Equations for the Soave-Redlich-Kwong equation of state for pure-component systems

Equations:

The values of ac and b are obtained from pure-component critical properties according to:

where

Tc is the critical temperature

Pc is the critical pressure

The alpha function, a(Tr), is given as a function of reduced temperature and the acentric factor, w:

where

Tr is the reduced temperature, Tr = T/Tc

w is the acentric factor

The constants in the expression for M were obtained from the reduction of vapor pressure data for a limited number of common hydrocarbons.