Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The values of density, q and ultrasonic speed, u of solutions of l-phenylalanine in aqueous-carbohydrate solvents (2.5 and 5% of arabinose/glucose/sucrose, w/w in water) at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K; and viscosities, g of these solutions at (298.15, 303.15, 308.15, 313.15, and 318.15) K and at atmospheric pressure were measured. From these experimental results, the apparent molar volume, Vf limiting apparent molar volume, Vf0 and the slope, Sv, transfer volume, Vfo,tr apparent molar compressibility, Ks,f limiting apparent molar compressibility, Ks,f0 and the slope, Sk, transfer volume, Vf,tr0 , transfer compressibility, Ks,f,tr0 limiting apparent molar expansivity, Ef, Hepler s constant, (d2Vf0/dT2), Falkenhagen Coefficient, A, Jones-Dole coefficient, B and hydration number, nH were calculated. The Gibbs free energies of activation of viscous flow per mole of solvent, Dmu10 and per mole of solute, Dmu20, entropies, DS0 and enthalpies, DHo of activation of viscous flow were also calculated and discussed in terms of transition state theory. The structure-making/breaking ability of the amino acid has also been discussed in terms of the sign of (d2Vf0/dT2) and dB/dT. The results have been interpreted in terms of solute solvent and solute solute interactions in these systems.