Group-contribution method for the molecular parameters of the pc-saft equation of state taking into account the proximity effect. application to nonassociated compounds
Résumé
A new group-contribution method to obtain the PC-SAFT molecular parameters of nonassociated compounds (linear alkanes, branched alkanes, linear monoethers, and esters) is developed on the basis of their regular trends against molecular mass. The method takes into account the proximity effect among all functional groups of a molecule in order to describe the deviations of shorter chain molecular parameters from the regular trend observed for the larger chain ones. The group-contribution scheme considers the molecular parameters as a linear combination of reference functional-group parameters and their mutual perturbations, which are responsible for the deviations from the reference ones. Both types of parameters (the reference functional-group parameters and the mutual perturbations) are optimized to the available molecular parameters published in the literature and obtained by direct fitting from experimental data of saturation pressures and saturated liquid densities.
Mots clés
Branched alkanes
Experimental data
Group contribution method
Group parameters
Group-contribution
Linear alkanes
Linear combinations
Molecular parameters
PC-SAFT
PC-SAFT equation
Proximity effects
Saturated liquid densities
Saturation pressure
Shorter chains Engineering controlled terms: Esters
Functional groups
Paraffins Engineering main heading: Equations of state