Loading AI tools
Chemical compound From Wikipedia, the free encyclopedia
Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue (400–500 nm peak) fluorescence under ultraviolet radiation.[13]
 |
| |
 | |
 | |
| Names | |
|---|---|
| IUPAC name
Anthracene | |
| Identifiers | |
3D model (JSmol) |
|
| 1905429 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.003.974 |
| EC Number |
|
| 67837 | |
| KEGG | |
PubChem CID |
|
| RTECS number |
|
| UNII | |
CompTox Dashboard (EPA) |
|
| |
| |
| Properties | |
| C14H10 | |
| Molar mass | 178.234 g·mol−1 |
| Appearance | Colorless |
| Odor | Weak aromatic |
| Density | 1.28 g/cm3 (25 °C)[1] 0.969 g/cm3 (220 °C) |
| Melting point | 216 °C (421 °F; 489 K)[1] at 760 mmHg |
| Boiling point | 341.3 °C (646.3 °F; 614.5 K)[1] at 760 mmHg |
| 0.022 mg/L (0 °C) 0.044 mg/L (25 °C) 0.29 mg/L (50 °C) 0.00045% w/w (100 °C, 3.9 MPa)[2] | |
| Solubility | Soluble in alcohol, (C2H5)2O, acetone, C6H6, CHCl3,[1] CS2[3] |
| Solubility in ethanol | 0.76 g/kg (16 °C) 19 g/kg (19.5 °C) 3.28 g/kg (25 °C)[3] |
| Solubility in methanol | 18 g/kg (19.5 °C)[3] |
| Solubility in hexane | 3.7 g/kg[3] |
| Solubility in toluene | 9.2 g/kg (16.5 °C) 129.4 g/kg (100 °C)[3] |
| Solubility in carbon tetrachloride | 7.32 g/kg[3] |
| log P | 4.56 |
| Vapor pressure | 0.01 kPa (125.9 °C) 0.1 kPa (151.5 °C)[4] 13.4 kPa (250 °C)[5] |
Henry's law constant (kH) |
0.0396 L·atm/mol[6] |
| UV-vis (λmax) | 345.6 nm, 363.2 nm[5] |
| −129.8×10−6 cm3/mol[7] | |
| Thermal conductivity | 0.1416 W/(m·K) (240 °C) 0.1334 W/(m·K) (270 °C) 0.1259 W/(m·K) (300 °C)[8] |
| Viscosity | 0.602 cP (240 °C) 0.498 cP (270 °C) 0.429 cP (300 °C)[8] |
| Structure | |
| Monoclinic (290 K)[9] | |
| P21/b[9] | |
| D5 2h[9] | |
α = 90°, β = 124.7°, γ = 90° | |
| Thermochemistry[10] | |
Heat capacity (C) |
210.5 J/(mol·K) |
Std molar entropy (S⦵298) |
207.5 J/(mol·K) |
Std enthalpy of formation (ΔfH⦵298) |
129.2 kJ/mol |
Std enthalpy of combustion (ΔcH⦵298) |
7061 kJ/mol[5] |
| Hazards | |
| GHS labelling: | |
  [11] | |
| Warning | |
| H302, H305, H315, H319, H335, H410[11] | |
| P261, P273, P305+P351+P338, P501[11] | |
| NFPA 704 (fire diamond) | |
| Flash point | 121 °C (250 °F; 394 K)[11] |
| 540 °C (1,004 °F; 813 K)[11] | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
100-149 mg/kg (rats, oral) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Crude anthracene (with a melting point of only 180°) was discovered in 1832 by Jean-Baptiste Dumas and Auguste Laurent[14] 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,[15] which is translated to English as paranaphthalene.[14] Two years later, however, he decided to rename the compound to its modern name derived from Ancient Greek: ἄνθραξ, romanized: anthrax, lit. 'coal' because after discovering other polyaromatic hydrocarbons he decided it was only one of isomers of naphthalene.[16] This notion was disproved in 1850s and 1860s.[17][18]
Coal tar, which contains around 1.5% anthracene, remains a major source of this material. Common impurities are phenanthrene and carbazole. The mineral form of anthracene is called freitalite and is related to a coal deposit.[19] 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.[20]
Reduction of anthracene with alkali metals yields the deeply colored radical anion salts M+[anthracene]− (M = Li, Na, K). Hydrogenation gives 9,10-dihydroanthracene, preserving the aromaticity of the two flanking rings.[21]
In any solvent except water,[22] anthracene photodimerizes by the action of UV light:
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 300 nm. Substituted anthracene derivatives behave similarly. The reaction is affected by the presence of oxygen.[23][24]
Anthracene also reacts with dienophile singlet oxygen in a [4+2]-cycloaddition (Diels–Alder reaction):
Chemical oxidation occurs readily, giving anthraquinone, C14H8O2 (below), for example using hydrogen peroxide and vanadyl acetylacetonate.[25]
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.[26] Bromination of anthracene gives 9,10-dibromoanthracene.[27]
Anthracene is converted mainly to anthraquinone, a precursor to dyes.[28]
Anthracene, a wide band-gap organic semiconductor is used as a scintillator for detectors of high-energy photons, electrons and alpha particles. Plastics, such as polyvinyltoluene, can be doped with anthracene to produce a plastic scintillator that is approximately water-equivalent for use in radiation therapy dosimetry. Anthracene's emission spectrum peaks at between 400 nm and 440 nm.
It is also used in wood preservatives, insecticides, and coating materials.[citation needed]
Anthracene is commonly used as a UV tracer in conformal coatings applied to printed wiring boards. The anthracene tracer allows the conformal coating to be inspected under UV light.[29]
A variety of anthracene derivatives find specialized uses. Derivatives having a hydroxyl group are 1-hydroxyanthracene and 2-hydroxyanthracene, homologous to phenol and naphthols, and hydroxyanthracene (also called anthrol, and anthracenol)[30][31] are pharmacologically active. Anthracene may also be found with multiple hydroxyl groups, as in 9,10-dihydroxyanthracene.
Some anthracene derivatives are used as pharmaceutical drugs, including bisantrene, trazitiline, and benzoctamine.
Anthracene, as many other polycyclic aromatic hydrocarbons, is generated during combustion processes. Exposure to humans happens mainly through tobacco smoke and ingestion of food contaminated with combustion products.
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.[28]
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
