Carbon copolymerization with alkenes

Drent, E. van Broekhoven, J. A. M. Doyle, M. J. Wong, P. K. Palladium Catalyzed Copolymerization of Carbon Monoxide with Alkenes to Alternating Polyketones and Polyspiroketals. Fink, G. Muelhaupt, R. Brintzinger, H. H. Eds. Ziegler Catal. Springer, Berlin, 1995, pp 481 496. 

There is a tendency toward alternation in the copolymerization of ethylene with carbon monoxide. Copolymerizations of carbon monoxide with tetrafluoroethylene, vinyl acetate, vinyl chloride, and acrylonitrile have been reported but with few details [Starkweather, 1987]. The reactions of alkenes with oxygen and quinones are not well defined in terms of the stoichiometry of the products. These reactions are better classified as retardation or inhibition reactions because of the very slow copolymerization rates (Sec. 3-7a). Other copolymerizations include the reaction of alkene monomers with sulfur and nitroso compounds [Green et al., 1967 Miyata and Sawada, 1988]. 

Addition of anionic nucleophiles to alkenes and to heteronuclear double bond systems (C=0, C=S) also lies within the scope of this Section. Chloride and cyanide ions are effieient initiators of the polymerization and copolymerization of acrylonitrile in dipolar non-HBD solvents, as reported by Parker [6], Even some 1,3-dipolar cycloaddition reactions leading to heterocyclic compounds are often better carried out in dipolar non-HBD solvents in order to increase rates and yields [311], The rate of alkaline hydrolysis of ethyl and 4-nitrophenyl acetate in dimethyl sulfoxide/water mixtures increases with increasing dimethyl sulfoxide concentration due to the increased activity of the hydroxide ion. This is presumably caused by its reduced solvation in the dipolar non-HBD solvent [312, 313]. Dimethyl sulfoxide greatly accelerates the formation of oximes from carbonyl compounds and hydroxylamine, as shown for substituted 9-oxofluorenes [314]. Nucleophilic attack on carbon disulfide by cyanide ion is possible only in A,A-dimethylformamide [315]. The fluoride ion, dissolved as tetraalkylammo-nium fluoride in dipolar difluoromethane, even reacts with carbon dioxide to yield the fluorocarbonate ion, F-C02 [840]. 

The copolymerization of alkenes with carbon monoxide has attracted the attention of chemists for many years [1]. Following the commerciahzation of Carilon, an alternating olefin carbon monoxide terpolymer based on ethene and small amounts (5-10%) of propene (Scheme 8.1, 1), by Shell [2, 3] in the 1990s interest in the identification of new and more active catalysts and of the stereochemical characteristics of the reaction has grown. 

In a patent filed as early as 1948, Reppe and Magin described the reaction of ethylene with carbon monoxide in the presence of an aqueous solution of potassium nickel(II) cyanide at 150°C and 150 bar [4], Along with propionic acid and diethyl ketone, higher molecular weight solid polyketones were obtained. The alternating copolymerization of alkenes with carbon monoxide has received continued industrial and academic interest, one reason being the low cost of carbon monoxide as a monomer [5],... 

Palladium-catalyzed copolymerization of alkenes with carbon monoxide leading to polyke-tones46 48 represents another example of dicarborative addition. With terminal or other unsymmetrically substituted prostereogenic alkenes a polymer with stereogenic centers along the polymer backbone is generated. 

A variety of reactants—including sulfur dioxide, carbon monoxide, and oxygen, which do not homopolymerize—undergo radical copolymerization with alkenes to form polymeric sul-fones [Bae et al., 1988 Cais and O Donnell, 1976 Dainton and Ivin, 1958 Floijanczyk et al., 1987 Soares, 1997], ketones [Sommazzi and Garbassi, 1997 Starkweather, 1987, and peroxides [Cais and Bovey, 1977 Mukundan and Kishore, 1987 Nukui et al., 1982] ... 

The first palladium-catalyzed copolymerization of carbon monoxide (CO) with olefins was described in 1982 [11], and as a consequence, carbonylative coupling reactions with alkenes were reported soon after. Notably, it was Negishi and Miller who discovered the first two examples of intramolecular carbonylative Heck reactions of 1-iodopenta-1,4-dienes by applying stoichiometric amounts of palladium [12]. 5-Methylenecyclopent-2-enones as the products were produced in moderate yields (Scheme 7.1). 

The stereochemistry from chain-end control and catalyst-control are not necessarily different. More details on the stereochemistry of alkene pol3mnerization are provided in Chapter 22. In brief, however, a symmetric catalyst like the ones used for the copolymerization of carbon monoxide with styrene will generate isotactic polymer, but polymerizations with stereochemistry dictated by chain-end control can form either syndiotactic or isotactic material. Catalysts displaying other symmetries have been designed for other types of polymerizations to generate polymer architectures beyond isotactic. 

Nozaki. K. Hiyama, T. Stereoselechve alternating copolymerization of carbon monoxide with alkenes. J. Organomet. Chem. 1998, 576, 248—253. 

Nozaki, K. Shibahara, R Elzner, S. Hiyama, T. Alternating copolymerization of w-perfluoroalkyl-1-alkenes with carbon monoxide catalyzed by homogeneous and polymer-supported Pd-complexes. Can. J. Chem. 2001, 79, 593-597. 

Other examples of compounds, which copolymerize with vinyl monomers are carbon monoxide, forming polyketones and sulfur dioxide which reacts forming a polysulfone. It should be noted that sulfur dioxide forms complex compounds with alkenes in the 1 1 ratio. 

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