Equilibria Data for the CO₂ + Ethanol + Ketoprofen Systems – Experimental and Modeling

This study investigated the solid–fluid and vapor–liquid equilibrium of varying the molar fraction of ketoprofen in binary system (CO₂ + ketoprofen), 3.14 × 10^–5, 4.70 × 10^–5 and 8.11 × 10^–5, and the concentration of ketoprofen in ternary system (CO₂ + ethanol + ketoprofen), 0.05073 and 0.10277 mol_Ketoprofen·kg_ethanol⁻¹, on a CO₂-free basis for both systems. The aim was to study the solubility of ketoprofen at different molar fractions and predict its behavior over a wide range of temperatures and pressures by means of thermodynamic modeling. Experiments were conducted as a function of temperature from 313 to 333 K and pressure up to 14 MPa, using a visual synthetic static method with a variable volume cell. The collected data highlight an increase of the ketoprofen solubility with the temperature, while a ketoprofen content has a low impact on the bubble point pressure of the tested ternary system. Data were then correlated by using the thermodynamic modeling employed the Redlich–Kwong–Peng–Robinson equation of state (RK–PR EoS) with quadratic mixing rules for fluid phases and a pure solid model for ketoprofen. Then, a number of complete isopleths at set global composition were computed for the CO₂ + ketoprofen binary system being indicated solid–fluid, solid–fluid–fluid, and fluid–fluid regions. The obtained results suggest that the thermodynamic models used in this work were able to describe the experimentally observed phase behavior.