Hydrophilic Catalysts with High Activity and Stability in the Aqueous Polymerization of Ethylene to High‐Molecular‐Weight‐Polyethylene

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 6.3×10(4) 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.