Polymerization of olefins through heterogeneous catalysis. XII. The influence of hydrogen in the solution copolymerization of ethylene

The copolymerization of ethylene with highly active TiCl 4 /MgCl 2 ‐supported catalysts in solution reactors at 185°C and 400 Psig pressure is presented. The performance of these supported catalysts at these conditions is characterized by a high initial rate that decays rapidly within the 10 min polymerization period. In the presence of hydrogen and a comonomer, catalyst yields up to about 300 kg/g (Ti) are achieved. The kinetic data indicate rate enhancement when hydrogen is added in moderate concentrations. However, a high concentration of hydrogen results in a decreasing rate of ethylene consumption. Increasing the H 2 /C 2 molar ratio in the range 0–10.66 ċ 10 −3 leads to a reduction in the M n values from 31,600 to 17,400. © 1993 John Wiley & Sons, Inc.