Anthracene

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Anthracene
Anthracene2.png
IUPAC name Anthracene
Molecular formula C14H10
Molar mass 178.23 g/mol
CAS number [120-12-7]
Density 1.099 g/cm³
Melting point

217.5 °C

Boiling point

340 °C

SMILES c23cc1ccccc1cc2cccc3
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

In chemistry, anthracene is a solid polycyclic aromatic hydrocarbon consisting of three benzene rings derived from coal-tar. Anthracene is used in the artificial production of the red dye alizarin. It is also used in wood preservatives, insecticides, and coating materials. Anthracene is colorless but exhibits a blue (400-500nm peak) fluorescence under ultraviolet light.

Contents

Synthesis

A classic method for the preparation of anthracene in the laboratory is by cyclodehydration of o-methyl- or o-methylene-substituted diarylketones in the so-called Elbs reaction (named for the German chemist Karl Elbs (September 13, 1858 – August 24, 1933)).

Reactions

Anthracene has the ability to photodimerize with irradiation by UV light. This results in considerable changes in the physical properties of the material.

Anthracene dimer

The dimer is connected by two covalent bonds resulting from the [4+4] cycloaddition. The dimer reverts to anthracene thermally or with UV irradiation below 300 nm. The reversible bonding and photochromic properties of anthracenes are the basis of many potential applications using poly and monosubstituted anthracene derivatives. The reaction is sensitive to oxygen.

In most other reactions of anthracene, the central ring is also targeted, as it is the most highly reactive. Electrophilic substitution occurs at the "9" and "10" positions of the center ring, and oxidation of anthracene occurs readily, giving anthraquinone, C14H8O2 (below).

Anthraquione

Uses

Anthracene can also have a hydroxyl group to form 1-hydroxyanthracene and 2-hydroxyanthracene, homologous to phenol and napthol, and hydroxyanthracene is also called anthrol, and anthracenol.[1][2] Hydroxyanthracene derivatives are pharmacologically active, and are contained in aloe, for example.[3][4]

Anthracene is an organic semiconductor.

Anthracene is used as a scintillator for detectors of high energy photons, electrons and alpha particles. Plastics such as polyvinyltolulene can be doped with Anthracene to produce a plastic scintillator that is approximately water equivalent for use in radiation therapy dosimetry. Anthracenes emission spectrum peaks at between 400nm and 440nm.

See also

Notes

  1. 1-Hydroxyanthracene NIST. Retrieved October 16, 2007.
  2. 2-Hydroxyanthracene NIST. Retrieved October 16, 2007.
  3. TGA News Issue 23 (April 1997): Labelling of herbs containing hydroxyanthracene derivatives Therapeutic Goods Administration, Australian Government. Retrieved October 16, 2007.
  4. Herbals and Breastfeeding U.S. Pharmacist. Retrieved October 16, 2007.

References

  • McMurry, John. 2004. Organic Chemistry. 6th ed. Belmont, CA: Brooks/Cole. ISBN 0534420052
  • Morrison, Robert T., and Robert N. Boyd. 1992. Organic Chemistry. 6th ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0-13-643669-2
  • Solomons, T.W. Graham, and Fryhle, Craig B. 2004. Organic Chemistry. 8th ed. Hoboken, NJ: John Wiley. ISBN 0471417998

External links

All links retrieved October 17, 2012.

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