Efficient responsive ionic liquids with multiple active centers for the transformation of CO2 under mild conditions: Integrated experimental and theoretical study

Abstract

The ideal catalyst for the coupling reaction of CO2 with epoxides is expected to have comprehensive advantages. An appealing ionic liquid, C[CMImBrTMG]2, with multiple active centers is synthesized to accomplish several goals in a single-component catalyst to adsorb CO2 and afford the robust electrophilic and nucleophilic groups. The 98.5 % yield of chloropropylene carbonate (CPC) is achieved at 50 °C under 1 bar CO2 pressure during 6 h. Moreover, C[CMImBrTMG]2 is easy to be simply separated from the catalytic system by washing with ethyl acetate. A new reaction mechanism is constructed by the density functional theory (DFT) along with the 13C NMR confirmation. The contribution of critical groups in C[CMImBrTMG]2 to the catalytic performance is further elucidated by the electrostatic potential (ESP), atoms in molecule (AIM), and electron localization function (ELF).