Nickel catalysts for preparation of ethylene-vinyl ether copolymers

The copolymers of ethylene with and vinyl ethers, are prepd. using a catalyst comprising Ni complexes with substituted salicylaldimine and cyclooctenyl ligands and an organoaluminum co-catalyst. The ligands are selected from (3,5-dinitro)-N-(2,6-isopropyl-phenyl)salicylaldimine, (3,5-dinitro)-N-(phenyl)-salicylaldimine, and (3-nitro)-N-(2,6-diisopropyl-phenyl)salicylaldimine and the cocatalysts are aluminoxanes. The polymn. is carried out in a suspension under low pressure, 20-100 bar, at 30-100°