Exploring the Dissolution Behavior of m-Hydroxybenzoic Acid in 14 Pure Solvents Using Thermodynamic, Molecular Simulation and Hansen Solubility Parameters

In this study, the solubility of m-hydroxybenzoic acid in 14 organic pure solvents (acetone, iso-propanol, ethanol, n-propanol, methanol, ethylene glycol, n-pentanol, n-butanol, methyl acetate, n-propyl acetate, ethyl acetate, butyl acetate, iso-propyl acetate, acetonitrile) at the pressure of 0.1 MPa (at T = 278.15-323.15 K) was studied by the static weight method. The order of solubility (molar fraction) of m-hydroxybenzoic acid in the 14 pure solvents at 278.15 K was acetone > iso-propanol > ethanol > n-propanol > methanol > ethylene glycol > n-pentanol > n-butanol > methyl acetate > n-propyl acetate > ethyl acetate > butyl acetate > iso-propyl acetate > acetonitrile. As the temperature improved, the solubility correspondingly increased. The m-hydroxybenzoic acid solubility data in pure solvents were connected using the modified Apelblat model, the lambda h model, the NRTL model, and the Wilson model, and the best-fit performance was obtained using a modified Apelblat model. Performance was obtained using a modified Apelblat model. Two molecular dynamics analysis methods, Hirshfeld surface analysis and molecular electrostatic potential surface (MEP) analysis, were used to determine the dissolution process of m-hydroxybenzoic acid crystals and the interaction sites with solvent molecules in solution. The Hansen solubility parameters (HSPs) were utilized to assess the solvent's capability and to elucidate its ability to dissolve m-hydroxybenzoic acid.