Solubility measurement and data correlation of 3-ethoxysalicylaldehyde in twelve pure solvents at temperatures from 278.15 to 313.15 K

Abstract

The solubility of 3-ethoxysalicylaldehyde in twelve pure solvents (water, methanol, ethanol, n-propanol, n-butanol, iso-propyl alcohol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, acetonitrile, and acetone) was determined by an isothermal saturation method over the temperatures ranging from 278.15 to 313.15 K at 101.6 ± 1.2 kPa. The solubility of 3-ethoxysalicylaldehyde in all studied solvents increases with the increase in temperature. The mole fraction solubility of 3-ethoxysalicylaldehyde is observed highest in acetone (0.6053 at 313.15 K), followed by methyl acetate, ethyl acetate (acetonitrile), propyl acetate, butyl acetate, methanol, ethanol, n-propanol, n-butanol, iso-propyl alcohol, and water. Three solubility fitting models were used to correlate the experimental mole solubility data, including the van’t Hoff model, modified Apelblat model, and λh model. The three models showed good fitting results, with the average RAD less than 5%. The thermodynamic properties of 3-ethoxysalicylaldehyde, including apparent standard dissolution enthalpy (ΔHsol), standard dissolution Gibbs energy (ΔGsol), and standard dissolution entropy change (ΔSsol), were calculated via the van’t Hoff equation. The positive values of ΔHsol and ΔGsol indicate that the dissolution process of 3-ethoxysalicylaldehyde is endothermic. The studied solubility data and the relevant thermodynamic analysis have an important guiding significance for the design and optimization of the crystallization process of 3-ethoxysalicylaldehyde.