Solubility Measurement and Thermodynamic Study of Pimelic Acid in Water, 1-propanol, and Their Binary Mixtures at 293.15–303.15 k

The solubility of pimelic acid in water, 1-propanol, and their binary mixtures was determined across the entire composition range (0 to 1 weight fraction of 1-propanol) at temperatures of 293.15, 295.15, 298.15, 300.15, and 303.15 K. Activity coefficients were calculated to assess solute–solvent molecular interactions. Thermodynamic parameters, including standard enthalpy (ΔH⁰_soln), entropy (ΔS⁰_soln), and Gibbs free energy (ΔG⁰_soln) of solution, were derived using the van’t Hoff equation. Additionally, enthalpic and entropic contributions (%ζH and %ζTS) were evaluated to better understand the dissolution process.