Single-component and mixture solubilities of ethyl p-hydroxybenzoate and ethyl p-aminobenzoate in supercritical CO2

The solubility of ethyl p-hydroxybenzoate, ethyl p-aminobenzoate in supercritical carbon dioxide was determined at (308, 318, 328 K) in the pressure range from 8 to 21 MPa in the case of pure ethyl p-hydroxybenzoate and pure ethyl p-aminobenzoate and for equalmolar mixtures of ethyl p-hydroxybenzoate and ethyl p-aminobenzoate. Experimental results show that in the binary systems the solubility of ethyl p-hydroxybenzoate was around one order of magnitude lower than that of ethyl p-aminobenzoate. In the ternary system the solubility of ethyl p-hydroxybenzoate was enhanced more significantly. This selectivity enhancement is larger at lower temperature and higher pressure. The binary and ternary solubility data were correlated using the Chrastil model with satisfactory agreement.