Ten Years with the CPA (Cubic-Plus-Association) Equation of State. Part 2. Cross-Associating and Multicomponent Systems

Abstract

In this second article of the review on the applications of the CPA (Cubic-Plus-Association) equation of state, the focus is placed on cross-associating systems. Various such mixtures are investigated, including (i) systems with two self-associating compounds (e.g., water−alcohol systems or glycols, mixtures with organic acids, or two alcohols) but also binaries with only one self-associating substance, where solvation is expected (e.g., CO2 or styrene with water). The method of accounting for cross-association (combining rules) and the association scheme of alcohols are investigated. Finally, the manuscript concludes with a summary of current capabilities and limitations of CPA and a list of future challenges.

Solubilities of hydrofluorocarbons in ionic liquids: Experimental and modelling study

“…When dealing with mixtures containing associating molecules, the association term of the CPA EoS, requires combining rules for the association energy and volume parameters [33], in order to calculate the value of the association strength in Eq. 9.…”

“…In the present work, the observed solubility values are analyzed by a predictive model based on a cubic plus association equation of state (CPA EoS) to verify the accuracy of the CPA equation of state for description of the solubility data. The CPA EoS proposed by Kontogeorgis and co-workers [33] has been developed and applied to diverse systems since 1995, allowing a good description of phase behaviour with both associating and/or non-associating components. Later, a semi-empirical model based on the Regular Solution Theory (RST) is also adjusted to the experimental data.…”

Correlation and prediction of biodiesel density for extended ranges of temperature and pressure

“…The relative deviations in density obtained from those correlations have been usually lower than 0.01%. Cubic equations of state such as the cubic-plus-association equation of state (CPA EoS) [29,30], and the volume translated Peng-Robinson (PR) equation of state (VTPR EoS) [31] have been applied to density correlation and prediction. The CPA EoS combines a physical contribution from a cubic density EoS (Soave-Redlich Kwong EoS) with an association term accounting for intermolecular hydrogen bonding and solvation effects, which disappears for non-associating components, such as esters.…”

- Accurate Force Fields for Molecular Simulation

“…This work is far from complete because only a few of the systems in the data base were tested and no contemporary EOS models, such as SAFT (Muller and Gubbins 2001;Economou 2002), PC-SAFT (Gross and Sadowski 2001) and CPA (Kontogeorgis et al 1996), which have been reviewed by Kontogeorgis andFolas (Kontogeorgis et al 2006a, 2006b) and by Polishuk and Mulero (Polishuk and Mulero 2011), were examined.…”