Ethylene polymerization by the chromium catalysts based on bidentate [O, PO] or [S, P] ligands
作者：Lipeng He, Hongliang Mu, Baixiang Li, Yue‐sheng Li · 发表于：Journal of Polymer Science Part A Polymer Chemistry · 年份：2009 · DOI：10.1002/pola.23785 · 被引用次数：26 · 研究领域：Organometallic Complex Synthesis and Catalysis、Carbon dioxide utilization in catalysis、Synthetic Organic Chemistry Methods
Abstract Novel chromium catalysts based on bidentate phenoxy‐phosphinoyl (HO‐2R 1 ‐4R 2 ‐6(Ph 2 PO)C 6 H 2 : R 1 = R 2 = H, 3a ; R 1 = t Bu, R 2 = H, 3b ; R 1 = R 2 = t Bu, 3c ; R 1 = R 2 = cumyl, 3d ; R 1 = anthracenyl, R 2 = H, 3e ) and thiophenol‐phosphine (HS‐2R 1 ‐4R 2 ‐6(Ph 2 P)C 6 H 2 : R 1 = R 2 = H, 4a ; R 1 = SiMe 3 , R 2 = H, 4b ) were prepared and characterized. Treatment with modified methyaluminoxane, these catalysts displayed moderate to high‐catalytic activities for ethylene polymerization. The activities of them were higher than those of the corresponding catalysts based on bidentate phenoxy‐phosphine ligands. Both the coordinated donors and the ortho ‐substituent of the ligands played an important role in improving catalytic activity. The effects of reaction parameters, such as cocatalyst and Al/Cr molar ratio as well as reaction temperature, on ethylene polymerization behaviors were investigated in detail for two favorable catalytic systems, 3b /CrCl 3 (thf) 3 and 4b /CrCl 3 (thf) 3 . Catalyst 4b /CrCl 3 (thf) 3 displayed higher catalytic activity and better temperature tolerance for ethylene polymerization than 3b /CrCl 3 (thf) 3 . © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 311–319, 2010