“…Equation 4, of course, holds only for azeotropic states. For the general vapor-liquid equilibrium problem, two quantities (T and P in this work) must be specified, and the following equations: In the calculations presented below, the equations for the pressure and for the fugacities were obtained using the extended form of the corresponding states principle with methane as the reference fluid (Teja and Rowlinson, 1973;Teja and Kropholler, 1975;Teja 1975. The method requires only the critical properties and acentric factors of the pure fluids as input parameters.…”