Ultrasonic Investigation Of The Thermo-Acoustical Properties Of Sorbic Acid In Aqueous Solutions Of Propylene Glycol And Hexylene Glycol

Abstract

This study investigates the thermodynamic and acoustic properties of sorbic acid in aqueous solutions containing propylene glycol (PG) and hexylene glycol (HG) as co-solvents. Measurements were performed across a temperature range of 293.15 K to 308.15 K at a fixed pressure of 0.1 MPa. The prepared solutions contained sorbic acid at concentrations of 0.01, 0.03, and 0.05 . Using the Anton Paar DSA 5000 M, density and sound velocity were recorded to evaluate key parameters such as thermal expansion coefficients, expansibilities, transfer volumes, and partial molar volumes. Additionally, the study examines the effects of sound velocity on isentropic compressibility, including apparent molar isentropic compression, partial molar isentropic compression, and second-order compressibility factors, providing insights into solute-solvent interactions. By determining pair and triplet interaction coefficients along with empirical constants, the extent of molecular interactions within the solution was assessed. The findings indicate that hexylene glycol exhibits stronger solute-solvent interactions than propylene glycol, as reflected in the derived thermophysical properties. These insights contribute to a better understanding of co-solvent behaviour in aqueous environments, with potential applications in pharmaceutical formulations and food sciences.