Copolymerization of carbon monoxide and 4-vinylcyclohexene with a palladium catalyst

In this work, carbon monoxide (CO) and 4-vinylcyclohexene (VCH) with Pd(CH₃CN)₄](BF₄)₂ were copolymerized under various conditions at 60°C. Elemental analysis and infrared, UV, and NMR spectra indicated that copolymers containing a ketone and a cyclic structure of cyclohexyl and norbornane groups are produced. Bidentate nitrogen ligands proved to be more effective at stabilizing catalytic activity than monodentate phosphorus or nitrogen ligands. Also, the bulk substituent on the bidentate ligand led to inactive catalysts. Methanol served as the coinitiator and chain transfer agent. Increasing the concentration of 4-vinylcyclohexene caused the copolymer's CO content to be enhanced. TGA revealed that the copolymer's mass loss starts at 120°C and the maximum peak of decomposition occurs at 450°C. Moreover, X-ray diffraction analysis demonstrated the copolymer to be partially crystalline. Furthermore, reduction of 4-vinylcyclohexene/CO copolymer with LiAlH₄ in THF yields a hydroxyl-containing polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2759–2768, 1997