Comments on “Thermodynamic modeling studies of aqueous solubility of caffeine, gallic acid and their cocrystal in the temperature range of 303 K-363 K”

The activity coefficients reported by Dabir and coworkers [Fluid Phase Equilib. 456 (2017) 65-76] were based on a thermodynamic relationship that failed to properly take into account the solid phase transition that both caffeine and gallic acid exhibited prior to melting. The calculation of activity coefficients for crystalline nonelectrolyte solutes exhibiting a solid phase transition is discussed.