Evaluation of quality of hydrogen peroxide-based antiseptic solutions available in Dar es Salaam, Tanzania

Kaale, Eliangiringa; Haule, A. F.; Mung’ong’o, S; Kishiwa, M.

doi:10.1111/j.1365-2710.2007.00868.x

Cited by 4 publications

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“…The resulting superoxide and hydroxyl radicals led to the formation of molecular oxygen. The influence of acids on H 2 O 2 decomposition is also known, and various mineral acids have been used to stabilize H 2 O 2 . ,, In addition, Hutchings and co-workers have found that an acid pretreatment of carbon supports for Au/Pd catalysts increases the yield of H 2 O 2 production from hydrogen and oxygen . In this context, note that acids could lead to leaching of Ti by protonolysis reactions of Ti–O–Si linkages in the catalytic materials.…”

Section: Discussionmentioning

confidence: 99%

Mechanism of the Decomposition of Aqueous Hydrogen Peroxide over Heterogeneous TiSBA15 and TS-1 Selective Oxidation Catalysts: Insights from Spectroscopic and Density Functional Theory Studies

et al. 2011

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The Ti-based heterogeneous catalysts TiSBA15, Bu cap TiSBA15, TS-1, and [Ti,Al]-MFI were investigated with respect to controlling factors for the competitive decomposition of aqueous H2O2 during selective catalytic oxidations. DRUV–vis spectroscopy revealed that the titanium species in these materials exist mainly in isolated, tetrahedral coordination environments. The observed rates of H2O2 decomposition at 65 °C in acetonitrile decreased in the following order: Bu cap TiSBA15 > TiSBA15 and TS-1 > [Ti,Al]-MFI. The decompositions of H2O2 were also monitored in the presence of inorganic additives and Brønsted acids and bases, in benzene/aqueous biphasic solutions. Significant retardation of the decomposition rates with the KH2PO4 additive was found with TiSBA15, which suggests that the KH2PO4 stabilizer may be useful for optimization of hydrogen peroxide efficiency in catalytic oxidations. DRUV–vis spectroscopy was employed to identify possible catalytically active intermediates, proposed to be Ti(IV)(OOH) species that are produced upon reaction of the Ti-based materials and H2O2. Density Functional Theory (DFT) studies starting from a molecular model, (HO)Ti[OSi(OH)3]3, suggest that three Ti(IV)(OOH) intermediates are in equilibrium, and the formation of Ti–O• and HOO• radical species may be involved in the H2O2 decomposition. In addition, the potential role of KH2PO4 in the H2O2 decomposition process, as a proton acceptor in a [Ti(OO)(HOP(O)(OH)2)] complex, has been investigated.

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