Liquid Viscosity and Interfacial Tension of Binary Mixtures of n-Pentane, n-Decane, n-Hexadecane, or Squalane with Dissolved Carbon Dioxide or Propane by Surface Light Scattering

The present study investigates the influence of dissolved gases on the liquid viscosity η_Land interfacial tension σ of linear and branched alkanes under saturated conditions by using surface light scattering (SLS). Five binary mixtures consisting of n-pentane, n-decane, n-hexadecane, or 2,6,10,15,19,23-hexamethyltetracosane (squalane) with dissolved propane or carbon dioxide are studied at temperatures T between 255.7 and 423.15 K, pressures p up to 7.8 MPa, and solute amount fractions up to 0.79. Using SLS, η_Land σ were determined with an average expanded experimental uncertainty (coverage factor k = 2) of 2.0%. Polarization-difference Raman spectroscopy was simultaneously applied to SLS experiments to determine the liquid-phase composition. The influence of the dissolved gas is discussed by comparing the thermophysical properties of the mixtures to those of the pure solvents. It could be observed that the molecular characteristics of the solute have a minimal influence on η_Lof the mixture, which is primarily determined by the solvent’s characteristics. In contrast, the molecular characteristics of the solvent and solute strongly influence σ. Overall, the results of this study contribute to expanding the database for η_Land σ for binary mixtures, which can be considered surrogate mixtures for refrigeration oil–refrigerant systems.