Kinetics of catalytic gas-phase homopolymerization of ethylene over SiO2/MgCl2 : supported TiCl4 catalysts

摘要: Commercial gas-phase polymerization of ethylene is commonly carried out over Ti-based catalysts in which the Ti complex supported on porous silica gel containing MgCl 2 . It almost always assumed kinetic and reactor modelling that rate functions for these catalyst systems are first order with respect to concentration. We have observed reaction orders from less than unity about 1.5 homopolymerization SiO /MgCl a tri-n-octylaluminum alkyl cocatalyst. Tri-n-octylaluminum was used obtain relatively time-invariant rates polymerization. Rates were measured two at temperatures 30 70 o C concentrations 15 750 mol/m 3 The found be strong function temperature. Langmuir-Hinshelwood describe kinetics; combination least required behavior. This strongly suggests catalytic sites, having different concentration dependencies, present