Activation of a Palladium-Based Catalyst by Hexafluoroisopropanol for Polyketone Synthesis via Homogeneous Solution Polymerization

Abstract

Polyketone (PK) is a promising material because of its superior qualities as an engineering plastic and the direct use of CO. It is typically produced using slurry polymerization techniques, which cause reactor fouling and low bulk density product. Here, solution polymerization of CO/ethene/propene with high-molecular-weight products (240.3 kDa) and high catalytic activity (36.1 kg PK•g −1 Pd•h −1 ) was achieved utilizing a mixture of hexafluoroisopropanol (HFIP) and methanol. Both the activity and M w are an order of magnitude higher than those reported in the literature. HFIP was able to activate the palladium-based precatalyst without using any strong acid. The 31 P NMR, singlecrystal X-ray diffraction, and density functional theory analysis prove that HFIP decreased the coordination between palladium and the acetate ligands of the precatalyst without the disassociation of the acetate. Furthermore, the active centers in the HFIP system were more stable than that in the catalytic system with strong acid.

Recent Advances in Catalytic Carbonylation Reactions in Alternative Reaction Media

“…High‐molecular‐weight polyketone products (240.3 Da) and high catalytic activity were achieved by the palladium‐based homogeneous catalyst. [ 191 ]…”

Mechanistic Insights into Cationic [P,O]-Pd-Catalyzed Chain-Transfer Copolymerization of Ethylene with Carbon Monoxide

“…The copolymerization of C1 sources, , such as carbon monoxide (CO) and carbon dioxide (CO 2 ), with olefins not only offers a methodology for the efficient utilization of unrecoverable fossil resources but these in-chain groups as breakpoints can also lower the environmental persistence of the corresponding polymers via the photo- or/and biodegradation reactions. , As a particularly plentiful and inexpensive bulk chemical, copolymerization of ethylene with CO affords polyketone materials. In comparison with conventional polyethylene, polyketones exhibit higher mechanical strength and melting temperature ( T m ), and the incorporated polar carbonyls also have considerably improved hydrophilicity and surface properties. , Research on polyketones has evolved over several decades, − and K 2 Ni­[CN] 4 is the first transition metal used to catalyze the copolymerization of ethylene with CO, but only low-melting oligomers were obtained in 1953 . In particular, as eco-friendly thermoplastics, polyketone materials are again receiving more and more attention from both academia and industry currently in order to promote environmental protection and the high-value-added utilization of fossil resources. − …”