Ionic liquid as a catalyst for utilization of carbon dioxide to production of linear and cyclic carbonate

In this review, primary focus on the ionic liquid (IL) catalysts and related catalytic systems for utilization of carbon dioxide to a production of linear as well as cyclic carbonate, and describes the innovative progress observed during last ten years. This review covers trend of various catalysts starting from first conventional ILs (tetrabutylammonium bromide and imidazolium IL) to the latest metal containing IL systems employed for the efficient production of dimethyl carbonate. Moreover, recent advances in DMC production also summarizes using the catalysts which contain novel super base facilitated tri-cationic IL systems. Similarly, cyclic carbonate synthesis reveals the benefits of using IL based catalyst on the verity of different supporting materials such as alumina, silica, carbon nanotubes, magnetic nanoparticles, poly(ethylene glycol), polystyrene, cellulose, and chitosan. The summary of ammonium, phosphonium and both functionalized and unfunctionalized imidazolium salts indicates that the turnover frequency for epoxide and propylene oxide enhances under mild reaction condition. Overall, it is clear that metal ions or super base in the combination of ILs can improve the conversions and the presence of hydroxyl, carboxyl, and other functional groups will enhance the yield multiple folds through hydrogen bonding interaction.

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