Elbs persulfate oxidation

The Elbs persulfate oxidation is the organic reaction of phenols with alkaline potassium persulfate to form para-diphenols.

Several reviews have been published.

A reaction mechanism has been postulated which accounts for the observed para substitution featuring the tautomeric para carbanion of the starting phenolate ion: 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.

The reaction is disadvantaged by low chemical yields with recovery of starting material and complete consumption of the persulfate. It is suggested that the phenol in many cases is a catalyst converting the persulfate into a sulfate.

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