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Alizarin
From Wikipedia, the free encyclopedia
| Alizarin | |
|---|---|
 |
|
| General | |
| Systematic name | 1,2-dihydroxy-9,10-anthracenedione |
| Other names | 1,2-dihydroxyanthraquinone, Turkey red, mordant red 11, alizarin B, alizarin red, 9,10-anthracenedione |
| Molecular formula | C14H8O4 |
| SMILES | Oc2c(O)c1C(=O)c3c(C(=O)c1cc2)cccc3 |
| Molar mass | 240.21 g/mol |
| Appearance | orange-red crystals or powder |
| CAS number | [72-48-0] |
| Properties | |
| Density and phase | ? g/cm³, ? |
| Solubility in water | ? g/100 ml (?°C) |
| Melting point | 279 - 283 °C |
| Boiling point | 430 °C |
| Acidity (pKa) | ? |
| Structure | |
| Crystal structure | ? |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | ? |
| NFPA 704 | |
| Flash point | ?°C |
| R/S statement | R: R36 R37 R38 S: S26 S36 |
| RTECS number | ? |
| Supplementary data page | |
| Related compounds | |
| Related compounds | anthraquinone, anthracene |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references |
|
Alizarin, or 1,2-dihydroxyanthraquinone or mordant red, is the red dye originally derived from the root of the madder plant. In 1869, it became the first natural pigment to be duplicated synthetically.
The word alizarin ultimately derives from the Arabic al-usara, juice. [1]
Contents |
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 and in the ruins of Pompeii and ancient Corinth. In the Middle Ages, Charlemagne encouraged madder cultivation. It grew well in the sandy soils of the Netherlands and became an important part of the local economy.
By 1804, the English dye maker George Field had developed a technique to lake madder by treating it with alum. This turned the water-soluble madder extract into a solid, insoluble pigment. This resulting madder lake had a longer-lasting color, and could be used more versatilely, 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 use in place of alum to give madder-based pigments of various other colors.
| Alizarin | ||
|---|---|---|
| — Color coordinates — | ||
| Hex triplet | #e32636 | |
| RGBa | (r, g, b) | (227, 38, 54) |
| HSV | (h, s, v) | (355°, 83%, 89%) |
| a: Normalized to [0–255] (byte) | ||
In 1826, the French chemist Pierre-Jean Robiquet found there were two colorants in madder root, 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. About the same time, the English dye chemist William Perkin independently discovered the same synthesis, although the BASF group filed their patent before Perkin by only one day.
The synthetic alizarin could be produced at less than half the cost of the natural product, and the market for madder collapsed virtually overnight. Alizarin itself has been in turn largely replaced today by the more light-resistant quinacridone pigments developed at DuPont in 1958.
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 mineralisation, a crucial step towards the formation of calcified extracellular matrix associated with true bone.
In clinical practice it is also used to stain synovial fluid to assess for basic calcium phosphate crystals.
- ^ alizarin. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/alizarin (accessed: January 02, 2007).