Investigation on Temperature-Dependent Volumetric and Acoustical Properties of Homologous Series of Glycols in Aqueous Sorbitol Solutions

In the present study, the combination of volumetric and acoustical studies is used to investigate the interactions of ethylene glycol, diethylene glycol, and triethylene glycol with sorbitol as a function of temperature. Densities and ultrasonic velocities of ethylene, diethylene, and triethylene glycol in (0.00, 0.01, 0.03, 0.05) mol·kg –1 aqueous solutions of sorbitol have been measured at temperatures T = (288.15, 298.15, 308.15, 318.15) K and experimental pressure p = 0.1 MPa. With the help of density data, the apparent molar volume V ϕ, the partial molar volume V ϕ o, and the partial molar volumes of transfer Δ V ϕ o, from water to aqueous sorbitol solutions have been computed. The values for partial molar expansibility (∂ V ϕ 0 /∂ T ) p and second order derivative (∂ 2 V ϕ 0 /∂ T 2 ) p have also been determined. From ultrasonic velocity values, apparent molar isentropic compression K ϕ,s, partial molar isentropic compression K ϕ, s o, and partial molar isentropic compression of transfer Δ K ϕ, s o, are evaluated. The computed values of partial molar volumes of transfer and partial molar isentropic compression of transfer are used to determine the pair and triplet coefficients. The parameters thus obtained have been discussed in terms of solute–solute/solute–solvent interactions prevailing in the present ternary system along with the structure making/structure breaking tendency of glycols in aqueous sorbitol solutions.