Measurements of Density and Heat Capacity for Binary Mixtures {x Benzonitrile + (1 −x) (Octane or Nonane)}

Abstract

Densities and isobaric heat capacities per unit volume have been measured for binary mixtures {x benzonitrile + (1 − x) octane} and {x benzonitrile + (1 − x) nonane} in the temperature ranges of (283.15 to 318.15) K and (283.15 to 313.15) K, respectively. Measurements covered the whole composition range at the ambient pressure. From these measured data, the excess molar volumes, excess isobaric thermal expansivities, and excess isobaric molar heat capacities were calculated and fitted with the Redlich−Kister equation. The excess molar volumes, excess isobaric thermal expansivities, and excess isobaric molar heat capacities of both systems were found to exhibit the S-shaped curves against the composition and the feature of the nonrandomness mixing. The dependences of these properties on the temperature and composition were analyzed and discussed in terms of the natures of the two pure components and the molecular interactions in the mixtures.