Amino acid-based ionic liquids for CO2 conversion to form cyclic carbonate under solvent-free conditions.

[Display omitted] • The ionic liquids were found to be single component bifunctional catalysts. • The amino acid ionic liquids show high catalytic efficiency to cyclic carbonates. • Catalytic activity enhances with increasing carbon chain length of anion. • No additional organic solvent required and halogen free. The amino acid ionic liquids of 1-butyl-3-methylimidazolium aspartic acid [bmim][ASP], 1-butyl-3-methylimidazolium glutamic acid [bmim][Glu], N -octyl- N -methylmorpholinium glutamic acid [mor 1,8 ][Glu] and N -hexylisoquinolinium aspartic acid [HiQuin][ASP] have been synthesized and characterized by 1H NMR, 13C NMR and IR spectroscopy. The catalytic performance of the amino acid ionic liquids for the coupling of various epoxides and CO 2 to produce cyclic carbonates was studied. The influence of anion type, catalyst dose, reaction temperature, reaction time and CO 2 pressure on the yields of cyclic carbonates was examined. The synthesized ionic liquids were found to be single component bifunctional catalysts in good yields and selectivity, no additional organic solvent required and halogen free. Furthermore, this system provides a reasonably environmentally benign chemical process in terms of potential industrial application. [ABSTRACT FROM AUTHOR]