Experimental determination of the critical loci for R-23+(n-propane or n-hexane) and R-116+n-propane binary mixtures

Abstract

Isothermal VLE for the R-23 + n-propane system was measured using a static-analytic apparatus at temperatures between T = (293.18 and 353.15) K. The critical loci for the systems R-23 + (n-propane or n-hexane) and R-116 + n-propane were measured using a critical point determination apparatus. The method of Ungerer et al. was used to extrapolate the isothermal VLE data to the isothermal critical locus. These extrapolated critical loci were compared with experimental data. The Redlich-Kister type correlations were used to correlate the critical loci of the systems. A critical locus curve for the R-23 + n-hexane system which was calculated by the method of Heidemann and Khalil was compared with the experimental critical loci. The systems were classified according to the van Konynenburg and Scott classification system.

Modeling of Trifluoromethane (R-23) or Hexafluoroethane (R-116) and Alkane Binary Mixtures using the Group-Contribution with Association Equation of State

“…The attractive energy parameters for the pure components were fitted for both R-23 and R-116 by using experimental pure component vapor pressures from literature. ,− Both the pure group parameters fitted to these vapor pressure data and those obtained from literature are presented in Table .…”

“…In recent years, investigations into the performance of supercritical fluorinated refrigerants as solvents for the separation of oil sludges were undertaken, − chiefly through measuring the phase equilibrium data for binary systems. Supercritical fluid extraction (SCFE) using fluorinated refrigerants, rather than the more commonly used carbon dioxide, was investigated by Williams-Wynn et al ,, In general, the addition of a cosolvent, such as ethanol, to supercritical carbon dioxide improves the performance of the extraction. , However, the addition of a cosolvent complicates the solvent recovery process and adds additional purification steps.…”

“…The aim of using alternative fluorinated solvents was to prevent the need for the addition of a cosolvent to enhance the solubilities for the SCFE. Trifluoromethane (R-23) and hexafluoroethane (R-116) were the two SCFE solvents proposed for use in the supercritical extraction of hydrocarbon mixtures . The chief reasons behind their proposal of these fluorinated compounds are their favorable critical properties and, in the case of R-23, the convenient dipole moment given by its asymmetric structure.…”

Experimental measurements and modelling of vapour-liquid equilibrium of 2,3,3,3-tetrafluoropropene (R-1234yf) + 1,1,1,2,2-pentafluoropropane (R-245cb) system

“…Flow diagram of the "static-analytic" apparatus[18][19][20][21].EC: equilibrium cell; LV: loading valve; MS: magnetic stirrer; PP: platinum resistance thermometer probe; PT: pressure transducer; RT: temperature regulator; LB: liquid bath; TP: thermal press; C1: more volatile compound; C2: less volatile compound; V: valve; GC: gas chromatograph; LS: liquid sampler; VS: vapor sampler; SC: sample controlling; PC: personal computer; VP: vacuum pump. the phases present within the cell are analysed with a gas chromatograph (PERICHROM, model PR2100) equipped with a thermal conductivity detector (TCD).…”