Study of thermodynamic properties of aqueous binary mixtures of glycine, L-alanine and β-alanine at low temperatures (T=275.15, 279.15, and 283.15) K

In the present communication, experimental values of density (rho) and speed of sound (u) of aqueous solutions of three amino acids, namely glycine, L-alanine and beta-alanine at different temperatures i.e. T = (275.15, 279.15, and 283.15) K are reported. From the experimental values, different derived parameters such as apparent molar volume of solute (phi(V)), isentropic compressibility of solution (beta(S)), apparent molar isentropic compressibility of solute (phi(KS)) have been calculated. The limiting values of apparent molar volume of solute (phi(0)(V)), apparent molar isentropic compressibility of solute (phi(0)(KS)) and apparent molar expansivity (phi(0)(E)) in the aqueous medium have also been obtained. The temperature coefficients of these limiting properties have also been computed. The results obtained were interpreted in terms of solute-solvent and solute-solute interactions, and structure making and structure breaking abilities of the solute in aqueous medium. (C) 2011 Elsevier Ltd. All rights reserved.