Solubilities of substituted phenols in supercritical carbon dioxide

The binary (solute + CO 2) equilibrium solubilities of six substituted phenols (2,5-dimethyl phenol, 2,3-dimethyl phenol, 2,4,6-trimethyl phenol, 2,3,5-trimethyl phenol, 4-phenyl phenol, and 4-tert-butyl phenol) were determined at a temperature of 308 K in the pressure range of 10.1 to 28.0 MPa. Solubility data were obtained using a dynamic approach with a simple and reliable apparatus. The mole fraction solubilities of substituted phenols ranged from 5.14 × 10 -5 to 2.56 × 10 -2. Solubilities of three ternary (two solutes + CO 2) systems were investigated at a temperature of 308 K in the pressure range of 10.1 to 28.0 MPa. In the 4-phenyl phenol + 2,3,5-trimethyl phenol and 4-phenyl phenol + 2,4,6-trimethyl phenol systems, the solubility of 4-phenyl phenol was enhanced relative to its binary solubility by 22.9 % and 217 %, respectively. The 2,3,5-trimethyl phenol and 2,4,6-trimethyl phenol did not exhibit any solubility enhancements in the two ternary systems. Accurate solubilities could not be measured for the 2,5-dimethyl phenol + 4-tert-butyl phenol ternary system due to the existence of a liquid phase under the conditions studied. © 2006 American Chemical Society