Anthraquinone dyes

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Anthraquinone Anthraquinone Numeration.svg
Anthraquinone

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. [1] Anthraquinone dyestuffs are structurally related to indigo dyestuffs and are classified together with these in the group of carbonyl dyes. [2]

Contents

Members of this dye group can be found in natural dyes as well as in synthetic dyes. Anthraquinone dyestuffs are represented in mordant and vat, but also in reactive and disperse dyes. They are characterized by very good light fastness. [3]

Natural anthraquinone dyes

Alizarin Alizarin.svg
Alizarin

One of the most important anthraquinone dyes of herbal origin is alizarin, which is extracted from the dyer's madder (Rubia tinctorum). Alizarin is the eponym 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 laccaic acids. The colorant carmine with the main component carminic acid is used, for example, as an approved food colorant E 120. [4] 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. [5] [6]

Synthetic anthraquinone dyes

The synthesis of most anthraquinone dyes is based on anthraquinone sulfonic acid (2) or nitroanthraquinone (3), which is obtained by sulfonation or nitration of anthraquinone (1).

Synthesis 1-Aminoanthraquinone.svg
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. Aminoanthraquinone (4) is thus accessible by reaction of anthraquinone sulfonic acid with ammonia or by reduction of nitroanthraquinone. [7]

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.

Synthesis Bromaminic Acid.svg
Synthesis of bromamic acid

By replacing the bromine substituent with an aliphatic or aromatic amine, vibrant blue dyes are obtained. [8] 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 with sulfuric acid.

Synthesis Reactive Blue 19.svg
Synthesis of C.I. Reactive Blue 19

Reactive Blue 19 is one of the oldest and still the most important reactive dyes, [9] patented in 1949. [10]

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 Indanthrone.svg
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. [11]

Related Research Articles

<span class="mw-page-title-main">Dye</span> Soluble chemical substance or natural material which can impart color to other materials

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 may require a mordant to improve the fastness of the dye on the fiber.

<span class="mw-page-title-main">Alizarin</span> Chemical compound and histologic stain

Alizarin is an organic compound with formula C
14H
8O
4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural dye to be produced synthetically.

<span class="mw-page-title-main">Indanthrone blue</span> Organic dye made from 2-aminoanthraquinone

Indanthrone blue, also called indanthrene, is an organic compound with the formula (C14H6O2NH)2. It is a dark blue solid that is a common dye as well as a precursor to other dyes.

<span class="mw-page-title-main">Sulfonic acid</span> Organic compounds with the structure R−S(=O)2−OH

In organic chemistry, sulfonic acid refers to a member of the class of organosulfur compounds with the general formula R−S(=O)2−OH, where R is an organic alkyl or aryl group and the S(=O)2(OH) group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound is the parent sulfonic acid, HS(=O)2(OH), a tautomer of sulfurous acid, S(=O)(OH)2. Salts or esters of sulfonic acids are called sulfonates.

<span class="mw-page-title-main">Acid dye</span> Dye applied to low pH textile

An acid dye is a dye that is typically applied to a textile at low pH. They are mainly used to dye wool, not cotton fabrics. Some acid dyes are used as food colorants, and some can also be used to stain organelles in the medical field.

<span class="mw-page-title-main">Aromatic sulfonation</span> Chemical reaction which replaces a hydrogen on an arene with sulfonic acid, –NH–SO3H

In organic chemistry, 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.

Vat dyes are a class of dyes that are classified as such because of the method by which they are applied. Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. The original vat dye is indigo, once obtained only from plants but now often produced synthetically.

<span class="mw-page-title-main">Benzanthrone</span> Chemical compound

Benzanthrone (BZA) is a polycyclic aromatic hydrocarbon. It is a yellow solid. Its derivatives are used as a dyestuff intermediate for anthraquinone-based dyes. Dehydrogenative coupling gives violanthrone. It is prepared by reduction of anthroquinone to anthrone followed by alkylation with a mixture of glycerol and sulfuric acid.

<span class="mw-page-title-main">Anthraquinones</span>

For the parent molecule 9,10-anthraquinone, see anthraquinone

<i>para</i>-Cresidine Chemical compound

para-Cresidine is an organic compound with the formula CH3OC6H3(CH3)NH2. It is a white solid that is soluble in organic solvents. The compound features both amine and methoxy functional groups. It is used as an intermediate in preparation of dyes and pigments.

<span class="mw-page-title-main">1,4-Dihydroxyanthraquinone</span> Chemical compound

1,4-Dihydroxyanthraquinone, also called quinizarin or Solvent Orange 86, is an organic compound derived from anthroquinone. Quinizarin is an orange or red-brown crystalline powder. It is formally derived from anthraquinone by replacement of two hydrogen atoms by hydroxyl (OH) groups. It is one of ten dihydroxyanthraquinone isomers and occurs in small amounts in the root of the madder plant, Rubia tinctorum.

Methine dyes are dyes whose chromophoric system consists of conjugated double bonds (polyenes) flanked by two end groups: an electron acceptor A and an electron donor D.


Structural of methine dyes

The Bohn–Schmidt reaction, a named reaction in chemistry, introduces a hydroxy group at an anthraquinone system. The anthraquinone must already have at least one hydroxy group. The reaction was first described in 1889 by René Bohn (1862–1922) and in 1891 by Robert Emanuel Schmidt (1864–1938), two German industrial chemists.

