3,5-Dibromo-4-hydroxybenzaldehyde dissolved in aqueous solutions of ethanol, n-propanol, acetonitrile and N,N-dimethylformamide: Solubility modelling, solvent effect and preferential solvation investigation

Abstract Equilibrium solubility of 3,5-dibromo-4-hydroxybenzaldehyde in four aqueous solutions of ethanol/n-propanol/acetonitrile/N,N-dimethylformamide (DMF) was determined at temperatures covering from 278.15 K to 323.15 K. All determinations were carried out by the well-known saturation shake-flask method under atmospheric pressure of 101.2 kPa. The maximum values of solubility data appeared in neat ethanol/n-propanol/acetonitrile/DMF for each solution. By Jouyban-Acree model, Apelblat-Jouyban-Acree model and van’t Hoff-Jouyban-Acree model, the 3,5-dibromo-4-hydroxybenzaldehyde solubility was well mathematically described obtaining RAD values smaller than 3.71 % and RMSD values smaller than 2.27×10-4. The Kamlet and Taft linear solvation energy relationships were employed to examine the chief factors describing solvent effect. The cavity formation energy of solvents played a significant role on the solubility variation of 3,5-dibromo-4-hydroxybenzaldehyde in different aqueous solutions. The local mole fractions of ethanol/n-propanol/acetonitrile/DMF and water molecules around the 3,5-dibromo-4-hydroxybenzaldehyde molecule were quantitatively studied via the Inverse Kirkwood–Buff integrals way used to the solubility values. 3,5-Bibromo-4-hydroxybenzaldehyde was preferentially solvated by water in water-rich compositions for the ethanol/n-propanol/acetonitrile/DMF + water mixtures; while within co-solvent-rich and intermediate compositions, 3,5-dibromo-4-hydroxybenzaldehyde was preferentially solvated by ethanol/n-propanol/acetonitrile/DMF.