In a reactive dye, a chromophore (an atom or group whose presence is responsible for the colour of a compound) contains a substituent that reacts with the substrate. Reactive dyes have good fastness properties owing to the covalent bonding that occurs during dyeing. Reactive dyeing is the most important method for coloring cellulose fibers. Reactive dyes can also be applied on wool and nylon; in the latter case they are applied under weakly acidic conditions. Reactive dyes have a low utilization degree compared to other types of dyestuff, since the functional group also bonds to water, creating hydrolysis.[1]
Reactive dyes had been tested in the late 1800s involving both adding functionalized dyes to the substrate and then activating the substrate first followed by fixation of the dye. The first commercial success was described in the early 1950s. Rattee and Stephens at Imperial Chemical Industries (ICI) popularized the chlorotriazines as linkers between the substrate and the chromophore.
Trichlorotriazine remain a popular platform for reactive dyes. The chromophore, with an amine functional group, is attached to the triazine, displacing one chloride:
(NCCl)3 + dye-NH2 → N3C3Cl2(NHdye) + HCl
The resulting dichlorotriazine can then be affixed to the cellulose fibre by displacement of one of the two chloride groups:
The fixation process is conducted in a buffered alkaline dye bath.
An alternative fixation process that is more dominant commercially is the vinylsulfonyl group. Like the chlorotriazines, this functional group adds to the hydroxyl groups of cellulose. The most popular version of this technology is Remazol. The dye is first attached to the ethylsulfonyl group.
Methods for attaching reactive dyes to fibres (Cell = cellulose; R = chromophore).
Reactive dyes are categorized by functional group.[2]
Dyestuffs with only one functional group sometimes have a low degree of fixation. To overcome this deficiency, dyestuffs containing two (or more) different reactive groups were developed. These dyestuffs containing two groups are also known as bifunctional dyestuffs although some still refer to the original combination. Some contain two monochlorotriazines, others have a combination of the triazines and one vinyl sulfone group). Bifunctional dyes can be more tolerant to temperature deviations (better process). Other bifunctionals have been created, some with fastness (better quality) or only fixation degree (better environment or economy) in mind.[1]
^ abHorst Tappe, Walter Helmling, Peter Mischke, Karl Rebsamen, Uwe Reiher, Werner Russ, Ludwig Schläfer and Petra Vermehren "Reactive Dyes"in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a22_651
For more info Fundamental Chemistry of reactive dyes Advancements in Reactive Textile Dyes
January 20, 2023
reactive, reactive, chromophore, atom, group, whose, presence, responsible, colour, compound, contains, substituent, that, reacts, with, substrate, have, good, fastness, properties, owing, covalent, bonding, that, occurs, during, dyeing, most, important, metho. In a reactive dye a chromophore an atom or group whose presence is responsible for the colour of a compound contains a substituent that reacts with the substrate Reactive dyes have good fastness properties owing to the covalent bonding that occurs during dyeing Reactive dyeing is the most important method for coloring cellulose fibers Reactive dyes can also be applied on wool and nylon in the latter case they are applied under weakly acidic conditions Reactive dyes have a low utilization degree compared to other types of dyestuff since the functional group also bonds to water creating hydrolysis 1 Contents 1 Usage 1 1 Bi and polyfunctional reactive dyes 2 See also 3 Footnotes 4 External linksUsage EditReactive dyes had been tested in the late 1800s involving both adding functionalized dyes to the substrate and then activating the substrate first followed by fixation of the dye The first commercial success was described in the early 1950s Rattee and Stephens at Imperial Chemical Industries ICI popularized the chlorotriazines as linkers between the substrate and the chromophore Trichlorotriazine remain a popular platform for reactive dyes The chromophore with an amine functional group is attached to the triazine displacing one chloride NCCl 3 dye NH2 N3C3Cl2 NHdye HClThe resulting dichlorotriazine can then be affixed to the cellulose fibre by displacement of one of the two chloride groups N3C3Cl2 NHdye HO cellulose N3C3Cl NHdye O cellulose HClThe fixation process is conducted in a buffered alkaline dye bath An alternative fixation process that is more dominant commercially is the vinylsulfonyl group Like the chlorotriazines this functional group adds to the hydroxyl groups of cellulose The most popular version of this technology is Remazol The dye is first attached to the ethylsulfonyl group Methods for attaching reactive dyes to fibres Cell cellulose R chromophore Reactive dyes are categorized by functional group 2 Functionality Fixation Temperature Included in BrandsMonochlorotriazine Haloheterocycle 80 C Basilen E amp P Cibacron E Procion H HEMonofluorochlorotriazine Haloheterocycle 40 C Cibacron F amp CDichlorotriazine Haloheterocycle 30 C Basilen M Procion MXDifluorochloropyrimidine Haloheterocycle 40 C Levafix EA Drimarene K amp RDichloroquinoxaline Haloheterocycle 40 C Levafix ETrichloropyrimidine Haloheterocycle 80 98 C Drimarene X amp Z Cibacron TVinyl sulfone activated double bond 40 RemazolVinyl amide activated double bond 40 RemazolBi and polyfunctional reactive dyes Edit Dyestuffs with only one functional group sometimes have a low degree of fixation To overcome this deficiency dyestuffs containing two or more different reactive groups were developed These dyestuffs containing two groups are also known as bifunctional dyestuffs although some still refer to the original combination Some contain two monochlorotriazines others have a combination of the triazines and one vinyl sulfone group Bifunctional dyes can be more tolerant to temperature deviations better process Other bifunctionals have been created some with fastness better quality or only fixation degree better environment or economy in mind 1 See also EditCarbene dye Cationization of cotton for salt free dyeing Dyeing Dispersing agent for dyeingFootnotes Edit a b Horst Tappe Walter Helmling Peter Mischke Karl Rebsamen Uwe Reiher Werner Russ Ludwig Schlafer and Petra Vermehren Reactive Dyes in Ullmann s Encyclopedia of Industrial Chemistry 2000 Wiley VCH Weinheim doi 10 1002 14356007 a22 651 Stig Hjortshoj 1999 pp 44 45 External links EditFor more info Fundamental Chemistry of reactive dyes Advancements in Reactive Textile Dyes Retrieved from https en wikipedia org w index php title Reactive dye amp oldid 1127381651, wikipedia, wiki, book, books, library,
