Surface Properties of Aqueous Solutions of Amino Acid Ionic Liquids: [C₃mim][Gly] and [C₄mim][Gly]

Glycine ionic liquids [C₃mim]­[Gly] (1-propyl-3-methylimidazolium glycine) and [C₄mim]­[Gly] (1-butyl-3-methylimidazolium glycine) have been prepared by the neutralization method and characterized by ¹H NMR spectroscopy and DSC trace. The values of density and surface tension of aqueous [C₃mim]­[Gly] and [C₄mim]­[Gly] with various molality were determined in the temperature range of (288.15 to 328.15 ± 0.05) K, and the experimental values of parachor for these solutions were calculated. Using the empirical equation of parachor, the surface tension of these aqueous solutions was estimated, and the estimated values are in good agreement with experimental values within error