Preferential Solvation of Boscalid in Ethanol/Isopropanol + Ethyl Acetate Mixtures from the Inverse Kirkwood–Buff Integrals Method

Abstract

The preferential solvation parameters (δx 1,3) of Boscalid in solvent mixtures of ethanol (1) + ethyl acetate (2), and isopropanol (1) + ethyl acetate (2) were derived from their available solubility data by means of the inverse Kirkwood–Buff integrals method. The values of δx 1,3 vary non-linearly with the solvent (1) proportion in the two solvent mixtures. For the ethanol (1) + ethyl acetate (2) system, the values of δx 1,3 are negative in ethanol-rich and ethyl acetate-rich mixtures, but positive in intermediate compositions; for the isopropanol (1) + ethyl acetate (2) system, the values of δx 1,3 are positive in ethyl acetate-rich mixtures and in intermediate compositions, but negative in isopropanol-rich mixtures. The δx 1,3 values are positive indicating that Boscalid is preferentially solvated by ethyl acetate. The magnitude of the preferential solvation of Boscalid by ethyl acetate is higher in isopropanol (1) + ethyl acetate (2) mixtures than in ethanol (1) + ethyl acetate (2) mixtures at 298.15, 308.15 and 313.15 K. The ethyl acetate action may be related to the disordered structure of ethanol or isopropanol molecules around the polar moieties of Boscalid, which increases the solvation, with maximum values near x 1 = 0.40–0.45 for the two solvent mixtures.