Elbs persulfate oxidation
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The Elbs persulfate oxidation is the organic reaction of phenols with alkaline potassium persulfate to form para-diphenols.[1] The reaction is generally performed in water at room temperatures or below, using equimolar quantities of reagents.
| Elbs persulfate oxidation | |
|---|---|
| Named after | Karl Elbs |
| Reaction type | Organic redox reaction |
| Identifiers | |
| RSC ontology ID | RXNO:0000179 |
Scope and mechanism
The reaction is disadvantaged by moderate to low chemical yields with recovery of starting material and complete consumption of the persulfate.[4] It is suggested that the phenol in many cases is a catalyst 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 groups, which are not oxidised under these conditions.[4]
A reaction mechanism has been postulated which accounts for the observed para substitution featuring the tautomeric para carbanion of the starting phenolate ion:[5] It begins with nucleophilic displacement on the peroxide oxygen of the peroxodisulfate (peroxydisulfate) ion, to give an intermediate sulfate group (3), which is then hydrolyzed to the hydroxyl group.
