Excess enthalpies of 2,2-dimethylbutane plus cyclohexane plus (octane or dodecane) at 25 degrees C

Measurements of excess molar enthalpies at 25 degrees C in a flow microcalo rimeter, are reported for the two ternary mixtures 2,2-dimethylbutane + cyc lohexane + n-octane and 2,2-dimethylbutane + cyclohexane + n-dodecane. Smoo th representations of the results are described and used to construct const ant enthalpy contours on Roozeboom diagrams. It is shown that useful estima tes of the ternary enthalpies can be obtained from the Flory theory using o nly the physical properties of the components and their binary mixtures.