High pressure phase equilibria in the systems ammonia plus potassium iodide, plus sodium iodide, plus sodium bromide, and plus sodium thiocyanate: Solid-liquid-vapor and liquid-liquid-vapor equilibria

Solid salt-liquid-vapor equilibria and liquid-liquid-vapor equilibria were determined 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, espectively, and, for the system NH3 + NaSCN, 409.2 K, 11.99 MPa and 409.6 K, 12.06 MPa.