Abstract: The target of this study was to investigate the feasibility of wax/catalyst separation process using near-critical hexane, by proposing two reasonable EOS`s used for hydrocarbons near-critical density/viscosity estimation. This target was accomplished by studying some theoretical correlations used for hydrocarbons density and viscosity prediction, which have the capability of functioning at near-critical region. According to this investigation, the reasonable VTPR equation-of-state was proposed for density calculation. Furthermore, based on the similarity between P-v-T and T-μ-P relationships, an appropriate MPR EOS-based viscosity model was suggested for viscosity estimation. The advantages of these correlations in terms of accuracy, applicability to both gas/liquid, high pressure/low pressure and having smooth phase transition in the near-critical region were investigated for n-hexane, wax and some hydrocarbon mixtures by making comparison between the calculated properties and the experimental one`s. At the last part, wax/catalyst separation tests using near-critical hexane were carried out in conjunction with physical properties calculations by the suggested EOS`s. The main objective was understanding the consistency of density/viscosity values with separation efficiencies amounts in quality and in fact the process analysis. Test results showed that maximum separation efficiency occurred in applying supercritical hexane state. In addition, based on the proposed EOS`s estimation, the lowest densities and viscosities values were gained at this phase, that these two outcomes of this investigation were also in line with the Stoke`s theorem.