<span class="mw-page-title-main">Tobias acid</span> Chemical compound

Tobias acid (2-amino-1-naphthalenesulfonic acid) is an organic compound with the formula C10H6(SO3H)(NH2). It is named after the German chemist Georg Tobias. It is one of several aminonaphthalenesulfonic acids, which are derivatives of naphthalene containing both amine and sulfonic acid functional groups. It is a white solid, although commercial samples can appear otherwise. It is used in the synthesis of azo dyes such as C.I. Acid Yellow 19 and C.I. Pigment Red 49. It is prepared via the Bucherer reaction of 2-hydroxynaphthalene-1-sulfonic acid with ammonia and ammonium sulfite.

<span class="mw-page-title-main">Dibromoanthanthrone</span> Chemical compound

Dibromoanthanthrone is a scarlet or orange-red-hue synthetic organic colourant.

<span class="mw-page-title-main">Desulfonation reaction</span>

In organic chemistry, the desulfonation reaction is the hydrolysis of sulfonic acids:

<span class="mw-page-title-main">Naphthalene-2-sulfonic acid</span> Chemical compound

Naphthalene-2-sulfonic acid is an organic compound with the formula C10H7SO3H. A colorless, water-soluble solid, it is often available as the mono- and trihydrates C10H7SO3H.2H2O. It is one of two monosulfonic acids of naphthalene, the other being naphthalene-1-sulfonic acid. The compound is mainly used in the production of dyes via nitration en route to aminonaphthalenesulfonic acids. The compound is prepared by sulfonation of naphthalene with sulfuric acid, however under equilibrating conditions that allow the 1-sulfonic acid isomer to convert to the more stable 2-sulfonic acid.

<span class="mw-page-title-main">Vinyl sulfone dyes</span> Class of dyes

Vinyl sulfone dyes are reactive dyes comprising a vinyl sulfone group as reactive group (a fiber-bonding site of the reactive dye, "reactive hook"). Due to the relatively high reactivity of the vinyl sulfone group with water (residual moisture, air humidity), it is present in many commercial products in a protected form. For protection, an ethylsulfonyl group is substituted with a leaving group. During the dyeing process under alkaline conditions, the vinyl sulfone group is released by an elimination reaction:


Formation of the vinyl sulfone group by alkaline elimination. R= alkyl or aryl radical, X=-OSO3H, -Cl

<span class="mw-page-title-main">Carbonyl dyes</span>

Carbonyl dyes are dyes which comprise at least two conjugated carbonyl groups. Both anthraquinone dyes and indigo dyes belong to the group of carbonyl dyes. The most important natural dyes - indigo, Tyrian purple, alizarin and carmine - have this partial structure. The most important synthetic carbonyl dyes are based on anthraquinone.

<span class="mw-page-title-main">Laccaic acid</span> Chemical compound

Laccaic acids or laccainic acids are a group of five anthraquinone derivatives, designated A through E, which are components of the red shellac obtained from the insect Kerria lacca, similar to carminic acid and kermesic acid. This article focuses primarily on laccaic acid A (LCA).

References

  1. ↑ Hunger, Klaus, ed. (2003), Industrial Dyes: Chemistry, Properties, Applications, Weinheim: WILEY-VCH Verlag, pp. 35 ff., ISBN   978-3-662-01950-4
  2. ↑ Zollinger, Heinrich (2003), Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments (3rd ed.), Weinheim: WILEY-VCH Verlag, pp. 255 ff., ISBN   3-906390-23-3
  3. ↑ Entry on Anthrachinon-Farbstoffe . at: Römpp Online . Georg Thieme Verlag, retrieved 14. Dezember 2018.
  4. ↑ Cooksey, C. J. (17 February 2019). "The red insect dyes: carminic, kermesic and laccaic acids and their derivatives". Biotechnic & Histochemistry. 94 (2): 100–107. doi:10.1080/10520295.2018.1511065. ISSN   1052-0295 . Retrieved 28 March 2022.
  5. ↑ Miller, Brittney J. (25 March 2022). "Cochineal, a red dye from bugs, moves to the lab". Knowable Magazine. doi: 10.1146/knowable-032522-1 . Retrieved 28 March 2022.
  6. ↑ Seo, Seung-Oh; Jin, Yong-Su (25 March 2022). "Next-Generation Genetic and Fermentation Technologies for Safe and Sustainable Production of Food Ingredients: Colors and Flavorings". Annual Review of Food Science and Technology. 13 (1): 463–488. doi:10.1146/annurev-food-052720-012228. ISSN   1941-1413 . Retrieved 28 March 2022.
  7. ↑ Hunger, Klaus, ed. (2003), Industrial Dyes: Chemistry, Properties, Applications, Weinheim: WILEY-VCH Verlag, pp. 200 ff., ISBN   978-3-662-01950-4
  8. ↑ Heinz-Gerhard Franck, Jürgen W. Stadelhofer (1978), Industrielle Aromatenchemie: Rohstoffe · Verfahren · Produkte (in German), Berlin, Heidelberg: Springer Verlag, pp. 365 ff., ISBN   978-3-662-07876-1
  9. ↑ DE 4422160,Andreas Von Der Eltz,"Verfahren zur Herstellung von C.I. Reactive Blue 19",issued 1996-04-01, assigned to Hoechst AG
  10. ↑ DE 965902,Johannes Heyna, Willy Schumacher,"Verfahren zum Fixieren wasserloeslicher organischer Verbindungen auf Unterlagen faseriger Struktur",issued 1957-09-19, assigned to Hoechst AG
  11. ↑ Zollinger, Heinrich (2003), Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments (3rd ed.), Weinheim: WILEY-VCH Verlag, p. 289, ISBN   3-906390-23-3
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