Kinetic study of ethylene polymerization by highly active silica supported TiCL4/MgCl2 catalysts

The kinetics of ethylene polymerization with TiCl₄/MgCl₂/SiO₂ has been investigated in the range of temperatures between 40 and 90°C and in the range of ethylene pressures between 4 and 12.4 kg/cm². The role of MgCl₂ was discussed from the dependence of the Mg/Ti ratio on the catalytic activity. The polymerzation rate was first order with respect to the monomer concentration and the dependence of the polymerization rate on the concentration of Al(C₂H₅)₃ could be described by the Langmuir–Hinshelwood mechanism. The dependence of initial rate and the time to reach the maximum polymerization rate on the concentration of Al(C₂H₅)₃ was also discussed. Polymerization rates as a function of the polymerization temperature showed a maximum and the activation energy was 11.8 kcal/mol between 50 and 80°C. The polymerization rate decreased with the increase of hydrogen partial pressure. The active site concentration (C^*) was 1.9 × 10^?2 mol/mol Ti by the inhibition method with carbon monoxide.