Experimental determination and thermodynamic modeling of solid–liquid-phase equilibrium for the 3-nitrotoluene and 4-nitrotoluene binary system

Solid–liquid-phase equilibrium is an important part of chemical thermodynamics, and its basic theoretical research plays a vital role in the advancement of the chemical industry. Solid–liquid equilibria for binary mixtures of 3-nitrotoluene and 4-nitrotoluene were measured using differential scanning calorimetry under atmospheric pressure (101.3 kPa). The results showed that the phase diagram of the 3-nitrotoluene + 4-nitrotoluene binary system presented a eutectic behavior, and the eutectic point was x 1  = 0.6487, T E  = 272.15 K. Furthermore, the experimental results were correlated with Wilson and nonrandom two-liquid (NRTL) activity coefficient models well. The relative standard deviations were 0.496 and 0.236, respectively, and the absolute mean deviations were 0.005 and 0.001, respectively.