Determination and correlation of solubility of 4,4′-difluorobenzophenone in pure and binary mixed solvents and thermodynamic properties of solution

The target of this study was to determine and correlate the solubility of 4,4′-difluorobenzophenone in various solvents from 293.15 K to 333.15 K by gravimetric method at 0.1 MPa, and at the same time got the thermodynamic parameters. In this work, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethyl acetate, methyl acetate, acetone, acetonitrile pure solvents and ethanol + n-propanol mixed solvents were selected as the experimental solvents. The results showed that the solubility of 4,4′-difluorobenzophenone in selected solvents increased with increasing temperature within the investigated temperature range. The effect of solvent properties on 4,4′-difluorobenzophenone solubility behaviors was discussed by solvent polarity, hydrogen bonding donor and acceptor propensity, and cohesive energy density. Furthermore, the dissolution behavior was explained using the Hansen solubility parameter (HSP). In pure solvents, the modified Apelblat equation, van't Hoff equation, λh equation, nonrandom two-liquid (NRTL) equation, Wilson equation and universal quasichemical (UNIQUAC) equation were used to correlate the experimental solubility of 4,4′-difluorobenzophenone. While the solubility in ethanol + n-propanol mixed solvents was correlated by the modified Apelblat equation, van't Hoff equation, λh equation, NRTL model, Wilson model, Jouyban-Acree and the modified Jouyban-Acree model. The results indicated that the calculated values of all selected equations were in good agreement with the experimental data. Furthermore, the thermodynamic properties (∆H°sol, ∆S°sol, ∆G°sol, %ξH and %ξTS) were measured by Van't Hoff analysis. In a word, the physicochemical data of 4,4′-difluorobenzophenone obtained in this work will be helpful for the purification, crystallization, recrystallization and designing a new synthetic route of 4,4′-difluorobenzophenone.