Pitzer-Curl acentric factor

Guggenheim Equations 1 and 2 are in corresponding-states form that is, the reduced-form equations pr(Tr) explicitly contain no material constants and are formally applicable to all substances (in practice, to substances having small nearly spherical molecules, with modest accuracy). The desirable corresponding-states formulation will be retained in the equation presented here in a modified form, by including (as is now usual) the Pitzer-Curl acentric factor w as an explicit material constant ... 

For non-polar molecules, Tsonopoulos [74-tso] modified the Pitzer and Curl [57-pit/cra] relationship for the reduced second virial coefficient in terms of T the temperature reduced by the critical temperature, and a third parameter, the acentric factor (O, which had been introduced to extend the application to non-spherical non-polar molecules, to give ... 

The acentric factor w is determined from the vapor pressure curve of the fluid [4], Prausnitz and Gunn [14] have developed mixture rules by modifying the relations of Pitzer and Curl ... 

Pitzer and co-workers and Curl and Pitzer developed a correlation for the compression factor for hydrocarbons and inorganic gases in terms of the reduced pressure and reduced temperature that is a linear function of acentric factor and is of the form... 

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