Naphthalene solubilities in 1-propanol were retrieved from papers by Sunier (1), Speyers (2) and Dickhut et al. (3). The first two studies report observed values at several temperatures, whereas Dickhut et al. determined only a single mole fraction solubility at 298 K. There is not a prior reason to exclude any of the three studies from the critical evaluation.
Regressional analysis of the experimental data as Ln x₁ versus 1/T yielded the following mathematical relationship: Ln x₁ = - 4803.1 (1/T) + 13.193 (r=0.9694) 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 1-propanol.