Elbs persulfate oxidation

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



Several review have been published.

Reaction mechanism
A reaction mechanism has been postulated accounting for the observed para substitution featuring the tautomeric para carbanion of the starting phenolate ion:



which gives a nucleophilic displacement on the peroxide oxygen of the peroxydisulfate ion. The intermediate sulfate group is then hydrolyzed to the alcohol.

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.