| Summary: | Synthesis of copolymers from carbon dioxide (CO<sub>2</sub>) and epoxides is an important research direction as such processes utilize the abundant greenhouse gas and deliver useful products. Specifically, cooligomers of CO<sub>2</sub> and propylene oxide (PO) with a non-alternating structure can be used for polyurethane preparation. They are synthesized by employing Zn-Co cyanide catalysts. The application of alternative metal cyanide complexes is interesting from scientific and practical points of view. The purpose of this work was to study the copolymerization of CO<sub>2</sub> and PO in the presence of Co-Ni cyanide catalysts and chain transfer agents (CTAs) in order to obtain low molecular weight products. Three Co-Ni catalysts with different contents of complexing agents were synthesized, characterized by several analytical methods and applied for this reaction. The complex without complexing agents was chosen for detailed investigation. 1,6-Hexanediol proved to be a more preferred CTA than poly(propylene glycol) and adipic acid. An oligo(ethercarbonate) (M<sub>n</sub> = 2560, PDI = 2.5, CO<sub>2</sub> = 20 mol.%) capped with OH groups was synthesized with relatively high productivity (1320 g<sub>PO+CO2</sub>/g<sub>cat</sub> in 24 h) and characterized by matrix-assisted laser desorption/ionization (MALDI) MS and NMR methods. The main chain transfer routes during the cooligomerization were suggested on the basis of the research results.
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