The concentration dependences of excess enthalpies were measured in an isothermal calorimeter within the range of 25-50 °C at six temperatures for the binary systems 1-butanol-cyclohexane and 2-butanol-cyclohexane and at five temperatures for the system 2-methyl-2-propanol-cyclohexane. A conspicuous temperature and concentration dependence of the maximum value of enthalpy of mixing was found for the latter system. Heats of mixing of all three systems were correlated by the SSF equation. The results of correlation are comparable with the experimental error (0.5%) in the entire range of mole fractions of alcohols.

Three models of continuously associated solution complemented by an assumption of polynomial temperature dependence of corresponding interaction parameters were used for simultaneous description of the concentration and temperature dependence of heats of mixing of 1-butanol, 2-butanol and 2-methyl-2-propanol with cyclohexane. Very good results were reached for the first two systems where the Liebermann and Wilhelm model has proved to be the most suitable. With respect to the probable existence of cyclic associates in solutions of 2-methyl-2-propanol, none of the used models which assume only linear association satisfied to the extent required.

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