Hydrophilic Catalysts with High Activity and Stability in the Aqueous Polymerization of Ethylene to...

Water-soluble synthetic transition metal catalysts have been studied extensively for many reactions, but for olefin polymerization such catalysts have been lacking. We report herein a straightforward synthesis of phosphinephenolato Ni^II catalysts endowed permanently with a hydrophilic sulfonate moiety bound to the chelating ligand. These catalysts' hydrophilic active sites promote aqueous ethylene polymerization with high activity (TOF up to 6.3×10⁴  mol_Ethylene  mol_Ni ^-1  h^-1 ) to high molecular weight polyethylene (HDPE), with half-lives on the order of hours also at elevated temperatures. The obtained polyethylene dispersions feature narrow particle size distributions without any aggregates.