Binary Gaseous Diffusion Coefficients IV. Sulfurhexafluoride with \u3cem\u3en\u3c/em\u3e-Hexane, \u3cem\u3en\u3c/em\u3e-Heptane, \u3cem\u3en\u3c/em\u3e-Octane, and 2,2,4-Trimethylpentane at 1 Atm at 10-70 Degrees Celsius

Abstract

Binary gaseous diffusion coefficients at 1-atm pressure of sulfur hexafluoride, with n-hexane, n-heptane, n-octane, and 2,2,4-trimethylpentane (isooctane) were measured at 10°, 25°, 40°, 55°, and 70°C by the capillary tube method of Stefan. Diffusion coefficients were calculated (a) by using Lennard-Jones (6, 12) pair potential parameters In conjunction with the Hudson-McCoubrey comblnlng rule and (b) with a semlemplrlcal method somewhat similar to that suggested by Chen and Othmer. Diffusion Coefficients calculated via method (b) were In much better agreement with experiment than those obtained via method (a). The experimental results were used to investigate certain regularities in diffusional behavior of homologous species in mixtures with a common gas. In particular, a strikingly simple correlation (first advanced by Wakeham and Slater) was tested and found applicable, even when the common gaseous component is a pseudospherical molecule of considerable size and mass, such as SF6. Provided that experimental data on two sufficiently spaced homologs are available, the correlation apparently offers a powerful predictive potential