Activation of hydrogen peroxide

The use of molybdenum catalysts in combination with hydrogen peroxide is not so common. Nevertheless, there are a number of systems in which molybdates have been employed for the activation of hydrogen peroxide. A catalytic amount of sodium molybdate in combination with monodentate ligands (e.g., hexaalkyl phosphorus triamides or pyridine-N-oxides), and sulfuric acid allowed the epoxidation of simple linear or cyclic olefins [46]. The selectivity obtained by this method was quite low, and significant amounts of diol were formed, even though highly concentrated hydrogen peroxide (>70%) was employed. 

Begue and coworkers recently achieved an improvement in this method by performing the epoxidation reaction in hexafluoro-2-propanol [120]. They found that the activity of hydrogen peroxide was significantly increased in this fluorous alcohol, in relation to trifluoroethanol, which allowed for the use of 30% aqueous H202. Interestingly, the nature of the substrate and the choice of additive turned out to have important consequences for the lifetime of the catalyst. Cyclic dis-ubstituted olefins were efficiently epoxidized with 0.1 mol% of MTO and 10 mol%... 

Activators of Hydrogen Peroxide, Functional Catalase-Peroxidase Replicas 494... 

Compounds and complexes of the early transition metals are oxophilic because the low d-electron count invites the stabilization of metal-oxo bonds by 7T-bond formation. To a substantial extent, their reactivity is typical of complexes of metals other than rhenium. That is particularly the case insofar as activation of hydrogen peroxide is concerned. Catalysis by d° metals - not only Revn, but also CrVI, WVI, MoVI, Vv, ZrIV and HfIV - has been noted. The parent forms of these compounds have at least one oxo group. Again the issue is the coordination of the oxygen donating substrate, HOOH, to the metal, usually by condensation ... 

Activation Chemistry Sobkowiak, Andrzej, Tung, Hui-Chan, and Sawyer, Donald T., Iron- and Cobalt-Induced Activation of Hydrogen Peroxide and Dioxygen for the 48 505... 

A. Berkessel and J. A. Adrio, Dramatic acceleration of olefin epoxidation in fluorinated alcohols Activation of hydrogen peroxide by multiple H bond networks. J. Am. Chem. Soc. 128, 13412 13420 (2006). 

Dramatic Acceleration of Olefin Epoxidation in Fluorinated Alcohols Activation of Hydrogen Peroxide by Multiple Hydrogen Bond Networks... 

A detailed discussion concerning this type of mechanism has been organized by Strukul in his book . In particular, kinetic studies concerning Pt hydroxo derivatives indicate that the metal plays two different roles activation of hydrogen peroxide by increasing its nucleophilicity and activation of the substrate toward nucleophilic attack by coordination to the metal center (Scheme 8). 

Nickel-containing polyfluorometalated [Ni(H20)H2FeNaWi7055] was capable of catalytic activation of hydrogen peroxide for allylic alcohol oxidation in biphasic conditions (catalyst substrate ratio 1 1000). Homoallylic alcohols are significantly less reactive than allylic homologues and cis > trans reactivity is found also in this case. 

Hydrogen peroxide was tested in mice by oral administration, skin application and subcutaneous administration and in hamsters by topical application to oral mucosa. In mice, adenomas and carcinomas of the duodenum were found following oral administration. The other studies in mice and the study in hamsters were inadequate for evaluation. One study in mice and one study in hamsters showed no promoting activity of hydrogen peroxide. 

Oya, Y, Yamamoto, K. Tonomura, A. (1986) The biological activity of hydrogen peroxide I. Induction of chromosome-type aberrations susceptible to inhibition by scavengers of hydroxyl radicals in human embryonic fibroblasts. Mutat. Res., 172, 245-253... 

Sun, Y. and J.J. Pignatello (1993). Activation of hydrogen peroxide by iron(III) chelates for abiotic degradation of herbicides and insecticides in water. J. Agile. Food Chem., 41 308-312. 

Collins,T.J. (2002) TAMLoxidantactivators a new approach to the activation of hydrogen peroxide for environmentally significant problems. Acc. Chem. Res., 35, 782. 

Radziszewski, Ber., 1887, 20, 2934 1885, 18, 355 Dubsky, J. prakt. Chem., 1916, [2], 93,137. Tor the hydrolytic activity of hydrogen peroxide towards other types of organic compounds, such as albumin, gelatin, and starch, see Neuberg and Muira, Btochem. Zeitsck, 1911, 36, 37. 

Collins, T.J., Horwitz, C., and Gordon-Wylie, S.W. Project Title TAML Activators General activation of hydrogen peroxide for green oxidation processes, provided by Mary Kirchhoff, Green Chemistry Institute, American Chemical Society, 1999. 

Activation of Hydrogen Peroxide Using Inorganic and Organic Species... 

The following two sections will discuss the activation of hydrogen peroxide in the presence of inorganic/organometallic species and organic compounds respectively. 

---