Partial molar enthalpies for the binary systems 2-methylfuran/p-dioxane and maleic anhydride/p-dioxane were measured via titration, isoperibol calorimetry at 318.15 K. The behavior of both binaries was correlated within experimental uncertainty with a three-parameter version of the Gmehling equation of state. Two-parameter models could successfully correlate the 2-methylfuran/p-dioxane binary but not the maleic anhydride/p-dioxane binary. © 1987 American Chemical Society.