Measurement of Solid–Liquid Phase Equilibrium for the Ternary 3-Nitrophthalic Anhydride + 4-Nitrophthalic Anhydride + 1,4-Dioxane System

Abstract

In this work, solid–liquid equilibria (SLE) data for the ternary 3-nitrophthalic anhydride + 4-nitrophthalic anhydride + 1,4-dioxane system were obtained at (283.15, 303.15, and 323.15) K. The solid–liquid phase diagrams of the ternary system were constructed based on the measured solubility data. There existed two pure solid phases at each temperature in the studied system, pure 3-nitrophthalic anhydride and 4-nitrophthalic anhydride, which were identified by the wet residue method of Schreinemaker. Furthermore, the density (ρ) of the equilibrium liquid phase was determined. The ternary phase diagram and solubility data for the system 3-nitrophthalic anhydride + 4-nitrophthalic anhydride + 1,4-dioxane, which shows a much more practical application for the region where pure 3-nitrophthalic anhydride and 4-nitrophthalic anhydride are obtained, are much larger than those in the system with 2-propanone as a solvent.