Densities and Speeds of Sound of Solutions of Glycine, l-Alanine, and l-Valine in Aqueous Ammonium Dihydrogen Phosphate at Different Temperatures

Abstract

Densities (ρ) and speeds of sound (c) of solutions of some α-amino acids such as glycine, l-alanine, and l-valine in aqueous ammonium dihydrogen phosphate (ADP) were measured at T = (288.15–318.15) K and experimental pressure p = 0.1 MPa. By using the experimentally measured densities, the apparent molar volume (Vϕ), the partial molar volume at infinite dilution (Vϕo), and partial molar volumes of transfer (ΔVϕo), from water to aqueous ADP have been calculated. Further, apparent molar isentropic compression (Kϕ,s), partial molar isentropic compression at infinite dilution (kϕ,so) and partial molar isentropic compression of transfer (ΔKϕ,so) were calculated from the ultrasonic speeds. The group contributions of amino acid to partial molar volumes have also been discerned. From partial molar volumes of transfer and partial molar isentropic compression of transfer, the pair and triplet interaction coefficients are attained. We have also intended partial molar expansion (∂Vϕo/∂T)p and second order derivative ...