ACTIVE-CENTER DETERMINATION OF ETHYLENE POLYMERIZATION CATALYSTS USING A QUENCHING METHOD WITH TRITIATED METHANOL

The subject of this work is ethylene polymerisation using Kaminsky typ e catalysts: Cp(2)MR(2)=methyl-aluminoxane M=Zr,W,Nb; R=Cl,CH3]. Activ e center determination and kinetic studies of the (Cp(2)WCl(2) + methy laluminoxane) and Cp(2)ZrCl(2) + methylaluminoxane) systems are descri bed, 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 Cp(2)WCl(2) and Cp(2)NbCl(2) was compared with that of Cp(2)ZrCl(2). The W and Nb complexes are found to be less active than the Zr complex.