DBU-Based Protic Ionic Liquids for CO2 Capture

The applications of the novel anion-functionalized protic ionic liquid (ILs), prepared from superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with imidazole, in the CO2 absorption have been investigated. It has been detected that this ionic liquid can reversibly capture about 1 mol of CO2 per mole ionic liquid. In addition, the influence of temperature, pressure, water, and substituent of anions has been uncovered. The capture of CO2 was significantly affected by the substituents in imidazole-based anion, suggesting that electric-charge distribution in imidazole ring system can play an important role in determining the reaction of ILs with CO2.