This paper presents the methodology of calculation of simultaneous chemical and phase equilibria in high-pressure processes using the hydration of propene to 2-propanol as an example. The mixture formed in the process is strongly nonideal. The calculations were carried out using the implementation (Wyczesany, A. Ind. Eng. Chem. Res. 1993, 32, 3072) of the intermediate method for nonideal systems based on the ideal system Brinkley-NASA-RAND (BNR) algorithm (Smith, W. R.; Missen, R. W. Chemical Reaction Equilibrium Analysis; Theory and Algorithms; Wiley : New York, 1982). Three approaches used for the description of system nonideality are compared. All approaches use appropriate equations of state (EOS) with mixing rules taking into account the fact that the interaction parameters k(ij) depend on temperature as well as on the composition. The models presented give a satisfactory description of simultaneous chemical and phase equilibria of the system containing supercritical components. The effect of temperature, pressure, and propane content in the feed stream on the equilibrium conversion is studied in detail.