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Palladium-catalyzed alternating copolymerization of carbon monoxide with olefin
Abstract
The alternating copolymerization of carbon monoxide with olefin is one of the very new field in the polymer chemistry. The ultimate goal of the dissertation work is to gain a broad knowledge about this polymerization reaction as well as the properties of the alternating copolymers. The alternating copolymerization of carbon monoxide with ethylene was systematic investigated using the catalyst system of (Pd(CH$\sb3$CN)$\sb4$) (BF$\sb4)\sb2$/phosphine complexes. Palladium bisphosphine complex has been found to be far more active and more stable than the monodente phosphine Pd catalyst. Methanol is a co-initiator as well as a chain transfer agent. Protonic acid enhances the rate of copolymerization but causes chain transfer. In the absence of methanol, the copolymerization was characterized by long induction period and slow rate. The end groups of alternating copolymers were isotope labeled (using radioactive isotope labeled methanol or deuterated methanol) and analyzed. The chain transfer reactions are alcoholysis of palladium acyl bond or $\beta$-hydrogen elimination reaction. The overall copolymerization mechanism was discussed. (Pd(CH$\sb3$CN)$\sb4$) (BF$\sb4)\sb2$/bisphosphine catalysts and methanol as co-initiator were found to be very active for the alternating copolymerization of carbon monoxide with propylene, 1-butene and 1-hexene. The palladium catalyst with bis(diphenylphosphino)propane shows higher activity but moderate regioselectivity. The catalyst with (-)DIOP has better regioselectivity and produces semi-crystalline CO/propylene alternating copolymer. The thermodegradation of alternating copolymer of carbon monoxide with ethylene was also studied using pyrolysis GC-Mass spectroscopy. Carbon monoxide, ethylene, water and oligomers of ketones were identified as volatile products during the thermodegradation.
Subject Area
Polymers
Recommended Citation
Zhao, Allen X, "Palladium-catalyzed alternating copolymerization of carbon monoxide with olefin" (1992). Doctoral Dissertations Available from Proquest. AAI9233178.
https://scholarworks.umass.edu/dissertations/AAI9233178