Ethylene polymerization using catalysts based on binuclear phenoxyimine titanium halide complexes

Nine new binuclear titanium halide complexes were obtained on the basis of first synthesized tetradentate bis-phenoxyimine ligand precursors with different bridge linkages, including sterically hindered ones, between imine groups. Their binuclear character is confirmed by molecular weights, measured using vapor phase osmometry, MALDI–ToF and diffusion coefficients as determined by NMR–DOSY method. Catalytic activities of catalytic systems on the basis of the binuclear bis-salicylaldimine titanium complexes in ethylene polymerization were investigated. The studied catalytic systems appeared to be rather highly active, (10–70 kg(PE)/[mmol(Ti)·MPa·h]) and considerably more thermostable as compared to mononuclear analogs and made it possible to obtain polyethylenes of high and superhigh molecular weights. The effects of the bridge linkage between imine nitrogens and o-, p-substituents in the phenoxy-group were established.