Of particular interest, it has been demonstrated that the limiting activity coefficient of each component in a binary mixture can be used to parameterize a binary interaction excess Gibbs free energy model to make phase equilibrium calculations over an entire range of concentrations . These parameterizations are particularly advantageous for maximizing the efficiency of separation processes, which comprise a large majority of chemical plant operations and costs. The underlying principle is that limiting activity coefficients are a direct measure of the interactions in solution, and correspond to maximum deviations from ideality. It is therefore reasonable to assume we can extrapolate to more concentrated solutions where the solution would be more ideal (i.e., closer to the pure component limit). Consider for example the use of Wilson's equation . For a binary system we can compute the composition dependent activity coefficient of component 1 and 2, at mole fraction composition x 1 and x 2 = 1x 1 as: