A gravimetric method was used to determine the solubility of azoxystrobin in seven monosolvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and ethyl acetate) and two binary mixed solvents (n-propanol + ethyl acetate and methanol + ethyl acetate) at different temperatures from 288.15 to 328.15 K. The solubility of azoxystrobin is positively related with temperature in all selected solvents. Moreover, the solubility of azoxystrobin in methanol + ethyl acetate binary mixed solvent reaches a maximum when the mole fraction of ethyl acetate is 0.8, differing from that in n-propanol + ethyl acetate binary mixed solvent. The Apelblat, λh, combined nearly ideal binary solvent/ Redlich−Kister, and nonrandom two-liquid model (NRTL) equations were applied to correlate the solubility of azoxystrobin, and all of the equations provided good fitting results to the data. In addition, the mixing thermodynamic properties of azoxystrobin in binary mixed solvents were calculated based on the NRTL equation. The results demonstrate that the mixing process in the experimental binary mixed solvents is endothermic and spontaneous.

The solubility of dipyridamole p-toluene sulfonate in seven monosolvents (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol, 2-butanol) and three different binary solvents (methanol + ethanol, methanol + 1-propanol, methanol + 1-butanol) was measured by a gravimetric method at temperatures ranging from 288.15 to 328.15 K. The experimental results indicate that the solubility of dipyridamole p-toluene sulfonate increases with increasing temperature while showing negative correlation with the mole fraction of organic solvents (ethanol, 1-propanol, 1-butanol) at a given temperature in binary solvents. The Apelblat model, the CNIBS/R-K model, and the modified version of Jouyban-Acree models (the Apel-JA equation) were used to correlate the experimental data, and the calculated results of above models were found to agree well with the experimental data.