Properties of Perfluorobenzene near the Critical Point

The density of vapor and liquid perfluorobenzene along the liquid–vapor coexistence curve has been studied by a gamma-ray attenuation technique over the temperature range from 299 to 517 K. According to measurements, the coordinates of the critical point are T_C = 516.66 ± 0.05 K and ρ _C = 550.5 ± 2 kg · m⁻³. The critical exponent β of the coexistence curve equals 0.343 ± 0.005, which agrees closely with the non-classical value. The results of our measurements were compared with data available in the literature. The height dependence of the density of a two-phase sample was investigated in relation to the temperature and time. These experiments made it possible to determine the isothermal compressibility of liquid and vapor phases near the critical point.Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5–8, 2005, Bratislava, Slovak Republic.