Overview of the Process and Polymer Properties

The copolymerization of carbon monoxide and olefins forms the polyketone in Equation 17.65, and this polymerization is closely related to the hydroesterification and hydrocarboxylation of olefins. The rate of reaction of the acyl intermediate that was generated in the hydroesterification process with olefin or alcohol differentiates the formation of copolymer from the formation of monomeric esters. This difference in relative rates for reaction of the acyl intermediate with olefin versus alcohol results from a change in the ancillary ligand on the palladium, as described in this section. 

The copolymer between ethylene and carbon monoxide has been known since the early 1940s. In 1941 this copolymer was produced at Bayer in a high-temperature, high-pressure process (230 °C, 200 atm). Roughly 10 years later, this polymer was produced through 

In the early 1980s, Sen reported the synthesis of CO-ethene oligomers using a combination of dicationic palladium complexes [Pd(NCMe)J(BF ), and triphenylphosphine as precatalysts, Tliese catalysts induced polymerization under milder conditions than the previous catalysts for this process. Although the material reported by Sen possessed relatively low molecular weight, and the catalysts were less reactive than those known today, tliis finding showed that cationic palladium complexes were more reactive than the neutral systems studied previously. 

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