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 <em>B</em>-coefficients employing Jones-Dole equation. The viscosity <em>B</em>-coefficients of transfer (Δ<em>_trB</em>), variation of <em>B</em> with temperature (<em>dB/dT</em>) and solvation number (<em>S_n</em>) 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 (<em>Δµ^°<img src='http://www.niscair.res.in/jinfo/hash1.gif' border=0></em>) as well as per mole of solute (<em>Δµ^°<img src='http://www.niscair.res.in/jinfo/hash2.gif' border=0></em>) along with activation enthalpy (<em>ΔH^°<img src='http://www.niscair.res.in/jinfo/hash2.gif' border=0></em>) and entropy (<em>ΔS^°<img src='http://www.niscair.res.in/jinfo/hash2.gif' border=0></em>) 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.