Formation of isolated titanium (III) ions in superactive titanium-magnesium catalysts with a low titanium content as active sites in ethylene polymerization

摘要

Superactive supported titanium-magnesium catalysts (TMCs) with a low titanium content (≤0.1 wt%), in distinction to conventional TMCs (≥ 1 wt.%), were shown to interact with AIR3 of different compositions to produce compounds with a high (30-70%) concentration of isolated (ESR visible) Ti~(3+) ions. For the first time a correlation between the content of isolated Ti~(3+) species in these catalysts and activity in ethylene polymerization was found.