Propylene polymerization using TiCln(OR)(4–n) catalysts: Theoretical analysis and experimental investigation

Publication date: Available online 10 November 2017Source: Journal of Organometallic ChemistryAuthor(s): Kefeng Xie, Bochao Zhu, Anping Huang, Wenxue Zhang, Jingcheng Xu, Peng LiuAbstractPropylene polymerization mechanism was investigated with density functional theory (DFT) using TiCln(OR)(4–n) catalysts, with active centers such as [TiCl2Et]+, [TiCl(OEt)Et]+, [TiCl(OPh)Et]+, or [Ti(OEt)2Et]+. Improving the stereoselectivity of Ziegler–Natta catalyst through introducing alkoxy groups, the active center became asymmetric structure, and consequently the polymerization of propylene using [TiCl(OEt)Et]+ and [TiCl(OPh)Et]+ was in 1,2-mode from the Re enantioface. Moreover, the polymerization using [Ti(OEt)2Et]+ with symmetric structure was favorable in 1,2-mode, but showed no stereoselectivity during polymerization. The results are supported by experimental studies of propylene polymerization using the MgCl2-supported TiCln(OR)(4–n) catalysts with triethylaluminum (TEA) as a co-catalyst. The present results demonstrated that propylene polymerization can be controlled through appropriate selection of R-in TiCln(OR)(4–n).

Source: Journal of Organometallic Chemistry - July 5, 2018 Category: Chemistry Source Type: research