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

Abstract

To investigate the effect of polarity of organic liquids and the dispersion state of CO2 in organic liquids on the volume expansion of CO2 + organic liquid systems, the solubility of CO2 in methylbenzene and ethanol and the volume of CO2 + methylbenzene and ethanol at different temperatures and pressures were measured with a PVT apparatus. The results imply that the microscopic dispersion state of CO2 molecules in organic liquids under near-critical or supercritical conditions play a dominant role for increasing the volume of the CO2 + organic liquid systems. The microscopic dispersion state and the solubility of CO2 in the organic liquids and the volume expansion of the CO2 + 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 CO2 molecule and the organic liquids and the intermolecular force operating within the organic liquids play a dominate role in the volume expansion of the CO2 + organic liquid systems.