Thermodynamics and solubilization behavior of (2Z)-N-cyclohexyl-2-(3-hydroxybenzylidine) hydrazine carbothioamide in polyethylene glycol-400 + water mixtures at (298.15 to 338.15) K

Highlights: • Solubility and dissolution of thiosemicarbazone derivative (CHBH) were evaluated. • The solubilities of CHBH were observed highest in pure PEG-400. • Experimental solubilities were correlated well with mathematical models. • The dissolution behavior of CHBH was found to be endothermic and spontaneous. - Abstract: Dissolution thermodynamics of (2Z)-N-cyclohexyl-2-(3-hydroxybenzylidine) hydrazine carbothioamide (CHBH) in various polyethylene glycol-400 (PEG-400) + water mixtures from (298.15 to 338.15) K were studied and correlated. The experimental solubilities were correlated with the modified Apelblat and Yalkowsky models. The root mean square deviations (RMSD) were observed as (0.88–4.28)% for the modified Apelblat model and (2.10–8.25)% for Yalkowsky model. The mole fraction solubility (7.12 × 10⁻² at 298.15 K) and mass fraction solubility (5.32 × 10⁻² kg kg⁻¹ at 298.15 K) of CHBH were observed highest in pure PEG-400. However, the lowest mole fraction (3.83 × 10⁻⁷ at 298.15 K) and mass fraction solubility (5.90 × 10⁻⁶ kg kg⁻¹ at 298.15 K) of CHBH were observed in pure water. Thermodynamic studies showed endothermic and spontaneous dissolution of CHBH in all co-solvent mixtures