Gas phase polymerization of ethylene with a silica-supported metallocene catalyst: influence of temperature on deactivation

Ethylene was polymerized at 5 bar in a stirred powder bed reactor with silica supported rac-Me2Si[Ind]2ZrCl2/methylaluminoxane (MAO) at temperatures between 40°C and 80°C using NaCl as support bed and triethylaluminium (TEA) as a scavenger for impurities. For this fixed recipe and a given charge of catalyst. the average catalyst activity is reproducible within 10% for low temperatures. The polymerization rate and the rate of deactivation increase with increasing temperature. The deactivation could be modeled using a first order dependence with respect to the polymerization rate

Liquid-phase polymerization of propylene with a highly active Ziegler-Natta catalyst. Influence of hydrogen, cocatalyst, and electron donor on the reaction kinetics

This paper presents an experimental kinetic study of the polymerization of propylene in liquid monomer with a high activity catalyst. The influences of the concentration of hydrogen and the molar ratios of the catalyst, cocatalyst, and electron donor on the activation period, the maximum activity, the yield, and the decay behavior have been investigated at a temperature of 42°C using a relatively simple kinetic model. On the basis of the experimental data, the reaction rate has been modeled as a function of the hydrogen concentration, the molar ratio of cocatalyst and titanium, and the molar ratio of the electron donor and the cocatalyst

Liquid phase polymerization of propylene with a highly active catalyst

An experimental setup and a kinetic study of the polymerization of propylene in liquid monomer with a highly active catalyst are presented. The purification system for monomer, the catalyst injection system, the temperature control system, and the polymerization procedures are described in detail. Further, reproducibility of the experiments is tested, the kinetics are described in the temperature range of 27 to 67°C, and the influence of prepolymerization in cold liquid propylene is investigated