Effect of free trimethylaluminum content in methylaluminoxane on performances of bis(salicylaldiminate)nickel(II)-based catalysts for ethylene polymerization

The performances of ethylene polymerization catalysts based on III and commercial methylaluminoxane were investigated by reducing the content of free trimethylaluminum in methylaluminoxane by its reaction with 2,6-di-tert-butylphenol. This allowed optimization of the formulation of the catalyst, affording a high-molecular-weight linear polyethylene (PE) with a productivity [(1900 kg of PE/(mol of Ni x h)], ten-fold higher than that previously achieved for the same system adopting commercial methylaluminoxane not pre-treated with the above phenol derivative