Solubility Measurement and Data Correlation of Topramezone in 16 Pure Solvents at Temperatures from 283.15 to 323.15 K

The solubility of herbicide topramezone (TOP) in 16 pure solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, acetone, acetonitrile, acetonitrile, tetrahydrofuran, and toluene) was measured by the gravimetric method over temperatures ranging from 283.15 to 323.15 K at 0.1 MPa. With an increase in temperature, the solubility of TOP also increased in all solvents. Isopropanol exhibited the lowest solubility at 283.15 K, whereas tetrahydrofuran showed the highest solubility at 323.15 K. The solvent effects, including polarity, hydrogen bond donor propensity, hydrogen bond acceptor propensity, and cohesive energy density, were used to analyze the solubility of TOP in various solvents. For the effect of solvent type on solubility, hydrogen bond donation is dominant in alcoholic solvents, whereas hydrogen bond acceptors are dominant in nonalcoholic solvents. The experimental solubility data were correlated with four models, namely, the modified Apelblat equation, λh equation, van’t Hoff equation, and NRTL equation, with a relative deviation of less than 5%. Furthermore, mixing thermodynamic properties of TOP in selected solvents were calculated by the NRTL model, which showed that the mixing process was spontaneous and entropy driven.