In this work, the capabilities and usefulness of several cubic equations of state (PR, SRK, SOF-PR, SOF-RK) as well as a molecular-based equation of state, PC-SAFT were explored. Specifically, the two phase fluid-fluid regions (VLE, LLE) of several demanding binary mixtures of aromatics as well as dichlorobenzoates (alkyl and semi-fluorinated) with supercritical CO(2) were evaluated. Group contribution approaches were used to estimate the pure fluid parameters for the alkyl and semi-fluorinated dichlorobenzoates needed for each equation of state. We show that these models can capture many important features of the complex phase behavior of highly asymmetric systems composed of supercritical CO2 and alkyl (nonfluorinated or semi-fluorinated) 2,5-dichlorobenzoates. (C) 2011 Elsevier B.V. All rights reserved.