Naphthalene with Methanol (IUPAC SDS Volume 59)
Evaluator
William E. Acree, Jr. Department of Chemistry University of North Texas
Evaluation
Naphthalene solubilities in methanol were retrieved from papers by Ward (1), Sunier (2), Speyers (3), Dickhut et al. (4) and pinal et al. (5). The first three studies report values at several temperatures, whereas Dickhut et al. and Pinal et al. measured only the mole fraction solubility at a single temperature of 298 K and 296 K, respectively. There is not a prior reason to exclude any of the five studies from the critical evaluation.
Regressional analysis of the experimental data as Ln x1 versus 1/T yielded the following mathematical relationship: Ln x1 = - 5574.0 (1/T) + 14.998 (r=0.9280) for variation of naphthalene solubility with absolute temperature (see graph below). Nonlinear behavior indicates a nonconstant enthalphy of solution, probably caused by self-associating hydrogen-bonding character of methanol.
Figure
Solubility graph
Sources:

1 Ward, H. L.; J. Phys. Chem. 1926, 30, 1316-1333.
2 Sunier, A. A.; J. Phys. Chem. 1930, 34, 2582-2597.
3 Speyers, C. L.; Am. J. Sci. 1902, 14, 293-302.
4 Dickhut, R. M.; Andren, A. W.; Armstrong, D. E.; J. Chem. Eng. Data 1989, 34, 438-443.
5 Pinal, R.; Rao, P. S. C.; Lee, L. S.; Cline, P. V.; Yalkowsky, S. H.; Environ. Sci. Technol. 1990, 24, 639-647.