View source for Anthraquinone

{{Short description|Yellow chemical compound: building block of many dyes}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 457132283
| Name = 9,10-Anthraquinone<ref name=crc/>
| ImageFile = Anthraquinone acsv.svg
| ImageClass = skin-invert-image
| ImageFile1 = Anthraquinone molecule ball from xtal.png
| ImageClass1 = bg-transparent
| ImageFile2= Anthraquinone powder.jpg
| ImageSize2= 230px
| PIN = Anthracene-9,10-dione<ref>{{cite book |author=[[International Union of Pure and Applied Chemistry]] |date=2014 |title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 |publisher=[[Royal Society of Chemistry|The Royal Society of Chemistry]] |pages=724 |doi=10.1039/9781849733069 |isbn=978-0-85404-182-4}}</ref>
| OtherNames = {{unbulletedlist | Anthraquinone | 9,10-Anthracenedione | Anthradione | 9,10-Anthrachinon | Anthracene-9,10-quinone | 9,10-Dihydro-9,10-dioxoanthracene | Hoelite | Morkit | Corbit }}
| Section1 = {{Chembox Identifiers
|   SMILES = O=C1c2ccccc2C(=O)c3ccccc13
|   ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|   ChemSpiderID = 6522
|   ChEBI_Ref = {{ebicite|changed|EBI}}
|   ChEBI = 40448
|   ChEMBL_Ref = {{ebicite|changed|EBI}}
|   ChEMBL = 55659
|   EC_number = 201-549-0 
|   CASNo_Ref = {{cascite|correct|CAS}}
|   CASNo = 84-65-1
|   KEGG_Ref = {{keggcite|correct|kegg}}
|   KEGG = C16207
|   Gmelin = 102870
|   Beilstein = 390030
|   PubChem = 6780
|   StdInChI=1S/C14H8O2/c15-13-9-5-1-2-6-10(9)14(16)12-8-4-3-7-11(12)13/h1-8H
|   StdInChIKey = RZVHIXYEVGDQDX-UHFFFAOYSA-N
|   RTECS = CB4725000
|   UNNumber = 3143
|   UNII = 030MS0JBDO
  }}
| Section2 = {{Chembox Properties
|   C=14 | H=8 | O=2
|   Appearance = Yellow solid
|   Density = 1.438{{nbsp}}g/cm<sup>3</sup><ref name=crc/>
|   Solubility = Insoluble
|   MeltingPtC = 284.8
|   MeltingPt_ref = <ref name=crc>{{cite book |ref=Haynes| editor= Haynes, William M. | date = 2016| title = [[CRC Handbook of Chemistry and Physics]] | edition = 97th | publisher = [[CRC Press]] | isbn = 9781498754293|page=3.28}}</ref>
|   BoilingPtC = 377
|   BoilingPt_ref = <ref name=crc/>
  }}
| Section7 = {{Chembox Hazards
|   MainHazards = possible carcinogen
|   FlashPtC = 185
|   GHSPictograms = {{GHS08}}
|   GHSSignalWord = Danger
|   HPhrases = {{H-phrases|350}}
|   PPhrases = {{P-phrases|201|202|281|308+313|405|501}}
  }}
| Section8 = {{Chembox Related
|   OtherCompounds = [[quinone]],<br> [[anthracene]]
  }}
}}

'''Anthraquinone''', also called '''anthracenedione''' or '''dioxoanthracene''', is an [[aromatic hydrocarbon|aromatic]] [[organic compound]] with formula {{chem|C|14|H|8|O|2}}. Several [[isomer]]s exist but these terms usually refer to 9,10-anthraquinone ([[IUPAC]]: 9,10-dioxoanthracene) wherein the [[ketone|keto]] groups are located on the central ring. It is used as a digester additive to [[Pulp (paper)|wood pulp]] for papermaking. Many [[Anthraquinones|anthraquinone derivatives]] are generated by organisms or synthesised industrially for use as [[Anthraquinone dyes|dyes]], pharmaceuticals, and [[Catalysis|catalysts]]. Anthraquinone is a yellow, highly crystalline solid, poorly [[solubility|soluble]] in [[water]] but soluble in hot organic solvents. It is almost completely insoluble in [[ethanol]] near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol. It is found in nature as the rare mineral [[hoelite]].

