Alizarin (also known as 1,2-dihydroxyanthraquinone , Mordant Red 11 , C.I. 58000 , and Turkey Red ) is an organic compound with formula C 14 H 8 O 4 that has been used throughout history as a 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.
24-487: Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as rose madder and alizarin crimson . Alizarin in the most common usage of the term has a deep red color, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue. A use of alizarin in modern times is as a staining agent in biological research because it stains free calcium and certain calcium compounds
48-820: A crucial step towards the formation of calcified extracellular matrix associated with true bone. Alizarin's abilities as a biological stain were first noted in 1567, when it was observed that when fed to animals, it stained their teeth and bones red. The chemical is now commonly used in medical studies involving calcium. Free (ionic) calcium forms precipitates with alizarin, and tissue block containing calcium stain red immediately when immersed in alizarin. Thus, both pure calcium and calcium in bones and other tissues can be stained. These alizarin-stained elements can be better visualized under fluorescent lights, excited by 440–460 nm. The process of staining calcium with alizarin works best when conducted in acidic solution (in many labs, it works better in pH 4.1 to 4.3). In clinical practice, it
72-419: A fraction of the cost of the natural product, and the market for madder collapsed virtually overnight. The principal synthesis entailed bromination of anthraquinone by bromine (in a sealed tube at 100 C) to give 1,2-dibromoanthraquinone. Then the two bromine atoms were substituted by -OH by heating (170 C) with KOH, followed by treatment with strong acid. The incorporation of two bromine atoms in 1 and 2 position
96-400: A longer-lasting color, and can be used more efficaciously, for example by blending it into a paint . Over the following years, it was found that other metal salts, including those containing iron , tin , and chromium , could be used in place of alum to give madder-based pigments of various other colors. This general method of preparing lakes has been known for centuries but was simplified in
120-476: A maroon shade that is also more weather resistant and light-fast. Both crystal modifications are more thermodynamically stable than the α crystal phase. The γ crystal modification is characterized by a criss-cross lattice where each quinacridone molecule hydrogen-bonds to four neighbors via single H-bonds. The β phase, meanwhile, consists of linear chains of molecules with double H-bonds between each quinacridone molecule and two neighbors. Basic modifications to
144-493: A red or light purple color. Alizarin continues to be used commercially as a red textile dye, but to a lesser extent than in the past. Madder has been cultivated as a dyestuff since antiquity in central Asia and Egypt , where it was grown as early as 1500 BC. Cloth dyed with madder root pigment was found in the tomb of the Pharaoh Tutankhamun , in the ruins of Pompeii , and ancient Athens and Corinth . In
168-415: A red pigment in paintings since antiquity. Lake pigment A lake pigment is a pigment made by precipitating a dye with an inert binder , or mordant , usually a metallic salt . Unlike vermilion , ultramarine , and other pigments made from ground minerals, lake pigments are chemically organic . Manufacturers and suppliers to artists and industry frequently omit the lake designation in
192-482: A source of natural red dye. Quinacridone Quinacridone is an organic compound used as a pigment . Numerous derivatives constitute the quinacridone pigment family, which finds extensive use in industrial colorant applications such as robust outdoor paints, inkjet printer ink , tattoo inks , artists' watercolor paints , and color laser printer toner . As pigments, the quinacridones are insoluble. The development of this family of pigments supplanted
216-447: Is not expected by an aromatic electrophilic substitution, and suggest the existence of an α,β unsaturated enol form of anthraquinone which suffer electrophilic addition by bromine. Alizarin, as a dye, has been largely replaced today by the more light-resistant quinacridone pigments developed at DuPont in 1958. Alizarin is one of ten dihydroxyanthraquinone isomers. It is soluble in hexane and chloroform , and can be obtained from
240-626: Is oxidized to quinacridone. Derivatives of quinacridone can be readily obtained by employing substituted anilines. Linear cis -Quinacridones can be prepared from isophthalic acid . Quinacridone-based pigments are used to make high performance paints. Quinacridones were first sold as pigments by Du Pont in 1958. Quinacridones are considered "high performance" pigments because they have exceptional color and weather fastness . Major uses for quinacridones include automobile and industrial coatings. Nanocrystalline dispersions of quinacridone pigments functionalized with solubilizing surfactants are
264-499: Is used to stain synovial fluid to assess for basic calcium phosphate crystals. Alizarin has also been used in studies involving bone growth, osteoporosis, bone marrow, calcium deposits in the vascular system, cellular signaling, gene expression, tissue engineering, and mesenchymal stem cells. In geology , it is used as a stain to differentiate the calcium carbonate minerals , especially calcite and aragonite in thin section or polished surfaces. Madder lake had been in use as
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#1732779644601288-426: The alizarin dyes. The name indicates that the compounds are a fusion of acridone and quinoline , although they are not made that way. Classically the parent is prepared from the 2,5-dianilide of terephthalic acid (C 6 H 2 (NHPh) 2 (CO 2 H) 2 ). Condensation of succinosuccinate esters with aniline followed by cyclization affords dihydroquinacridone, which are readily dehydrogenated . The latter
