Kinetics and mechanism of the oxidation of indoles by alkaline potassium hexacyanoferrate [III]

ABSTRACT

The reaction of indoles with hexacyanoferrate [III] in alkaline media to produce the corresponding oxindole has been studied at constant temperature and ionic strength. The reaction followed first order kinetics with respect to [indole] and [OH[-], whereas fractional order with respect to [Fe[CN][6][-3]] was found. The effects of added electrolytes, potassium hexacyanoferrate [II], relative permitivity and temperature have also been studied. On the basis of experimental observations, a probable reaction mechanism has been proposed