Chemical transformations of captured CO₂ into cyclic and polymeric carbonates

Alkylcarbonate ionic liquids are shown to be chemically active species for trans-carboxylating cyclohexene oxide to produce polycarbonates. Catalytic equivalents of alkylcarbonate ionic liquids can be added to co-polymerizations of cyclohexene oxide/CO₂ to increase the yield and selectivity of the polymer. On the other hand, in the case of propylene oxide, polymerization is suppressed, and propylene oxide is converted to propylene carbonate. The suppression of polymerization is due to the high activity of the alkylcarbonate ionic liquids towards carboxylation of epoxides for cyclic carbonate formation. The reactivity of alkylcarbonate ionic liquids with propylene oxide is sufficient enough that propylene carbonate is produced in the absence of catalyst at pressures as low as 1 atm at 60 °C.