Partial Molar Volumes, Partial Molar Compressibilities, and Viscosities of α,ω-Amino Acids in Water and in Aqueous Solutions of Sodium Chloride over a Temperature Range of 293.2-333.2 K

Density, sound velocity, and viscosity were measured in the temperature range of 288.15-308.15 K at intervals of 5 K for glycine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-aminopentanoic acid, and 6-aminohexanoic acid in water and in aqueous solutions of sodium chloride. The apparent molar volumes and the apparent molar cornpressibilities were determined as a function of composition from the density and sound velocity data. Infinite dilution partial molar volumes and partial molar adiabatic compressibilities of the amino acids in water and in aqueous sodium chloride solutions were obtained by extrapolation at the selected temperatures. The relative viscosity values were fitted by least-squares to an equation of the type used by Tsangaris-Martin to obtain the empirical viscosity B and D coefficients. The results show that the addition of NaCl produces an increase in the partial molar volumes, the compressibilities, and the viscosity B coefficients of the solutes. The results are a consequence of the interaction between the zwitterionic groups and the hydrated ions of the salt.