The paper contains the results of measurements of the viscosity of six binary mixtures: CO2–Kr; H2–N2; He–O2; CH4–CO2; CH4–C4H10; H2–He. Measurements were made in an oscillating-disk viscometer at 20° and 30°C and at pressures from 1–25 atm, approximately; they were evaluated by the relative method. An analysis of the data shows that the interaction quantity μ12 which appears in the Chapman–Enskog theory for low densities is sensibly independent of composition. Although no direct check on the accepted mixing rules can be made owing to the narrowness of the temperature range covered, it is concluded that a knowledge of the viscosities μ1 and μ2 of the pure components together with that of μ12 at each temperature is sufficient to determine the dependence of the viscosity of the mixture on composition with the aid of the Chapman–Enskog theory. This dependence is reproduced well by the theory at virtually zero density and at a constant temperature. The experimental values of μ12 are used to calculate the binary diffusion coefficient D12 for all mixtures. The results agree well with the correlations provided by Mason and Marrero. The system H2–He does not exhibit the anomaly detected for thermal conductivity by Mukhopadhyay and Barua.

Measurements of the thermal conductivity of five alternative refrigerants, namely, difluoromethane (HFC-32), pentafluoroethane ( H FC-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 range 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 of each 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.

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