Process for preparing low molecular-weight poly-1-olefins

摘要

A catalyst formed by reacting a magnesium alkoxide dispersion whose particle size is from 100 to 3000 nm with a compound of a metal from the group consisting of titanium, zirconium, vanadium and chromium and then with a chlorine-containing organoaluminium compound has very good hydrogen sensitivity and high activity even in the presence of molecular weight regulators such as hydrogen. This makes the catalyst highly suitable for the preparation of low-molecular-weight polyolefins. The catalyst enables the preparation of waxes having a reduced residual ash content. The large particle diameter and the low fines content of the polymer powder prepared by suspension polymerisation using this catalyst enable ready separation and drying of the suspension medium. The catalyst is furthermore advantageous in solution polymerisation and, due to the large particle diameter, can be used in gas-phase polymerisation for the preparation of low-molecular-weight poly-1-olefins.