Copolymerization of carbon dioxide and propylene oxide with highly effective zinc hexacyanocobaltate(III)-based coordination catalyst

Copolymerization of propylene oxide and carbon dioxide was successfully carried out by using double metal cyanide complex (DMC) based on Zn3[Co(CN)6]2. It has been found that this catalyst demonstrated highly enhanced catalytic activity over 1000 g copolymer per gram of Zn3[Co(CN)6]2 compared with its analog based on Zn3[Fe(CN)6]2. The copolymers prepared were characterized by IR, 1H NMR, the molar fraction of CO2 (FCO2) for copolymer was as high as 0.31 under optimum condition. Propylene carbonate was also identified as co-product by the spectrometry. The study showed that lower temperature is favorable for incorporation of CO2 into copolymer instead of propylene carbonate, and FCO2 is significantly influenced by amount of catalyst used. The kind of complexing agent employed in preparation impacted on the catalytic activity, but not yet for FCO2.