Editing Butylated hydroxyanisole

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| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 399698891
| ImageFile = 2-tert-Butyl-4-hydroxyanisole_and_3-tert-butyl-4-hydroxyanisole_2D.svg
| ImageSize =
| PIN = 2-''tert''-Butyl-4-methoxyphenol and 3-''tert''-butyl-4-methoxyphenol (mixture)<!-- no substitution on anisole for PINs -->
| OtherNames = {{ubl
 | 2-''tert''-Butyl-4-hydroxyanisole and 3-''tert''-butyl-4-hydroxyanisole (mixture)
 | BOA
 | BHA
 | ''tert''-Butyl-4-hydroxyanisole
 | (1,1-Dimethylethyl)-4-methoxyphenol
 | ''tert''-Butyl-4-methoxyphenol
 | Antioxyne B<ref name=AboutChemistry>{{cite web|url=http://chemistry.about.com/od/foodcookingchemistry/a/bha-bht-preservatives.htm|title=BHA and BHT|access-date=Nov 20, 2009|archive-date=October 31, 2009|archive-url=https://web.archive.org/web/20091031131459/http://chemistry.about.com/od/foodcookingchemistry/a/bha-bht-preservatives.htm|url-status=dead}}</ref>
 }}
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 23068
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 76359
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 502074
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = REK4960K2U
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = A03IJ8ROOP
| UNII1_Comment = (''2-tert'')
| UNII2_Ref = {{fdacite|correct|FDA}}
| UNII2 = 62RAC24292
| UNII2_Comment = (''3-tert'')

| InChI = 1/2C11H16O2/c1-11(2,3)9-7-8(13-4)5-6-10(9)12;1-11(2,3)9-7-8(12)5-6-10(9)13-4/h2*5-7,12H,1-4H3
| InChIKey = CZBZUDVBLSSABA-UHFFFAOYAZ
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/2C11H16O2/c1-11(2,3)9-7-8(13-4)5-6-10(9)12;1-11(2,3)9-7-8(12)5-6-10(9)13-4/h2*5-7,12H,1-4H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = CZBZUDVBLSSABA-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 25013-16-5
| CASNo2_Ref = {{cascite|correct|CAS}}
| CASNo2 = 121-00-6
| CASNo2_Comment = (''2-tert'')
| CASNo3_Ref = {{cascite|correct|CAS}}
| CASNo3 = 88-32-4
| CASNo3_Comment = (''3-tert'')
| PubChem = 24667
| SMILES1 = O(c1ccc(O)cc1C(C)(C)C)C.O(c1ccc(O)c(c1)C(C)(C)C)C
}}
| Section2 = {{Chembox Properties
| C=11|H=16|O=2
| MolarMassUnit = g/mol
| Appearance = Waxy solid
| Density = 1.0587{{nbsp}}g/cm<sup>3</sup> at 20{{nbsp}}°C
| MeltingPtC = 48 to 55
| BoilingPtC = 264 to 270
| Solubility = Insoluble in water
| SolubleOther = Freely soluble in [[ethanol]], [[methanol]], [[propylene glycol]]; soluble in fats and oils
| RefractIndex = 1.5303 at 589.3{{nbsp}}nm<ref name='Scifinder'>{{cite web|url=https://scifinder.cas.org |title=SciFinder&nbsp;— Experimental properties for 121-00-6|access-date=Nov 20, 2009 }}</ref>
  }}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
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| Section4 = {{Chembox Related
| OtherCompounds = [[Butylated hydroxytoluene]]
  }}
}}

'''Butylated hydroxyanisole''' ('''BHA''') is a synthetic, waxy, solid [[petrochemical]]. Its [[antioxidant]] properties have caused it to be widely used as a preservative in food, food packaging, animal feed, cosmetics, pharmaceuticals, rubber, and petroleum products.<ref>[http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB Hazardous Substances Database], National Library of Medicine</ref> BHA has been used in food since around 1947.<ref name="SA">{{cite news |title=BHA and BHT: A Case for Fresh? |url=https://www.scientificamerican.com/article/bha-and-bht-a-case-for-fresh/ |access-date=27 December 2022 |work=Scientific American |date=December 19, 2013}}</ref>

==Chemistry==
BHA consists of a mixture of two [[isomer]]ic organic compounds, 2-''tert''-butyl-4-hydroxyanisole and 3-''tert''-butyl-4-hydroxyanisole. It is prepared from [[Mequinol|4-methoxyphenol]] and [[isobutylene]].

The conjugated aromatic ring of BHA is able to stabilize [[free radical]]s, sequestering them. By acting as free radical [[scavenger (chemistry)|scavenger]]s, further free radical reactions are prevented.

