Density of 1,1-dichloro-1-fluoroethane (HCFC 141b) as a function of temperature and pressure

The density of HCFC 141b has been measured at several temperatures between 260 and 320 K, Mid pressures up to 20 MPa, with a mechanical oscillator densimeter. The densimeter was calibrated with 2,2,4-trimethylpentane, whose density was obtained from a correlating cyuation with 0.3% uncertainty. The density data obtained for HCFC 14H) hits a reproducibility of 0.05% and an uncertainty of 0.3%. The data obtained were fitted to a Tait-type equation. which reproduced the experimental densities within 0.11 % and were compared with the data obtained in other works.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Thermal conductivity of alternative refrigerants in the liquid phase

Measurements ofthe thermal conductivity of five alternative refrigerants. namely, difluoromethane HFC-321. pentafluoroethane (HFC-125), 1,1,1-trifluoroethane (HFC-143a), and dichloropentafluoropropanes (HCFC-225ca and HCFC-225cb). are carried out in the liquid phase, The range of temperature is 253–324 K for HFC-32, 257–305 K for HFC-125, 268–314 K for HFC-134a. 267–325 K for HCFC-225ca, and 286–345 K for HCFC-225cb, The pressure rank is from saturation to 30 MPa, The reproducibility of the data is better than 0.5% and the accuracy of the data is estimated to be of the order of 1%. The experimental results for the thermal conductivity ofeach substance are correlated by an equation which is a function of temperature and pressure. A short discussion is given to the comparison of the present results with literature values for HFC-125, The saturated liquid thermal conductivity values of HFC-32. HFC-125, and HFC-143a are compared with those of chlorodifluoromethane (HCFC-22) and tetrafluoroethane (HFC-134a) and it is shown that the value of HFC-32 is highest, while that of HFC-125 is lowest, among these substances, The dependence of thermal conductivity on number of fluorine atoms among the refrigerants with the same number of carbon and hydrogen atoms is discussed.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994. Boulder, Colorado. U.S.A.     

The density of 1,1-dichloro-1-fluoroethane (HCFC 141b)

In this Note we present the density of HCFC 141b, measured between 293.15 and 300.15 K, with an mechanical oscillator densimeter, with an uncertainty of 0.007%. The results are compared with the densities estimated by the reduced hard-sphere-DeSantis equation of state and with the experimental data obtained by several authors.     

Saturated liquid densities and bubble-point pressures of the binary HFC 152a+HCFC 142b system

Forty-eight sets of the saturated liquid densities and bubble-point pressures of the binary HFC 152a + HCFC 142b system were measured with a magnetic densimeter coupled with a variable-volume cell. The measurements obtained at four compositions, 20, 40, 60, and 80 wt%, of HFC 152a cover a range of temperatures from 280 to 400 K. The experimental uncertainties in temperature, pressure, density, and composition were estimated to be within ±15mK, ±20kPa, ±0.2%, and between –0.14 and ±0.01 wt% HFC 152a (–0.01 and + 0.14 wt% HCFC 142b), respectively. The purities of the samples were 99.9 wt% for HFC 152a and 99.8 wt% for HCFC 142b. A binary interaction parameter, k _ij , in the Peng-Robinson equation of state was determined as a function of temperature for representing the bubble-point pressures. On the other hand, two constant binary-interaction parameters, k _ij and l _ij , were introduced into the mixing rule of the Hankinson-Brobst-Thomson equation for representing the saturated liquid densities.     

The dielectric constant of liquid HFC 134a and HCFC 142b

This paper presents measurements of the dielectric constant of HFC 134a and HCFC 1426, as a function of pressure and temperature, in the temperature range from 200 to 300 K and pressures up to 20 M Pa, using a direct capacitance method, The samples used had a stated purity of 99.8 and 99.9%, respectively, The values of the dielectric constant have a precision of 0.01 % and an accuracy of 0.1%, The data obtained were correlated as a function of density and pressure, The theory developed by Vedam et al,, based on the Eulerian strain. and the Kirkwood equation for the variation of modified molar polarization with temperature and density were applied to analyze the data and to obtain the dipole moment of both refrigerants in the liquid state.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

The thermal conductivity of CFC alternatives HFC-125 and HCFC-141b in the liquid phase

The liquid thermal conductivities of the CFC alternatives, HFC-125, and HCFC-141b measured by a transient hot-wire apparatus with one bare platinum wire are reported in the temperature ranges from 193 to 333 K (HFC-125, CHF₂, CF₃) and from 193 to 393 K (HCFC-141b,CCI₂F-CF₃), in the pressure ranges from 2 to 30 MPa (HFC-125) and from 0.1 to 30 MPa (HCFC-141b), respectively. The results have been estimated to have an accurancy of ±0.5%. The liquid thermal conductives obtained have been correlated by a polynomial of temperature and pressure which can represent the experimental results within the standard deviations of 0.49% for HFC-125 and 0.46% for HCFC-141b, respectively.     

