Solid-liquid equilibrium and phase diagram for the ternary (2-naphthaldehyde + o-phthalic anhydride + 1,4-dioxane) system

• Solubility for 2-naphthaldehyde + o-phthalic anhydride + 1,4-dioxane were measured.
• Three isothermal phase diagrams were plotted based on solubility data.
• Experimental solubility data were correlated by NRTL and Wilson models.

In this research, solid-liquid equilibrium for the ternary system (2-naphthaldehyde + o-phthalic anhydride + 1,4-dioxane) was measured at 283.15 K, 293.15 K and 303.15 K, respectively. Three isothermal phase diagrams of the system were plotted using the values of the experimental solubility. Pure 2-naphthaldehyde and o-phthalic anhydride were formed at (283.15, 293.15 and 303.15) K, and were determined by Schreinemaker’s wet residue method. The crystallization region of o-phthalic anhydride was found to be much larger than that of 2-naphthaldehyde at a certain temperature. The experimental solubility at multiple temperatures was correlated by the NRTL and Wilson models. The NRTL model was more accurate than the Wilson model in this system. The diagram of density versus component was also constructed.