Solubility of dihydroxybenzene isomers in supercritical carbon dioxide

The equilibrium solubilities of dihydroxybenzene isomers pyrocatechol, resorcinol and hydroquinone have been measured in supercritical carbon dioxide using a simple static method. The measurements were performed in the pressure range from 120 to 400 atm at temperatures 35, 45, 55 and 65°C for pyrocatechol and resorcinol and in the pressure range from 120 to 200 atm at temperature 35°C for hydroquinone. The solubility of the isomers in supercritical CO2 was found to vary in the order pyrocatechol>resorcinol≫hydroquinone. The experimental data were correlated by use of the density based model proposed by Chrastil.