The Oxidation of Phenol by Ferrate(VI) Andferrate(V). A Pulse Radiolysis and Stopped-Flow Study

Potassium ferrate. K₂FeO₄, is found to oxidize phenol in aqueous solution (5.5 ± pH ± 10) by a process which is second order in both reactants; -dFe^vt]/dt=kiFe^VI]phenol], kI = 10⁷M^-1s^-1. Product analysis by HPLC showed a mixture of hydroxylated products, principally paraquinone. and biphenols that indicate that oxidation of phenol occurs by both one-electron and two-electron pathways. The two-electron oxidant. producing both para- and ortho-hydroxylated phenols is considered to be ferrate(V) which is itself produced by the initial one-electron reduction of ferrate(VI). The rate of ferrate(V) reaction with phenol was determined by pre-mix stopped flow pulse-radiolysis and found to be k7 = (3.8 ± 0.4)± 10⁵M^-1s^-1.