WordNet

(mechanics) the equal and opposite force that is produced when any force is applied to a body; "every action has an equal and opposite reaction"
a response that reveals a persons feelings or attitude; "he was pleased by the audiences reaction to his performance"; "John feared his mothers reaction when she saw the broken lamp"
a bodily process occurring due to the effect of some antecedent stimulus or agent; "a bad reaction to the medicine"; "his responses have slowed with age" (同)response
doing something in opposition to another way of doing it that you dont like; "his style of painting was a reaction against cubism"
an idea evoked by some experience; "his reaction to the news was to start planning what to do"
extreme conservatism in political or social matters; "the forces of reaction carried the election"

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{名}(…に対する)『反応』《+『to』+『名』》 / 〈U〉(…に対する)(政治的・社会的な)『反動』,逆コース《+『against』+『名』》 / 〈U〉〈C〉化学反応,化学変化 / 〈U〉〈C〉(物理学で)反作用

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/12/12 17:29:29」(JST)

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Fenton's reagent is a solution of hydrogen peroxide with ferrous iron as a catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (perchloroethylene, PCE). It was developed in the 1890s by Henry John Horstman Fenton as an analytical reagent.^[1] ^[2]

Overview

Iron(II) is oxidized by hydrogen peroxide to iron(III), forming a hydroxyl radical and a hydroxide ion in the process. Iron(III) is then reduced back to iron(II) by another molecule of hydrogen peroxide, forming a hydroperoxyl radical and a proton. The net effect is a disproportionation of hydrogen peroxide to create two different oxygen-radical species, with water ( $H + + OH -$ ) as a byproduct.

Fe²⁺ + H₂O₂ → Fe³⁺ + HO• + OH⁻

(1)

Fe³⁺ + H₂O₂ → Fe²⁺ + HOO• + H⁺

(2)

The free radicals generated by this process then engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.^[3]

Reaction (1) was suggested by Haber and Weiss in the 1930s as part of what would become the Haber–Weiss reaction.^[4] Iron(II) sulfate is typically used as the iron catalyst. The exact mechanisms of the redox cycle are uncertain, and non-OH• oxidizing mechanisms of organic compounds have also been suggested.^{[citation needed]} Therefore, it may be appropriate to broadly discuss Fenton chemistry rather than a specific Fenton reaction.

In the electro-Fenton process, hydrogen peroxide is produced in situ from the electrochemical reduction of oxygen.^[5]

Fenton's reagent is also used in organic synthesis for the hydroxylation of arenes in a radical substitution reaction such as the classical conversion of benzene into phenol.

C₆H₆ + FeSO₄ + H₂O₂ → C₆H₅OH

(3)

A recent hydroxylation example involves the oxidation of barbituric acid to alloxane.^[6] Another application of the reagent in organic synthesis is in coupling reactions of alkanes. As an example tert-butanol is dimerized with Fenton's reagent and sulfuric acid to 2,5-dimethyl-2,5-hexanediol.^[7]

Biomedical applications

The Fenton reaction has importance in biology because it involves the creation of free radicals by chemicals that are present in vivo. Transition-metal ions such as iron and copper donate or accept free electrons via intracellular reactions and help in creating free radicals. Most intracellular iron is in ferric (+3 ion) form and must be reduced to the ferrous (+2) form to take part in Fenton reaction. Superoxide ions and transition metals act in a synergistic manner in the creation of free radical damage.^[8] Therefore, although the clinical significance is still unclear, it is one of the viable reason to avoid iron supplementation in patients with active infections, whereas other reasons include iron-mediated infections.^[9]

References

^ Fenton H.J.H. (1894). "Oxidation of tartaric acid in presence of iron". J. Chem. Soc., Trans. 65 (65): 899–911. doi:10.1039/ct8946500899.
^ Hayyan M., Hashim M.A., AlNashef I.M., Superoxide Ion: Generation and Chemical Implications, Chem. Rev., 2016, 116 (5), pp 3029–3085. DOI: 10.1021/acs.chemrev.5b00407]
^ http://geocleanse.com/fentonsreagent.asp
^ Haber, F.; Weiss, J. (1932). "Über die Katalyse des Hydroperoxydes". Naturwissenschaften. 20 (51): 948–950. doi:10.1007/BF0150471.
^ Juan Casado; Jordi Fornaguera; Maria I. Galan (January 2005). "Mineralization of Aromatics in Water by Sunlight-Assisted Electro-Fenton Technology in a Pilot Reactor". Environ. Sci. Technol. 39 (6): 1843–47. Bibcode:2005EnST...39.1843C. doi:10.1021/es0498787. PMID 15819245.
^ Brömme HJ, Mörke W, Peschke E (November 2002). "Transformation of barbituric acid into alloxan by hydroxyl radicals: interaction with melatonin and with other hydroxyl radical scavengers". J. Pineal Res. 33 (4): 239–47. doi:10.1034/j.1600-079X.2002.02936.x. PMID 12390507.
^ E. L. Jenner (1973). "α,α,α',α'-Tetramethyltetramethylene glycol". Organic Syntheses. ; Collective Volume, 5, p. 1026
^ Robbins & Cotran (2008). Pathologic Basis of Disease (7th ed.). Elsevier. p. 16. ISBN 9780808923022.
^ Lapointe, Marc (2004-01-01). "Iron supplementation in the intensive care unit: when, how much, and by what route?". Critical Care. 8 (2): 1–5. doi:10.1186/cc2825. ISSN 1364-8535. PMC 3226152 . PMID 15196322.

