Phase diagram studies of methanol-CHF3 and methanol-H2O-CHF3 mixtures

Comprehensive phase diagrams of methanol/CHF3 and methanol/H2O/CHF3 mixture s over the temperature range of 25-100 degrees C and pressure range of atmo spheric to 340 atm are reported. Fluoroform is expected to be useful as an alternative to CO2 for enhancing the fluidity of liquid mixtures due to its high polarity and low viscosity. Therefore, these mixtures will be studied as mobile phases for enhanced-fluidity liquid chromatography and extractio n. The phase behavior of methanol/CHF3 and methanol/H2O/CHF3 was compared t o that of methanol/CO2 and methanol/H2O/CHF3. Fluoroform is markedly more m iscible with methanol or methanol/H2O than is CO2. Data for methanol/CHF3 b inary mixtures were also modeled by the Peng-Robinson equation of state. Th e correlation results showed that the PR equation of state with two tempera ture-independent binary parameters was capable of representing the experime ntal data over the entire temperature range with an average relative deviat ion within 6%. (C) 1999 Elsevier Science B.V. All rights reserved.