Solid-liquid phase equilibrium and thermodynamic functions: 2-Nitrobenzaldehyde in different neat solvents and ternary system of 2-nitrobenzaldehyde + 4-nitrobenzaldehyde + ethyl acetate

Abstract

Equilibrium solubility data were determined for binary systems of 2-nitrobenzaldehyde in ethanol, isopropanol, n-butanol, n-butyl acetate, acetone, ethyl acetate, toluene, cyclohexane, n-propanol and for ternary system of 2-nitrobenzaldehyde+4-nitrobenzaldehyde+ethyl acetate by the static method under atmospheric pressure of 101.1kPa. The binary systems were measured at T=278.15, 280.65, 283.15, 285.65, 288.15, 290.65, 293.15, 295.65 and 298.15K, and the ternary system were determined at the three temperatures of 278.15K, 288.15K and 298.15K. The solubility of 2-nitrobenzaldehyde in neat solvents increased with increasing temperature, and obeyed the following order from high to low in the selected solvents: acetone>ethyl acetate>n-butyl acetate>toluene>ethanol>n-propanol>n-butanol>isopropanol>cyclohexane. Three isothermal phase diagrams were constructed according to the ternary solubility data. Each ternary phase diagram included one invariant point, two boundary curves, and two crystalline regions which corresponded to pure 2-nitrobenzaldehyde and pure 4-nitrobenzaldehyde confirmed by Schreinemaker's method of wet residue. The crystallization region of 2-nitrobenzaldehyde is smaller than that of 4-nitrobenzaldehyde at each temperature. Two thermodynamic models, NRTL model and Wilson model were employed to correlate the experiment data. The maximum root mean square deviation was 36.41×10−3; and the relative average deviation, 4.06×10−2. Furthermore, the mixing properties were derived for 2-nitrobenzaldehyde in neat solvents.