Liquid Viscosity and Surface Tension of<i>n</i>-Hexane,<i>n</i>-Octane,<i>n</i>-Decane, and<i>n</i>-Hexadecane up to 573 K by Surface Light Scattering

Abstract

In the present study, the simultaneous and accurate determination of liquid viscosity and surface tension of the <i>n</i>-alkanes <i>n</i>-hexane (<i>n</i>-C₆H₁₄), <i>n</i>-octane (<i>n</i>-C₈H₁₈), <i>n</i>-decane (<i>n</i>-C₁₀H₂₂), and <i>n</i>-hexadecane (<i>n</i>-C₁₆H₃₄) by surface light scattering (SLS) in thermodynamic equilibrium is demonstrated. Measurements have been performed over a wide temperature range from 283.15 K up to 473.15 K for <i>n</i>-C₆H₁₄, 523.15 K for <i>n</i>-C₈H₁₈, and 573.15 K for <i>n</i>-C₁₀H₂₂ as well as <i>n</i>-C₁₆H₃₄. The liquid dynamic viscosity and surface tension data with average total measurement uncertainties (<i>k</i> = 2) of (2.0 and 1.7) % agree with the available literature and contribute to a new database at high temperatures. Over the entire temperature range, a Vogel-type equation for the dynamic viscosity and a modified van der Waals equation for the surface tension represent the measured data for the four <i>n</i>-alkanes within experimental uncertainties. By also considering our former SLS data for <i>n</i>-dodecane (<i>n</i>-C₁₂H₂₆) and <i>n</i>-octacosane (<i>n</i>-C₂₈H₅₈), empirical models for the liquid viscosity and surface tension of <i>n</i>-alkanes were developed as a function of temperature and carbon number covering values between 6 and 28. Agreement between these models and reference correlations for further selected <i>n</i>-alkanes which were not included in the development procedure was found.