Highly efficient synthesis of alkylidene cyclic carbonates from low concentration CO2 using hydroxyl and azolate dual functionalized ionic liquids

Abstract

A highly efficient catalytic system was developed for the reaction between CO₂ and propargylic alcohols for alkylidene cyclic carbonates. Ionic liquids (ILs) with different anions and cations were designed as cocatalysts, in order to find out the effect of the cation and the anion on this reaction. The results indicated that the effect of the cation was significant, especially the hydroxyl group on the cation played an important role due to the presence of a hydrogen bond. It was also found that the basicity of the anion was important for its catalytic activity, where the anion with moderate basicity gave the best activity. Moreover, this hydroxyl and azolate dual functionalized catalytic system showed excellent reusability and generality. It is worth mentioning that at a low concentration of CO₂, this dual functionalized catalytic system showed excellent catalytic activity even in a gram-scale reaction, indicating its potential in carbon capture and utilization processes.