I ions act as a source of hydroxyl radicals

Since Cu(I) ions are usually powerful electron donors, the reaction with H202 to give OH radicals is highly probable. However, the reaction [4.13] is less useful as a method of inducing oxidation because the disproportionation reaction to give Cu(II) and copper metal ensures that [Cu(I)] is always low. 

A strong case against this reaction [4.13] has been given by Johnson and co-workers (1988), who favour Cu3+ as an intermediate. This is an exactly analogous problem to that outlined above for 

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