In this study, high-pressure phase behavior data, the pressure-composition (P-x) isotherms for the CO2 + T3EGDMA and CO2 + T4EGDMA binary mixture system, were measured using the static method with a variable-volume view cell at temperatures ranging from 313.2 to 363.2K. The experimental data correlation was performed using the Peng-Robinson Equation of State (PR-EOS) and the van der Waals one-fluid mixing rule. The critical constants for the PR-EOS were estimated using the several group contributions. The acentric factor was estimated using the Lee-Kesler method. The Joback method shows the better correlation results than the others. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.