Anthraquinone dyes on:
[Wikipedia]
[Google]
[Amazon]
Anthraquinone dyes are an abundant group of dyes comprising a anthraquinone unit as the shared structural element. Anthraquinone itself is colourless, but red to blue dyes are obtained by introducing electron donor groups such as hydroxy or amino groups in the 1-, 4-, 5- or 8-position. Anthraquinone dyestuffs are structurally related to indigo dyestuffs and are classified together with these in the group of carbonyl dyes.
Members of this dye group can be found in
One of the most important anthraquinone dyes of herbal origin is
:Synthesis of 1-aminoanthraquinone
Sulfonation in α position is reversible and both the sulfonic acid groups and the nitro groups can be relatively easily replaced by amino, alkylamino, hydroxy and 
:Synthesis of bromamic acid
By replacing the bromine substituent with an aliphatic or aromatic amine, vibrant blue dyes are obtained. For example, bromamic acid can be condensed with 3-(2-hydroxyethylsulfonyl)-aniline (7) to form the vibrant blue dye (8) (oxysulfone blue), from which the reactive dye C.I. Reactive Blue 19 is obtained after 
:Synthesis of C.I. Reactive Blue 19
Reactive Blue 19 is one of the oldest and still the most important reactive dyes, patented in 1949.
The first anthraquinone-based synthetic vat dye was indanthrone (C.I. Vat Blue 4) - the synthesis of which was developed by René Bohn in 1901:
:
:Synthesis of indanthrone
By dimerization of 2-aminoanthraquinone (1) under strongly alkaline conditions at 220-235 °C, intermediate stage 3 is obtained in two steps, which is cyclized intramolecularly and oxidized to indanthrone 5.{{citation , first=Heinrich , last=Zollinger , edition=3rd , publisher=WILEY-VCH Verlag, publication-place=Weinheim, page=289, isbn=3-906390-23-3, date=2003 , title=Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments
Anthraquinone dyes are an abundant group of dyes comprising a anthraquinone unit as the shared structural element. Anthraquinone itself is colourless, but red to blue dyes are obtained by introducing electron donor groups such as hydroxy or amino groups in the 1-, 4-, 5- or 8-position. Anthraquinone dyestuffs are structurally related to indigo dyestuffs and are classified together with these in the group of carbonyl dyes.
Members of this dye group can be found in natural dyes
Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, and wood—and other biological sources such as fungi.
Archaeolo ...
as well as in synthetic dyes
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...
. Anthraquinone dyestuffs are represented in mordant
A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in ...
and vat
A value-added tax (VAT), known in some countries as a goods and services tax (GST), is a type of tax that is assessed incrementally. It is levied on the price of a product or service at each stage of production, distribution, or sale to the en ...
, but also in reactive
Reactive may refer to:
*Generally, capable of having a reaction (disambiguation)
*An adjective abbreviation denoting a bowling ball coverstock made of reactive resin
*Reactivity (chemistry)
*Reactive mind
*Reactive programming
See also
*Reactanc ...
and disperse dyes. They are characterized by very good light fastness.
Natural anthraquinone dyes
One of the most important anthraquinone dyes of herbal origin is alizarin
Alizarin (also known as 1,2-dihydroxyanthraquinone, Mordant Red 11, C.I. 58000, and Turkey Red) is an organic compound with formula that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historic ...
, which is extracted from the dyer's madder ( Rubia tinctorum). Alizarin is the eponym
An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''.
Usage of the word
The term ''epon ...
for a number of structurally related dyes that use alizarin dyes (sometimes synonymous with anthraquinone dyes). It was the first natural dye for which an industrial synthesis was developed as early as 1869.
Anthraquinone dyes include red insect dyes derived from scale insects such as carminic acid, kermesic acid and laccainic acids. The colorant carmine with the main component carminic acid is used, for example, as an approved food colorant
Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used in both commercial fo ...
E 120. The traditional methods for carmine production are labour, land, and insect-intensive. Because demand for red dyes is predicted to increase, researchers are exploring metabolic engineering approaches for the production of synthetic carminic acid.
Synthetic anthraquinone dyes
The synthesis of most anthraquinone dyes is based on anthraquinone sulfonic acid (2) or nitroanthraquinone (3), which is obtained bysulfonation Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. Aryl sulfonic acids are used as detergents, dye, and drugs.
Stoichiometry a ...
or nitration
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols an ...
of anthraquinone (1).
:
:Synthesis of 1-aminoanthraquinone
Sulfonation in α position is reversible and both the sulfonic acid groups and the nitro groups can be relatively easily replaced by amino, alkylamino, hydroxy and alkoxy groups
In chemistry, the alkoxy group is an alkyl group which is singularly bonded to oxygen; thus . The range of alkoxy groups is vast, the simplest being methoxy (). An ethoxy group () is found in the organic compound ethyl phenyl ether (, also k ...
. Aminoanthraquinone (4) is thus accessible by reaction of anthraquinone sulfonic acid with ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
or by reduction of nitroanthraquinone.
An important intermediate product for many acid anthraquinone dyes is bromamic acid (1-amino-4-bromoanthraquinone-2-sulfonic acid) (6), which can be obtained from 1-aminoanthraquinone (4) by sulfonation with chlorosulfonic acid and subsequent bromination
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polyme ...
.
:
:Synthesis of bromamic acid
By replacing the bromine substituent with an aliphatic or aromatic amine, vibrant blue dyes are obtained. For example, bromamic acid can be condensed with 3-(2-hydroxyethylsulfonyl)-aniline (7) to form the vibrant blue dye (8) (oxysulfone blue), from which the reactive dye C.I. Reactive Blue 19 is obtained after esterification
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
with sulfuric acid.
:
:Synthesis of C.I. Reactive Blue 19
Reactive Blue 19 is one of the oldest and still the most important reactive dyes, patented in 1949.
The first anthraquinone-based synthetic vat dye was indanthrone (C.I. Vat Blue 4) - the synthesis of which was developed by René Bohn in 1901:
:
:Synthesis of indanthrone
By dimerization of 2-aminoanthraquinone (1) under strongly alkaline conditions at 220-235 °C, intermediate stage 3 is obtained in two steps, which is cyclized intramolecularly and oxidized to indanthrone 5.{{citation , first=Heinrich , last=Zollinger , edition=3rd , publisher=WILEY-VCH Verlag, publication-place=Weinheim, page=289, isbn=3-906390-23-3, date=2003 , title=Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments
References