Catalysis Letters

The first organic–inorganic lacunary polyoxometalate catalytic oxidation system with H2O2 as an oxidant for the preparation of aliphatic carboxylic acids from primary alcohols has been developed. This new catalytic system not only exhibits good catalytic activity with high selectivity toward acids, but also satisfactorily resolves the separation of the catalyst for reuse.

The RhIII(Br8TMPyP)5+ showed a catalytic DNA cleavage in the presence of ascorbic acid. The UV–visible, Cyclic Votlammetric (CV) and Electron Spin Resonance (ESR) data confirmed involvement of the reduced form of the RhIII-Br8TMPyP, RhIII(Br8TMPyP)4+· radical, in the catalytic cycle. Gel-electrophoresis, results revealed that, RhIII(Br8TMPyP)5+ could cleave DNA at 0.01–0.1 μM levels which is significantly higher than that of other metalloporphyrins.

Although Au (100) does not adsorb oxygen at either 295 K or 80 K, a barium modified Au(100) surface is active in oxygen dissociation resulting, through surface diffusion of oxygen adatoms, in the formation of a chemisorbed oxygen adlayer. This oxygen species is inactive for ethene oxidation, as is the oxygen species pre-adsorbed at an Au(100)–Ba surface at 80 K, and the clean Au(100)–Ba surface. However, when molecularly adsorbed ethene present at a Au(100)–Ba surface at 80 K is exposed to dioxygen and warmed to 140 K, surface carbonate is observed. We conclude that a transient oxygen species is the oxidant.

The aqueous-phase hydrogenation of propanoic acid was performed over the Ru/ZrO2 and Ru/Al2O3 catalysts with different Ru loading. Combined with multiple characterization techniques, such as H2-TPR, XRD, CO-FTIR, and DRIFTS of propanoic acid, the effect of Ru loading on the decarbonylation/hydrogenation of propanoic acid was investigated. Although hydrogenation/decarbonylation of carboxylic acids were strongly affected by the nature of supports, the increase of metal loading can cause the larger Ru particles and more bare Ru metal sites, which can facilitate the C–C bond cleavage reaction derived from the decarbonylation of propanoyl species over Ru metal sites.