Volumetric and acoustic studies of glycine in aqueous solutions of sulphathiazole drug at T=(288.15 to 308.15) K

Abstract

The densities (ρ) and speeds of sound (u) for glycine in aqueous solutions of (0.01, 0.02, 0.03, and 0.04) mol·kg^-1sulphathiazole drug have been measured at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K, using vibrating tube digital densimeter and sound analyser Anton–Paar Model DSA - 5000. The apparent molar properties like apparent molar volume (<em>V</em>_φ), apparent molar adiabatic compressibility (<em>K</em>_φ, _s⁰) and the apparent molar volume (<em>V</em>_φ⁰) and adiabatic compressibility at infinite dilution (<em>K</em>_φ,_s ⁰) of glycine have been determined in water as well as in ternary mixtures containing sulphathiazole drug at different concentrations and at different temperatures from experimental data of densities and speeds of sound under atmospheric pressure. These data were also used to calculate the transfer parameters. Transfer parameters have been explained from the point of view of concentration dependence of solute-solute and solute-solvent interactions. The limiting apparent molar expansibility (<em>E</em><img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>) values for glycine in aqueous solutions of drug have been calculated. The calculated values of thermal expansion coefficient (<em>α</em>₂) have small and positive values. These results are explained on the basis of drug-amino acid - water interactions and hydrophobic –hydrophilic interactions.