Temperature dependence of the excess volumes of binary mixtures containing cyclohexane plus some higher n-alkanes

Excess molar volumes, V-E, for three binary liquid mixtures of cyclohexane + n-dodecane, n-tetradecane, and n-hexadecane were determined from density measurements at seven different temperatures in the range from 283.15 to 313.15 K and atmospheric pressure, over the entire range of mole fractions. The V-E values were derived and the results show a regular negative pattern of behaviour for each of the three sets of the binary system. For cyclohexane, the magnitude of V-E increases with the alkane chain length. The Prigogine-Flory-Patterson theory was applied to analyze the experimental behaviour by calculating three different contributions to V-E, i.e., interactional, free volume, and internal pressure. The theory gives a representation of the main feature of the systems studied by using a fitted parameter to describe the behaviour throughout the composition range.