HIGH-PRESSURE PHASE-EQUILIBRIA OF THE SYSTEM PHENOL-M-CRESOL-CARBON DIOXIDE

The ternary system composed of phenol, m-cresol and supercritical carb on dioxide is characterized by unusual phase behaviour. In fact the te rnary diagram shows five distinct regions: a three phase region of sol id-liquid-gas, two two phase regions liquid-solid and liquid-gas, and two single phase regions liquid and gas. In addition when pressure was increased and temperatures were below the temperature of fusion of ph enol, it was observed that the carbon dioxide causes recrystallization of phenol from the liquid phase. To understand and to describe all th ese phenomena, several experimental measurements were performed and ar e reported in this paper. Finally, using all the available data for th e pure compounds as well as for the three binary sub-systems, a modifi ed Peng-Robinson Equation of State was parametrized and then used to d escribe, at least qualitatively, the multicomponent multiphase behavio ur in the whole range of composition under different values of pressur e and temperature.