Liquid viscosities and densities of HFC-134a+glycol mixtures

Liquid viscosity and density of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (400), and polypropylene glycol (2000)] have been measured in the temperature range from 273 to 333 K. The viscosity was measured by a rolling-ball viscometer calibrated with standard liquids of viscosities and densities (JS5, JS10, JS20, and JS50). The density was measured with a glass pycnometer. The uncertainties of the measurements were estimated to be less than 3.4 % for viscosity and 0.04 % for density, respectively. An equation is given to represent the obtained viscosity values as a function of weight fraction and temperature.     

Viscosity of Gaseous HCFC-123 (2,2-Dichloro-1,1,1-Trifluoroethane) in the Temperature Range from 323.15 to 423.15 K and at Pressures up to 2 MPa

The viscosity of gaseous HCFC-123 (2,2-dichloro-1,1,1-trifluoroethane) was measured with an oscillating-disk viscometer of the Maxwell type at temperatures from 323.15 to 423.15 K and at pressures up to the saturated vapor pressure at each temperature in subcritical conditions or up to 2 MPa under supercritical conditions.     

Measurements of the viscosities of saturated and compressed liquid normal butane and isobutane

The shear viscosity coefficients of saturated and compressed liquid normal butane and isobutane have been measured with the torsional piezoelectric crystal method at temperatures beween 115 and 300 K and at pressures to 30 MPa. The measurements have been correlated with a modified Hildebrand equation. The experimental error is estimated to be smaller than 3%. The measurements of normal butane and isobutane have been compared with a global extended corresponding states model and with each other. Differences between measured and calculated viscosities are discussed.     

The viscosities and densities of selected organic compounds and mixtures of interest in coal liquefaction studies

Experimental measurements are presented for the density and viscosity of selected organic compounds and mixtures at ambient pressure (0.083 MPa) and at temperatures of 298, 318, 338, and 358 K. The compounds studied were decalin, 1-methylnaphthalene, tetralin, m-xylene, tetrahydrofuran, thiophene, quinoline 2,6-lutidine, and m-cresol. Measurements were also made on three mixtures of the compounds decalin, 1-methylnaphthalene, tetralin, m-xylene, and m-cresol. The experimental results are compared with predictions made using a modified corresponding states procedure called TRAPP. The density predictions for the individual compounds and mixtures are good in all cases. For the viscosity, however, the predictions are in reasonable agreement with experiment only for nonassociating compounds and mixtures at reduced densities less than 3. These results suggest that TRAPP may prove very useful as a screening test to distinguish between nonassociating and highly associating mixtures. Such a test would be extremely useful when dealing with mixtures of unknown composition, such as coal liquids.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

The thermal conductivity of R22, R142b,R152a,and their mixtures in the liquid state

An experimental apparatus for measuring the thermal conductivity of liquids by the transient hot-wire method was constructed and tested with toluene as a standard liquid. Measurements were performed on R22, R142b, and R152a. The thermal conductivities of mixtures of R142b and R152a with R22 were also measured by varying the weight fraction of R22. Experiments were performed in the range from –50 to 50°C and from 2 to 20 MPa and the measured data are analyzed to obtain a correlation in terms of temperature, pressure, and composition of the mixture. While the thermal conductivity of R22 + R152a mixtures varies monotonously with composition, that of R22 + R142b mixtures turned out to go through an extremum value. The accuracy of our measurements is estimated to be within 2%.Paper dedicated to Professor Joseph Kestin.     

Thermal conductivity and viscosity of 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123)

The thermal conductivity and the viscosity data of CFC alternative refrigerant HCFC-123 (2,2-dichloro-1,1,1-trifluoroethane: CHCI₂-CF₃) were critically evaluated and correlated on the basis of a comprehensive literature survey. Using the residual transport-property concept, we have developed the three-dimensional surfaces of the thermal conductivity-temperature-density and the viscosity-temperature-density. A dilute-gas function and an excess function of simple form were established for each property. The critical enhancement contribution was taken no account because reliable crossover equations of state and the thermal conductivity data are still missing in the critical region. The correlation for the thermal conductivity is valid at temperatures from 253 to 373 K, pressures up to 30 MPa, and densities up to 1633 kg m^–3. The correlation for the viscosity is valid at temperatures from 253 to 423 K, pressures up to 20 MPa. and densities up to 1608 kg·m^–3. The uncertainties of the present correlations are estimated to be 50% for both properties, since the experimental data are still scarce and somewhat contradictory in the vapor phase at present.     

Viscosity and Surface Tension of Saturated Toluene from Surface Light Scattering (SLS)

It is demonstrated that dynamic light scattering (DLS) on a horizontal gas– liquid interface can be used for the reliable determination of surface tension and liquid kinematic viscosity. In contrast to the more usual approaches of surface light scattering (SLS) spectroscopy, a setup is used and described here which makes it possible to measure the capillary wave propagation characteristics in the forward scattering direction at variable wave numbers. The experiments in this work rely on a heterodyne detection scheme and signal analysis by photon correlation spectroscopy (PCS). Surface tension and liquid viscosity data of the important and, thus, well-documented reference fluid toluene have been measured under saturation conditions over a wide temperature range, from 263 to 383 K. These data demonstrate the excellent performance of the surface light scattering technique. The achievable accuracy of this technique is discussed in detail for both properties in connection with reference values available in the literature.     

