Solubility of 1,5-Diaminobromo-4,8-dihydroxyanthraquinone in Supercritical Carbon Dioxide with or without Cosolvent

Dissolution of 1,5-diaminobromo-4,8-dihydroxyanthraquinone (C.I. Disperse Blue 56) in supercritical carbon dioxide was investigated at 393.15 K and 30 MPa over a wide range of contact times. Saturated solubility data of the disperse dyestuff in supercritical carbon dioxide with or without cosolvent were also measured at temperatures from (353.15 to 393.15) K and pressures up to 30 MPa. Either ethanol or dimethyl sulfoxide (DMSO) was used as a cosolvent. The experimental results showed that the equilibrium solubility can be effectively enhanced in the presence of both cosolvents. DMSO was found to yield higher solubility enhancement. The saturated solubility data were correlated with the Charstil and the Mendez-Santiago and Teja models. These two models correlated the solubility data to about within the experimental uncertainty.