Solvation behavior of glycine and diglycine in aqueous 1-butyl-3-methylimidazolium chloride ionic liquid solutions at different temperatures

Abstract

In the present work, apparent molar volume and isentropic compression of glycine and diglycine in aqueous 1-butyl-3-methylimidazolium chloride, [C4mim][Cl] solutions have been calculated from the measured experimental data on density and speed of sound at temperature, T=(288.15, 298.15 and 308.15) K. The apparent molar volumes at infinite dilution, Vϕ0 and the apparent molar isentropic compression at infinite dilution Kϕ,S0, were also calculated. These results have been interpreted in terms of effect of temperature and concentration on interactions such as solute–solute, solute–solvent and solvent–solvent which exist in the mixtures. Furthermore, apparent molar expansivity, Eϕ0, and Hepler's constant values, ∂Eϕ0∂TPhave been evaluated to support the conclusions obtained from the volumetric and acoustic studies. The Hepler's constant values were found negative which indicating the amino acids under study are predominantly a structure breaker due to hydrophobic hydration of amino acid in aqueous [C4mim][Cl].