Solid–Liquid Equilibrium Solubility and Correlation of Uniconazole in 13 Monosolvents and Binary Solvents from 278.15 to 323.15 K

Uniconazole (UCZ) is an important plant growth regulator, and its solubility has not been comprehensively studied. In this study, the static method was employed to determine the solubility of UCZ in 13 monosolvents (ethylene glycol, n-propanol, isopropanol, 1,2-propanediol, iso-butanol, n-butanol, n-octanol, methyl acetate, ethyl acetate, butyl acetate, n-propyl acetate, isobutyl acetate, and water) and n-propanol-water binary mixtures at T = (278.15 to 328.15) K and P = 0.1 MPa. Experiments have shown that the solubility of UCZ in the selected solvent system exhibits a positive temperature correlation, and it significantly increases with the n-propanol mole fraction in binary systems. The solubility in 13 monosolvents was correlated using Apelblat, Van’t Hoff, Jouyban, and NRTL equations, and solubility data in binary solvents were correlated using Apelblat, GCM, and Van’t-JA equations. The oriented root-mean-square deviation (ORMSD) values for all models remain below 0.22%, indicating a good fitting effect. X-ray diffraction (XRD) showed no crystal transition in UCZ during dissolution. The dissolution behavior was analyzed using Hansen solubility parameters (HSPs). The KAT-LSER model showed that the solvent–solvent interaction affects the solubility of UCZ more than the solute–solvent interaction.