Volumetric, ultrasonic and viscometric studies of solute-solute and solute-solvent interactions of l-threonine in aqueous-sucrose solutions at different temperatures

Densities, rho of solutions of l-threonine in aqueous-sucrose solvents 5%, 10%, 15%, and 20% of sucrose, w/w in water at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K; and ultrasonic speeds, u 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(o) and the slope, S-v, apparent molar compressibility, K-s,K-phi, limiting apparent molar compressibility, K-s,phi(o) and the slope, S-k, transfer volume, V-phi,tr(o), transfer compressibility, K-s,phi,tr(o), limiting apparent molar expansivity, E-phi(o), Hepler's constant, (partial derivative V-2(phi)o/dT(2)), Falkenhagen coefficient, A, Jones-Dole coefficient, B and hydration number, n(H) have been calculated. The results have been interpreted in terms of solute-solvent and solute-solute interactions in these systems. The Gibbs energies of activation of viscous flow per mole of solvent, Delta mu(o#)(1) and per mole of solute, Delta mu(o#)(2) were also calculated and discussed in terms of transition state theory. It has been observed that there exist strong solute-solvent interactions in these systems and these interactions increase with increase in sucrose concentration in solution. (c) 2013 Elsevier Ltd. All rights reserved.