==Synthesis==
There are several current industrial methods to produce 9,10-anthraquinone:
# The oxidation of [[anthracene]]. [[Chromium(VI)]] is the typical oxidant. 
# The [[Friedel–Crafts reaction]] of [[benzene]] and [[phthalic anhydride]] in presence of [[AlCl3|AlCl<sub>3</sub>]]. o-Benzoylbenzoic acid is an intermediate. This reaction is useful for producing substituted [[anthraquinones]].
# The [[Diels-Alder reaction]] of [[naphthoquinone]] and [[butadiene]] followed by oxidative dehydrogenation.
# The acid-catalyzed dimerization of [[styrene]] to give a 1,3-diphenylbutene, which then can be transformed to the anthraquinone.<ref name=Ullmann>{{ Ullmann | author = Vogel, A. | title = Anthraquinone | doi = 10.1002/14356007.a02_347 }}</ref> This process was pioneered by [[BASF]].

It also arises via the Rickert–Alder reaction, a [[retro-Diels–Alder reaction]].

==Reactions==
Hydrogenation gives [[9,10-Dihydroxyanthracene|dihydroanthraquinone]] (anthrahydroquinone). Reduction with copper gives [[anthrone]].<ref>{{cite journal|doi= 10.15227/orgsyn.014.0004|title= Benzanthrone|journal= Organic Syntheses|year= 1934|volume= 14|pages= 4|first1=L. C. |last1= Macleod|first2=C. F. H.|last2=Allen}}</ref>  Sulfonation with sulfuric acid gives anthroquinone-1-sulfonic acid,<ref>{{cite journal|doi= 10.15227/orgsyn.018.0072|title= Potassium Anthraquinone-α-Sulfonate|journal= Organic Syntheses|year= 1938|volume= 18|pages= 72|first1=W. J. |last1=Scott|first2=C. F. H.|last2=Allen}}</ref> which reacts with sodium chlorate to give 1-chloroanthaquinone.<ref>{{cite journal|doi= 10.15227/orgsyn.018.0015|title= α-Chloroanthraquinone|journal= Organic Syntheses|year= 1938|volume= 18|pages= 15|first1=W. J. |last1=Scott|first2=C. F. H.|last2=Allen}}</ref>

==Applications==
{{see also|Anthraquinones}}

===Digester additive in papermaking===
9,10-Anthraquinone is used as a digester additive in production of [[pulp (paper)|paper pulp]] by [[alkali]]ne processes, like the [[kraft process|kraft]], the alkaline [[sulfite process|sulfite]] or the [[soda pulping|Soda-AQ]] processes. The anthraquinone is a [[redox]] [[catalyst]]. The reaction mechanism may involve [[single electron transfer]] (SET).<ref>{{Cite thesis | first = J. C. | last = Samp | title = A comprehensive mechanism for anthraquinone mass transfer in alkaline pulping | year = 2008 | page = 30 | institution = Georgia Institute of Technology | hdl=1853/24767 }}</ref> The anthraquinone oxidizes the reducing end of polysaccharides in the pulp, i.e., [[cellulose]] and [[hemicellulose]], and thereby protecting it from alkaline degradation (peeling). The anthraquinone is reduced to [[9,10-dihydroxyanthracene]] which then can react with [[lignin]]. The lignin is degraded and becomes more watersoluble and thereby more easy to wash away from the pulp, while the anthraquinone is regenerated. This process gives an increase in yield of pulp, typically 1–3% and a reduction in [[kappa number]].<ref>{{ cite book | editor = Goyal, G. C. | last1 = Sturgeoff | first = L. G. | last2 = Pitl | first2 = Y. | chapter = Low Kappa Pulping without Capital Investment | title = Anthraquinone Pulping | publisher = TAPPI Press | pages = 3–9 | orig-year = 1993 | year = 1997 | isbn = 0-89852-340-0 }}</ref>

