Cl-vacancy on the MgC12 support, presented stronger adsorption of TiCl4 than that of EB on （110） surface. Since the TIC14 and ethyl benzoate （EB） would compete to adsorb on the support surface, it seems reasonable to assume that TIC14 might predominately occupy this site, which can act as the most plausible active site for propylene polymerization. The first insertion of propylene monomer into the A5 active site model showed that it exhibited good regioselectivity but poor stereospecificity in the absence of electron donor.
The formations of defective MgC12 surfaces, and subsequent adsorption of Ti species and electron donor, as well as propylene polymerization over the Ziegler-Natta catalyst have been investigated using density functional theory （DFT） method. Twelve possible support models of regular and defective MgC12 （110） and （100） surfaces were built. The individual adsorptions of titanium chlorides as mononuclear or dinuclear, and ethyl benzoate （EB） as electron donor, on these models were evaluated. The analysis of energies presented the cases of EB adsorption were generally more stable than titanium chlorides on both surfaces. Thus, EB as internal electron donor mainly prevented TIC14 from coordinating on the MgC12 surfaces where mostly non-stereospecific active sites could be formed. Exceptionally, A5 the site model with terminal Cl-vacancy on the MgC12 support, presented stronger adsorption of TiCl4 than that of EB on （110） surface. Since the TIC14 and ethyl benzoate （EB） would compete to adsorb on the support surface, it seems reasonable to assume that TIC14 might predominately occupy this site, which can act as the most plausible active site for propylene polymerization. The first insertion of propylene monomer into the A5 active site model showed that it exhibited good regioselectivity but poor stereospecificity in the absence of electron donor.