Revealing Solid–Liquid
Equilibrium Behavior
of 4‑Fluorobenzoic Acid in 12 Pure Solvents from 283.15 to
323.15 K by Experiments and Molecular Simulations
The solubility of 4-fluorobenzoic acid (4FBA) in 12 pure
solvents
(methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol,
1-pentanol, ethyl formate, methyl acetate, ethyl acetate, acetonitrile,
and acetone) from 283.15 to 323.15 K at atmospheric pressure was determined
using the gravimetric method. Within the experimental temperature
range, the solubility of 4FBA increased with increasing temperature
in all solvents. Four thermodynamic models (modified Apelblat model,
NRTL model, Van’t Hoff model, and λh model) were selected to correlate the experimental solubility data
of 4FBA and assess the goodness of fit. The results revealed that
the modified Apelblat equation exhibited the highest fitting accuracy.
Furthermore, the mixing thermodynamic properties (mixing Gibbs free
energy, mixing enthalpy, and mixing entropy) derived from the NRTL
equation indicated that the mixing process of 4FBA in the selected
solvents is spontaneous and entropy-driven. To elucidate the solid–liquid
equilibrium behavior of 4FBA in pure solvents, the structural properties
of the solute–solvent molecules were investigated. The physicochemical
properties of solvents, solvation free energies, and radial distribution
functions were studied to explain the solid–liquid equilibrium
behavior of 4FBA.