Crude anthracene (with a melting point of only 180°) was discovered in 1832 by Jean-Baptiste Dumas and Auguste Laurent<ref name=":0">Template:Cite journal</ref> who crystalized it from a fraction of coal tar later known as "anthracene oil". Since their (inaccurate) measurements showed the proportions of carbon and hydrogen of it to be the same as in naphthalene, Laurent called it paranaphtaline in his 1835 publication of the discovery,<ref>Template:Cite wikisource</ref> which is translated to English as paranaphthalene.<ref name=":0" /> Two years later, however, he decided to rename the compound to its modern name derived from Template:Langx because after discovering other polyaromatic hydrocarbons he decided it was only one of isomers of naphthalene.<ref>Template:Cite book</ref> This notion was disproved in 1850s and 1860s.<ref>Template:Cite web</ref><ref>Template:Cite journal</ref>
The mineral form of anthracene is called freitalite and is related to a coal deposit.<ref>Freitalite, Mindat, https://www.mindat.org/min-54360.html</ref> Coal tar, which contains around 1.5% anthracene, remains a major industrial source of this material. Common impurities are phenanthrene and carbazole.
A classic laboratory method for the preparation of anthracene is by cyclodehydration of o-methyl- or o-methylene-substituted diarylketones in the so-called Elbs reaction, for example from o-tolyl phenyl ketone.<ref>Template:Cite web</ref>
Reactions
Reduction
Reduction of anthracene with alkali metals yields the deeply colored radical anion salts M+[anthracene]− (M = Li, Na, K). Reduction with sodium in ethanol gives 9,10-dihydroanthracene, preserving the aromaticity of the two flanking rings.<ref>Template:OrgSynth</ref>
The dimer, called dianthracene (or sometimes paranthracene), is connected by a pair of new carbon-carbon bonds, the result of the [4+4] cycloaddition. It reverts to anthracene thermally or with UV irradiation below Template:Val. Substituted anthracene derivatives behave similarly. The reaction is affected by the presence of oxygen.<ref>Template:Cite book</ref><ref>Template:Cite journal</ref>
Electrophilic substitution of anthracene occurs at the 9 position. For example, formylation affords 9-anthracenecarboxaldehyde. Substitution at other positions is effected indirectly, for example starting with anthroquinone.<ref>Template:Cite journal</ref> Bromination of anthracene gives 9,10-dibromoanthracene.<ref>Template:Cite journal</ref>
A variety of anthracene derivatives find specialized uses. Industrially, anthracene is converted mainly to anthraquinone, a precursor to dyes.<ref name=Ullmann>Collin, Gerd; Höke, Hartmut and Talbiersky, Jörg (2006) "Anthracene" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. Template:Doi</ref> Derivatives having a hydroxyl group are 1-hydroxyanthracene and 2-hydroxyanthracene, homologous to phenol and naphthols, and hydroxyanthracene (also called anthrol, and anthracenol)<ref>1-Hydroxyanthracene. NIST datapage</ref><ref>2-Hydroxyanthracene. NIST datapage</ref> are pharmacologically active.
Anthracene may also be found with multiple hydroxyl groups, as in 9,10-dihydroxyanthracene.
Many investigations indicate that anthracene is noncarcinogenic: "consistently negative findings in numerous in vitro and in vivo genotoxicity tests". Early experiments suggested otherwise because crude samples were contaminated with other polycyclic aromatic hydrocarbons. Furthermore, it is readily biodegraded in soil. It is especially susceptible to degradation in the presence of light.<ref name=Ullmann/> The International Agency for Research on Cancer (IARC) classifies anthracene as IARC group 2B, possibly carcinogenic to humans.<ref>Template:Cite web</ref>
