Vapor pressure and liquid density of 1-butyl-3-methylimidazolium hexafluorophosphate and ammonia mixtures

Vapor pressures and liquid densities for 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]) and ammonia (NH₃) mixtures were measured over a wide range of temperatures (283.15 to 363.15 K) and mole fractions. The vapor pressures of the mixtures were measured with a static method. The measurement expanded uncertainty in the vapor pressure was 0.5%-5.0% (k = 2). The experimental values were compared with literature data and correlated with Antoine's equation with an average absolute deviations of 1.85% and a bias of 0.01%. The estimated expanded uncertainty (0.95 level of confidence) of this correlation was 5%. Liquid densities of the [BMIM][PF₆] and NH₃ mixtures were measured in the temperature range of 283.15-363.15 K and a pressure range of 10.0 to 30.0 MPa. Liquid densities were measured with a piezometer. The measurement expanded uncertainty in the density was 0.2% (k = 2). The experimental values were correlated with a Tait equation with an average absolute deviations of 0.06% and a bias of -0.01%. The estimated expanded uncertainty (0.95 level of confidence) of this correlation was 0.2%.