Carbon dioxide as carbon source: Activation via electrogenerated O2− in ionic liquids

The activation of carbon dioxide has been obtained in O2/CO2 saturated ionic liquids, via electrochemically generated O2−, at a less negative potential than the one of the direct cathodic reduction of CO2. This electrochemical activation has been applied to the C–N bond formation from amines and carbon dioxide in the synthesis of organic carbamates. A competitive reaction between electrogenerated superoxide ion and imidazolium cations yielding 2-imidazolones has been pointed out. This procedure allows to avoid the utilization of volatile and toxic organic solvents, supporting electrolytes and catalysts.

► Electrochemical activation of carbon dioxide. ► Electrogenerated superoxide ion by cathodic reduction of dioxygen. ► Electrogenerated peroxydicarbonate anion as carboxylating agent. ► Synthesis of carbamates in ionic liquids. ► Reaction between superoxide ion and IL to yield 2-imidazolone.