Biphenyl with n-Heptane (IUPAC SDS Volume 58)
Evaluator
William E. Acree, Jr. Department of Chemistry University of North Texas
Evaluation
Biphenyl solubilities in n-heptane were retrieved from papers by Warner et al. (1), Acree et al. (2), Acree (3), Chang (4), and Lissi and Abuin (5). The first study reportes observed values at several temperatures, Acree et al. determined values at 303, 308 and 313 K, and the latter three studies give the mole fraction solubility at either 298 K or 293 K. The value of Lissi was excluded from the critical evaluation since the n-heptane solvent was saturated with water, rather than a dried solvent.
Regressional analysis of the experimental data as Ln x1 versus 1/T yielded the following mathematical relationship:
Ln x1 = - 5153.7 (1/T) + 15.229 (r = 0.9982)
for variation of biphenyl solubility with absolute temperature (see graph below). Back-calculated solubility at 298 K is x1 = 0.1279, and differs by about 8 - 10% from experimental values of x1 = 0.1381 (3) and x1 = 0.138 (4).
Figure
Solubility graph
Sources:

1 Warner, J. C.; Scheib, R. C.; Svirbely, W. J.; J. Chem. Phys. 1934, 2, 590-594.
2 Acree Jr., W. E.; Pontikos, N. M.; Judy, C. L.; Int. J. Pharm. 1986, 31, 225-230.
3 Acree Jr., W. E.; Int. J. Pharm. 1984, 18, 47-52.
4 Chang, W.; Ph.D Dissertation, North Dakota State University, ND, 1969.
5 Lissi, E. A.; Abuin, E. B.; Bol. Soc. Chil. Quim. 1981, 26, 19-34.