Volumetric, ultrasonic and viscometric behavior of l-methionine in aqueous-glucose solutions at different temperatures

Densities, rho, ultrasonic speeds, u, and viscosities, eta, of aqueous-glucose (2.5, 5, 10, 15 and 20% of glucose, w/w in water) and of solutions of L-methionine in four aqueous-glucose solvents were measured at 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15 K. From these experimental data, apparent molar volume, V-phi limiting apparent molar volume, V degrees(phi) and the slope, S-v, apparent molar compressibiliity, K-s,K-phi limiting apparent molar compressibility, V-s,V-phi degrees and the slope, S-k, transfer volume, V degrees(phi,tr), transfer compressibility, K-s,K-phi,K-tr degrees, Falkenhagen coefficient, A, Jones-Dole coefficient, B, free energy of activation of viscous flow per mole of solvent, Delta mu(1)degrees(#) and per mole of solute, Delta mu(2)degrees(#) were calculated. The results are interpreted in terms of solute-solvent and solute-solute interactions in these systems. It is observed that there exist strong solute-solvent interactions in these systems, which increase with increase in glucose concentration. It is observed that L-methionine act as structure-breaker in aqueous-glucose solvents. The thermodynamics of viscous flow has also been discussed. (C) 2011 Elsevier B.V. All rights reserved.