The NRTL model was published by Henri Renon and John M. Prausnitz as “Local composition in thermodynamic excess functions for liquid mixtures” in AICHE Journal **14**:135-44, 1968.

NRTL equation and NRTL excess Gibbs free energy

Binary parameters: α_{ij}, (g_{ji} – g_{ii}), and (g_{ij} – g_{jj}).

Binary reduced form