Dispersion Property of CO2 in Oil. 2: Volume Expansion of CO2 + Organic Liquid at Near-Critical and Supercritical Conditions of CO2

To investigate the effect of polarity of organic liquids and the dispersion state of CO 2 in organic liquids on the volume expansion of CO 2 + organic liquid systems, the solubility of CO 2 in methylbenzene and ethanol and the volume of CO 2 + methylbenzene and ethanol at different temperatures and pressures were measured with a PVT apparatus. The results imply that the microscopic dispersion state of CO 2 molecules in organic liquids under near-critical or supercritical conditions play a dominant role for increasing the volume of the CO 2 + organic liquid systems. The microscopic dispersion state and the solubility of CO 2 in the organic liquids and the volume expansion of the CO 2 + organic liquid systems are affected by the polarity and the structure of the organic liquid molecule obviously. When pressure and temperature are fixed, the intermolecular force between CO 2 molecule and the organic liquids and the intermolecular force operating within the organic liquids play a dominate role in the volume expansion of the CO 2 + organic liquid systems.