==Applications==
Since 1947, BHA has been added to edible fats and fat-containing foods for its antioxidant properties as it prevents [[rancidification]] of food which creates objectionable odors.<ref name=Lam>{{cite journal | doi = 10.1021/jm00191a020 | author = Lam, L. K. | author2 = R. P. Pai | author3 = L. W. Wattenberg | name-list-style = amp | year = 1979 | title = Synthesis and chemical carcinogen inhibitory activity of 2-''tert''-butyl-4-hydroxyanisole | journal = J Med Chem | volume = 22 | issue = 5 | pages = 569–71 | pmid = 458807}}</ref> It has been assigned the [[E number]] E320. It is often combined with a similar chemical, [[butylated hydroxytoluene]] (BHT).<ref name="SA"/>

BHA also is commonly used in medicines, such as [[cholecalciferol]] (vitamin D<sub>3</sub>), [[isotretinoin]], [[lovastatin]], and [[simvastatin]], among others.

==Health effects==
The U.S. [[National Institutes of Health]] report that BHA is reasonably anticipated to be a human [[carcinogen]] based on evidence of carcinogenicity in experimental animals. In particular, when administered in high doses as part of their diet, BHA causes [[papilloma]]s and [[squamous cell carcinoma]]s of the forestomach in rats and Syrian golden [[hamster]]s.<ref name=ROC>[https://ntp.niehs.nih.gov/ntp/roc/content/profiles/butylatedhydroxyanisole.pdf Butylated Hydroxyanisole (BHA), CAS No. 25013-16-5] {{Webarchive|url=https://web.archive.org/web/20100605124129/http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s027bha.pdf# |date=2010-06-05 }}, ''Report on Carcinogens'', Eleventh Edition, [[National Institutes of Health]]</ref>  In mice, there is no carcinogenic effect;<ref name=ROC/> in fact, there is evidence of a protective effect against the carcinogenicity of other chemicals.<ref name=Lam/>

When examining human [[population statistics]], the usual low intake levels of BHA show no significant association with an increased risk of cancer.<ref>{{cite journal | doi = 10.1016/S0278-6915(00)00042-9 | vauthors = ((Botterweck AAM)), Vergaen H, GoldBohm RA, KleinJans J, van den Brant PA | title = Intake of Butylated Hydroxyanisole and Butylated Hydroxytoluene and Stomach Cancer Risk: Results from Analyses in the Netherlands Cohort Study | journal = [[Food and Chemical Toxicology]] | year = 2007 | volume = 38 | issue = 7 | pages = 599–605 | pmid = 10942321| url = https://cris.maastrichtuniversity.nl/portal/en/publications/intake-of-butylated-hydroxyanisole-and-butylated-hydroxytoluene-and-stomach-cancer-risk-results-from-analyses-in-the-netherlands-cohort-study(7abde0bd-1682-4da8-8ebf-b8373b7ed481).html }}</ref>

The European Commission has conducted an evaluation of literature. They noted the lack of potential for the compound to induce carcinogenic effects in humans; studies showing carcinogenic effects in hamsters are not relevant to humans (which lack a forestomach). Also noted is that endocrine disruption, if any, is only likely to be present at levels vastly exceeding the intake as a food. <ref>{{cite journal |doi=10.2903/j.efsa.2011.2392|title=Scientific Opinion on the re-evaluation of butylated hydroxyanisole - BHA (E 320) as a food additive|journal=EFSA Journal|year=2011|volume=9|issue=10|page=2392|doi-access=free}}</ref>

The [[International Agency for Research on Cancer|International Agency for Research on Cancer (IARC)]] – Summaries & Evaluations stated butylated hydroxyanisole was tested for carcinogenicity in two experiments in rats and in two experiments in hamsters by administration in the diet, inducing benign and malignant tumours of the forestomach. <ref>{{Cite web|title=Butylated Hydroxyanisole (BHA) (IARC Summary & Evaluation, Volume 40, 1986)|url=https://inchem.org/documents/iarc/vol40/butylatedhydroxyanisole.html|access-date=2022-01-30|website=inchem.org}}</ref>

One of its metabolites is [[TBHQ]] (''t''-butylhydroquinone), a preservative made infamous by food writer [[Michael Pollan]].<ref name="SA"/>

== See also ==
* [[Anisole]]
* [[Butylated hydroxytoluene]] (BHT)

== References ==
{{Reflist}}

[[Category:Phenols]]
[[Category:Food antioxidants]]
[[Category:IARC Group 2B carcinogens]]
[[Category:Alkylphenols]]
[[Category:Tert-butyl compounds]]
[[Category:E-number additives]]