Determination of the Upper Critical Solution Temperature in the Phenol-Water Binary System Thermodynamic Analysis

Rebie.M.N. Jallah; Abdunnaser megrahi; Khayriya Rahouma; Fatma Hebail

Authors

Rebie.M.N. Jallah Chemistry Department, Faculty of Education Janzour, University of Tripoli, Libya Author
Abdunnaser megrahi Chemistry Department, Faculty of Education Janzour, University of Tripoli, Libya Author
Khayriya Rahouma Chemistry Department, Faculty of Education Janzour, University of Tripoli, Libya Author
Fatma Hebail Chemistry Department, Faculty of Education Janzour, University of Tripoli, Libya Author

Keywords:

Upper critical solution temperature, UCST, phenol and water, phase equilibrium, liquid-liquid equilibrium, partial miscibility, thermodynamic properties.

Abstract

This study investigates the phase behavior of binary phenol-water mixtures by determining the upper critical solution temperature (UCST). Eight mixtures were prepared with phenol weight percentages ranging from 12.0% to 65.4%, each with a total mass of 4 grams. The mixtures were heated to complete miscibility and then gradually cooled while observing the phase transitions. The temperature at which turbidity first appeared was recorded and averaged with the homogenization temperature to determine the UCST for each formulation. The UCST curve showed a maximum value of approximately 66.0 °C at a phenol weight percentage of 45.4%, a value consistent with those reported in the scientific literature but with improved accuracy. These results provide valuable thermodynamic data for industrial applications involving phase separation processes, particularly in the chemical and pharmaceutical fields where phenol-water systems are prevalent. The methodology used provides a reliable approach for conducting similar studies on other binary liquid mixtures.