Viscometric and volumetric studies of some amino acids in binary aqueous solutions of urea at various temperatures

Abstract

The viscosities and densities of l-glycine, l-alanine and l-valine have been measured at 288.15, 298.15, 308.15 and 318.15 K in aqueous urea solutions ranging from 5 to 25% urea by mass. The viscosity data have been analysed by using Jones–Dole equation. The activation parameters of viscous flow have been obtained to throw light on the mechanism of viscous flow. The values of apparent molar volume, limiting apparent molar volume and relative viscosity have been evaluated from the density and viscosity data. Transfer volumes and the infinite dilution partial molar expansibilities have been calculated from the temperature dependence of the limiting apparent molar volumes. The results were interpreted in the light of ion–ion and ion–solvent interactions and of structural effects of the solutes in solutions.