Measurement And Correlation Of Solubilities Of The New Environment-Friendly Trichromatic Disperse Dyes In Supercrtical Carbon Dioxide

Compared with the traditional water dyeing technology, supercritical carbon dioxide dyeing has received wide attention recently, which is a green and innovative method to reduce wastewater discharge and energy consumption and need less time with desired dyeing effect. For further development of the above research field, solubilities of dyes in supercritical fluid are necessary technological data.The solubilities of disperse red 73, blue 183 and yellow 119, which were the new environment-friendly trichromatic dyes, were measured over the temperature and pressure ranges of 343.2 K to 403.2 K and 12 MPa to 28 MPa by static recirculation method. As evidenced from the experimental results, over the entire experimental conditions, the solubilities increased with increasing pressure. The transition-pressure point (Before and behind this point, the solubility changes with temperature contrarily) of disperse blue 183 was at about 16 MPa, while the disperse red 73 and yellow 119's didn't appear. The solubilities were also affected obviously by molecular polarity of dyes.The solubilities of the mixture dyes were measured over the same experimental conditions. Disperse red 73 and disperse blue 183 promoted their solution in supercritical CO₂ each other. Therefore, the solubilities of disperse red 73 were higher than that in binary system (disperse red 73 + CO₂), and the disperse blue 183's were also higher after 16MPa.At mixed system of disperse red 73 and yellow 119, compared with the binary system, the solubilities of disperse red 73 in ternary system (disperse red 73 + disperse yellow 119 +CO₂ ) were lower, while the disperse yellow 119's were higher since entrainer effect and competition phenomenon appeared during the solving process of mixed dyes in supercritical CO₂.At mixed system of disperse blue 183 and yellow 119, owing to entrainer effect, the solubilities of disperse blue 183 were greater after 16MPa, and the disperse yellow 119's were also higher, compared with the binary system.The experimental solubilities of disperse dyes were correlated with two types of empirical models—the Chrastil, MT models and their modified models. The correlation results of modified models were in better agreement with the experimental data than their original models. Generally speaking, the calculation precision of Chrastil equation was better than MT's.