文献类型：期刊文献

英文题名：Adsorption of TiCl4 and electron donor on defective MgCl2 surfaces and propylene polymerization over Ziegler-Natta catalyst: A DFT study

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

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]China Natl Petr Corp, Petrochem Res Inst, Beijing 100195, Peoples R China

年份：2013

卷号：31

期号：4

起止页码：591

外文期刊名：CHINESE JOURNAL OF POLYMER SCIENCE

收录：;EI(收录号：20212810631677);WOS:【SCI-EXPANDED(收录号:WOS:000316079600006)】；

基金：The work was financially supported by the Program of Introducing Talents of Discipline to Universities (B08021) and Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：Supported Ziegler-Natta catalyst; Propylene polymerization; Defective MgCl2 surfaces; Electron donor; Density functional theory

摘要：The formations of defective MgCl2 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 MgCl2 (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 TiCl4 from coordinating on the MgCl2 surfaces where mostly non-stereospecific active sites could be formed. Exceptionally, A5 the site model with terminal Cl-vacancy on the MgCl2 support, presented stronger adsorption of TiCl4 than that of EB on (110) surface. Since the TiCl4 and ethyl benzoate (EB) would compete to adsorb on the support surface, it seems reasonable to assume that TiCl4 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.