Organic colorants reactive dyes

Organic colors caused by this mechanism are present in most biological colorations and in the triumphs of the dye industry (see Azinedyes Azo dyes Eluorescent whitening agents Cyanine dyes Dye carriers Dyes and dye intert diates Dyes, anthraquinone Dyes, application and evaluation Dyes, natural Dyes, reactive Polymethine dyes Stilbene dyes and Xanthenedyes). Both fluorescence and phosphorescence occur widely and many organic compounds are used in tunable dye lasers such as thodamine B [81-88-9], which operates from 580 to 655 nm. 

Resist Printing. In resist printing, print pastes are used that can inhibit the development or fixation of different dyes that are apphed to the textile prior to or after printing. These resists can be of a chemical or mechanical nature, or combine both methods. For example, fiber-reactive dyes, which require alkaU for their fixation, can be made resistant by printing a nonvolatile organic acid, such as tartaric acid, on the textile. Colored resists are obtained by printing pigments with a nonvolatile acid. 

In some cases (particularly reactive dyes) dyes can pass the aerobic, anaerobic degradation step and colored water is observed at the end of the treatment. In such cases a special treatment of the colored wastewater (reduction, adsorption, precipitation) has to be introduced [105,134-137]. In the presence of low concentrations of organic compounds, ozonation can be used as a final polishing step. 

Synthetic dyes are mainly aromatic organic compounds, and they can be classified as cationic (basic dyes), anionic (direct, acid, and reactive dyes), or nonionic (disperse dyes) type [134]. Synthetic dyes are mainly used in the textile industries, but they have many other applications such as in printing, leather, papermaking, drug, and food industries [85]. Total world colorant production is estimated to be... 

C. V. Stead, Chemistry of reactive dyes, in Colorants and Auxiliaries Organic Chemistry and Application Properties, ed. J. Shore, Society of Etyers and Colourists, Bradford, 1990, vol. 1, eh. 7. 

Nakazumi H., Amano S. Coloration of Glasses with organic reactive dyes. J. Chem. Soc. Chem. Conunun. 1992 1079-1080... 

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