Hydrogen peroxide, as oxidizing

G. Stmkul, ki G. Stmkul, ed.. Catalytic Oxidations with Hydrogen Peroxide as Oxidant, Kluwer Academic Pubhshers, Dordrecht, 1993, Chapt. 6. 

Catalysts were prepared with 0.5, 1.0, 2.0 and 5.0 wt% of iron loaded on activated carbon. Benzene hydroxylation with hydrogen peroxide as oxidant was carried out. The conversion of benzene, selectivity and yield of phenol for these catalysts are shown in Fig. 4. As the weight of loaded metal increased the benzene conversion increased by about 33% but the selectivity to phenol decreased. The yield of phenol that was obtained with S.OFe/AC was about 16%. 

The preparation of iron impregnated activated carbon as catalysts and the catalytic performance of these catalysts were studied in benzene hydroxylation with hydrogen peroxide as oxidant. 5.0Fe/AC catalyst containing 5.0 wt% iron on activated carbon yielded about 16% phenol. The addition of Sn on 5.0Fe/AC catalyst led to the enhancement of selectivity towards phenol. 

Under microwave irradiation and applying MCM-41-immobilized nano-iron oxide higher activity is observed [148]. In this case also, primary aliphatic alcohols could be oxidized. The TON for the selective oxidation of 1-octanol to 1-octanal reached to 46 with 99% selectivity. Hou and coworkers reported in 2006 an iron coordination polymer [Fe(fcz)2Cl2]-2CH30H with fez = l-(2,4-difluorophenyl)-l,l-bis[(l//-l,2,4-triazol-l-yl)methyl]ethanol which catalyzed the oxidation of benzyl alcohol to benzaldehyde with hydrogen peroxide as oxidant in 87% yield and up to 100% selectivity [149]. An alternative approach is based on the use of heteropoly acids, whereby the incorporation of vanadium and iron into a molybdo-phosphoric acid catalyst led to high yields for the oxidation of various alcohols (up to 94%) with molecular oxygen [150]. 

New materials are also finding application in the area of catalysis reiated to the Chemicals industry. For example, microporous [10] materials which have titanium incorporated into the framework structure (e.g. so-calied TS-1) show selective oxidation behaviour with aqueous hydrogen peroxide as oxidizing agent (Figure 5). Two processes based on these new catalytic materials have now been developed and commercialized by ENl. These include the selective oxidation of phenol to catechol and hydroquinone and the ammoxidation of cyclohexanone to e-caproiactam. 

Abstract We briefly underline the relevance of TS-1 catalyst for industrial applications in mild oxidation reactions using hydrogen peroxide as oxidant and review the experimental works employed over last two decades for imderstanding the structme of the Ti centers in the bare TS-1 material. After an animated and controversial debate that has lasted in the literature until 1994, several works (reviewed here in depth) have definitively assessed that Ti atoms occupy framework positions substituting a Si atom and forming tetrahedral... 

Anderson, R. L. et al., Clin. Chim. Acta, 1982, 121, 111-116 The standard method for assaying organophosphorus compounds can be modified to use sulfuric acid to digest the samples and hydrogen peroxide as oxidant in place of perchloric acid. 

The performance of these catalysts is excellent, but only under anhydrous conditions, i.e., with BulOOH as the oxidant. With aqueous hydrogen peroxide as oxidant, the catalytic activity drops sharply. The properties are considerably improved when the residual silanol groups are annealed by silanization. 

Previous studies carried out with clay based catalysts pillared by Fe hydroxo complexes [13] or mixed (Al-Cu or Al-Fe) complexes, have shown that the mixed PILCs lead to the most promising results for organic compounds total oxidation in water, by using hydrogen peroxide as oxidant [14-16],... 

For analysis in solutions, the most frequently used CL reaction is alkaline oxidation of luminol and lucigenin in the presence of hydrogen peroxide as oxidant, although sodium hypochlorite, sodium perborate, or potassium ferricyanide may also be used. CL reactions involving alkaline oxidation have been used to indicate acid-base, precipitation, redox, or complexometric titration endpoints either by the appearance or the quenching of CL when an excess of titrant is present [114, 134], An example of these mechanisms is shown in Figure 14. 

Bertsch-Frank, B., Dorfer, A., Goor, G., and Suss, H. U., in Industrial Inorganic Chemicals Production and Use, Thompson, R., Ed., Royal Society of Chemistry, Cambridge, 1995, 176. Goor, G., in Catalytic Oxidations with Hydrogen Peroxide as Oxidant, Stmkul, G., Ed., Kluwer Academic Publishers, Dordrecht, England, 1993, 13. 

Sheldon, R. A. Catalytic Oxydations with Hydrogen Peroxides as Oxidant Kluwer Rotterdam, 1992. 

Scheme 36 Epoxidation of a, 3-unsaturated aldehydes using hydrogen peroxide as oxidant...

Titanium in the framework of pentasil zeolites induces oxygenation activity with diluted hydrogen peroxide as oxidant, thus constituting a new catalytic system. 

The effect of structural variation and the use of different caboxylate salts as cocatalysts was investigated by Pietikainen . The epoxidation reactions were performed with the chiral Mn(III)-salen complexes 173 depicted in Scheme 93 using H2O2 or urea hydrogen peroxide as oxidants and unfunctionalized alkenes as substrates. With several soluble carboxylate salts as additives, like ammonium acetate, ammonium formate, sodium acetate and sodium benzoate, good yields (62-73%) and moderate enantioselectivities (ee 61-69%) were obtained in the asymmetric epoxidation of 1,2-dihydronaphthalene. The results were better than with Ai-heterocycles like Ai-methylimidazole, ferf-butylpyridine. 

---