=== Hydrogen peroxide production ===
2-Alkyl-9,10-Anthroquinones are used as a catalyst in the [[anthraquinone process]] for the production of hydrogen peroxide. This process is the dominant industrial method of hydrogen peroxide production.<ref>{{Cite journal |last=Campos-Martin |first=Jose M. |last2=Blanco-Brieva |first2=Gema |last3=Fierro |first3=Jose L. G. |date=2006 |title=Hydrogen Peroxide Synthesis: An Outlook beyond the Anthraquinone Process |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.200503779 |journal=Angewandte Chemie International Edition |language=en |volume=45 |issue=42 |pages=6962–6984 |doi=10.1002/anie.200503779 |issn=1521-3773|url-access=subscription }}</ref>

===Niche uses===
9,10-anthraquinone is used as a bird repellant on seeds, and as a gas generator in satellite balloons.<ref>{{Cite web |url=http://www.americanheritage.com/articles/magazine/it/2007/1/2007_1_38.shtml |title=www.americanheritage.com |access-date=2009-09-22 |archive-url=https://web.archive.org/web/20090609235239/http://www.americanheritage.com/articles/magazine/it/2007/1/2007_1_38.shtml |archive-date=2009-06-09 |url-status=dead }}</ref> It has also been mixed with lanolin and used as a wool spray to protect sheep flocks against [[kea]] attacks in New Zealand.<ref>{{cite news |last=Dudding |first=Adam |date=29 July 2012 |title=How to solve a problem like a kea |url=http://www.stuff.co.nz/science/7370200/How-to-solve-a-problem-like-the-kea |newspaper=Sunday Star Times |location=New Zealand |access-date=11 November 2014}}</ref>

==Other isomers==
Several other isomers of anthraquinone exist, including the 1,2-, 1,4-, and 2,6-anthraquinones. They are of minor importance compared to 9,10-anthraquinone.

==Safety==
Anthraquinone has no recorded {{LD50}}, probably because it is so insoluble in water.

In terms of metabolism of substituted anthraquinones, the enzyme encoded by the gene [[UGT1A8]] has glucuronidase activity with many substrates including anthraquinones.<ref name="pmid1339448">{{ cite journal |author1= Ritter, J. K. |author2=Chen, F. |author3=Sheen, Y. Y. |author4=Tran, H. M. |author5=Kimura, S. |author6=Yeatman, M. T. |author7=Owens, I. S.  | title = A Novel Complex Locus UGT1 Encodes Human Bilirubin, Phenol, and other UDP-Glucuronosyltransferase Isozymes with Identical Carboxyl Termini | journal = Journal of Biological Chemistry | year = 1992 | volume = 267 | issue = 5 | pages = 3257–3261 |doi=10.1016/S0021-9258(19)50724-4 | pmid = 1339448 | url = http://www.jbc.org/content/267/5/3257.full.pdf |doi-access=free }}</ref>

== See also ==
* [[Benzoquinone]]
* [[Naphthoquinone]]
* [[Parietin]]
* [[2-Ethylanthraquinone]]

==References==
{{reflist}}

==External links==
*[http://www.npi.gov.au/database/substance-info/profiles/74.html National Pollutant Inventory — Polycyclic Aromatic Hydrocarbon Fact Sheet]
*[https://www.sciencedaily.com/releases/2006/08/060818014819.htm Molecules Spontaneously Form Honeycomb Network]

{{Authority control}}
{{Organic reactions}}
[[Category:Anthraquinones| ]]