Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Isobaric thermal expansivity for a set of nonpolar compounds is determined in the temperature and pressure intervals of (278.15 to 348.15) K and (0.6 to 55) MPa using a calorimetric method. The selected compounds are benzene, tetrachloromethane, and the alkane series, from nonane to pentadecane. These results are compared with literature data, with most of them obtained from density measurements. Temperature behavior is revealed to be highly dependent on the experimental pressure; at low pressure, isobaric thermal expansivity clearly increases with temperature. This dependence becomes milder as pressure is raised, and for some liquids at high pressure, it is undoubtedly observed that ?p decreases against T. These results are rationalized by relating them with phase transition properties, concretely, vapor pressure and critical coordinates. Finally, well-known thermodynamic relations are used to obtain density and isobaric molar heat capacity as a function of temperature and pressure from isobaric thermal expansivity, density, and heat capacity at atmospheric pressure. The results thus obtained were compared with directly measured data.