Correlation and estimation of solubilities of fatty acids in supercritical carbon dioxide using solution model approach

⿢Solid solubility data of five fatty acids and three triglycerides in supercritical carbon dioxide are correlated using a two-parameter solution model.⿢Two new predictive solution models are proposed for predicting the solubilities of fatty acids and triglycerides in supercritical carbon dioxide.⿢The predictive solution models yielded average deviation in predicted solubilities of 22.1% and 29.8% for fatty acids and triglycerides.

In this study, solid solubility data of five fatty acids in supercritical carbon dioxide (CO2) at different temperatures and pressures are correlated using a two-parameter solution model developed from the regular solution model coupled with the Flory⿿Huggins equation. The developed solution model with fewer parameters yields correlated results comparable to those from commonly used semi-empirical equations. In addition, both parameters in the solution model can be further generalized with the chain length of fatty acids and a new predictive solution model is proposed for solubility prediction. The predictive solution model proposed in this study provides better predicted results and yields average deviation in predicted solubilities of 22.1%. To further apply this solution model to other compounds, solid solubility data of three triglycerides in supercritical CO2 at 313 K are also correlated. After model simplification and generalization, a new predictive solution model for triglycerides is also proposed, which yields average deviation in predicted solubilities of 29.8%. These results demonstrate that the solution model used in this study is applicable for correlation and prediction of solid solubilities of structure-related compounds in supercritical CO2.

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