Solubilities of disperse dyes of blue 79, red 153, and yellow 119 in supercritical carbon dioxide

Extraction of disperse blue 79, red 153, and yellow 119 with supercritical carbon dioxide was investigated, respectively, at 393.2 K and 30 MPa over a wide range of contact times. The dissolution rates of these three dyestuffs were compared. Equilibrium solubilities were also measured over the temperature and pressure ranges of 353.2–393.2 K and 15–30 MPa. As evidenced from the experimental results, the solubilities increase dramatically with increasing pressure and are not as sensitive to temperature. The magnitudes of the solubilities are in the sequence of disperse blue 79>disperse yellow 119>disperse red 153 as pressures higher than 20 MPa. The equilibrium solubility data were correlated with the Chrastil equation. The association numbers of the Chrastil model are approximately 10, 8, and 7 for disperse blue 79/CO2, disperse red 153/CO2, and disperse yellow 119/CO2, respectively.