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Alizarin



Alizarin
IUPAC name 1,2-dihydroxy-9,10-anthracenedione
Other names 1,2-dihydroxyanthraquinone, Turkey red, mordant red 11, alizarin B, alizarin red, 9,10-anthracenedione
Identifiers
CAS number 72-48-0
SMILES Oc2c(O)c1C(=O)c3c(C(=O)c1cc2)cccc3
Properties
Molecular formula C14H8O4
Molar mass 240.21 g/mol
Appearance orange-red crystals or powder
Melting point

279 - 283 °C

Boiling point

430 °C

Solubility in water  ? g/100 ml (?°C)
Hazards
MSDS External MSDS
R-phrases R36 R37 R38
S-phrases S26 S36
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, 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]

Additional recommended knowledge

Contents

History

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[2] had refined the technique to lake madder by treating it with alum, and an alkali,[3] that turns the water-soluble madder extract into a solid, insoluble pigment. This resulting madder lake has a longer-lasting color, and can 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. This general method of preparing lakes has been known for centuries.[4]

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 Henry 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.

Applications

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 Crimson

Alizarin Crimson
— Color coordinates —
Hex triplet #E32636
RGBB (r, g, b) (227, 38, 54)
HSV (h, s, v) (348°, 90%, 77%)
Source BF2S Color Guide
B: Normalized to [0–255] (byte)

At right is displayed the color alizarin crimson.




See also

References

  1. ^ alizarin. Dictionary.com. Dictionary.com Unabridged (v 1.1). Random House, Inc. http://dictionary.reference.com/browse/alizarin (accessed: January 02, 2007).
  2. ^ Field's notes are held at the Courtauld Institute of Art. See: http://www.aim25.ac.uk/cgi-bin/search2?coll_id=4107&inst_id=2 (accessed: 2007/09/05)
  3. ^ Winsor Newton's madder pigment is made according to his process. See http://www.winsornewton.com/artnews/EN/artnewsletterA4_english03_2002.pdf page 6. (accessed: 2007/09/03). Note that Henry Charles Newton, founder of Winsor Newton, was his assistant and friend.
  4. ^ Daniel V. Thompson - The Materials and Techniques of Medieval Painting - Dover - pp115-124. ISBN 0-486-20327-1
   
Alizarin Amaranth Burgundy Cardinal Carmine Cerise Chestnut Coral Red Crimson Dark Pink Falu red
                     
Fire engine red Hollywood Cerise Magenta (Process) Maroon Mauve taupe Orange-Red Persian red Pink Persimmon Red Red-violet
                     
Rose Ruby Rust Puce Sangria Scarlet Terra cotta Venetian red Vermilion
                 
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Alizarin". A list of authors is available in Wikipedia.
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