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

ABSTRACT

For {xCl(CH2)6Cl + (1 - x) n-C7H16}, densities ? were measured with a vibrating-tube densimeter at (293.15, 298.15, 303.15, 308.15, and 313.15) K, covering the whole composition range. From the densities the corresponding isobaric expansivities ap and the excess molar volumes VE were calculated. At the same temperatures, the molar heat capacities at constant pressure Cp were also measured over the whole composition range using a differential scanning calorimeter (DSC III from Setaram), and excess molar heat capacities at constant pressure CpE were calculated therefrom. In addition, ultrasound speeds u were determined with a pulse-echo-overlap apparatus. From these results, isentropic compressibilities ?S, isothermal compressibilities ?T, molar heat capacities at constant volume CV, and internal pressures ? were obtained for this system at all five temperatures. The VE are negative throughout; they are somewhat skewed with minima around x = 0.6, and they become less negative with decreasing temperature. The CpE are all negative and strongly asymmetric with minima around x = 0.3 and rather broad shoulders at larger mole fractions of 1,6-dichlorohexane. With decreasing temperature, the CpE(x) curves become less negative with more pronounced shoulders, which behavior is reminiscent of the onset of a W-shaped composition dependence.