Dipole moment and heat capacity in the ideal gas state derived from relative permittivity and speed of sound measurements for HFO-1123 and HCFO-1224yd(Z)

Abstract

Abstract The dielectric relative permittivity and speed of sound were simultaneously measured for HFO-1123 and HCFO-1224yd(Z) in the gas phase by using a cylindrical acoustic-electromagnetic cavity resonator. The measurement data for HFO-1123 were obtained in the temperature range of 263 to 333 K and the pressure range of 50 to 520 kPa, and those for HCFO-1224yd(Z) were obtained in the temperature range of 303 to 353 K and the pressure range of 20 to 200 kPa. Both of the fractional standard uncertainties for the relative permittivity and speed of sound measurements were estimated to be typically smaller than 0.02% without taking the sample impurities into account. The dipole moment and density were derived from the relative permittivity data through the dielectric virial equation. Meanwhile, the isobaric heat capacity in the ideal gas state were also derived from the speed of sound data with the acoustic virial equation. The temperature correlations for the ideal gas heat capacities were formulated and compared with the estimated values by the atomic-group contribution methods. It was found from the comparison that the estimated ideal gas heat capacities differed from the present data by more than 2%.