MEASUREMENT AND CORRELATION OF SOLUBILITIES FOR TRIFLUOROMETHYLBENZOIC ACID ISOMERS IN SUPERCRITICAL CARBON DIOXIDE

摘要

The solubilities of 2- and 3-trifluoromethylbenzoic acids in supercritical carbon dioxide were measured at 308.2, 313.2 and 323.2 K by a flow-type apparatus. The pressure range of the measurement was from 9 to 23 MPa. The enhancements of solubility by fluorination were markedly observed. The experimental data were correlated by the Peng-Robinson equation of state. The correlated results show good agreement with the experimental data by adjusting binary interaction parameters. A molecular dynamics simulation was applied to investigate interactions between carbon dioxide and solutes. The interaction between carbon dioxide and 3-trifluoromethylbenzoic acid is larger than that between carbon dioxide and 2-trifluoromethylbenzoic acids. This fact coincide with the tendency of solubility enhancement.