Solubility and thermodynamics properties of salicylic acid in binary mixtures 1-propanol and propylene glycol/ethylene glycol monomethyl ether at different temperatures.

The research aimed to investigate the solubility and thermodynamics of salicylic acid in two binary solvent mixtures of (1-propanol+propylene glycol) and (ethylene glycol monomethyl ether+1-propanol). The study was conducted in the temperature range of 293.2 to 313.2K. To analyze the experimental solubility data, several linear and nonlinear cosolvency models, such as the van't Hoff, Jouyban-Acree, Jouyban-Acree-van't Hoff, mixture response surface, and modified Wilson models were employed. The models' effectiveness was evaluated by comparing the mean relative deviations of the back-calculated solubility data to the experimental values. In addition, the apparent thermodynamic parameters, including Gibbs energy, enthalpy, and entropy, were calculated using the van't Hoff and Gibbs equations. Furthermore, the study measured the density values for salicylic acid-saturated mixtures and represented them mathematically through the Jouyban-Acree model.