Switchable ionic liquids (SILs) are promising solvents for CO2 separation due to their high CO2 capturing efficiency and easy preparation compared to 'classical' ionic liquids. Considering viscosity, the present study has demonstrated that SILs formed at least two times stronger chemical bonds with CO2 than studied classical ionic liquids (ILs). Furthermore, the reversible properties of SILs were confirmed by evaluation of different regeneration methods. On average, molar fractions of CO2 were more than 0.3 outperforming acetate-based ILs (molar fraction of CO2 around 0.25) and more than ten times the capacity of physical ionic liquids (molar fraction 0.02). Consequently, SILs are found to be efficient CO2 absorbents operating at atmospheric pressure. (C) 2012 Elsevier B.V. All rights reserved.