The system nitromethane + 1-nonanol + naphthalene + water includes a four-phase region, although only four of six binary pairs of components, nitromethane + 1-nonanol, nitromethane + water, 1-nonanol + water and naphthalene + water are partially miscible. The data for this system were compiled and critically evaluated (Sazonov et al.,³ Barton,⁴ and Shaw⁵). The UCST (upper critical solution temperature) of the binary system nitromethane + 1-nonanol has been reported in Sazonov and Chernysheva¹ as 327.96 K which agrees with the recommended value in Sazonov et al.,³
The solubility temperatures of the liquid and solid phases were determined (Sazonov and Chernysheva¹) by the synthetic method in quaternary mixtures with constant mass content of naphthalene and water; in quaternary mixtures with a constant mass content of water and with a constant mass relationship of nitromethane and 1-nonanol, and also in quaternary mixtures with a constant relationship of (1), (2) and (3). Experimental errors were reported as ±0.02 K (288 K to 323 K) and ±0.1 K (above 323 K). Maximal temperature of the four-phase equilibrium was reported to be as 296.1 K (Sazonov and Chernysheva¹). Above 296.1 K exist three separate regions of three-phase state.

Compositions of coexisting liquid phases for the system nitromethane + 1-nonanol + naphthalene + water were determined (Sazonov and Chernysheva²) at 293.2 K, 296.2 K and 303.2 K by gas chromatography. Thus, the water-rich phase contains traces of alcohol and naphthalene, and the solid phase is pure naphthalene. Relative error of 3 to 5 determinations less than 1%.
All experimental data are considered tentative.