Critical curves in mixtures of carbon dioxide with ethane and ethylene based on a generalized fluctuation form of the van der waals equation of state

Critical curves of CO₂-C₂H₄ and CO₂-C₂H₄ mixtures are investigated using a new fluctuation equation of state. Particular attention is paid to the behavior of thermodynamic sensitives in the vicinity of the critical azeotropic points, at which the derivative of the molar volume with respect to the composition, which has no special features in the vicinity of the critical points of the pure components, becomes zero. Reliable agreement between the results of describing the critical curves of the mixtures and the known (including volumetric measurements) experiment is obtained. Possible intensification of supercritical extraction in using the CO₂-C₂H₆ mixture in the vicinity of the azeotropic point is predicted. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 2, pp. 407–413, March–April, 2000.