Binary and ternary solubility of amino- and nitro-benzoic acids in supercritical carbon dioxide

In this paper, the solubility of 3-aminobenzoic acid (3-ABA) in supercritical carbon dioxide (SCCO2) was measured in a flow-type apparatus at temperatures of 308, 318, and 328 K within the pressure range of 10.0–21.0 MPa. Moreover, the solubility of the mixture of 3-ABA and 3-nitrobenzoic acid (3-NBA) with mass ratio of 1:1 was also investigated under the same condition. Its solubility reduction factor (SE), separation efficiency (HE) and mixture separation factor (μ) were also studied. Furthermore, a modified Bartle model was proposed for correlating the solubility of the solid chemicals in SCCO2 with solvent density and experimental temperature. The accuracy of the modified and the traditional Bartle model was compared by data from experiment and literature, in which 1106 solubility data points of two solutes in experiments and 49 solutes in literature were considered. The calculation results showed that the modified Bartle model can give a better prediction on the solubility of different solid solutes in SCCO2 than the traditional one.

► Solubility of 3-aminobenzoic acid and its mixture with 3-nitrobenzoic acid in SCCO2 was measured.
► A modified Bartle model was proposed.
► The accuracy of the new model was evaluated by experimental and literature solubility data in SCCO2.