02229nas a2200241   4500008004100000022001400041245017300055210006900228260007300297300001200370490000800382520125300390653003301643653002201676653002201698653002801720653002101748653002201769100002601791700001801817700002201835856013001857       2007                        eng d  a0926-860X00aGeneration of hydrogen peroxide via the selective reduction of oxygen by hydrazine sulfate over Br-promoted Pd/Al2O3 catalyst in an aqueous medium at ambient conditions0 aGeneration of hydrogen peroxide via the selective reduction of o  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR  a202-2090 v3233 a<p>The in situ generation of H2O2 via the selective reduction of OZ by hydrazine sulfate (in an aqueous medium) has been thoroughly investigated over the Br-promoted Pd(or PdO)/Al2O3 catalyst. The influence of the following factors have been addressed in this study: (a) Br concentration (in the reaction medium or incorporated in the catalyst); (b) reaction conditions (viz. reaction time, temperature); (c) concentrations of reducing agent and phosphoric acid in the reaction medium. Decomposition of N2H4 (from NH4-H2SO4) and its reaction with H2O2 under similar reaction conditions (in the absence of O-2) have also been studied. H2O2, which is an intermediate product of the O-2 reduction, is involved in further consecutive reactions. It can be converted to water via its decomposition and/or reaction with the unconverted NZH(4). In the presence of Br promoter, the later (reaction with unconverted N2H4) is more dominant. Both the consecutive reactions are drastically retarded in the presence of protons and Br promoter. A plausible reaction mechanism has been proposed for illustrating the role of the protons and Br promoter in the selective formation of H2O2 in the O-2 reduction process. (C) 2007 Elsevier B.V. All rights reserved.</p>10abrominated Pd/Al2O3 catalyst10ahydrazine sulfate10aHydrogen peroxide10ain situ H2O2 generation10aoxygen reduction10aPd/Al2O3 catalyst1 aChoudhary, Vasant, R.1 aJana, Prabhas1 aSamanta, Chanchal  uhttps://library.ncl.res.in/content/generation-hydrogen-peroxide-selective-reduction-oxygen-hydrazine-sulfate-over-br-promoted01558nas a2200229   4500008004100000022001400041245018500055210006900240260007300309300001400382490000600396520062400402653002201026653001801048653002601066653002801092653001101120653002101131100002601152700001801178856013201196       2007                        eng d  a1566-736700aIn situ generation of hydrogen peroxide from reaction of O-2 with hydroxylamine from hydroxylammonium salt in neutral aqueous or non-aqueous medium using reusable Pd/Al2O3 catalyst0 aIn situ generation of hydrogen peroxide from reaction of O2 with  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV  a1578-15820 v83 a<p>In situ generation of H2O2 with high yield can be accomplished by reacting 02 with NH2OH from hydroxylammonium salt [NH2OH.HCl or (NH2OH)(2) . H2SO4] in a neutral aqueous medium using a reusable heterogeneous Pd (1.0 wt%)/Al2O3 catalyst, even at low temperature (10 degrees C), with the formation of harmless by-products (viz. N-2 and water). The presence of KCl or KBr in the medium has beneficial effect. The H2O2 generation is strongly influenced by the pH of medium, reaction period and temperature; best results are obtained at the optimum pH and reaction medium. (c) 2007 Elsevier B.V. All rights reserved.</p>10aHydrogen peroxide10ahydroxylamine10aHydroxylammonium salt10ain situ H2O2 generation10aoxygen10aPd/AlO3 catalyst1 aChoudhary, Vasant, R.1 aJana, Prabhas  uhttps://library.ncl.res.in/content/situ-generation-hydrogen-peroxide-reaction-o-2-hydroxylamine-hydroxylammonium-salt-neutral-001964nas a2200265   4500008004100000022001400041245017500055210006900230260007300299300001200372490000600384520095100390653002101341653001301362653001301375653001101388653002201399653001801421653002701439653002801466100002601494700001801520700002801538856013201566       2007                        eng d  a1566-736700aReduction of oxygen by hydroxylammonium salt or hydroxylamine over supported Au nanoparticles for in situ generation of hydrogen peroxide in aqueous or non-aqueous medium0 aReduction of oxygen by hydroxylammonium salt or hydroxylamine ov  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a811-8160 v83 a<p>Reaction of O-2 with hydroxylamine or its salts over a number of supported gold catalysts containing An nanoparticles (at 10-70 degrees C) has been studied at atmospheric pressure for the in situ generation of H2O2 (required for organic oxidation reactions in the synthesis of fine/specialty chemicals) in aqueous (water) or non-aqueous medium. Hydrogen peroxide in high yields with harmless by-products (viz. water and nitrogen) can be generated in situ by the reduction Of O-2 by hydroxylammonium sulfate (or chloride) or hydroxylamine using the supported gold catalysts particularly Au/Gd2O3, Au/La2O3 and Au/MgO, in aqueous (water) or non-aqueous (viz. methanol) medium at close to ambient conditions. The reduction of O-2 by hydroxylammonium salt to H2O2, however, requires preneutralization of the salt by alkali; in the absence of the neutralization, only water is formed in the reaction. (c) 2006 Elsevier B.V. All rights reserved.</p>10aAu Nanoparticles10aAu/Gd2O310aAu/La2O310aAu/MgO10aHydrogen peroxide10ahydroxylamine10ahydroxylammonium salts10ain situ H2O2 generation1 aChoudhary, Vasant, R.1 aJana, Prabhas1 aBhargava, Suresh, Kumar  uhttps://library.ncl.res.in/content/reduction-oxygen-hydroxylammonium-salt-or-hydroxylamine-over-supported-au-nanoparticles-situ