Highly Efficient CO₂ Capture by Imidazolium Ionic Liquids through a Reduction in the Formation of the Carbene–CO₂ Complex

Abstract

A strategy for improving CO 2 capture by imidazolium ionic liquids (ILs) through a reduction in the formation of carbene–CO 2 complex was reported. The carbene–CO 2 complex content in CO 2 capture by imidazolium ILs was determined by a quantitative NMR method, and the carbene–CO 2 complex formation was decreased through a reduction in the basicity of the anion and an enlargement in the steric hindrance of the cation. Thus, both enhanced absorption capacity and improved desorption were achieved, where an ideal IL, [Ipmim][Triz], exhibited a very high capacity of 0.21 g of CO 2 /g of IL and excellent reversibility.