Deactivation Kinetics of Metallocene-Catalyzed Ethene Polymerization at High Temperature and Elevated Pressure

The kinetics of ethene polymerization with metallocene/[Me 2 PhNH] + [B(C 6 F 5 ) 4 ] - /Al i Bu 3 (ternay system) and metallocene/methylaluminoxan (MAO) systems respectively has been investigated at 100-140°C and 7 MPa. Overall, eight different unbridged and ansa-metallocenes were tested. The effect of ligand structure, cocatalyst and catalyst concentration on the thermostability and the activation energy of deactivation were studied. Deactivation with respect to the catalyst concentration followed a first order reaction. The half-life as well as the activation energy of the ternary systems depended strongly on ligand structure while the ligand structure of MAO-activated metallocenes merely influenced the half-life. The half-life associated with MAO activation is approximately twice as high as that in ternay activation. Based on these results, conclusions about the activation reactions have been drawn.