Suppression of Chain Transfer at High Temperature in Catalytic Olefin Polymerization

Abstract

AbstractLiving polymerization by suppressing chain transfer is a very useful method for achieving precise molecular weight and structure control. However, the suppression of chain transfer at high temperatures is extremely challenging in any catalytic polymerization. This has been a severe limitation for catalytic olefin polymerization, which is one of the most important chemical reactions. Here, we report the unprecedented living polymerization of ethylene at 130 °C, with a narrow molecular weight distribution range of 1.04 to 1.08. This is a significant increase in the reaction temperature. Tailor‐made α‐diimine nickel catalysts that exhibit both the steric shielding and fluorine effects play an essential role in this breakthrough. These nickel catalysts are even active at 200 °C, and enable the formation of semi‐crystalline, ultrahigh‐molecular‐weight polyethylene at 150 °C. Mechanistic insights into the key chain transfer reaction are elucidated by density functional theory calculations.