Tuning ionic liquids with imide-based anions for highly efficient CO2 capture through enhanced cooperations.

Graphical abstract Highlights • Among the studied imide-based ILs, [P 4442 ][Cy-Suc] has the lowest density and the highest viscosity. • CO 2 capture can be efficiently tuned by substitute on the imide-based anions of the ILs. • The capture capacity of CO 2 by [P 4442 ][Cy-Suc] is as high as 2.21 mol of CO 2 per mole of the IL. • The absorption process by imide-based ILs was highly reversible and energy-saving. Abstract Minimizing the release of CO 2 into the atmosphere is highly important due to the CO 2 concentration dependence of climate change. In this work, highly efficient capture of CO 2 is investigated through tuning ionic liquids (ILs) with imide-based anions. It is found that a superior high CO 2 capacity (2.21 mol mol⁻¹) be achieved by the imide-based IL with 1,2-cyclohexanedicarboximide anion at 20 °C and 1.0 bar through a combination of chemical and physical absorption. Quantum chemical calculations and spectroscopic analysis suggests that the significant increase in the CO 2 capacity is due to the enhanced cooperative interactions between CO 2 and three active sites in the anion with electron-donating group. Furthermore, the adsorbed CO 2 can be readily stripped from the CO 2 -saturated IL through slightly heating or bubbling N 2 , and the IL may be recycled without loss of efficiency. [ABSTRACT FROM AUTHOR]