Phase equilibria for chain-fluid mixtures near to and far from the critical region

A recently established crossover equation of state for pure chain fluids is extended to chain-fluid mixtures. Far from the critical region, where dens ity fluctuations are small, it reduces to the classic equation of state. Ne ar or at the critical point, the crossover equation of state incorporates c ontributions form long-wavelength density fluctuations. Using segment - seg ment parameters for pure components and one cross parameter k(12) for every binary pair as obtained from vapor - liquid equilibrium data remote from t he critical region, this crossover equation of state glues vapor-liquid equ ilibria in good agreement with experiment for binary asymmetric mixtures of n-alkanes far from near to, and at the critical point.