Active center determination of ethylene polymerisation catalysts using a quenching method with tritiated methanol |
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Authors: | J A Justino A R Dias J P Tait |
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Institution: | (1) Instituto Politécnico de Santarém-ESAS, Apartado 310, 2004 Santarém Codex, Portugal;(2) C.Q.E.-I.S.T., Av. Rovisco Pais, 1096 Lisboa Codex, Portugal;(3) Department of Chemistry, UMIST, M60 1QD Manchester, UK |
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Abstract: | The 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. |
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