Thermal, Mutual, and Self-Diffusivities of Binary Liquid Mixtures Consisting of Gases Dissolved in n-Alkanes at Infinite Dilution

• DOI: 10.1021/acs.jpcb.8b00733
• Publication Date: 2018-02-27T18:37:09Z
• Authors: Cédric Giraudet; Tobias Klein; Guanjia Zhao; Michael H. Rausch; Thomas M. Koller; Andreas P. Fröba
• Keywords: Dilution; Mole fraction

In the present study, dynamic light scattering (DLS) experiments and molecular dynamics (MD) simulations were used for investigation of diffusion in binary mixtures liquids with dissolved gases at macroscopic thermodynamic equilibrium. Model systems based on n-alkane n-hexane or n-decane hydrogen, helium, nitrogen, carbon monoxide studied temperatures between 303 423 K gas mole fractions below 0.06. With DLS, relaxation behavior microscopic equilibrium fluctuations concentration temperature is analyzed to determine simultaneously mutual thermal diffusivity an absolute way. The measurements document that even 0.007 Lewis numbers close 1, reliable diffusivities average expanded uncertainty (k = 2) 13% can be obtained. By use suitable models mixture components, self-diffusion coefficient was determined by MD averaged 7%. DLS showed not affected agrees reference data pure n-alkanes. agreement theory, self-diffusivities found equal mostly within combined uncertainties conditions approaching infinite dilution gas. Our results, representing first available systems, reveal distinctly larger mass containing hydrogen helium compared nitrogen monoxide. On basis broad range gas–liquid covering about 2 orders magnitude from 10–9 10–7 m2·s–1, effects solvent solute properties temperature-dependent are discussed. This contributed development a simple semiempirical correlation n-alkanes varying chain length as function temperature. generalized expression requiring only information kinematic viscosity molar well acentric factor represents database this work further literature deviation 11%.