Effect of concentration and temperature variations on interactions in (L-serine/L-valine + aqueous glucose/sucrose/lactose) systems: Viscometric and activation parametric study

Abstract

Viscosities of (L-serine/L-valine + 0.1 mol dm^-3 aqueous glucose/sucrose/lactose) systems have been measured as a function of molal concentration of amino acids at different temperatures; 293.15 K, 298.15 K, 303.15 K, 308.15 K and 313.15 K. The viscosity data has been utilized to determine viscosity B-coefficients employing Jones-Dole equation. The viscosity B-coefficients of transfer (Δ_trB), variation of B with temperature (dB/dT) and solvation number (S_n) of L-serine/L-valine have been obtained using the experimental viscosity values. Further, Gibbs free energy of activation of viscous flow per mole of solvent (Δµ^°) as well as per mole of solute (Δµ^°) along with activation enthalpy (ΔH^°) and entropy (ΔS^°) have been computed using Feakin’s transition state theory to throw light on the mechanism of viscous flow. The results have been discussed in terms of solute-solvent interactions; and structure making tendency of amino acid molecules in aqueous saccharides solutions.