Justino, JorgeDias, A.R.Tait, J.P.2023-09-082023-09-081995-09Justino, J.A.; Dias, A.R. & Tait, J.P. (1995) Active center determination of ethylene polymerisation catalysts using a quenching method with tritiated methanol. Journal of Radioanalytical and Nuclear Chemistry, Articles, 195(2), 355–362. https://doi.org/10.1007/BF020359760236-5731http://hdl.handle.net/10400.15/4530The subject of this work is ethylene polymerisation using Kaminsky type catalysts: Cp2MR2=methylaluminoxane [M=Zr,W,Nb; R=Cl,CH3]. Active center determination and kinetic studies of the (Cp2WCl2 + methylaluminoxane) and Cp2ZrCl2 + methylaluminoxane) systems are described, using a quenching method with tritiated methanol. The activity of the polymer was determined by liquid scintillation counting. We have found 0.5% and 87% of active centers, respectively for W and Zr system. The catalytic activity of complexes Cp2WCl2 and Cp2NbCl2 was compared with that of Cp2ZrCl2. The W and Nb complexes are found to be less active than the Zr complex.engZiegler-catalystspolymerizationaluminoxanejournal articlehttps://doi.org/10.1007/BF02035976