Electrochemical activation of CO2 in ionic liquid ( BMIMBF4): synthesis of organic carbonates under mild conditions

A new electrochemical procedure for electrosynthesis of organic carbonates from CO2 and alcohols has been established in CO2-saturated room temperature ionic liquid BMIMBF4 solution, followed by addition of an alkylating agent. The synthesis was carried out under mild (P-CO2 = 1.0 atm, T = 55 degrees C) and safe conditions. The use of volatile and toxic solvents and catalysts as well as of any additional supporting electrolytes has been avoided. The influence of temperature, cathode material, working potential, alcohol concentration and the charge passed on the reaction using methanol (1a) as the model compound was examined. The ionic liquid used for the reaction was recyclable. The obtained results showed that the primary and secondary alcohols were converted in good yields, whereas tertiary alcohol and phenol were unreactive.