High Pressure Phase Equilibria in the Systems Ammonia+Potassium Iodide, +Sodium Iodide, +Sodium Bromide, and +Sodium Thiocyanate: Solid–Liquid–Vapor and Liquid–Liquid–Vapor Equilibria

Solid salt liquid vapor equilibria and liquid liquid vapor equilibria were deter- mined experimentally for the binary system NH3+KI in the temperature range 333 to 673 K and at pressures up to 80 MPa. It is found that the system NH3+ KI belongs to Type V of fluid phase behavior according to the classification of van Konynenburg and Scott. The pressure of the three-phase curve solid salt liquid vapor is monotonically increasing in the temperature range investigated and reaches a value of 76 MPa at 670 K. The three-phase liquid liquid vapor curve starts in a lower critical end point at 407.3 K and 11.59 MPa and ends in an upper critical end point at 408.8 K and 11.92 MPa. For the systems NH3+ NaI, NH3+NaBr, and NH3+NaSCN, Type V fluid phase behavior is also found. In the system NH3+NaI, the lower critical end point is found at 406.8 K and 11.52 MPa and the upper critical end point at 408.5 K and 11.86 MPa. For the system NH3+NaBr, these coordinates are 404.6 K, 11.03 MPa and 408.8 K, 11.90 MPa, respectively, and, for the system NH3+NaSCN, 409.2 K, 11.99 MPa and 409.6 K, 12.06 MPa.