Volumetric properties under pressure for 1,2-dichlorofluoroethane (R141), 1-fluoro-1,1,2-trichloroethane (R131a), and 1,2-dichloro-1,1-difluoroethane (R132b)

The effect of pressure on the volume of R141, R131, and R132b is reported as volume ratios (the volume under pressure relative to its value at atmospheric pressure) at six temperatures covering the range 278.15 to 338.13 K and pressures up to 380 MPa for R141 and R131a. For R132b the same temperature range has been used, but above its normal boiling point experimental arrangements have limited maximum pressures to below 300 MPa, with some loss of accuracy. Densities have been measured at atmospheric pressure for each liquid. The experimental data have been used to calculate isothermal compressibilities, thermal expansivities, and internal pressures: the change in isobaric heat capacity from its value at atmospheric pressure has also been estimated. The volume ratios for all three compounds can be represented by a version of the Tait equation based on previously reported data for 1,2-dicloroethane and 1,1,2-trichloroethane with the inclusion of allowances for the substitution in the former of chlorine or fluorine for the hydrogens on one of the carbons.     

Measurements of the viscosities of saturated and compressed fluid 1-chloro-1,2,2,2-tetrafluoroethane (R124) and pentafluoroethane (R125) at temperatures between 120 and 420 K

The shear viscosities of saturated and compressed fluid 1-chloro-l,2,2,2-tetrafluoroethane (R124) and pentafluoroethane (R125) have been measured with two torsional crystal viscometers at temperatures between 120 and 420 K and at pressures up to 50 MPa. At small molar volumes, the fluidity (reciprocal viscosity) increases linearly with molar volume at fixed temperature and weakly with temperature at fixed volume. We have described this behavior with simple empirical equations and have compared the data of Shankland and of Ripple with them. The data of Ripple are in good agreement with our data for both fluids.     

High-Pressure (up to 140 MPa) Dynamic Viscosity of the Methane+Decane System

The dynamic viscosity of n-decane and methane mixtures containing 31.24, 48.67, 60.00, 75.66 and 95.75% (mol%) of methane has been measured using a falling-body viscometer. The measurements (295 data points) have been performed in the temperature range 293.15 to 373.15 K and at pressures up to 140 MPa for viscosity. The data have been used to calculate the excess activation energy of viscous flow using a mixing law. Moreover, a self-referencing model, previously developed in the laboratory, gives an average absolute deviation of the viscosity of about 3% with a maximum deviation of 16%.     

Measurements of the viscosity of R11, R12, R141b,and R152a in the temperature range 270–340 K at pressures up to 20 MPa

This paper reports new measurements of the liquid viscosity of R11, R12, R1416, and R152a in the temperature range 270 to 340 K and pressures up to 20 MPa. The measurements have been carried out in a vibrating-wire instrument calibrated with respect to the standard reference value of the viscosity of water. It is estimated that the uncertainty of the present viscosity data is one of 0.5%. The experimental data have been represented by polynomial functions of temperature and pressure for the purposes of interpolation. A recently developed semiempirical scheme, based on considerations of hard-sphere theory, is employed to correlate successfully the viscosity and the thermal conductivity of these refrigerants as a function of their density.     

Viscosities of nonelectrolyte liquid mixtures. II. Binary and quaternary systems of some n-alkanes

This paper is the second in a series of viscosity and density studies on multicomponent mixtures of n-alkanes from 303 to 338 K. Reported here are the results of binary mixtures of n-tetracosane + n-octane as well as quaternary mixtures of n-tetracosane + n-octane + n-decane + n-hexane at 318.16, 328.16, and 338.16 K. Viscosities were determined using a standard U-tube Ostwald viscometer, and densities were determined using a flask-type pycnometer. Empirical relations tested include the Grunberg and Nissan equation and the method of corresponding states. In addition, comparisons were made regarding the behavior of this quaternary system and homologous binary mixtures of n-hexadecane + n-octane and n-tetracosane + n-octane at the same temperatures.     

High-Pressure (up to 140 MPa) Dynamic Viscosity of the Methane and Toluene System: Measurements and Comparative Study of Some Representative Models

The dynamic viscosity of toluene and methane mixtures containing 25.03, 37.19, 49.95, 64.11, and 95.00 mol% methane has been measured using a falling-body viscometer. The measurements (280 data points) have been performed in the temperature range 293.15 to 373.15 K and at pressures up to 140 MPa. The data have been discussed in the framework of recent representative models (hard-sphere scheme, friction theory, and free-volume model) as well as with simple mixing laws and empirical models (particularly the LBC model and the self-referencing model) used in the literature. This comparative study shows that the average absolute deviation of the models is between 4.9 and 26.8%, and the maximum deviation is between 11.6 and 49.5%.