Volumetric, viscosity and ultrasonic studies of solute-solute and solute-solvent interactions of glycine and diglycine in water and in aqueous citric acid at different temperatures

Densities, ρ, ultrasonic speeds, u and viscosities, ƞ of glycine and diglycine in water and 0.1 mol·kg− 1 aqueous citric acid solutions were measured over the temperature range (298.15 to 313.15) K at the interval of 5 K at atmospheric pressure. From these experimental data apparent molar volume ФV, limiting apparent molar volume ФVO and the slope SV, partial molar expansibilities ФEO, adiabatic compressibility β, transfer volume ФVOtr, Falkenhagen coefficient A, Jone- Dole coefficient B, the temperature derivative of B coefficient dB/dT, intermolecular free length (Lf), specific acoustic impedance (Z), and molar compressibility (W) were calculated. The results are interpreted in terms of solute-solute and solute-solvent interactions. It was observed that glycine and diglycine act as structure breakers in aqueous citric acid at different temperatures.