A new model for the solubility of dye compounds in supercritical carbon dioxide

• A new model was proposed based on response surface methodology (RSM).
• The proposed model needs only the density of SCCO2 and temperature data.
• Existing fourteen density based models were evaluated for 29 dye compounds.
• New model was found to correlate better than the existing models in terms of %AARD.

The experimental data on the solubilities of solids in SCCO2 are important for the proper design of separation equipment's. But conducting solubility experiments for all the process conditions is time consuming, expensive and laborious. Therefore, modeling the solubilities of solids in SCCO2 is imperative. The empirical models are quite successful in correlating the solubilities of solids in SCCO2. In this work, the solubilities of literature reported data for 29 dye compounds were correlated using some of the commonly used density based semi-empirical models. The new model based on response surface methodology relates the solubility in terms of mole fraction to the density and temperature. The new model was found to correlate better for the set of dye compounds considered in this study than the most frequently used fourteen density based semi-empirical models in terms of percentage average absolute relative deviation (% AARD).