Effect of pressurized carbon dioxide on mutual miscibility temperatures for methanol + hydrocarbon binary liquid mixtures

An apparatus has been developed for the measurement of mutual miscibility temperatures of binary liquid mixtures coexisting with a high pressure gas to examine to what extent the phase behavior changes. Methanol + hydrocarbon (cyclohexane, hexane, octane, and decane) binary mixtures were selected as typical polar and non-polar mixtures. And their mutual miscibility temperatures were measured at temperatures from 275.4 to 363.9 K and pressures up to 2.2 MPa with pressurized carbon dioxide (CO₂. The experimental results were correlated with the NRTL equation by adopting a pseudo-binary mixture treatment. The NRTL interaction parameters between methanol and hydrocarbons were assumed to vary due to the presence of CO₂. A good agreement between the experimental and the correlated mutual miscibility temperatures is obtained.