Comparisons between homogeneous and immobilized 1-(2,6-dibenzhydryl-4-nitrophenylimino)-2-mesityliminoacenaphthylnickel bromide as a precatalyst in ethylene polymerization

The 1-(2,6-dibenzhydryl-4-nitrophenylimino)-2-mesityliminoacenaphthylnickel bromide (1) is supported on the silica modified by adding different aluminum compounds. The immobilized catalysts show high activities toward ethylene polymerization being initiated by the co-catalyst either ⁱ Bu ₃ Al or Et ₂ AlCl. The resultant polyethylenes display moderate branching (30–50 CH ₃ /1000C) along with high molecular-weights (up to 1.5 × 10 ⁶ g mol ⁻¹ ) as well as narrow molecular weight distributions (2.1–2.4). The kinetic study of immobilized catalysts has been conducted and compared with that of homogeneous 1/Et ₂ AlCl system. The supported nickel catalysts produce spherical particles of branched PEs at slurry polymerization without reactor fouling and could be practically attractive.