REACTIVE DYE

Reactive Dyes Reactive dyes are dyes which usually have the basic structure of acid, direct, or mordant dyes but which in addition have a reactive group capable of covalent bond formation with the fiber. Since the fiber must have reasonable reactivity toward the dye reactive group, application of these dyes has been limited to cellulosic, protein, and nylon fibers for the most part. 

The fastness of reactive dyes covalently bound to the fiber is excellent. Reactive functional groups have been selected for incorporation into reactive dyes which will react readily with the fiber after diffusion into the structure but which will not hydrolyze (decompose) in the water solvent used in dye application. Acidic or basic conditions are necessary for successful and rapid reaction of the reactive dye with the fiber, so dye appl ication is carried out at either si ightly acid or basic pH (hydrogen ion concentration). Procion dyes are the best known of the reactive dyes. 

Dves Containing Cationic Groups tBasic Dvest 

The most important distinguishing characteristic of reactive dyes is that they form covalent bonds with the substrate that is to be colored during the application process. Thus, the dye molecule contains specific functional groups that can undergo addition or substitution reactions with the OH, SH, and NH2 groups present in textile fibers. 

Cross and Bevan first succeeded in fixing dyes covalently onto cellulose fibers (in 1895) [1], but their multistep process was too complicated for practical application. Early work by Schroter with sulfonyl chloride-based dyes was unsuccessful [2], but Gunther later did succeed in fixing derivatives of isatoic anhydride onto cellulose fibers [3], 

The first industrially important reactive dye systems were developed for wool, and took advantage of the chloroacetylamino [6] and the chloroethanesulfonyl groups [7], Vinylsulfonyl- and 2-sulfooxyethanesulfonyl groups were found to be applicable to both wool and cellulose. Heyna and Schumacher patented some of the first dyes of this type in the 1940s [8,9], and vinylsulfone dyes continue to be of great importance. 

The dyes described in [8] entered the market for wool in 1952 under the trade name Remalan, followed a year later by the Cibalan dyes from Ciba-Geigy, which contained monochlorotriazinyl reactive groups [10], In 1953 Rattee and Stephen 

Contrary to other dye groups reactive dyes are characterized by known chromo-phore systems, as described in this book, and by bearing various reactive moeties in their molecules. Thus, dye systems which are used to form reactive dyes comprise all industrial important groups of dyes. Consequently, the classification in this section is primarily according to the various reactive groups. 

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Azopyrazolones Azopyridones Azo reactive dyes Azoreductases Azorhizobium... 

Black phosphorus Black powder Black reactive dyes Black Rubber 3773... 

Bluepnnts Blue reactive dyes Blue-Shield Blue-sky estimating Blue steel... 

Dyes for leather Dyes, natural Dyes, reactive Dyes, sensitizing... 

Fiber optics cables Fiber optic waveguides Fiber-reactive dyebath Fiber reactive dyes... 

See also phosphorous acid.) [PHOSPHORUS COMPOUNDS] (Vol 18) Phosphomc acid reactive dyes... 

Procion dyes Procion H Procion H dyes Procion HE Procion H-E dyes Procion MX Procion MX dyes Procion P dyes Procion reactive dyes Procion Red H-E 7B Procion SP Procion supra dyes Procion T PROCOmi Proconvertin [9001-25-6] Proctitis... 

Violet leaf absolute Violet reactive dyes Viologens... 

Yellow reactive dyes Yellow-tip index Yerba santa Yersinia Yersinia pestis Yield stresses Yittnum Ylang-ylang Ylang-ylang oil... 

A series of fiber-reactive dyes have been made by the reaction of Sulforhodamine B with chlorosulfonic acid, an appropriately substituted diamine, and cyanutic chloride to yield dyes, eg, a Sulforhodamine B derivative (34), with good hghtfastness (42). 

Standard polyester fibers contain no reactive dye sites. PET fibers are typically dyed by diffusiag dispersed dyestuffs iato the amorphous regions ia the fibers. Copolyesters from a variety of copolymeri2able glycol or diacid comonomers open the fiber stmcture to achieve deep dyeabiHty (7,28—30). This approach is useful when the attendant effects on the copolyester thermal or physical properties are not of concern (31,32). The addition of anionic sites to polyester usiag sodium dimethyl 5-sulfoisophthalate [3965-55-7] has been practiced to make fibers receptive to cationic dyes (33). Yams and fabrics made from mixtures of disperse and cationicaHy dyeable PET show a visual range from subde heather tones to striking contrasts (see Dyes, application and evaluation). 

For fluorine-free products, the labiUty of fluorine in fluoronitrobenzenes and other activated molecules permits it to serve as a handle in hair-dye manufacturing operations, high performance polymers such as polyetheretherketone (PEEK), production of dmgs such as diuretics, and fiber-reactive dyes. Labile fluorine has also been used in analytical appHcations and biological diagnostic reagents. 

FLUOROPYRIMIDINES Fluoropyrknidines find diverse use in cancer chemotherapy and other dmg appHcations, as well as in fiber-reactive dyes. Table 13 fists physical properties of representative fluoropyrknidines. 

Chloro-2,4,6-trifluoropyrimidine [697-83-6] has gained commercial importance for the production of fiber-reactive dyes (465,466). It can be manufactured by partial fluoriaation of 2,3,5,6-tetrachloropyrimidine [1780-40-1] with anhydrous hydrogen fluoride (autoclave or vapor phase) (467) or sodium fluoride (autoclave, 300°C) (468). 5-Chloro-2,4,6-trifluoropyrimidine is condensed with amine chromophores to provide the... 

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