The Analysis of the Equilibrium Cluster Structure in Supercritical Carbon Dioxide


The monomer fraction density based analysis of precise thermophysical data for pure fluids is developed to study the molecular structures in supercritical fluids in general and in CO2 in particular. The series expansion by powers of the monomer fraction density of the potential energy density is used to discover the cluster structure in supercritical fluids and the clusters’ bond energies in CO2. The method of clusters separation between classes of loose and dense clusters in the CO2 supercritical fluid is developed. The method of the energetically averaged number of dense clusters is developed to study the mechanism of the soft structural transition between the gas-like and liquid-like fluids in the supercritical CO2.

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B. Sedunov, "The Analysis of the Equilibrium Cluster Structure in Supercritical Carbon Dioxide," American Journal of Analytical Chemistry, Vol. 3 No. 12A, 2012, pp. 899-904. doi: 10.4236/ajac.2012.312A119.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] M. A. McHugh and V. J. Krukonis, “Supercritical Fluid Extraction: Principles and Practice,” Butterworth Publishers, Stoneham, 1986.
[2] L. T. Taylor, “Supercritical Fluid Extraction,” John Wiley & Sons Ltd., New York, 1996.
[3] NIST, “Thermophysical Properties of Fluid Systems,” 2012.
[4] K. Nishikawa and T. Morita, “Inhomogeneity of Molecu- lar Distribution in Supercritical Fluids,” Chemical Phys- ics Letters, Vol. 316, No. 3, 2000, pp. 238-242. doi:10.1016/S0009-2614(99)01241-5
[5] K. Nishikawa, et al., “Raman Spectral Changes of Neat CO2 across the Ridge of Density Fluctuation in Super- critical Region,” Chemical Physics Letters, Vol. 320, No. 3-4, 2000, pp. 323-327. doi:10.1016/S0009-2614(00)00249-9
[6] K. Nishikawa, et al., “Local Density Enhancement in Neat Supercritical Fluid Due to Attractive Intermolecular In- teractions,” Chemical Physics Letters, Vol. 368, No. 1-2, 2003, pp. 209-214. doi:10.1016/S0009-2614(02)01851-1
[7] B. Sedunov, “Structural Transition in Supercritical Flu- ids,” Journal of Thermodynamics, Vol. 2011, 2011, Arti- cle ID: 194353, 5 p.
[8] B. Sedunov, “Soft Phase Transition in Supercritical Flu- ids,” The 21st IUPAC International Conference on Che- mical Thermodynamics, Tsukuba, 2010, p. 104.
[9] B. Sedunov, “Soft Structural Transitions in Fluids,” The 22nd International Conference on Chemical Thermody- namics (ICCT) and the 67th Calorimetry Conference (CALCON), Buzios, 2012.
[10] B. Sedunov, “Monomer Fraction in Real Gases,” Interna- tional Journal of Thermodynamics, Vol. 11, No. 1, 2008, pp. 1-9.
[11] B. Sedunov, “Equilibrium Molecular Interactions in Pure Gases,” Journal of Thermodynamics, Vol. 2012, 2012, Article ID: 859047, 13 p.

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