312-608: The Middle Ages, Charlemagne encouraged madder cultivation. Madder was widely used as a dye in Western Europe in the Late Medieval centuries. In 17th century England, alizarin was used as a red dye for the clothing of the parliamentary New Model Army . The distinctive red color would continue to be worn for centuries (though also produced by other dyes such as cochineal ), giving English and later British soldiers
336-677: The chemical structure of quinacridones include the addition of CH 3 and Cl substituents. Some magenta shades of quinacridone are labeled under the proprietary name "Thio Violet" and "Acra Violet". Quinacridone derivatives exhibit intense fluorescence in the dispersed state, and high carrier mobility . These properties complement good photo-, thermal, and electrochemical stability. These properties are desired for optoelectronic applications including organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs). Due to interplay of intermolecular H-bonding and pi-pi stacking , quinacridone can form
360-512: The dye determines the color of the resulting precipitate . In ancient times chalk , white clay , and crushed bones were used as sources of the calcium salts. Today, the metallic salts are typically salts of chromium or cobalt , and the resulting lake pigment is diluted with an inert material such as alumina . Lake pigments have a long history in decoration and the arts. Some have been produced for thousands of years and traded over long distances. The red lakes were particularly important in
384-627: The history of art; because they were translucent, they were often used in layers of glazes over a more opaque red (sometimes the mineral-based pigment vermilion , or sometimes a red lake mixed with lead white or vermilion) to create a deep, rich red color. They are common in paintings by Venetian artists of the 16th century, including Titian , to depict fine draperies and fabrics. Indigo and rose madder are now produced more cheaply from synthetic sources, although some use of natural products persists, especially among artisans . The food and cosmetics industries have shown renewed interest in cochineal as
408-592: The late 18th and early 19th centuries. In 1826, the French chemist Pierre-Jean Robiquet found that madder root contained two colorants, the red alizarin and the more rapidly fading purpurin . The alizarin component became the first natural dye to be synthetically duplicated in 1868 when the German chemists Carl Graebe and Carl Liebermann , working for BASF , found a way to produce it from anthracene . The Bayer AG company draws its roots from alizarin as well. About
432-482: The latter as red-purple crystals, melting point 277–278 °C. Alizarin changes color depending on the pH of the solution it is in, thereby making it a pH indicator . Alizarin Red is used in a biochemical assay to determine, quantitatively by colorimetry , the presence of calcific deposition by cells of an osteogenic lineage. As such it is an early stage marker (days 10–16 of in vitro culture) of matrix mineralization,
456-473: The most common magenta printing ink. Typically deep red to violet in color, the hue of quinacridone is affected not only by the R-groups on the molecule but by the crystal form of the solid. For example, the γ crystal modification of unsubstituted quinacridone provides a strong red shade that has excellent color fastness and resistance to solvation. Another important modification is the β phase which provides
480-488: The name). It was a complex and multi-step technique in its Middle Eastern formulation, some parts of which were unnecessary. The process was simplified in late 18th-century Europe. By 1804, dye maker George Field in Britain had refined a technique to make lake madder by treating it with alum , and an alkali , that converts the water-soluble madder extract into a solid, insoluble pigment. This resulting madder lake has
504-545: The name. Many lake pigments are fugitive because the dyes involved are not lightfast . Red lakes were particularly important in Renaissance and Baroque paintings; they were often used as translucent glazes to portray the colors of rich fabrics and draperies. The term lake is derived from the term lac , the secretions of the Indian wood insect Kerria lacca (formerly Laccifer lacca or Coccus lacca ). It has
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#1732779644601528-526: The nickname of " redcoats ". The madder dyestuff is combined with a dye mordant . Depending on which mordant is used, the resulting color may be anywhere from pink through purple to dark brown. In the 18th century, the most valued color was a bright red known as "Turkey Red". The combination of mordants and overall technique used to obtain the Turkey Red originated in the Middle East or Turkey (hence
552-607: The same root as the word lacquer , and comes originally from the Hindi word lakh , through the Arabic word lakk and the Persian word lak . Many lake pigments are azo dyes . They characteristically have sulfonate and sometimes carboxylate substituents, which confer negative charge to the chromophore (colored species). The metallic salts or binders used are typically colourless or almost so. The organic component of
576-532: The same time, the English dye chemist William Henry Perkin independently discovered the same synthesis, although the BASF group filed their patent before Perkin by one day. The subsequent discovery (made by Broenner and Gutzhow in 1871) that anthracene could be abstracted from coal tar further advanced the importance and affordability of alizarin's artificial synthesis. The synthetic alizarin could be produced for
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