The thermodynamics of alkyne-containing mixtures is fundamental to the petroleum and chemical industries. Such mixtures are made complex both by the quantity and the variety of the species present thus justifying the need for a predictive model capable of guesstimating energetic and phase-equilibrium mixture properties. In this respect, the E-PPR78 (enhanced-predictive 1978, Peng− Robinson equation of state) model appears as a suitable candidate since it combines the well-established Peng−Robinson equation of state and an original groupcontribution method making it possible to estimate the temperature-dependent binary interaction parameters, k ij (T), involved in the van der Waals one-fluid mixing rules. With the 37 groups defined in previous works, such a model could be used to predict fluid-phase equilibria and energetic properties of systems containing hydrocarbons, permanent gases (CO 2 , N 2 , H 2 S, H 2 , CO, He, Ar, SO 2 , O 2 , NO, COS, NH 3 , NO 2 /N 2 O 4 , N 2 O), mercaptans, fluoro-compounds, and water. In this study, three alkyne groups ("HCCH", "CCH", and "CC") are added in order to accurately predict phase-equilibrium properties and enthalpies of mixing of alkyne-containing multicomponent mixtures. The determination of the group-interaction parameters (involved in the k ij (T) expression) between two groups including at least one alkyne group is performed with the help of a comprehensive database of binary-system phaseequilibrium and mixing-enthalpy data.
