Responsive ionic liquids to catalyze the transformation of carbon dioxide under atmospheric pressure

The efficient conversion of carbon dioxide (CO2) to the valuable chemicals is of great significance but the development of robust catalyst is still an interesting and challenging issue. Four novel ionic liquids are facilely synthesized with the ability to adsorb carbon dioxide (CO2). [BZTMA(+)][(-)O(2)EEPZ(+)][Br-] and [DBUH+] [(-)O(2)EEPZ(+)][Br-] could catalyze the cycloaddition of CO2 into cyclic carbonates under atmospheric pressure at 50 degrees C with 99.3 % and 97.5 % yields in the absence of co-catalyst and solvent. Moreover, the [DBUH+] [(-)O(2)EEPZ(+)][Br-] could be reutilized by 11 times with a slightly decreased product yield. A new mechanism is proposed by the density functional theory (DFT). The excellent catalytic performance is mainly attributed to the ability of ionic liquids to adsorb CO2. After the CO2 is adsorbed, the formed intermediate would push the electrons towards the Br- anion leading to the stronger nucleophilic activation. This work introduces a new pathway to explore the ionic liquids for the chemical fixation of CO2.

Automated summary

Novel ionic liquids with the ability to adsorb CO2 were synthesized and demonstrated efficient catalytic ability for the conversion of CO2 into cyclic carbonates without the need for co-catalysts or solvents. The reusability of the catalyst was also established, presenting a new pathway for exploring the potential of ionic liquids in chemical fixation of CO2.