LAUSR

Abstract The modified group-contribution PC-SAFT (NguyenHuynh, Fluid Phase Equilibria 2016, 430, 33–46) is applied to simultaneously predict vapor-liquid and liquid-liquid equilibria of nitrile + alkane mixtures (from n-butane to n-hexadecane) using a single temperature-independent binary interaction parameters. Nitriles were considered specific polar and associative compounds. The EoS parameters were regressed on pure compound data and the binary interaction parameter was fitted on liquid-liquid phase equilibrium data of nitrile + n-hexane mixture. The association and dipolar interactions of nitrile in PC-SAFT were investigated with an emphasis on the difficulties in modeling LLE of nitrile + alkanes, water and aromatics binary mixtures. The modeling results were however disappointing when nitrile was studied as unique dipolar or associative compound. It was found in fact that a cross-association interaction between nitrile and aromatic was necessary to accurately calculate the mixtures phase equilibria. The results were finally compared with the induced Polar PC-SAFT EoS.