6533b7dcfe1ef96bd1272114

RESEARCH PRODUCT

Oxovanadium(IV) complexes with [ONNO]-chelating ligands as catalysts for ethylene homo- and copolymerization

subject

description

Oxovanadium(IV) complexes with (ONNO)-type tetradentate Schiff base ligands: salen, acacen, aceten, acetph (H2salen = N,N'-ethylenebis(salicylideneimine), H2aceten = N,N'-ethylenebis(2-hydroxyacetophenoneimine), H2acacen = N,N'-ethylenebis(acetylacetonimine), H 2 acetph = N ,N ' -phenylene-1,2-b is (2-hydroxyacetophenoneimine)), were the first time investi- gated in ethylene polymerization and ethylene/1-octene copo- lymerization processes. In general, all these complexes are moderately active precatalyst for ethylene polymerization up- on activation with EtAlCl2 and they give high molecular weight linear polyethylenes. Their activity in copolymeriza- tion was found relatively low. However, they yielded copoly- mers with high 1-octene incorporation even at low comono- mer concentrations in the feed. The catalytic performance in homo- and copolymerization was influenced by both the ligand structure and polymerization parameters (Al/ V molar ratio, polymerization temperature, comonomer feed concentration). In addition, the (VO(acacen)) was supported onto magnesium supports, and in the presence of various cocatalyst and at different reaction conditions it was screened as the catalyst of choice for ethylene homo- and copolymerization.