Measurement and Modeling of Epigallocatechin Gallate Solubility in Supercritical Carbon Dioxide Fluid with Ethanol Cosolvent

To extract epigallocatechin gallate (EGCG) by supercritical carbon dioxide, it is necessary to determine the solubility of EGCG in supercritical carbon dioxide fluid with cosolvents. In this study, the solubility of EGCG was determined in supercritical fluid with different mole fractions of ethanol cosolvent of 0.044 and 0.084 at temperatures ranging from (313 to 333) K and pressures from (15 to 35) MPa. EGCG solubility increased with the mole fraction of ethanol cosolvent. The maximum mole fraction solubility of EGCG under supercritical carbon dioxide is 7.34.10(-4) at a pressure of 35 MPa, temperature of 313 K, and mole fraction of ethanol of 0.084. The thermodynamic model, modified Chrastil model, and Mendez-Santiago and Teja model were applied to correlate the solubility data of EGCG in supercritical fluid containing an ethanol mole fraction of 0.084, with an average absolute relative deviation (AARD) of 0.1316, 0.1103, and 0.1109, respectively. While in supercritical CO2 containing 0.044 ethanol, AARDs of the modified Chrastil model, Mendez-Santiago and Teja model are 0.0745 and 0.0776, respectively. The results show that the modified Chrastil model and Mendez-Santiago and Teja model have a better correlation effect than the thermodynamic model.