Homo- and Co-polymerization of Ethylene with 1-Hexene Using Heterogeneous Catalysts Consisting of Bis(imino)pyridinevanadium Complex Supported on Clay Minerals and Alkyl Aluminum Compounds

• Published in: Journal of the Japan Petroleum Institute 2011, Vol.54(2), pp.108-113
• Main Authors: Kurokawa, Hideki, Kawada, Yusuke, Hiyama, Yuto, Ishihama, Yoshiyuki, Sakuragi, Tsutomu, Shitara, Hiroaki, Miura, Hiroshi
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts; Copolymerization; Copolymers; Crude oil; Ethylene; Ethylene polymerization; Fluorotetrasilicic mica; Mica; Montmorillonite; Polymerization; Polymerization catalyst
• ISSN: 1346-8804; 1349-273X; 1349-273X
• DOI: 10.1627/jpi.54.108

Bis(imino)pyridinevanadium(III) complexes [2,6-(Ph’-N = C(CH3))2C5H3NVCl3, Ph’ = complex 1: 2,4,6-(CH3)3C6H2 and complex 2: 2,6-((CH3)2CH)2C6H3] supported on Mg2+-exchanged fluorotetrasilicic mica (Mg2+-Mica) and montmorillonite (Mg2+-Mont) were prepared as heterogeneous catalysts for ethylene polymerization. These catalysts combined with conventional alkylaluminum compounds were tested for the ethylene or ethylene/1-hexene polymerization. The catalysts supported on Mg2+-Mont showed a significantly higher activity compared to those supported on Mg2+-Mica during the polymerization of ethylene or ethylene/1-hexene. The catalyst based on complex 1 promoted the ethylene/1-hexene copolymerization to afford a linear low-density polyethylene. In contrast, no copolymerization took place using the complex 2-based catalyst because of the high steric bulk around the active center. A bimodal distribution was specifically observed in the GPC profiles of the ethylene/1-hexene copolymers, suggesting that multiple active species were formed by the reaction of the vanadium complex and the trialkylaluminum compound.