Modeling of polycyclic aromatic hydrocarbon SLE in aromatic solvents

Equilibrium solubilities of polycyclic aromatic hydrocarbon (PAH) solutes naphthalene, fluorene, acenaphthalene, fluoranthene, anthracene, phenanthrene, pyrene, chrysene and triphenylene in benzene and substituted benzene solvents are predicted using the Dortmund-AU model. The Dortmund-AU method performs better than the UNIFAC and modified UNIFAC (Dortmund) models when applied to PAH in benzene systems, but the accuracy of predictions deteriorates in the case of PAHs that have melting points greater than 380 K. Accounting for the heat capacity change on melting term makes considerable difference to the ideal solubility calculation in the case of higher-melting PAHs. A new term is added to the residual part of activity coefficient in the UNIFAC model to derive a modified empirical version. Application of this model to PAH solid liquid equilibria is verified and the results are compared with those of Dortmund-AU model. (c) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.