Prediction of Solid Solubility in Supercritical CO₂ Using Cubic Equations of State: A Comparative Study on Pharmaceuticals and Dyes

Upasana T Singh, Bhumika B Makwana

Abstract: Supercritical carbon dioxide (scCO₂) has emerged as a green and efficient solvent for the extraction of pharmaceuticals, dyes, and natural products. Accurate prediction of solid solubility in scCO₂ is critical for process design and optimization. This paper compares the performance of cubic equations of state (EOS) namely the Peng-Robinson (PR) and Soave Redlich Kwong (SRK) models combined with different mixing rules, in predicting the solubility of representative solutes. Literature data for pharmaceuticals such as ibuprofen, naproxen, ketoprofen, flurbiprofen, and loxoprofen, along with anthraquinone dye derivatives, were analyzed. Group contribution methods were employed to estimate missing physical constants. Results indicate that the PR EOS with van der Waals mixing rules provides the best agreement with experimental data, with average absolute relative deviations below 10% for most cases. The study highlights the applicability of cubic EOS-based thermodynamic modeling to complex solute systems, while also noting the limitations for associating compounds that may require molecular-based EOS such as SAFT.

Keywords: Supercritical Fluid, Solubility, Cubic Equation of State, Thermodynamic Modeling, Pharmaceuticals, Dyes

How to Cite?: Upasana T Singh, Bhumika B Makwana, "Prediction of Solid Solubility in Supercritical CO₂ Using Cubic Equations of State: A Comparative Study on Pharmaceuticals and Dyes", Volume 11 Issue 11, November 2022, International Journal of Science and Research (IJSR), Pages: 1559-1563, https://www.ijsr.net/getabstract.php?paperid=SR221212163804, DOI: https://dx.doi.org/10.21275/SR221212163804