Probing coumarin solubility and solvation energetics in diverse aqueous–organic solutions across a temperature range: A debut exploration

Abstract

In this research, an investigation was conducted to explore the solubility of coumarin in both aqueous solutions and binary mixtures, specifically in pure and aqueous ethylene glycol (EG), aqueous 2-methoxyethanol (ME), and aqueous 1,2-dimethoxyethane (DME). Solubility experiments were conducted first time using UV–Vis spectroscopy at a temperature range of 288.15–313.15 K at a pressure of 0.1 MPa for the current solute solvent systems. A digital thermostat was used to maintain the precise temperature. The findings indicated that coumarin exhibits its highest solubility in pure DME (3.0824 mol·kg−1) and its lowest solubility in pure EG (0.0169 mol·kg−1) across all temperatures. Various solvation parameters were calculated to enable the determination of solvation-related thermodynamic properties. The experimental results were used to evaluate various thermodynamic parameters including solution Gibbs free energies, transfer Gibbs free energies associated with cavity and dipole–dipole interactions, enthalpy of transfer, and non-covalent transfer energies. The focus of this research was on to provide insights into the thermodynamics of coumarin-like organic molecules when dissolved in solutions. The study aimed to contribute valuable information regarding the stability of coumarin, particularly in relation to non-covalent interactions. These insights have potential to influence the manufacturing and purification processes, thereby expanding its potential applications across various industries.