Densities, viscosities, refractive indices, and electrical conductivities of aqueous alkali salts of α-alanine

• Thermophysical properties of aqueous Na and K salts of α-alanine were studied.
• Properties are density, viscosity, refractive indices, and thermal conductivity.
• The concentrations of amino acid salt ranges from (0.5 to 3.5) M.
• The temperature range studied was (333.15 to 343.15) K.
• The measured data were represented satisfactorily by using the applied correlations.

In this work, physicochemical properties such as density, viscosity, refractive index, and electrical conductivity of aqueous alkali (potassium or sodium) salts of the amino acid α-alanine (ALA), were measured at temperatures from (303.15 to 343.15) K and concentrations ranging from (0.5 to 3.5) M. Density and viscosity measurements were performed using the vibrating tube and the falling ball techniques, respectively. The refractive index at the sodium D line was measured in an automatic refractometer, while the electrical conductivity was measured using a commercial conductivity meter. An empirical equation was applied to correlate the density, refractive index, and electrical conductivity of the amino acid salt solutions with temperature and amino acid salt concentration, which gave average absolute deviation values of 0.03%, 0.01%, and 0.6%, respectively. The variation of the viscosity as a function of temperature and amino acid salt concentration was accurately represented by a modified Vogel–Tamman–Fulcher equation at an average absolute deviation of 0.5%.