Catalytic polymerization op olefins

Summary

• 1. In the polymerization of ethylene, nickel silicate has low activity and high initial selectivity, which, however, falls sharply as the reaction proceeds. A mixture of nickel silicate and silica gel (KSK) obtained by grinding the two components together in the dry state has no catalytic activity in the above reaction.

• 2. A mixture of nickel silicate and silica gel (KSK) containing alumina prepared in a similar way has considerable activity, selectivity, and regenerability. A mixture of nickel silicate and aluminum silicate having fine spherical grains has high activity, but medium selectivity.

• 3. Catalysts consisting of finely spherical aluminum silicate to which nickel silicate has been applied from aqueous suspension have approximately the same properties as a mixture prepared by grinding the two components together. Analogous catalysts with tablet-form or spherical-grain aluminum silicates as carriers are inactive for the polymerization of ethylene.