A Protic Ionic Liquid Catalyzes CO 2 Conversion at Atmospheric Pressure and Room Temperature: Synthesis of Quinazoline‐2,4(1 H ,3 H )‐diones

The chemical fixation of CO 2 under mild reaction conditions is of significance from a sustainable chemistry viewpoint. Herein a CO 2 ‐reactive protic ionic liquid (PIL), [HDBU + ][TFE − ], was designed by neutralization of the superbase 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) with a weak proton donor trifluoroethanol (TFE). As a bifunctional catalyst for simultaneously activating CO 2 and the substrate, this PIL displayed excellent performance in catalyzing the reactions of CO 2 with 2‐aminobenzonitriles at atmospheric pressure and room temperature, thus producing a series of quinazoline‐2,4(1 H ,3 H )‐diones in excellent yields.