Synthesis And Characterization Of Special Reactive Disperse Dyes Applicable In Supercritical Carbon Dioxide Fluid

Reactive disperse dyes not only have the hydrophobic property of disperse dyes, but also involve active groups which can reactive with natural fibers and combined with covalent bonds. Therefore, reactive disperse dyes with its excellent characteristics in dyeing of natural fibers in supercritical carbon dioxide have a good developing prospect.A lot of strong acid at high concentrations is generally used to prepare the diazonium salt of weakly alkaline aromatic amines. As a result, resources are wasted and a large amount of wastewater is discharged into the environment.In response to these circumstances, the mixed solvent of polyethylene glycol peg 200 and water was used as an environmental and mild reaction medium in this paper. Using weakly alkaline aromatic amines 2-chloro-4-nitroaniline as the diazo component, aniline, m-toluidine, m-methoxyaniline as coupling components, three azoic intermediates of special reactive disperse dyes in supercritical carbon dioxide fluid were prepared by diazotization and coupling reaction. The yields of of the crude products of three intermediates were 96.38%, 92.25%, 97.55% respectively. The purities of the crude intermediates determined by HPLC were 96.11%, 75.96%, 36.60%, respectively. The maximum characteristic wavelengths of three intermediates determined by the UV-visible spectra in ethanol were 381 mn, 395 nm, 496 nm respectively. The structures of three intermediates were characterized by mass spectrometry and elemental analysis. The synthetic process of the intermediate of reactive disperse dyes without purification using aniline as the coupling component was optimized and the recommended process was: the mole ratio of the diazo component 2-chloro-4-nitroaniline to hydrochloric acid, sodium nitrite and aniline was 1:10:1.1:1.1, the diazotization temperature was 0~10 ℃, the diazotization time was 2.5h, the p H value of the coupling reaction system was around 6, the coupling reaction temperature was 0~5℃, the coupling reaction time was 4h.Using the above prepared intermediates of reactive disperse dyes without purification as the parent, cyanuric chloride as the active group, Na OH as the acid binding agent, three special triazine reactive disperse dyes in supercritical carbon dioxide fluid were synthesized by condensation reaction at low temperatures. The yields of the crude products of the three reactive disperse dyes were 55.29%, 70.62%, 94.73%, and their purities were 98.31%, 49.15%, 30.20%, respectively. The maximum characteristic wavelengths of three reactive disperse dyes determined by the UV-visible spectra in ethanol were 357 nm, 326 nm, 370 nm respectively. The structures of three reactive disperse dyes were characterized by FT-IR, 1HNMR and mass spectrometry. The synthetic process of the special triazine reactive disperse dyes in supercritical carbon dioxide fluid without purification using aniline as the coupling component was optimized and the recommended process was: the mole ratio of the intermediate of reactive disperse dyes without purification using aniline as the coupling component to cyanuric chloride, Na OH was 1:1.5:1, the condensation reaction time was 2h.