Nanosized gold-catalyzed selective oxidation of alkyl-substituted benzenes and n-alkanes

We report the synthesis of nanoporous silica-supported gold nanoparticle catalysts and their selective and efficient catalytic properties toward oxidation reactions of various substituted alkylbenzenes and linear alkanes. The Au nanoparticles were synthesized by reducing Au(III) ions in situ within the nanopores of hemiaminal-functionalized mesoporous silica by using the supported hemiaminal groups as reducing agents. The resulting mesoporous silica-supported gold nanoparticles efficiently catalyzed the oxidation reactions of different alkyl-substituted benzenes and linear alkanes with t-butyl hydroperoxide (TBHP) as an oxidant. The catalytic reactions gave up to ∼99% reactant conversion and up to ∼100% selectivity toward ketone products in some cases. This high selectivity toward ketone products by the catalysts was unprecedented, especially considering the fact that only mild reaction conditions and no additives were employed during the reactions.

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► Supported Au nanoparticles within the pores of mesoporous silica were synthesized.
► Au(III) ions were reduced with hemiaminal groups grafted onto the surface of SBA-15.
► Efficient and selective catalysis for oxidation of various alkanes obtained.
► Oxidative catalytic reaction produced predominantly ketone products.
► Versatile Au/SBA-15 catalyst for oxidation of various substituted and n-alkenes.