Elbs persulfate oxidation
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The Elbs persulfate oxidation is the
organic reaction Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical ...
of
phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it r ...
s with alkaline potassium persulfate to form ''
para Para, or PARA, may refer to: Businesses and organizations * Paramount Global, traded as PARA on the Nasdaq stock exchange * Para Group, the former name of CT Corp * Para Rubber, now Skellerup, a New Zealand manufacturer * Para USA, formerly ...
''-diphenols. The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents. Several reviews have been published.


Scope and mechanism

The reaction is disadvantaged by moderate to low
chemical yield In chemistry, yield, also referred to as reaction yield, is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. Yield is one of the pr ...
s with recovery of starting material and complete consumption of the
persulfate A persulfate (sometimes known as peroxysulfate or peroxodisulfate) is a compound containing the anions or . The anion contains one peroxide group per sulfur center, whereas in , the peroxide group bridges the sulfur atoms. In both cases, sulfu ...
. It is suggested that the phenol in many cases is a
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
converting the persulfate into a sulfate. Despite this, the Elbs reaction remains generally useful in a research setting, as it is simple to perform and is tolerant of a wide range of other
functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the r ...
s, which are not oxidised under these conditions. A
reaction mechanism In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs. A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage o ...
has been postulated which accounts for the observed ''para'' substitution featuring the
tautomer Tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hy ...
ic ''para''
carbanion In organic chemistry, a carbanion is an anion in which carbon is trivalent (forms three bonds) and bears a formal negative charge (in at least one significant resonance form). Formally, a carbanion is the conjugate base of a carbon acid: :R3 ...
of the starting phenolate ion:{{cite journal , author = Behrman, E. J. , title = The Elbs and Boyland-Sims peroxydisulfate oxidations , year = 2006 , journal = Beilstein Journal of Organic Chemistry , volume = 2 , issue = 1 , pages = 22 , doi = 10.1186/1860-5397-2-22 , pmid = 17090305 , pmc = 1697820 It begins with nucleophilic displacement on the peroxide oxygen of the peroxodisulfate (peroxydisulfate) ion, to give an intermediate
sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
group (3), which is then hydrolyzed to the
hydroxyl group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
.


See also

*
Boyland–Sims oxidation The Boyland–Sims oxidation is the chemical reaction of anilines with alkaline potassium persulfate, which after hydrolysis forms ''ortho''-hydroxyl anilines. The reaction is generally performed in water at room temperatures or below, using equim ...
* Dakin reaction


References

Organic oxidation reactions Name reactions Add the following: E. J. Behrman, The Elbs & Boyland-Sims Oxidations: An Updated Literature Survey. Mini-Rev. Org. Chem, 18(2021)621-625.