High-pressure investigations on the solubility of dispersion dyestuffs in supercritical gases by VIS/NIR-spectroscopy. Part I - 1,4-Bis-(octadecylamino)-9,10-anthraquinone and disperse orange in CO2 and N2O Up to 180 MPa

Abstract

Solubilities of 1-benzazo-4-(4′-hydroxybenzazo)-naphthalene (Disperse Orange 13) and 1,4-bis-(octadecylamino)-9,10-anthraquinone in supercritical CO2 and N2O were measured using VIS/NIR-spectroscopy over the pressure and temperature ranges of 7 to 180 MPa and 305 to 410 K, respectivel. The solubility measurements were performed using VIS-spectroscopy for the concentration range of 10-6 < 10-4, whereas the higher concentrations (10-2 < 10-1) of the anthraquinone dyestuff in N2O at 360 K were measured using NIR-spectroscopy. Separate measurements were also performed according to the synthetic method. For Disperse Orange 13 in CO2 some p(c) isotherms are observed to intersect. This behavior is explained in terms of a density effect. For the anthraquinone dyestuff dissolved in CO2 or N2O, maxima concentrations on the c(p) isotherms were found at about 65 MPa. © 1995.