Abstract: Viscosities and densities at 293.15 and 298.15 K are reported in this paper for glycine and DL-alanine in methanol-water mixed solvent. The viscosity B coefficients and partial molar volumes at infinite dilution have been calculated. The experimental results show that B coefficients reach a minimum at about 15% for glycine and 25% for DL-alanine respectively. The effect of amino acids on solvent structure has been discussed. Also, the activation parameters for viscous flow for amino acids in methanol-water mixtures have been calculated.

Key words: Viscosity β coefficient, Solvation, Prtial molar volume, Activation parameter