Ethylene oligomerization using hyperbranch-macromolecule-bridged salicylaldimine cobalt catalysts

Three novel hyperbranch-macromolecule-bridged salicylaldimine cobalt catalysts were synthesized by Schiff and complex reactions of 1.0G hyperbranched macromolecules, salicylaldehyde, and cobalt chloride hexahydrate, and were characterized by FT-IR, UV, MS and TG. The influences of solvent, co-catalyst, reaction temperature, reaction pressure, and Al/Co molar ratio on their catalytic performances in ethylene oligomerization were studied. The results showed that the hyperbranch-macromolecule-bridged salicylaldimine cobalt catalysts had excellent catalytic activities and selectivity for ethylene oligomerization of high carbon number olefins (C10+). The catalytic activity first increased and then decreased with the increase of reaction temperature and Al/Co molar ratio, however, it continuously increased with the increase of reaction pressure. The highest activity of 1.87×105 g·(mol Co)-1·h-1 and 42.90% selectivity for high carbon number olefins were achieved under the condition of toluene as solvent, DEAC as co-catalyst, reaction temperature at 25℃, reaction pressure at 0.5 MPa, and Al/Co molar ratio at 500. © All Right Reserved.