Solubilities of CI Disperse Orange 25 and CI Disperse Blue 354 in supercritical carbon dioxide

Solubilities of C.I. Disperse Orange 25 (3-[N-ethyl-4-(4-nitrophenylazo)phenylamino]propionitrile) and C.I. Disperse Blue 354 ([2-[[4-(dihexylamino)-2-methylphenyl]methylene]-1,1-dioxidobenzo[b]thien-3(2H)-ylidene]propanedinitrile) in supercritical carbon dioxide were measured by a flow-type apparatus. The solubility measurements were carried out at the temperature range from (323.15 to 383.15) K and the pressures from (10.0 to 30.0) MPa. The solubility of the dyes was examined in terms of pressure, temperature, and the density of supercritical carbon dioxide. An empirical equation was used to correlate the experimental solubilities of the dyes in terms of the density of carbon dioxide. Furthermore, the experimental data were represented successfully using a modified form of the PRSV (Peng-Robinson-Stryjek-Vera) EOS (equation of state), where vapor pressures and molar volumes of the dyes were calculated simultaneously.