Metallocenes in ethylene polymerization studied by cyclic and differential pulse voltammetry

The relationship between redox characteristics and catalytic activity in ethylene polymerization, with methylaluminoxane (MAO) as the cocatalyst, was evaluated for a series of homogeneous metallocenes (Cp2ZrCl2, (MeCp)2ZrCl2, (nBuCp)2ZrCl2, (iBuCp)2ZrCl2, (tBuCp)2ZrCl2, Cp2TiCl2, Cp2HfCl2, Et(Ind)2ZrCl2, Et(IndH4)2ZrCl2 and MeSi2(Ind)2ZrCl2). Catalytic activity is discussed in terms of the coordination sphere and metal center of the metallocene and compared with their electrochemical behavior in the presence of ethylene and MAO. The resulting polyethylenes were analyzed by GPC. The catalytic activity in the ethylene polymerization reaction is discussed in terms of half-life (t1/2) and electrochemical gap of the metallocene species.

A series of homogeneous metallocenes was characterized by cyclic and differential pulse voltammetry and by UV–vis absorption spectrophotometry. Catalyst activity and molecular weight of obtained polymers were discussed in terms of the coordination sphere and metal center, compared with their electrochemical behavior in the presence of ethylene/MAO and discussed in terms of half-life (t1/2) and electrochemical gap of the metallocene species.Figure optionsDownload as PowerPoint slide