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| Names | |
|---|---|
| IUPAC name Anthracene | |
| Identifiers | |
| |
3D model (JSmol) | |
| 1905429 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| DrugBank |
|
| ECHA InfoCard | 100.003.974 |
| EC Number |
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| 67837 | |
| KEGG |
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| RTECS number |
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| UNII | |
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| 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 inalcohol,(C2H5)2O,acetone,C6H6,CHCl3,[1]CS2[3] |
| Solubility inethanol | 0.76 g/kg (16 °C) 19 g/kg (19.5 °C) 3.28 g/kg (25 °C)[3] |
| Solubility inmethanol | 18 g/kg (19.5 °C)[3] |
| Solubility inhexane | 3.7 g/kg[3] |
| Solubility intoluene | 9.2 g/kg (16.5 °C) 129.4 g/kg (100 °C)[3] |
| Solubility incarbon tetrachloride | 7.32 g/kg[3] |
| logP | 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] | |
a = 8.562 Å,b = 6.038 Å,c = 11.184 Å[9] α = 90°, β = 124.7°, γ = 90° | |
| Thermochemistry[10] | |
| 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 theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Anthracene is a solidpolycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fusedbenzene rings. It is a component ofcoal tar. Anthracene is used in theproduction of the reddyealizarin and other dyes, as ascintillator to detect high energy particles, as production of pharmaceutical drugs. Anthracene is colorless but exhibits a blue (400–500 nm peak)fluorescence underultraviolet radiation.[13]
Crude anthracene (with a melting point of only 180°) was discovered in 1832 byJean-Baptiste Dumas andAuguste 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 innaphthalene, Laurent called itparanaphtaline in his 1835 publication of the discovery,[15] which is translated to English asparanaphthalene.[14] Two years later, however, he decided to rename the compound to its modern name derived fromAncient 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]
Anthracene, as many otherpolycyclic aromatic hydrocarbons, is generated during combustion processes. Most human exposure is throughtobacco smoke or ingestion ofcharred food.
The mineral form of anthracene is called freitalite and is related to a coal deposit.[19] Coal tar, which contains around 1.5% anthracene, remains a major industrial source of this material. Common impurities arephenanthrene andcarbazole.
A classic laboratory method for the preparation of anthracene is by cyclodehydration of o-methyl- or o-methylene-substituted diarylketones in the so-calledElbs reaction, for example fromo-tolyl phenyl ketone.[20]
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.[21]
In any solvent except water,[22] anthracenephotodimerizes by the action ofUV light:
Thedimer, 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 withUV irradiation below300 nm. Substituted anthracene derivatives behave similarly. The reaction is affected by the presence ofoxygen.[23][24]
Anthracene also reacts with dienophilesinglet oxygen in a [4+2]-cycloaddition (Diels–Alder reaction):
Chemicaloxidation occurs readily, givinganthraquinone, C14H8O2 (below), for example usinghydrogen peroxide andvanadyl acetylacetonate.[25]
Electrophilic substitution of anthracene occurs at the 9 position. For example, formylation affords9-anthracenecarboxaldehyde. Substitution at other positions is effected indirectly, for example starting with anthroquinone.[26] Bromination of anthracene gives 9,10-dibromoanthracene.[27]
Anthracene proper has application as anorganic semiconductor andchemical feedstock for various preservatives and dyes.
Anthracene is a wide band-gaporganic semiconductor, with anemission spectrum peaking between400 nm and 440 nm. Organicfield-effect transistors have been constructed from it. Inparticle physics, it is used as ascintillator to detect high-energyphotons,electrons, oralpha particles.[28] Plastics, such aspolyvinyltoluene, can be doped with anthracene to produce an approximately water-equivalent scintillator inradiation therapydosimetry.
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]
It is also used inwoodpreservatives,insecticides, and coatingmaterials.[citation needed]
A variety of anthracene derivatives find specialized uses. Industrially, anthracene is converted mainly toanthraquinone, a precursor to dyes.[30] Derivatives having ahydroxyl group are 1-hydroxyanthracene and 2-hydroxyanthracene, homologous tophenol andnaphthols, and hydroxyanthracene (also called anthrol, and anthracenol)[31][32] arepharmacologically active. Anthracene may also be found with multiple hydroxyl groups, as in9,10-dihydroxyanthracene.
Some anthracene derivatives are used as pharmaceutical drugs, includingbisantrene,trazitiline, andbenzoctamine.
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.[30] Nevertheless, theInternational Agency for Research on Cancer (IARC) classifies anthracene asIARC group 2B, possibly carcinogenic to humans.[33]
Anthracene is readily biodegraded in soil. It is especially susceptible to degradation in the presence of light.[30]
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