Hydrogen peroxide reaction with iron

Fig. 3 Fenton reaction. Hydrogen peroxide reacts with iron(II) to form iron(III), hydroxyl...

Luminol chemiluminescence has also been recommended for measuring bacteria populations (304,305). The luminol—hydrogen peroxide reaction is catalyzed by the iron porphyrins contained in bacteria, and the light intensity is proportional to the bacterial concentration. The method is rapid, especially compared to the two-day period required by the microbiological plate-count method, and it correlates weU with the latter when used to determine bacteria... 

As has already been mentioned, during the iron(II)-hydrogen peroxide reaction a number of organic compounds which do not react, or react only slowly with hydrogen peroxide, are readily oxidizable. In the induced oxidation of organic compounds, hydrogen peroxide plays the role of the actor and iron(II) is the inductor. 

An interesting alternative to the use of chromium(VI) oxidants for the conversion of 1 to 2 involves the use of a low-valent iron reagent prepared in situ by the action of hydrogen peroxide on an iron(II) complex of 1 (73). Vinblastine (as the free base) is treated with 2 equiv of perchloric acid in acetonitrile at -20°C. Ferrous perchlorate is then added, followed by the addition of excess 30% hydrogen peroxide. Work-up of the reaction mixture with a saturated solution of ammonium hydroxide gives 2 in yields of 35-50% after chromatography. 

Attack by alkoxycarbonyl radicals, which are isoelectronic with but less nucleophilic than carbamoyl radicals, has been less well studied than acylation and amidation. An example is provided by the reaction of quinoline with ethyl pyruvate, hydrogen peroxide and an iron(II) salt (Scheme 213) (73TL645). 

In the presence of metals, such as iron, hydrogen peroxide reacts with superoxide anion to produce hydroxyl radicals (OH ) and singlet oxygen ( O2) by the reaction shown below ... 

The direct oxidation of benzene to phenol is usually affected by a poor selectivity due to the lack of kinetic control. Indeed, phenol is more reactive towards oxidation than benzene itself and consecutive reactions occur, with substantial formation of overoxidized products like catechol, hydroquinone, benzoquinones and tars. This is the usual output of the oxidation of aromatic hydrocarbons by the classical Fenton system, a mixture of hydrogen peroxide and an iron(II) salt, usually ferrous sulfate, most often used in stoichiometric amounts [8]. 

Hemoglobin and myoglobin in their ferric forms show rudimentary peroxidatic and catalatic activity, but ferrous peroxidase does not combine reversibly with molecular oxygen. Ionic iron also gives the hydrogen peroxide reactions but not the combination with oxygen. 

Contact with many organic compounds can lead to immediate fires or violent explosions (consult Bretherick for references and examples). Hydrogen peroxide reacts with certain organic functional groups (ethers, acetals, etc.) to form peroxides, which may explode upon concentration. Reaction with acetone generates explosive cyclic dimeric and trimeric peroxides. Explosions may also occur on exposure of hydrogen peroxide to metals such as sodium, potassium, magnesium, copper, iron, and nickel. 

---