Polymerization of ethylene with the (C5H5)4Zr-methylaluminoxane soluble catalytic system

The effects of catalyst concentration, Al-to-Ti molar ratio, hydrogen additives, and time of aging of catalyst components on the kinetic features of ethylene polymerization in the presence of the (C₅H₅)₄Zr-methylaluminoxane soluble catalytic system in toluene and hexane at 60°C and an ethylene pressure of 0.6 MPa have been studied. It has been demonstrated that the highest activity and productivity of the title system is achieved in the presence of 0.9% H₂ in the gas phase of a reactor (2180 kg PE/(g Zr h)). When polymerization is carried out in hexane, the rate constant of chain propagation is lower by a factor of ～1.5 than that in the case of toluene and the catalytic system is characterized by a long lifetime.