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

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 (Δ V 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 (Δ K 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.