Editing Phenols (section)

==Properties==
===Acidity===
Phenols are more [[acid]]ic than typical alcohols. The acidity of the hydroxyl group in phenols is commonly intermediate between that of [[aliphatic]] alcohols and [[carboxylic acid]]s (their pK<sub>a</sub> is usually between 10 and 12). Deprotonation of a phenol forms a corresponding negative phenolate ion or phenoxide ion, and the corresponding [[Salt (chemistry)|salt]]s are called phenolates or phenoxides (aryloxides, according to the IUPAC Gold Book).{{cn|date=July 2024}}

===Condensation with aldehydes and ketones===
Phenols are susceptible to [[electrophilic aromatic substitution]]s. Condensation with [[formaldehyde]] gives resinous materials, famously [[Bakelite]].{{cn|date=July 2024}}

Another industrial-scale electrophilic aromatic substitution is the production of [[bisphenol A]], which is produced by the [[condensation reaction|condensation]] with [[acetone]].<ref name="Fiege">{{Ullmann |author1=Fiege H |author2=Voges H-W |author3=Hamamoto T |author4=Umemura S |author5=Iwata T |author6=Miki H |author7=Fujita Y |author8=Buysch H-J |author9=Garbe D |author10=Paulus W |year=2000 |title=Phenol Derivatives |doi=10.1002/14356007.a19_313}}</ref>
:[[File:Synthesis Bisphenol A.svg|frameless|upright=2.5]]

===C-Alkylation with alkenes===
Phenol is readily alkylated at the ortho positions using alkenes in the presence of a Lewis acid such as [[aluminium phenoxide]]:{{citation needed|date=April 2024}}
: CH<sub>2</sub>=CR<sub>2</sub>  +  C<sub>6</sub>H<sub>5</sub>OH  →  R<sub>2</sub>CHCH<sub>2</sub>-2-C<sub>6</sub>H<sub>4</sub>OH
More than 100,000 tons of [[tert-butyl]] phenols are produced annually (year: 2000) in this way, using [[isobutylene]] (CH<sub>2</sub>=CMe<sub>2</sub>) as the alkylating agent. Especially important is [[2,6-Di-tert-butylphenol|2,6-ditert-butylphenol]], a versatile [[antioxidant]].<ref name="Fiege"/>

===Other reactions===<!-- This section is linked from [[Organic reaction]] -->
Phenols undergo [[esterification]]. Phenol esters are [[active ester]]s, being prone to [[hydrolysis]]. Phenols are [[Reactivity (chemistry)|reactive]] species toward [[oxidation]]. Oxidative cleavage, for instance cleavage of [[1,2-dihydroxybenzene]] to the monomethylester of 2,4-hexadienedioic acid with oxygen, [[copper chloride]] in [[pyridine]].<ref>2,4-Hexadienedioic acid, monomethyl ester, (Z,Z)- [[Organic Syntheses]], Coll. Vol. 8, p. 490 (1993); Vol. 66, p. 180 (1988) [http://www.orgsynth.org/orgsyn/prep.asp?prep=cv8p0490 Article].</ref> Oxidative de-aromatization to [[quinone]]s also known as the [[Teuber reaction]]. Oxidizing reagents are [[Fremy's salt]]<ref>{{cite journal |year=1972 |title=2,5-Cyclohexadiene-1,4-dione, 2,3,5-trimethyl |journal=Organic Syntheses |volume=52 |page=83}}</ref> and [[oxone]].<ref>{{cite journal |last1=Carreño |first1=M. Carmen |last2=González-López |first2=Marcos |last3=Urbano |first3=Antonio |year=2006 |title=Oxidative De-aromatization of para-Alkyl Phenols into para-Peroxyquinols and para-Quinols Mediated by Oxone as a Source of Singlet Oxygen |journal=[[Angewandte Chemie International Edition]] |volume=45 |issue=17 |pages=2737–2741 |doi=10.1002/anie.200504605 |pmid=16548026}}</ref> In reaction depicted below 3,4,5-trimethylphenol reacts with [[singlet oxygen]] generated from [[oxone]]/[[sodium carbonate]] in an [[acetonitrile]]/water mixture to a para-peroxyquinole. This [[hydroperoxide]] is reduced to the quinole with [[sodium thiosulfate]].
:[[Image:OxonePhenolDearomatization.png|600px|Oxone phenol dearomatization]]
Phenols are oxidized to [[hydroquinone]]s in the [[Elbs persulfate oxidation]].

Reaction of naphtols and hydrazines and sodium bisulfite in the [[Bucherer carbazole synthesis]].