(Co)polymerization Reactions with Participation of Cyclic Monomers Catalyzed by Double Metal Cyanide Catalysts

Abstract

Double metal cyanide catalysts are unique heterogeneous catalysts having no alternative in the industrial polymerization of propylene oxide to produce poly(propylene oxide) with properties demanded for special-purpose applications: a low degree of unsaturation and high molecular weights and hydroxyl values. These catalysts are known since the 1960s, but academic publications addressing them started to appear only in the early 2000s, which coincided with interest in epoxide/CO₂ copolymerization and other catalytic processes. The present literature review aims to systematize information on the application of double metal cyanide catalysts in (co)polymerization reactions involving epoxides and other cyclic monomers. Much attention is paid to chemo- and regioselectivity issues and mechanistic aspects of epoxide/CO₂ copolymerization. Due to the use of ionic liquids and other homo- and heterogeneous catalyst in the reaction of epoxides and CO₂, double metal cyanide catalysts can be tuned for the selective synthesis of poly(ether carbonates), polycarbonates, or cyclic carbonates. Information on the application of these processes for the synthesis of functionalized (co)polymers is covered. Epoxide/cyclic anhydride copolymerization and epoxide/cyclic anhydride/CO₂ and epoxide/ε-caprolactone/CO₂ multicomponent reactions, including those using multicomponent catalytic systems based on the catalysts under consideration, are highlighted. Progress in this area suggests that double metal cyanide catalysts and multicomponent catalytic systems based on them will hold a prominent position in the synthesis of polymer materials of the future.