Fenton Chemistry: An Introduction

Abstract

In 1876, Fenton described a colored product obtained on mixing tartaric acid with hydrogen peroxide and a low concentration of a ferrous salt. Full papers in 1894 and 1896 showed the product was dihydroxymaleic acid. Haber, Weiss and Willstätter proposed in 1932-1934 the involvement of free hydroxyl radicals in the iron(II)/hydrogen peroxide system, and Baxendale and colleagues around 1950 suggested that superoxide reduces the iron(III) formed on reaction, explaining the catalytic nature of the metal. Since Fridovich and colleagues discovered the importance of superoxide dismutase in 1968, numerous studies have sought to explain the deleterious effects of cellular oxidative stress in terms of superoxide-driven Fenton chemistry. There remain questions concerning the involvement of free hydroxyl radicals or reactions of metal/oxo intermediates. However, these outstanding questions may obscure a wider appreciation of the importance of Fenton chemistry involving hypohalous acids rather than hydrogen peroxide as the oxidant.

Role of cytochrome P450 reductase in nitrofurantoin-induced redox cycling and cytotoxicity

“…2B). Production of hydroxyl radicals was dependent on iron, a finding consistent with the ability of nitrofurantoin to generate H 2 O 2 during redox cycling, and its subsequent conversion to hydroxyl radicals via the Fenton reaction [23]. As observed with H 2 O 2 production, diphenyleneiodonium also inhibited cytochrome-P450-reductase-mediated production of superoxide and hydroxyl radicals (data not shown).…”

Mecanismo e aplicações da reação de fenton assistida por compostos fenólicos redutores de ferro

“…Um dos POA mais promissores consiste na reação entre Fe 2+ e H 2 O 2 , conhecida como a reação de Fenton (Equação 1), que gera os radicais OH que possuem elevado potencial de oxi-redução (2,3 V), atacando indistintamente todas as espécies presentes no meio reacional 2,3 . A alta reatividade do radical OH resulta em reações rápi-das, da ordem de 1 x 10 10 , e inespecíficas com os distintos substratos, o que implica que a velocidade de reação normalmente é limitada pela velocidade de difusão 4,5 . Quando é utilizado Fe 3+ ao invés de Fe 2+ e H 2 O 2 em excesso (reação tipo Fenton), outros radicais de menor potencial de oxidação como hidroperoxila (HO 2…”

Heterogeneously catalyzed lignin depolymerization

“…Hydrogen peroxide is widely used in organic transformations and, generally, considered as a green oxidant with water as the sole byproduct [80]. The in situ production of reactive oxygen species from peroxy species by reaction with Cu or Fe is termed the Fenton reaction [81], and been utilised for the degradation of veratryl alcohol [82].…”