Predicting VLE of heavy esters and their mixtures using GC-SAFT

A group contribution method combined with a SAFT equation of state (GC-SAFT from Tamouza et al. [S. Tamouza, J.-P. Passarello, P. Tobaly, J.-C. de Hemptinne, Fluid Phase Equilibria 222/223 (2004) 67–76; S. Tamouza, J.-P. Passarello, P. Tobaly, J.-C. de Hemptinne, Fluid Phase Equilibria 228/229 (2005) 409–419], previously extended to polar molecular fluids NguyenHuynh et al. [D. NguyenHuynh, J.-P. Passarello, P. Tobaly and J.-C. de Hemptinne, Fluid Phase Equilibria 264 (2008) 62–75], is here applied to model vapor–liquid phase equilibria of various ester containing binary mixtures such as: ester + ester, ester + alkane, ester + cyclohexane, ester + alkyl-benzene, ester + xylene and ester + alcohols.These systems are modeled using three different versions of SAFT-EOS (original, VR-SAFT and PC-SAFT) in a purely predictive manner: binary interaction parameters kij and lij are all set to zero.In the case of ester + alcohol systems, a cross-association interaction between ester and alcohol molecules is shown to improve significantly the predictivity of the method for VLE calculations. The corresponding parameters are estimated by simple hypotheses, using auto-association parameters of pure 1-alkanols.The above cited systems have been treated in a comprehensive manner. The general agreement between GC-SAFT and experimental data is good (within 4–5% deviation on pressure), similar to the one obtained on previously investigated systems.