Liquid-Liquid Phase Equilibria and Critical Phenomena of the Binary Mixture Nitrobenzene plus n-Nonane

The liquid-liquid coexistence curve for nitrobenzene + n-nonane has been measured in a wide temperature range. The values of the critical exponent beta obtained from the liquid liquid equilibrium data in the critical region were found to be in good agreement with that of the 3D Ising universality. The monotonous crossover behavior from Ising criticality to mean-field one was observed. The isobaric heat capacities per unit volume were measured, with which the asymmetric behavior of the diameter of the coexistence curve was well-described by the complete scaling theory. Moreover, the turbidity data near the critical point were obtained to deduce the critical amplitudes of the correlation length and the osmotic compressibility, which together with the amplitudes related to the coexistence curve and the heat capacity were used to calculate the universal scaling ratios and to confirm their theoretical predictions.