Kinetic study of ethylene polymerization by highly active silica supported TiCL 4 /MgCl 2 catalysts

The kinetics of ethylene polymerization with TiCl 4 /MgCl 2 /SiO 2 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/cm 2 . The role of MgCl 2 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(C 2 H 5 ) 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(C 2 H 5 ) 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.