Copolymerization of propylene oxide and CO₂ catalyzed by dinuclear salcy–CoCl complex

Abstract

The development of catalytic systems is always a research focus on the field of epoxides/carbon dioxide (CO₂) copolymerization. A novel bimetallic Cobalt complex (1) bearing a piperazine-bridged salcy ligand and ancillary chloride group (salcyCoCl) has been exploited as catalyst for the ring-opening copolymerization (ROCOP) of propylene oxide (PO) and CO₂ to afford poly(propylene carbonate) (PPC). The catalyst loading, CO₂ pressure, polymerization temperature, reaction time, type of cocatalyst were employed in order to explore the influences on the polymeration activity of 1. It was found that after adding the cocatalyst PPNCl, the bimetallic salcy–CoCl complex can exhibit relatively good activity under mild conditions in the catalytic copolymerization of PO and CO₂. A reasonable bimetallic polymerization mechanism has been proposed according to the polymer structure and the interaction between metal complex catalyst system and monomer.

Graphical Abstract

Keywords:

• Bimetallic complex
• cobalt complex
• polycarbonate
• propylene oxide
• ring-opening polymerization

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research work was supported by the National Natural Science Foundation of China (51473045).