Study of solute-solute and solute-solvent interactions of L-threonine in aqueous-glucose solutions at different temperatures by using volumetric and viscometric methods

Densities, rho of solutions of l-threonine in water and in aqueous-glucose solvents (5, 10, 15 and 20% of glucose, w/w in water) at T = (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and viscosities, eta of these solutions at (298.15, 303.15, 308.15, 313.15 and 318.15) K were measured at atmospheric pressure. From these experimental results, the apparent molar volume, V-phi, limiting apparent molar volume, V-phi(degrees) and the slope, S-v, transfer volume, V-phi,tr(degrees), Falkenhagen coefficient, A, Jones-Dole coefficient, B, temperature derivative of B-coefficients, dB/dT, Gibbs free energies of activation of viscous flow per mole of solvent, Delta mu(degrees#)(1) and per mole of solute, Delta mu(degrees#)(2) and hydration number, H-n were calculated. The results are interpreted in terms of solute-solvent and solute-solute interactions in these systems. It has been observed that there exist strong solute-solvent interactions in these systems, which increase with increase in glucose concentration. It is also observed that L-threonine acts as structure-breaker in these aqueous-glucose solvents. The thermodynamics of viscous flow are also discussed. (C) 2013 Elsevier Ltd. All rights reserved.