Study of Thermodynamic and Acoustic Properties of Niacin in Aqueous Hexylene Glycol and Propylene Glycol at Different Temperatures

[Image: see text] The densities and speed of sound for liquid mixtures containing vitamin B(3) (niacin) at 0.01, 0.03, and 0.05 mol·kg(–1) concentrations in aqueous propylene glycol and hexylene glycol at the variation of temperatures from 293.15 to 308.15 K have been measured using an Anton Paar DSA 5000 M. From volumetric experimental data, apparent molar volume (V(ϕ)), partial molar volume (V(ϕ)(0)), and partial molar volume of transfer (ΔV(ϕ)(0)) are calculated along with the apparent molar isentropic compression (K(ϕ, S)), partial molar isentropic compression (K(ϕ, S)(0)), and partial molar isentropic compression of transfer (ΔK(ϕ)(0)) using experimental acoustic data. The positive volumetric data (i.e., apparent molar volume and partial molar volume) indicates strong solute–solvent interactions inside the mixture. Along with these values, the empirical constants a, b, and c with the pair and triplet coefficients (V(AB), V(ABB), K(AB), K(ABB)) are also calculated.