Palladium(II) catalyzed synthesis of copolymers with carbon monoxide as the carbonyl source.

摘要

Olefins and carbon monoxide copolymerized by a coordination mechanism to form polyketones with a palladium (II) catalyst. The olefins alternated strictly with carbon monoxide during polymerization. A trend was found that with greater steric bulk, ethylene ;Initiation of polymerization was found to occur by a palladium methoxide complex. The complex is formed in situ with the solvent methanol as source of the methoxide. Termination of polymerization was also due to methanol by either proton cleavage or methanolysis. It was determined that removing methanol from the system was necessary in order to increase the molecular weights of the polymers. The synthesis of a catalyst with an alkyl group bonded directly to the metal was established, so initiation resulted from the facile CO insertion. The resultant catalyst activity increased markedly, and the molecular weights of the polymers increased. The structure of the catalyst obviated the need for solvent, so the reaction was heterogeneous.;The synthesis and characterization of copolymers containing the oxamide and urea moieties is discussed. Iodine was found to promote the catalytic formation of the oxamide (dicarbonylation) and urea (monocarbonylation) moieties from ;Polymers containing the carbonate and oxalate linkage were formed by replacing the diamine with a dialcohol. Ethanol was used as a probe for ideal polymer conditions. It was found that mono- and dicarbonylation was dependent on the solvent polarity, and increasing the base concentration increased the yields.