Basic Chemistry of Hydrogen Peroxide

On the face of the E° value alone, one would expect the compound to be a relatively powerful oxidant (Table 2.1). However, hydrogen peroxide is, in fact, a relatively weak oxidizing agent. It can achieve some oxidations unaided, e.g. it reacts slowly with substrates such as olefins, aromatic hydrocarbons, alkanes, etc., but for the majority of applications, it requires activation in some way or other. This is reflected by the fact that hydrogen peroxide has been employed for bleaching purposes for over a century1 and some activation methods such as Fenton s reagent are almost as old.2 

By far the bulk of useful peroxygen chemistry has been discovered in the last 50 years, and many catalytic methods, described later, are even more recent. The low intrinsic reactivity of hydrogen peroxide is actually an advantage, since it 

Undissociated hydrogen peroxide behaves, to some extent, as a nucleophile, being about 104 times more nucleophilic than water. For example, hydrogen peroxide readily adds to carbonyl bonds giving rise to hydroxyhydroperoxides (peracetals and perketals). Such compounds are often used as polymerization initiators on account of their radical decomposition at moderate temperatures (0-0 bond homolysis). Neutral hydrogen peroxide can also react with activated acyl compounds such as anhydrides to give peroxyacids. 

The resulting strong electrophile can be used in some oxidations, notably phenol hydroxylation, however the extreme acidic conditions required limit the 

The hydroxyl radical can also be generated from several one-electron reducing metal ions,4 of which the most common is iron(II), this combination being known as Fenton s reagent (see Section 3). 

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