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

Comprehensive phase diagrams of methanol/CHF3 and methanol/H2O/CHF3 mixtures over the temperature range of 25–100°C and pressure range of atmospheric 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 extraction. The phase behavior of methanol/CHF3 and methanol/H2O/CHF3 was compared to that of methanol/CO2 and methanol/H2O/CHF3. Fluoroform is markedly more miscible with methanol or methanol/H2O than is CO2. Data for methanol/CHF3 binary mixtures were also modeled by the Peng–Robinson equation of state. The correlation results showed that the PR equation of state with two temperature-independent binary parameters was capable of representing the experimental data over the entire temperature range with an average relative deviation within 6%.