Heterogeneous Nickel-Catalyzed Carbonylative Polymerization of Ethylene

Abstract

Earth-abundant nickel-catalyzed carbonylative polymerization of olefins offers a cost-effective alternative to conventional precious palladium catalysis, but the homogeneous nature of this catalyst causes severe reactor fouling that precludes industrial application. Herein, we report the first heterogeneous nickel-catalyzed carbonylative polymerization based on immobilization of a phosphine-sulfonate nickel complex onto silica. The supported nickel catalyst exhibits high activity and enhanced thermal stability, enabling production of polyketones with markedly increased molecular weight while virtually eliminating fouling (as low as 3%), and affording a high bulk density of 0.23 g mL−1. Remarkably, it yields polyketones with exclusive α-phase and unique flower-like morphology composed of interstacked petals, in stark contrast to the disordered porous β-phase obtained with homogeneous catalysis. The system also tolerates carbonylative polymerization with propylene or 1-hexene while preserving morphological control. This work represents a pioneering study in heterogeneous nickel-catalyzed carbonylative polymerization of ethylene, thus establishing the industrial practicability of nickel-based polyketone resin and fiber products.