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 6 7 T , and the influence of prepolymerization in cold liquid propylene is investigated.
The polymerization of propylene in the gas phase has been studied with the same high-acti®ity catalyst as was used for liquid-phase polymerizations in earlier work. Catalyst injection, the influence of the support bed, and precontacting of the catalyst with the cocatalyst and the electron donor ha®e been in®estigated. Furthermore, different ways of prepolymerization were tested. The kinetics can be described with the same model as was used for the liquid-phase polymerizations. The reaction rate was proportional to the pressure at pressures abo®e 5 bar; at lower pressures the rates are lower. Comparison of the reaction rates in the gas phase and liquid phase showed the rates in the gas phase were still lower than in the liquid phase. The fast decay obser®ed in the gas-phase polymerizations indicated that thermal runaway and deacti®ation may occur at temperatures abo®e 40 ᎐ 45ЊC.
Ethylene was polymerized at 5 bar in a stirred powder bed reactor with silica supported r~c-Me~Si[Ind]~ZrC1~/rnethylaluminoxane (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.
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