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Coulombic and non-Coulombic contributions to the criticality of ionic fluids. An experimental approach

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Abstract

The recent discovery of liquid-liquid phase separations in electrolyte solutions with critical points near room temperature enables the systematic study of the critical behavior of ionic fluids. Depending on the nature of the molecular interactions, either sharp mean-field or Ising behavior is obtained in the temperature range down tot=(T−T c )/T c =10−4 or less. Mean-field-like criticality is obtained with systems which in the framework of a simple corresponding states model are fairly close to the critical point of the “restricted primitive model” (RPM) of equally-sized charged spheres in a dielectric continuum. In these cases the phase separation is driven by the Coulombic forces (so-calledCoulombic phase separations). This type of unmixing occurs for 1∶1 electrolytes in solvents of low dielectric constant. Simple mechanisms for unmixing suggested in the literature are discussed in relation to the available data. Some evidence for departures from the simple RPM prediction is found. The presence of additional short-range interactions leads to sharp Ising behavior. Examples are solutions of tetraalkylammonium salts in water and other highly structured solvents, where phase separation results from the peculiar solvophobic nature of ions (solvophobic phase separations). Previous speculations that this type of unmixing shows the tendency toward closed loops are confirmed by the first direct observation of a lower consolute point in an aqueous solution of propyl-tributylammonium iodide. By light scattering studies and measurements of the coexistence curve near the upper and lower consolute points Ising criticality is confirmed. A new mechanism for phase separation is reported for the system ethylammonium nitrate+octanol, where ion pairs are stabilized by hydrogen bonding beyond what is expected from the RPM. This comparatively subtle additional interaction (so-calledstricky ions) already changes the behavior of otherwise RPM-like systems from mean-field to Ising criticality. The results are discussed with particular emphasis on their implications for possible scenarios for explaining a mean-field critical point or crossover from mean-field to Ising behavior beyond the accessible temperature range.

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References

  1. L. Onsager,Phys. Rev. 65:117 (1944).

    Google Scholar 

  2. R. R. Singh and K. S. Pitzer,J. Chem. Phys. 92:6775 (1990).

    Google Scholar 

  3. H. Weingärtner, S. Wiegand, and W. Schröer,J. Chem. Phys. 96:848 (1992).

    Google Scholar 

  4. K. C. Zhang, M. E. Briggs, R. W. Gammon, and J. M. H. Levelt Sengers,J. Chem. Phys. 97:8692 (1992).

    Google Scholar 

  5. M. Buback and E. U. Franck,Ber. Bunsenges. Phys. Chem. 76:350 (1972).

    Google Scholar 

  6. I. G. Dillon, P. A. Nelson, and B. S. Swanson,J. Chem. Phys. 44:4229 (1966).

    Google Scholar 

  7. H. Weingärtner, T. Merkel, U. Maurer, J.-P. Conzen, H. Glasbrenner, and S. Käshammer,Ber. Bunsenges. Phys. Chem. 95:1579 (1991).

    Google Scholar 

  8. R. R. Singh and K. S. Pitzer,J. Am. Chem. Soc. 110:8723 (1988).

    Google Scholar 

  9. V. L. Ginzburg,Sov. Phys. Solid 2:1824 (1962).

    Google Scholar 

  10. D. J. Amit,J. Phys. C. 7:3369 (1974).

    Google Scholar 

  11. M. A. Anisimov, S. B. Kiselev, J. V. Sengers, and S. Tang,Physica A 188:487 (1992).

    Google Scholar 

  12. M. Kac, G. E. Uhlenbeck, and P. C. Hemmer,J. Math. Phys.,4:216 (1963).

    Google Scholar 

  13. R. F. Kayser and H. J. Raveche,Phys. Rev. A 29:1013 (1984).

    Google Scholar 

  14. G. Stell,Phys. Rev. B 1:2265 (1970).

    Google Scholar 

  15. M. E. Fisher, S.-K. Ma, and B. G. Nickel,Phys. Rev. Lett. 29:917 (1972).

    Google Scholar 

  16. P. Pfeuty and G. Toulouse,Introduction to Renormalization Group and to Critical Phenomena (Wiley, New York, 1977), p. 33.

    Google Scholar 

  17. J. G. Kirkwood,J. Chem. Phys. 2:351 (1934).

    Google Scholar 

  18. G. Stell, K. C. Wu, and B. Larsen,Phys. Rev. Lett. 37:1369 (1976).

    Google Scholar 

  19. K. S. Pitzer and D. R. Schreiber,Mol. Phys. 60:1067 (1987).

    Google Scholar 

  20. A. Z. Panagiotopoulos,Fluid Phase Equil. 76:97 (1992).

    Google Scholar 

  21. B. Hafsköld and G. Stell, InThe Liquid State of Matter, E. W. Montroll and J. L. Lebowitz, eds. (North-Holland, New York, 1982), p. 175.

