Solubility of the Schiff Base Ligand and the Organoaluminum Supported by the Ligand in Pure Solvents: Characterization, Determination, Analysis, and Model Correlation

Schiff bases and organoaluminum compounds have wide applications in medicine and catalysis. TG-DSC provided melting points and melting enthalpies for the Schiff base ligand (1, 2-[[(2,6-difluorophenyl)imino]methyl]phenol, CAS: 26672-04-8), with T_m at 349.55 K and ΔH_fus at 22.797 kJ/mol, and for the organoaluminum compound supported by the ligand (2, [2-[[(2,6-difluorophenyl)imino]methyl]phenoxy]dimethylaluminum, CAS: 2851050-89-8), with T_m at 396.04 K and ΔH_fus at 11.137 kJ/mol. The range of molecular electrostatic potentials for the two compounds was obtained by molecular electrostatic potential analysis, with the potential range for compound 1 being from +95.1 kJ/mol to −133.2 kJ/mol and that for compound 2 being from +139.9 kJ/mol to −132.7 kJ/mol. Hirshfeld surface analysis indicated that H···H contacts were the dominant contact interactions in these two molecules. In addition, the solubilities of the two compounds in 11 pure solvents were determined, and experimental data were correlated using 7 thermodynamic equations. The results displayed that the NRTL model had the best correlation result for the two compounds. These experimental results will have significant implications for the purification, crystallization, and industrial applications of similar types of substances.