Universal Thermodynamics at the Liquid-Vapor Critical Point

作者：Sanchez Isaac C^*; Boening Kevin L

来源：Journal of Physical Chemistry B, 2014, 118(47): 13704-13710.

DOI：10.1021/jp510096e

For 68 fluids that include hydrogen bonding and quantum fluids, the fugacity coefficient that defines the residual chemical potential adopts a near universal value of 2/3 at the critical point. More precisely, the reciprocal of the fugacity coefficient equals 1.52 +/- 0.02 and includes fluids as diverse as helium (1.50), dodecafluoropentane (1.50), and water (1.53). For 65 classical fluids, a dimensionless thermal pressure coefficient and internal pressure attain critical values of 1.88 +/- 0.11 and 1.61 +/- 0.11, respectively. From equations of state, values of these new critical constants have been calculated and agree favorably with experimental values. Specifically, for the critical fugacity coefficient, the following results were obtained for its reciprocal: van der Waals (1.44), lattice gas (1.43), scaled particle theory (1.46), and the RedlichKwong eq (1.50). The semiempirical RedlichKwong equation is also the most accurate for the thermal pressure coefficient (1.86) and internal pressure (1.53). Physical interpretations of these results are discussed as well as their implications for other critical phenomena.

• 出版日期2014-11-27