    Google Scholar 

  22. G. Stell,Phys. Rev. A 45:7628 (1992).

    Google Scholar 

  23. G. Stell,J. Stat. Phys., this issue.

  24. M. E. Fisher,J. Stat. Phys. 75:1 (1994).

    Google Scholar 

  25. A. L. Khodolenko and A. L. Beyerlein,J. Chem. Phys. 93:8403 (1990).

    Google Scholar 

  26. A. L. Khodolenko and A. L. Beyerlein,Phys. Lett 132:347 (1988).

    Google Scholar 

  27. R. Baxter,Exactly Solvable Models in Statistical Mechanics (Academic Press, New York, 1982).

    Google Scholar 

  28. M. E. Fisher,J. Chem. Phys. 96:3352 (1992).

    Google Scholar 

  29. M. L. Japas and J. M. H. Levelt Sengers,J. Phys. Chem. 94:5361 (1990).

    Google Scholar 

  30. H. Weingärtner,Ber. Bunsenges. Phys. Chem. 93:1058 (1989).

    Google Scholar 

  31. E. Steinle and H. Weingärtner,J. Phys. Chem. 96:2407 (1992).

    Google Scholar 

  32. H. Xu, H. L. Friedman, and F. O. Raineri,J. Solution Chem. 20:739 (1991).

    Google Scholar 

  33. J. L. Caillol,J. Chem. Phys. 100:2161 (1994).

    Google Scholar 

  34. L. Verlet,Phys. Rev. 159:98 (1967).

    Google Scholar 

  35. K. S. Pitzer,Acc. Chem. Res. 23:333 (1990).

    Google Scholar 

  36. V. M. McGahay and M. Tomozawa,J. Chem. Phys. 97:2609 (1990).

    Google Scholar 

  37. H. L. Friedman and B. Larsen,J. Chem. Phys. 70:92 (1979).

    Google Scholar 

  38. P. Walden and M. Centnerszwer,Z. Phys. Chem. 42:432 (1903).

    Google Scholar 

  39. M. J. Sienko, ed.,Metal-Ammonia Solutions (Benjamin, New York, 1964).

    Google Scholar 

  40. P. Chieux and M. J. Sienko,J. Chem. Phys. 53:566 (1970).

    Google Scholar 

  41. F. Leclerc, P. Damaya, and P. Chieux,Z. Phys. Chem. 156:183 (1988).

    Google Scholar 

  42. J. F. Jal, P. Chieux, P. Dupuy, and J. P. Dupin,J. Phys. (Paris)41:657 (1980).

    Google Scholar 

  43. V. M. Nabutovskii, N. A. Nemov, and Yu. G. Peisakhovich,Mol. Phys. 54:979 (1985).

    Google Scholar 

  44. J. S. Hoye and G. Stell,J. Phys. Chem. 94:7899 (1990).

    Google Scholar 

  45. D. W. Jepsen and H. L. Friedman,J. Chem. Phys. 38:846 (1963).

    Google Scholar 

  46. C. W. Outwhite,Mol. Phys. 33:1229 (1977).

    Google Scholar 

  47. C. F. J. Böttcher,Theory of Electric Polarization, Vol. 1 (Elsevier, Amsterdam, 1973), p. 77; see also W. Schröer,Adv. Chem. Phys. 48:183 (1981).

