Naphthalene with Benzene (IUPAC SDS Volume 59)
Evaluator
William E. Acree, Jr. Department of Chemistry University of North Texas
Evaluation
Naphthalene solubilities in benzene were retrieved from papers by Choi et al. (1), McLaughlin and Zainal (2), Ward (3), Kravchenko (4), Acree et al. (5), Heric and Posey (6) and Chang (7). The first four studies report values at several temperatures, Acree et al. determined values at 303, 308 and 313 K, and both Heric and Posey and Chang measured the mole fraction solubility at the single temperature of 298 K. There is not a prior reason to exclude any of the six studies from the critical evaluation.
Regressional analysis of the experimental data as Ln x1 versus 1/T yielded the following mathematical relationship: Ln x1 = - 2301.9 (1/T) + 6.5066 (r=0.9996) for variation of naphthalene solubility with absolute temperature (see graph below). Back-calculated solubility at 298 K is x1 = 0.2974, and differs by less than 2% from experimental values of x1 = 0.2946 (6) and x1 = 0.292 (7).

Experimental data from papers by Ward and Kravchenko were used to construct the phase diagram shown below. Binary mixtures of naphthalene and benzene exhibit a simple eutectic system (see graph below).

Figures
Solubility graph
Solubility graph
Sources:

1 Choi, P. B.; Williams, C. P.; Buehring, K. G.; McLaughlin, E.; J. Chem. Eng. Data 1985, 30, 403-409.
2 McLaughlin, E.; Zainal, H. A.; J. Chem. Soc. 1959, 863-867.
3 Ward, H. L.; J. Phys. Chem. 1926, 30, 1316-1333.
4 Kravchenko, V. M.; Zh. Fiz. Khim. 1939, 13, 133-145.
5 Acree Jr., W. E.; Pontikos, N. M.; Judy, C. L.; Int. J. Pharm. 1986, 31, 225-230.
6 Heric, E. L.; Posey, C. D.; J. Chem. Eng. Data 1964, 9, 35-43.
7 Chang, W.; Ph.D Dissertation, North Dakota State University, ND, 1969.