Anthraquinone (9,10-dioxoanthracene) is an aromatic organic compound. It is a derivative of anthracene. It has the appearance of yellow or light gray to gray-green solid crystalline powder.
Its other names are 9,10-anthracenedione, anthradione, 9,10-anthrachinon, anthracene-9,10-quinone, 9,10-dihydro-9,10-dioxoanthracene, and trade names Hoelite, Morkit, Corbit, and others.
Physical propertiesIt is semisoluble in water but dissolves in alcohol, nitrobenzene and aniline. It is chemically fairly stable under normal conditions.
Natural occurrencesAnthraquinones naturally occur in some plants (eg. aloe, senna, rhubarb, and Cascara buckthorn), fungi, lichens, and insects, where they serve as a basic skeleton for their pigments. Natural anthraquinone derivatives tend to have laxative effects.
ChemistryThere are several ways to obtain anthraquinone:
- Oxidation of anthracene
- Condensation of benzene with phthalic anhydride in presence of AlCl3 (Friedel-Crafts substitution). The resulting o-benzoylbenzoic acid then undergoes cyclization, forming anthraquinone.
- Diels-Alder reaction (from naphthoquinone and a 1,3-diene followed by oxidation)
- Retro-DA reaction: the Rickert-Alder reaction.
In a classic organic reaction called the Bally-Scholl synthesis (1905), anthraquinone condenses with glycerol forming benzanthrone. In this reaction the quinone is first reduced with copper metal in sulfuric acid (converting one ketone group into a methylene group) after which the glycerol is added.
Industrial applicationsAnthraquinone is used in production of dyes, such as alizarin. Many natural pigments are derivatives of anthraquinone. Anthraquinone is also used as a catalyst in production of wood pulp in pulp and paper industry. Another use is as a bird repellant on seeds.
A derivative of anthraquinone (2-ethylanthraquinone) is used to produce hydrogen peroxide commercially.
anthraquinone in German: Anthrachinon
anthraquinone in Spanish: Antraquinona
anthraquinone in French: Anthraquinone
anthraquinone in Korean: 안트라퀴논
anthraquinone in Italian: Antrachinone
anthraquinone in Japanese: アントラキノン
anthraquinone in Norwegian: Antrakinon
anthraquinone in Polish: Antrachinon
anthraquinone in Portuguese: Antraquinona
anthraquinone in Russian: Антрахинон
anthraquinone in Slovak: Antrachinón
anthraquinone in Finnish: Antrakinoni
anthraquinone in Ukrainian: Антрахінон
anthraquinone in Chinese: 蒽醌