alizarin

Structural formula
General
Surname	alizarin
other names	1,2-dihydroxy-9,10-anthraquinone ( IUPAC ) CI 58000 CI 58000 ( INCI )
Molecular formula	C 14 H 8 O 4
Brief description	orange-yellow needles
External identifiers / databases
CAS number 72-48-0 EC number 200-782-5 ECHA InfoCard 100,000,711 PubChem 6293 ChemSpider 6056 Wikidata Q267813
properties
Molar mass	240.20 g mol −1
Physical state	firmly
density	1.1725 g cm −3
Melting point	290 ° C
boiling point	430 ° C ( sublimation )
pK s value	6.77
solubility	Very little soluble in boiling water, soluble in alcohols, ethers, aromatic hydrocarbons and glacial acetic acid
Refractive index	1.5190
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 319 P: 305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Alizarin is a naturally occurring chemical compound from the group of anthraquinones that is mainly used as a dye . Alizarin must not be confused with the azo dye alizarin yellow . In nature Alizarin comes with Primverose to ruberythric glycosidically linked , in the root of the dyers madder before.

etymology

The word alizarin probably comes from the Spanish alizari , which is derived from the Arabic al-usara . Both words designate the madder ( lat. Rubia tinctorum "Färberröte").

history

Madder ( rubia tinctorum )

As early as the 13th and 14th centuries , the process of dyeing Turkish red led to high growth in Asia Minor . Wool and silk were stained in a treatment lasting several weeks (with the help of chalk and alum slurries ) and then dyed with madder . The fabrics to be dyed were also treated with a suspension of dried cow and sheep dung.

In 1869, the BASF chemist Heinrich Caro , in collaboration with the Berlin professors Carl Graebe and Carl Liebermann, succeeded in synthesizing a natural dye: alizarin, the red dye of madder, mainly used in cotton dyeing.

Manufacturing

Sample of alizarin

synthesis

Alizarin is obtained by an alkali melt of the anthraquinone-2-sulfonic acid, whereby not only the sulfonic acid group is hydrolyzed, but a second hydroxyl group is introduced in the 1-position. For technical purposes, alizarin is also obtained by AlCl ₃ -catalyzed condensation of phthalic anhydride with pyrocatechol .

In the chemical laboratory, however, the sodium salt of alizarin sulfonic acid is used more frequently , due to the sulfonation of alizarin with sulfuric acid and the subsequent addition of sodium hydroxide . It is available from chemical dealers under the name Alizarin S or Alizarin Red S or ( CI 58005 ). Alizarin S appears a little more yellow than Alizarin, but can hardly be distinguished from the outside.

Development of synthesis

Carl Graebe and Carl Liebermann determined the structure of alizarin for the first time in 1868 and in 1869 applied for a patent for the production of anthracene in Prussia (March 23, 1869), France and England. Heinrich Caro , together with Graebe, improved the process at BASF and on June 25, 1869, the three of them were granted a patent for the sulphonation process in England. Only one day later, the competitor from England tried to have William Henry Perkin patent this process. In order to avoid legal disputes, Perkin and the BASF founder Friedrich Engelhorn agreed on production for the then lucrative English market.

Due to the development of the technical synthesis of alizarin, its extraction from the root of the madder became meaningless. Their cultivation, which was particularly widespread in southern France, Alsace and the Netherlands, came to an almost complete standstill by 1876.

use

Colorants

With various metal oxides or metal salts, alizarin forms very colorful complexes , which are known as madder lakes (e.g. alizarin-aluminum-calcium complex ). Alizarin only adheres to fabrics if it has been previously stained in a solution of aluminum sulfate or aluminum acetate. Madder also serves as a pigment e.g. B. for the production of lightfast wallpapers , for artist paints and printing inks .

In clinical chemistry and histology , alizarin is used as a stain for examining z. B. Calcium deposits in brain tissue .

pH indicator

Alizarin can also be used as an indicator . The color change takes place at pH values ​​in the range from 4.5 to 6.0 from yellow to red and (weaker) in the range from 10 to 12 from red to purple.

Individual evidence

1. ↑ Entry on CI 58000 in the CosIng database of the EU Commission, accessed on March 21, 2020.
2. ↑ ^{a b c d} Entry on alizarin. In: Römpp Online . Georg Thieme Verlag, accessed on January 14, 2030.
3. ^ ^{A b} Carl L. Yaws: The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals: Elsevier, 2015, ISBN 978-0-12-801146-1 , p. 438.
4. ↑ RW Sabnis: Handbook of Biological Dyes and Stains: John Wiley & Sons, 2010, ISBN 978-0-470-40753-0 , p. 10.
5. ↑ Entry on alizarin in the GESTIS substance database of the IFA , accessed on January 14, 2020(JavaScript required) .
6. ↑ Alizarin data sheet from Sigma-Aldrich , accessed on January 14, 2020 ( PDF ).
7. ^ KG Gilbert (nee Stoker), DT Cooke: Dyes from plants: Past usage, present understanding and potential. In: Plant Growth Regulation , 34, 2001, pp. 57-69; doi: 10.1023 / A: 1013374618870 .
8. ↑ EJ Tiedemann, Y. Yang: Fiber-Safe Extraction of Red Mordant Dyes from Hair Fibers. In: Journal of the American Institute for Conservation (JAIC), 34, No. 3, 1995, pp. 195-206; doi: 10.2307 / 3179540 .
9. ↑ Dictionary.com: alizarin at Dictionary.com Unabridged (v 1.1). Random House, Inc.
10. ↑ 1865–1901: The Age of Colors . basf.com. Retrieved November 9, 2018.
11. ↑ Alizarin S on seilnacht.com, accessed August 10, 2016.
12. ↑ Werner Abelshauser (ed.): The BASF - A company history. CH Beck Verlag, Munich 2002, ISBN 3-406-49526-5 .
13. ↑ J.-C. Lievens et al .: Characterization of Striatal Lesions Produced by Glutamate Uptake Alteration: Cell Death, Reactive Gliosis, and Changes in GLT1 and GADD45 mRNA Expression . In: Glia , 29, 2000, pp. 222-232. PMID 10642749 .
14. ↑ Ali A. Ensafi, A. Kazemzadeh: Optical pH Sensor Based On Chemical modification of polymer film. In: Microchemical Journal , 63, 1999, pp. 381-388.

Web links

Commons : Alizarin  - collection of images, videos and audio files

• Thomas Hapke: From madder to alizarin. Technical University of Harburg

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