140191-83-9Relevant academic research and scientific papers
Ethylene polymerization with long-lifetime monopendant thienyl-substituted group 4 metallocenes
Li, Aike,Xiao, Wei,Ma, Haiyan,Huang, Jiling
, p. 495 - 503 (2014/07/07)
A series of group 4 metallocenes (RCp)[Cp-(bridge)-(2-C4H 3S)]MCl2 [M = Ti (C1, C2, C3, C4); M = Zr (C5, C6, C7, C8)] bearing a pendant thiophene group on a cyclopentadienyl ring have been synthesized, characterized and tested as catalyst precursors for ethylene polymerization. The molecular structures of representative titanocenes C2 and C4 were confirmed by single-crystal X-ray diffraction and revealed that both complexes exist in an expected coordination environment for a monomeric bent metallocene. No intramolecular coordination between the thiophene group and the titanium center could be observed in the solid state. Upon activation by methylaluminoxane (MAO), titanocenes C1, C2, C3, C4 showed moderate catalytic activities and produced high- or ultra-high-molecular-weight polyethylene (Mv 70.5-227.1 × 104gmol-1). Titanocene C3 is more active and long-lived, with a lifetime of nearly 9h at 30C. At elevated temperatures of 80-110C, zirconocenes C5, C6, C7, C8 displayed high catalytic activities (up to 27.6 × 105g PE (mol Zr) -1h-1), giving high-molecular-weight polyethylene (M v 11.2-53.7 × 104gmol-1). Even at 80C, a long lifetime of at least 2h was observed for the C8/MAO catalyst system. Copyright
