anthraquinone

Anthraquinone
IUPAC name	Anthraquinone
Other names	9,10-anthracenedione, anthradione, 9,10-anthrachinon, anthracene-9,10-quinone, 9,10-dihydro-9,10-dioxoanthracene, Hoelite, Morkit, Corbit
Identifiers
CAS number	84-65-1 Y
SMILES	O=C1c2ccccc2C(=O)c3ccccc13
ChemSpider ID	6522
Properties
Molecular formula	C14H8O2
Molar mass	208.21 g mol−1
Appearance	yellow or light gray to gray-green solid
Melting point	286 °C
Boiling point	379.8 °C
Solubility in water	Insoluble
Hazards
R-phrases	R36/37/38
Flash point	185°C
Related compounds
Related compounds	quinone, anthracene
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 properties

It is semisoluble in water but dissolves in alcohol, nitrobenzene and aniline. It is chemically fairly stable under normal conditions.

Natural occurrences

Anthraquinones naturally occur in some plants (eg. aloe latex, 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.

Chemistry

There 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 buta-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^[1]. 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 applications

• Anthraquinone is used in production of dyes, such as alizarin.
• Many natural pigments are derivatives of anthraquinone.
• Anthraquinone may be used as a catalyst in production of chemical pulp by the Kraft or Soda-AQ processes.
• Another use is as a bird repellant on seeds.
• As a gas generator in Satellite balloons[1]
• A derivative of anthraquinone called 2-ethylanthraquinone is used to produce hydrogen peroxide commercially.

Catalytic hydrogen peroxide production with the anthraquinone process

Medical uses

Anthraquinone is used as a laxative. Prolonged use and abuse leads to melanosis coli.^[2][3]

External links

• National Pollutant Inventory - Polycyclic Aromatic Hydrocarbon Fact Sheet
• Molecules Spontaneously Form Honeycomb Network

References