Exploration of the solvation behavior of the synthesized 1-hexyl-3-methylimidazolium bromide [C6mim][Br] ionic liquid with L-cysteine and N-acetyl L-cysteine) in aqueous medium at different temperatures

Abstract

The interactions of L-cysteine and N-acetyl L-cysteine with imidazolium-based ionic liquid 1-hexyl-3-methylimidazolium bromide [C6mim] [Br] as a function of temperature have been studied by a combination of volumetric and acoustic properties. Densities and speeds of the sound of L-cysteine and N-acetyl L-cysteine in (0.00, 0.005, 0.01, 0.03 and 0.05) mol.kg−1 aqueous solutions of 1-hexyl-3-methylimidazolium bromide have been measured at T = (288.15, 298.15, 308.15 and 318.15) K. From density data, the apparent molar volume (Vϕ) the partial molar volume (Vϕ0) and standard partial molar volumes of transfer (ΔVϕ0) for L-cysteine and N-acetyl L-cysteine from water to aqueous 1-hexyl-3-methylimidazolium bromide solutions have been calculated. Partial molar isentropic compression (Kϕ,s) and partial molar isentropic compression of transfer (ΔKϕ, S0) have been calculated from the speed of sound data. The pair and triplet interaction coefficient have been calculated from both these properties. The parameters obtained have been used to describe the results in terms of (solute-solute), (solute-solvent) interactions, structure building and structure floating behavior of amino acids in aqueous 1-hexyl-3-methylimidazolium bromide solutions.