Dual amino-functionalized ionic liquids as efficient catalysts for carbonate synthesis from carbon dioxide and epoxide under solvent and cocatalyst-free conditions

•The dual amino-functionalized ionic liquids were used as catalysts without the need for organic solvents and halogen free.•The amino acids ionic liquids have high catalytic activity and the reaction conditions are mild.•The catalyst system was found to be applicable to a variety of terminal epoxides with high activity and selectivity.•The ionic liquids can be reused for five runs without significant loss of activity under the optimum reaction conditions.

In the present study, the dual amino-functionalised imidazolium ionic liquids of 1-(3-aminopropyl)-3-butylimidazolium glutamic acid [APbim][Glu], 1-(3-aminopropyl)-3-butylimidazolium aspartic acid [APbim][Asp], 1-(3-aminopropyl)-3- butylimidazolium glycine [APbim][Gly], have been synthesized and characterized by 1H NMR, 13C NMR spectroscopy and IR spectroscopy. The synthesis of cyclic carbonate by cycloaddition reaction of CO2 and various epoxides catalyzed by dual amino-functionalized imidazolium ionic liquids, was carried out under no additional organic solvent required and halogen free condition. Simultaneously, the influence of anion type, catalyst dose, reaction temperature, reaction time and CO2 pressure on the yields of cyclic carbonates was examined. The dual amino-functionalized imidazolium ionic liquids possess good yields and selectivity and provide a reasonably environmentally benign and recycled chemical process.

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