External links

USGS definition
Reference Library Peroxide Applications
Companies that use Fenton's Reagent for chemical remediation: ORIN

UpToDate Contents

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English Journal

Removal of selenite by zero-valent iron combined with ultrasound: Se(IV) concentration changes, Se(VI) generation, and reaction mechanism.

Fu F1, Lu J2, Cheng Z2, Tang B2.
Ultrasonics sonochemistry.Ultrason Sonochem.2016 Mar;29:328-36. doi: 10.1016/j.ultsonch.2015.10.007. Epub 2015 Oct 20.
In this paper, the performance and application of zero-valent iron (ZVI) assisted by ultrasonic irradiation for the removal of selenite (Se(IV)) in wastewater was evaluated and reaction mechanism of Se(IV) with ZVI in such systems was investigated. A series of batch experiments were conducted to det
PMID 26585013

Heterogeneous sono-Fenton-like process using nanostructured pyrite prepared by Ar glow discharge plasma for treatment of a textile dye.

Khataee A1, Gholami P2, Vahid B3.
Ultrasonics sonochemistry.Ultrason Sonochem.2016 Mar;29:213-25. doi: 10.1016/j.ultsonch.2015.09.012. Epub 2015 Sep 30.
The plasma-treated pyrite (PTP) nanostructures were prepared from natural pyrite (NP) utilizing argon plasma due to its sputtering and cleaning effects resulting in more active surface area. The NP and PTP were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-
PMID 26585001

SonoFenton degradation of an azo dye, Direct Red.

Harichandran G1, Prasad S2.
Ultrasonics sonochemistry.Ultrason Sonochem.2016 Mar;29:178-85. doi: 10.1016/j.ultsonch.2015.09.005. Epub 2015 Sep 21.
The degradation of a reactive azo dye, Direct Red 81 (DR81), by Fenton process and in conjunction with sonolysis (SonoFenton) was studied. The synergistic effect of Fenton process and sonolysis enhanced the degradation of Direct Red 81 in aqueous solutions and the reaction followed the mechanism of
PMID 26584996

Japanese Journal

A Novel Nrf2-Mediated Antioxidative and Antiinflammatory Mechanism through Ferroportin 1 Induction : A Potential Cytoprotective Mechanism against Ischemia-Reperfusion Injuries

Harada Nobuhiko,Matsuura Shin,Kanayama Masaya,Yoshida Aruto,Itoh Ken
弘前医学 64(Supplement), S74-S80, 2013-04-02
… On the other hand, free intracellular iron is detrimental to cells by enhancing both inflammation and Fenton reaction-mediated oxidative stress. …
NAID 120005230055

Improving the Biodegradability of Non-Biodegradable Compounds Using Photo-Fenton Reaction

TOKUMURA Masahiro,HATAYAMA Rurika,KAWASE Yoshinori,YANAGISAWA Yukio
Journal of Water and Environment Technology 11(2), 121-130, 2013
… The feasibility of using the photo-Fenton reaction to improve the biodegradability of non-biodegradable compounds that originated from sewage was examined. … Non-biodegradable compounds are degraded by hydroxyl (OH) radicals generated by the photo-Fenton reaction. …
NAID 130003363010

Influence of Chelating Agents on Fenton-Type Reaction Using Ferrous Ion and Hypochlorous Acid

KISHIMOTO Naoyuki,KITAMURA Takuya,KATO Masaaki,OTSU Hideo
Journal of Water and Environment Technology 11(1), 21-32, 2013
… Iron-based advanced oxidation technologies, such as the Fenton process, are widely used for industrial wastewater treatment. … In this research, we investigated the influence of chelating agents on Fenton-type reaction using ferrous ion (Fe<SUP>2+</SUP>) and hypochlorous acid (HOCl). …
NAID 130003363005