Critical Parameters and Saturated Densities in the Critical Region for trans-1,3,3,3-Tetrafluoropropene (HFO-1234ze(E))

Abstract

Measurements of the saturated vapor and liquid densities near the critical point for trans-1,3,3,3-tetrafluoropropene (CFH═CHCF3; HFO-1234ze(E)) were carried out in the reduced temperature range of 0.962 < T/Tc < 1 and in the reduced density range of 0.40 < ρ/ρc < 1.70. Taking into consideration the meniscus disappearing level as well as the intensity of the critical opalescence, the critical temperature Tc and critical density ρc were determined experimentally. The critical pressure Pc was calculated by extrapolating the vapor-pressure equation to the critical temperature. The critical parameters reported in this paper are Tc = (382.51 ± 0.01) K, ρc = (486 ± 3) kg·m−3, Vc = (235 ± 2) cm3·mol−1, and Pc = (3632 ± 3) kPa. The saturated liquid density correlation is formulated using the present data. In addition, the critical exponent β along the coexistence curve was also discussed.