Alternating copolymerization of carbon dioxide and cyclohexene oxide and their terpolymerization with lactide catalyzed by zinc complexes of N,N ligands

For the alternating copolymerization of CO2 and cyclohexene oxide, a variety of zinc acetate complexes with new aminoimidoacrylate ligands has been synthesized and tested as catalysts. All complexes catalyzed the reaction and structure-activity investigations revealed that the highest activities and selectivities were reached when the ligand's aromatic rings were 2,6-substituted by alkyl groups of different size (isopropyl versus methyl) and when the ligand backbone embodied an electron-withdrawing cyano group. Furthermore, these complexes catalyzed the terpolymerization of CO2, cyclohexene oxide and lactide to give poly(cyclohexyl carbonate-co-lactide) and the composition of the polymer was adjustable by the monomer feed.