Fenton’s reagent oxidation

The combination of Fe2+ and H202, called Fenton s reagent, oxidizes organic material in dilute aqueous solutions. For example, organic components of urine could be destroyed in 30 min at 5()°C to release traces of mercury for analysis.17 To do so, a 50-mL sample was adjusted to pH 3-4 with 0.5 M H2S04. Then 50 xL of saturated aqueous ferrous ammonium sulfate, Fe(NH4)2(S04)2, were added, followed by 100 p,L of 30% H202. 

For phenol hydroxylation it is shown that Fe2+ and Fe3+ ion activity increases in the presence of other ions, among which the highest activity is displayed by salts and complexes of the following metals Co, Mn, Mo, Cu, Fe, etc. In aqueous solution Fenton s reagent oxidizes substrates according to the radical mechanism in which reactions with 0H radicals play the central role. In aprotic solvents oxidation with Fenton s reagent suggests the participation of different intermediates—complexes with iron ions, Fe=0, for example. 

On the basis of this study, Sudoh et al. [78] proceeded to generate hydrogen peroxide in an acidic solution (1 M H2SO4) for use in Fenton s reagent oxidation of wastewater streams (Fig. 20). The peroxide, produced at the cathode in an alkaline KOH electrolyte, was transferred by electrodialysis to a central chamber, separated by anion exchange membrane (ACLE-5P, Tokuyama Soda, Japan) on the cathode side and a cation exchange membrane (CM-2, Tokuyama Soda, Japan) on the anode side. At a current of 4 A, 2.2 kmol/m of H2O2 was found to accumulate in the cen-... 

In this section, brief fundamental reaction mechanisms for each AOP are addressed. Included as AOPs are individual and combinational processes in the use of ultraviolet (UV) irradiation, catalyzed titanium dioxide oxidation, Fenton s reagent oxidation, ozonation, peroxone oxidation, and permanganate oxidation. 

Another common method of generating OH for the oxidation of organic compounds is via Fenton s reagent. Fenton s reagent oxidation involves the decomposition of hydrogen peroxide in the presence... 

This section introduces unconventional reaction mechanisms and the results of Fenton s reagent oxidation. 

Hydrogen peroxide may react directiy or after it has first ionized or dissociated into free radicals. Often, the reaction mechanism is extremely complex and may involve catalysis or be dependent on the environment. Enhancement of the relatively mild oxidizing action of hydrogen peroxide is accompHshed in the presence of certain metal catalysts (4). The redox system Fe(II)—Fe(III) is the most widely used catalyst, which, in combination with hydrogen peroxide, is known as Fenton s reagent (5). 

Oxidation. Coumarin is not readily oxidized by chromic acid but, by action of the Fenton s reagent, it is converted into 7-hydroxycoumarin (umbeUiferone) [93-35-6] (28). 

Oxidation. Oxidation is one of the main chemical methods to treat and decompose dyes in wastewater. The oxidation agents used ate chlorine, bleach, ozone, hydrogen peroxide, Fenton s reagent, and potassium permanganate. 

The Tf- CF system is preferred over Fenton s reagent because Ti4 is a less powerful oxidizing agent than Fc5+ and the above mentioned pathway and other side reactions are therefore of less consequence.252 Much of the discussion on redox initiation in Section 3.3.2.6.1 is also relevant to hydrogen peroxide. 

The reverse reaction (that is, the oxidation of a vinyl radical by Fe to the corresponding vinyl cation) may be involved in the reaction of the dimethyl ester of acetylenedicarboxyUc acid 261 with Fenton s reagent [Fe —H2O2, (217)] (216). When 261 was treated with Fe —H2O2 and the reaction mixture was extracted with ether, a small amount of furan 262 was isolated. A possible mechanism (216) for its formation may be addition of hydroxyl radical to the triple bond of 261, followed by addition of the intermediate vinyl radical to a second molecule of 261 and oxidation of the resulting radical with Fe to the corresponding vinyl cation, followed by cyclization to 262, as shown in Scheme XX. 

Sedlak DL, AW Andren (1991) Oxidation of chlorobenzene with Fenton s reagent. Environ Sci Technol 25 777-782. 

Xu X-R, Zhao Z-Y, Li X-Y, Gu J-D (2004) Chemical oxidative degradation of mehyl tert-butyl ether in aqueous solution by Fenton s reagent. Chemosphere 55 73-79... 

Yields of osones obtained by the oxidation of sugars by Fenton s reagent are low, and the osones are invariably contaminated both with starting material and with the products of further oxidation in consequence, the method has had only limited application.44... 

When lactose is oxidized by Fenton s reagent,23 no osone is formed. 

Lewis201 postulated maltosone as the first product in the oxidation of maltose by Fehling solution, but no osone was detected when maltose was treated with Fenton s reagent.23 Oxidation of maltosone with bromine water gave 2-oxo-maltobionic acid, isolated as its brucine salt.191... 

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