Reduction of oxygen by hydroxylammonium salt or hydroxylamine over supported Au nanoparticles for in situ generation of hydrogen peroxide in aqueous or non-aqueous medium

Abstract

Reaction of O₂ with hydroxylamine or its salts over a number of supported gold catalysts containing Au nanoparticles (at 10-70 ° 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 O₂ 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 O₂ 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.