Synthesis of bis(cyclic carbonate) and propylene carbonate via a one-pot coupling reaction of CO2, bisepoxide and propylene oxide

Abstract

The effective transformation of carbon dioxide (CO₂) into valuable products is promising in green and sustainable chemistry. The coupling reaction of CO₂ with epoxides to afford cyclic carbonates is an atom-economic pathway for CO₂ fixation. Many catalysts have been developed for this coupling reaction, however, very few of them were reported for the coupling reaction of CO₂ with bisepoxides. This work describes an efficient one-pot coupling reaction of CO_2, propylene oxide (PO) and bisepoxides without the addition of external organic solvents by using a nanolamellar zinc-cobalt double metal cyanide complex (Zn–Co(III) DMCC) as the catalyst and cetyltrimethyl-ammonium bromide (CTAB) as the co-catalyst. Propylene carbonate (PC) and bis(cyclic carbonate)s were obtained at the same time with high monomer conversions (PO: 93.6%, bisepoxides: 82.9%). The in situ produced PC acted as a good solvent for the coupling reaction of CO₂ with bisepoxides. Two products could be easily separated by distillation or precipitation. The application of the obtained bis(cyclic carbonate)s was also preliminarily investigated. A non-isocyanate route for synthesizing polyurethanes with massive hydroxyl groups was proposed.