Critical Parameters and Critical-Region (p, ρ, T) Data of trans-1,1,1,3-Tetrafluorobut-2-ene [HFO-1354mzy(E)]

This study presents the experimental measurement of the pρT properties and critical parameters of a low GWP type refrigerant, trans-1,1,1,3-Tetrafluorobut-2-ene (HFO-1354mzy(E)). The sample purity of the substance was 99 area %. pρT property measurements and visual observations of the meniscus of HFO-1354mzy(E) were carried out using a metal-bellows volumometer with an optical cell. The critical temperature was determined by observation of the critical opalescence. The critical pressure and critical density were determined as the inflection point of the isothermal pρT property data at the critical temperature. For more precise clarification of the thermodynamic surface in the vicinity of the critical point, additional pρT property measurements were carried out on three isotherms in the supercritical region. The expanded uncertainties (k= 2) in the temperature, pressure, and density measurements were estimated to be less than 3 mK, 1.2 kPa, and 0.32 kg · m ^{- 3}, respectively. The expanded uncertainties of the critical parameters were estimated to be less than 13 mK, 1.4 kPa, and 2.3 kg · m ^{- 3}, respectively. These values are the first reported for HFO-1354mzy(E) and are necessary for the development of its equation of state in the near future.