    Google Scholar 

  48. J. S. Hoye and G. Stell,J. Chem. Phys. 65:18 (1976);71:1985(1979).

    Google Scholar 

  49. G. Stell, G. N. Patey, and J. S. Hoye,Adv. Chem. Phys. 48:183 (1981).

    Google Scholar 

  50. V. Steinberg, A. Voronel, D. Linsky, and U. Schindewolf,Phys. Rev. Lett. 45: 1338 (1980).

    Google Scholar 

  51. M. E. Fisher and Y Levin,Phys. Rev. Lett, in press.

  52. N. Bjerrum,Kgl. Danske Vidensk. Selsk. Mat.-Fys., Medd. 7:1 (1926).

    Google Scholar 

  53. R. M. Fuoss and C. A. Kraus,J. Am. Chem. Soc. 55:2387 (1933).

    Google Scholar 

  54. H. L. Friedman,J. Phys. Chem. 66:1595 (1962).

    Google Scholar 

  55. D. R. Schreiber, M. C. P. de Lima, and K. S. Pitzer,J. Phys. Chem 91:4087 (1987).

    Google Scholar 

  56. L. C. Kenausis, E. C. Evers, and C. A. Kraus,Proc. Natl. Acad. Sci. USA 48:121 (1962).

    Google Scholar 

  57. L. C. Kenausis, E. C. Evers, and C. A. Kraus,Proc. Natl. Acad. Sci. USA 49:141 (1963).

    Google Scholar 

  58. A. M. Sukhotin,Russ. J. Phys. Chem. 34:29 (1960), and references therein.

    Google Scholar 

  59. K. S. Pitzer and J. M. Simonson,J. Am. Chem. Soc. 106:1973 (1984).

    Google Scholar 

  60. W. E. Price and H. Weingärtner,J. Phys. Chem. 95:8933 (1991).

    Google Scholar 

  61. H. Weingärtner, W. E. Price, A. V. J. Edge, and R. Mills,J. Phys. Chem. 99: 6289 (1993).

    Google Scholar 

  62. H. L. Friedman, F. O. Raineri, and D. M. Wood,Chem. Scripta 29A:49 (1989).

    Google Scholar 

  63. E. C. Zhong and H. L. Friedman,J. Phys. Chem. 92:1685 (1988).

    Google Scholar 

  64. S. C. Greer and M. R. Moldover,Annu. Rev. Phys. Chem. 32:233 (1981).

    Google Scholar 

  65. J. V. Sengers and J. M. H. Levelt Sengers,Annu. Rev. Phys. Chem. 37:189 (1986).

    Google Scholar 

  66. R. R. Singh and K. S. Pitzer,J. Chem. Phys. 90:5742 (1989).

    Google Scholar 

  67. D. Kawasaki, InPhase Transitions and Critical Phenomena, Vol. 5A, QC. Domb and J. L. Lebowitz, eds. (Academic Press, New York, 1983).

    Google Scholar 

  68. D. Woermann and W. Sarholtz,Ber. Bunsenges. Phys. Chem. 69:319 (1965).

    Google Scholar 

  69. W. Schröer, M. Kleemeier, and H. Weingärtner, to be published.

  70. W. Schröer, S. Wiegand, W. Staude, and Th. Peters,Ber. Bunsenges. Phys. Chem. 95:1126 (1991)

    Google Scholar 

  71. A. R. Kortan, H. V. Känel, R. J. Birgeneau, and J. D. Lister,Phys. Rev. Lett. 47:1206 (1981).

    Google Scholar 

  72. C. A. Kraus,J. Phys. Chem. 60:129 (1956), and references therein.

    Google Scholar 

  73. H. Weingärtner, T. Merkel, S. Käshammer, W. Schröer, and S. Wiegand,Ber. Bunsenges. Phys. Chem. 97:970 (1993).

    Google Scholar 

  74. S. H. Lee, J. C. Rasaiah, and P. T. Cummings,J. Chem. Phys. 83:317 (1985).

    Google Scholar 

  75. G. Stell and Y. Zhou,J. Chem. Phys. 91:3618, (1989).

    Google Scholar 

  76. W. Schröer, S. Wiegand, and H. Weingärtner,Ber. Bunsenges. Phys. Chem. 97:975 (1993).

    Google Scholar 

  77. J. M. H. Levelt Sengers and J. A. Given,Mol. Phys. 80:899 (1993).

    Google Scholar 

  78. G. Meier, D. Schwan, K. Mortensen, and S. Jansen,Europhys. Lett. 22:577 (1993).

    Google Scholar 

  79. J. Kendall, E. D. Grittenden, and K. H. Miller,J. Am. Chem. Soc. 45:963 (1923).

    Google Scholar 

  80. C. Sinistri, P. Franzosini, A. Timidei, and M. Rolla,Z. Naturforsch. A 20:561 (1965).

    Google Scholar 

  81. F. Hensel,J. Phys. (Cond. Matter) Spec. Issue “Liquids” 3A:SA33 (1991), and references therein.

    Google Scholar 

  82. Static Dielectric Constants of Pure Liquids and Liquid Mixtures, Landolt-Börnstein Series, Group IV, Vol. 6 (Springer, Berlin, 1991).

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Authors and Affiliations

  1. Institut für Physikalische Chemie und Elektrochemie der Universität Karlsruhe, D-76128, Karlsruhe, Germany

    Hermann Weingärtner

  2. Institut für Anorganische und Physikalisch Chemie, Universität Bremen, D-28334, Bremen, Germany

    M. Kleemeier, S. Wiegand & W. Schröer

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  1. Hermann Weingärtner
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Weingärtner, H., Kleemeier, M., Wiegand, S. et al. Coulombic and non-Coulombic contributions to the criticality of ionic fluids. An experimental approach. J Stat Phys 78, 169–196 (1995). https://doi.org/10.1007/BF02183345

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