Measurement and Correlation of the Solubilities of Azoxystrobin, Flutriafol, and Tebuconazole in Subcritical 1,1,1,2-Tetrafluoroethane

The equilibrium solubilities of azoxystrobin, flutriafol, and tebuconazole in subcritical 1,1,1,2-tetrafluoroethane (R134a) were measured using a static method. After tests to confirm the reliability of the experimental apparatus were carried out and the reliability was confirmed, measurements of the solubilities of the three fungicides were implemented at temperatures of 298.15, 313.15, and 333.15 K over the pressure range of 6.0–16.0 MPa. The results indicated that the solubilities increased with increasing pressure under isothermal conditions and increased with increasing temperature at a fixed pressure. To generalize the experimental results, five semiempirical density-based models were employed to correlate the solubility data, including the Chrastil, Kumar and Johnston (K–J), Mendez-Santiago and Teja (M–S–T), Sung and Shim (S–S), and Adachi and Lu (A–L). The measured data showed reasonable agreement with the calculated results from models, for which the average absolute deviation (AARD) in the solubility correlation is from 0.0924 to 4.06%. Additionally, naphthalene has the effect of promoting dissolution as a cosolute in the process of determining the solubilities of fungicides by shorting the equilibrium time.