Thermodynamic aggregation behaviour of p-cymene in hydrotropic solution

Abstract

The paper deals with the thermodynamic properties and aggregation behaviour of p-cymene through hydrotropy. Different hydrotropes namely urea, resorcinol, sodium cumene sulfonate and pyrogallol has been used to study the solubility under a wide range of hydrotrope concentrations (0 to 3.00 mol.kg–1) and different system temperatures (303.15 to 333.15 K). The effectiveness of hydrotrope with respect to the system was measured by Setschenow constant KS and reported for all hydrotropes used in this study. The influence of different system temperatures on thermodynamic properties like standard Gibbs free energy change (ΔG°), standard enthalpy change (ΔH°) and standard entropy change (ΔS°) of solubilisation with respect to p-cymene has been ascertained. The aggregation behaviour between the solute and the hydrotrope and among the hydrotrope molecules have also been studied using step wise association model.