A general mixture equation of state for double bonding carboxylic acids with >= 2 association sites

Abstract

In this paper we obtain the first general multi-component solution to thermodynamic perturbation theory for the case that molecules can participate in cyclic double bonds. In contrast to previous authors, we do not restrict double bonding molecules to a 2-site association scheme. Each molecule in a multi-component mixture can have an arbitrary number of donor and acceptor association sites. The one restriction on the theory is that molecules can have at most one pair of double bonding sites. We also incorporate the effect of hydrogen bond cooperativity in cyclic double bonds. We then apply this new association theory to 2-site and 3 site models for carboxylic acids within the polar PC-SAFT equation of state. We demonstrate the accuracy of the approach by comparison to both pure and multi-component phase equilibria data. We also demonstrate that inclusion of hydrogen bond cooperativity has a substantial effect on liquid phase hydrogen bonding structure.