Investigations on the solubility of anthraquinone dyes in supercritical carbon dioxide by a flow method

The solubility of 1,4-bis-(n-propylamino)-9,10-anthraquino in supercritical CO2 was measured spectroscopically by a flow method. Isotherms were record ed for temperatures and pressures from 305 to 340 K and from 7.5 to 20 MPa, respectively. Within the range of the experiments, the equilibrium concent rations become higher with increasing pressures and densities at constant t emperature. In the concentration vs. pressure plot the isotherms show inter section points, which can be explained by a density effect. (C) 1999 Elsevi er Science B.V. All rights reserved.