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International Journal of Thermophysics

, Volume 11, Issue 3, pp 537–554 | Cite as

Composition dependence of binary diffusion coefficients in alkane mixtures

  • S. F. Y. Li
  • L. S. Yue
Article

Abstract

The binary diffusion coefficients of mixtures of n-heptane with n-hexane and 2,2,4-trimethylpentane with n-hexane have been measured at various compositions at 308.1, 312.2, and 316.5 K using the Taylor dispersion technique. The experimental results for the n-hexane/n-heptane system were in good agreement with the literature values (<1.5%). The observed binary diffusion coefficients for this system exhibit a linear dependence on composition. On the contrary, the results of the n-hexane/2,2,4-trimethylpentane system reveal an interesting behavior of the composition dependence of the binary diffusion coefficients, presenting a slight maximum, for composition at a molar fraction of n-hexane of 0.86. In order to explain this difference in behavior, the influence of branching of molecules on diffusion is discussed. It was found that although the Enskog hard-sphere model for binary diffusion can reproduce the experimental results for the n-hexane/n-heptane system within 3%, it failed to predict the composition dependence of the n-hexane/2,2,4-trimethylpentane system within the experimental accuracy. The results showed that there is significant effect of branching in alkane molecules on the diffusion coefficient. This effect has been quantified using the roughness parameter, which represents the magnitude of coupling between translational and rotational motions.

Key words

composition dependence diffusion coefficient n-heptane n-hexane mixtures 2,2,4-trimethylpentane 

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References

  1. 1.
    H. Tyrrell and K. R. Harris, Diffusion in Liquids (Butterworths, London, 1984), pp. 102–234.Google Scholar
  2. 2.
    S. F. Y. Li and W. A. Wakeham, Int. J. Thermophys. (in press).Google Scholar
  3. 3.
    S. F. Y. Li and L. S. Yue (in press).Google Scholar
  4. 4.
    J. H. Dymond, Physica 75:100 (1974).Google Scholar
  5. 5.
    K. J. Czworniak, H. C. Anderson, and R. Pecora, Chem. Phys. 11:451 (1975).Google Scholar
  6. 6.
    D. Chandler, J. Chem. Phys. 62:1358 (1975).Google Scholar
  7. 7.
    E. Gruska and P. Schnipelsky, J. Phys. Chem. 80:1509 (1976).Google Scholar
  8. 8.
    E. Gruska and V. R. Maynard, J. Phys. Chem. 77:1437 (1973).Google Scholar
  9. 9.
    E. Gruska and P. Schnipelsky, J. Phys. Chem. 78:1428 (1974).Google Scholar
  10. 10.
    R. W. Elliot and H. Watts, Can. J. Chem. 50:31 (1972).Google Scholar
  11. 11.
    W. A. Wakeham and D. H. Slater, J. Phys. B 7:197 (1974).Google Scholar
  12. 12.
    F. Bachl and H. D. Ludemann, Physica 139:100 (1986).Google Scholar
  13. 13.
    M. L. Matos Lopes, C. M. Padrel de Oleveira, and C. A. Nieto de Castro, Fluid Phase Equil. 36:195 (1987).Google Scholar
  14. 14.
    C. M. Padrel de Oliveira, J. M. N. A. Fareleira, and C. A. Nieto de Castro, Int. J. Thermophys. (in press).Google Scholar
  15. 15.
    M. A. Matthews and A. Akgerman, J. Chem. Phys. 87:2285 (1987).Google Scholar
  16. 16.
    M. L. Matos Lopes and C. A. Nieto de Castro, High Temp. High Press. 17:599 (1985).Google Scholar
  17. 17.
    J. H. Dymond and B. J. Alder, J. Chem. Phys. 48:343 (1967).Google Scholar
  18. 18.
    J. H. Dymond and B. J. Alder, J. Chem. Phys. 45:2061 (1966).Google Scholar
  19. 19.
    J. H. Dymond, J. Chem. Phys. 60:969 (1974).Google Scholar
  20. 20.
    S. H. Chen, H. T. Davis, and D. F. Evans, J. Chem. Phys. 77:2540 (1982).Google Scholar
  21. 21.
    A. J. Easteal, L. A. Woolf, and D. L. Jolly, Physica A 121:286 (1982).Google Scholar
  22. 22.
    N. B. Vargaftik, Handbook on Physical Properties of Liquid and Gases, Pure Substances and Mixtures (Wiley, New York, 1983).Google Scholar
  23. 23.
    A. Heintz and R. N. Lichtenthaler, Angew. Chem. Int. Ed. Engl. 21:184 (1982).Google Scholar
  24. 24.
    P. Bothorel, C. Clement, and P. Maraval, C.R. Acad. Sci. 264:658 (1967).Google Scholar
  25. 25.
    C. Muckenfuss and C. F. Curtiss, J. Chem. Phys. 29:1257 (1957).Google Scholar
  26. 26.
    S. I. Sandler and J. S. Dahler, J. Chem. Phys. 47:2621 (1967).Google Scholar
  27. 27.
    A. A. Alizadeh and W. A. Wakeham, Int. J. Thermophys. 3:307 (1982).Google Scholar

Copyright information

© Plenum Publishing Corporation 1990

Authors and Affiliations

  • S. F. Y. Li
    • 1
  • L. S. Yue
    • 1
  1. 1.Department of ChemistryNational University of SingaporeSingaporeRepublic of Singapore

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