Highly Active and Thermally Robust Nickel Enolate Catalysts for the Synthesis of Ethylene‐Acrylate Copolymers
Shuoyan Xiong, Alexandria Hong, B.C. Bailey, Heather A. Spinney, Todd D. Senecal, Hannah Bailey, Theodor Agapie
Abstract
Abstract The insertion copolymerization of polar olefins and ethylene remains a significant challenge in part due to catalysts′ low activity and poor thermal stability. Herein we demonstrate a strategy toward addressing these obstacles through ligand design. Neutral nickel phosphine enolate catalysts with large phosphine substituents reaching the axial positions of Ni achieve activity of up to 7.7×10 3 kg mol −1 h −1 (efficiency >35×10 3 g copolymer/g Ni) at 110 °C, notable for ethylene/acrylate copolymerization. NMR analysis of resulting copolymers reveals highly linear microstructures with main‐chain ester functionality. Structure‐performance studies indicate a strong correlation between axial steric hindrance and catalyst performance.