Solubility Measurement and Hansen Solubility Parameter of Forchlorfenuron in 12 Organic Pure Solvents at Various Temperatures

In this work, the solubility of forchlorfenuron [N-(2-chloro-4-pyridinyl)-N′-phenylurea (CPPU)] in 12 selected pure solvents (n-pentanol, n-butanol, n-propanol, ethanol, methanol, ethyl acetate, n-propyl acetate, n-butyl acetate, i-propyl acetate, i-butyl acetate, i-amyl acetate, and acetone) was determined under the conditions of 0.1 MPa and 278.15–323.15 K using the laser detection method. The results indicate that the solubility of CPPU in the selected solvents is proportional to temperature. Five models (Two-Suffix Margules, NRTL, λh, Universal Quasi-Chemical, and the modified Apelblat) were selected to fit the solubility data of CPPU in pure solvents. By comparison, it is found that the modified Apelblat model has a better fitting effect. The solubility rules of CPPU in different solvents were analyzed using Hansen solubility parameters and polarity. The solvent effect of CPPU solubility in different solvents studied was discussed using the KAT-LSER model. The above studies can supply some primary data for the crystallization process of CPPU.