Nitrogen functionalized carbon nanostructures supported Pd and Au-Pd NPs as catalyst for alcohols oxidation

Two different carbon nanotubes (CNTs) PR24-PS and Baytubes were functionalized by oxidation with nitric acid and further amination with gaseous NH3. Thus Au and Au-Pd nanoparticles were prepared by PVA/NaBH4 system and anchored on the surface of pristine CNTs and N-CNTs (Nitrogen functionalized carbon nanotubes). TEM analysis revealed that the introduction of nitrogen functionalities improves the dispersion of the metal nanoparticles on the surface of the support. This phenomena leads to an improved activity of N-CNTs based catalysts with the respect of pristine CNTs when tested in the liquid phase oxidation of alcohols

P1367Effects of levosimendan therapy in patients with severe functional mitral regurgitation and chronic heart failure undergoing mitraclip implantation: a single-centre experience

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Multislice computed tomography SYNTAX score for coronary artery disease evaluation prior to transcatheter aortic valve implantation

Background: Coronary computed tomography angiography (CCTA) is a useful tool for the evaluation of coronary anatomy prior to both surgical and transcatheter aortic valve implantation (TAVI). Multislice Computed Tomography (MSCT) SYNTAX score (SXscore) strongly correlates with the traditional angiographic SXscore, and the latter has proven to predict cardiovascular events in patients with coronary artery disease (CAD) referred to TAVI. Purpose: The aim of the study is to evaluate the feasibility and accuracy of the calculation of MSCT SXscore in TAVI patients, compared to the gold standard angiographic SXscore. Materials and methods: We evaluated 65 patients eligible for TAVI who underwent both CCTA and invasive coronary angiography (ICA) prior to valve replacement. CCTA was compared to ICA in terms of sensitivity, specificity, and positive and negative predictive values. CCTA performance was evaluated at 3 levels: patient level, vessellevel and segmentlevel. MSCT SXscore was calculated, when possible (i.e. only in fullyevaluable scans), and compared to the angiographic SXscore. Results: Overall CCTA diagnostic performance was good, with high sensitivity and negative predictive values (97.2% and 96.0%, respectively) and good agreement with ICA (k=0.81). As expected, specificity and positive predictive values were lower (82.8% and 87.5%, respectively). At vessellevel, the circumflex artery (CA) was more often misdiagnosed than the other arteries. We were able to calculate MSCT SXscore in 50/65 scans (76.9%). The correlation between MSCT and angiographic SXscore was excellent (Pearson's R=0.965, P<0.001). Conclusions: MSCT SXscore emerges as an interesting tool with strong agreement with angiographic SXscore, providing a noninvasive ambulatory alternative to assess CAD severity in TAVI patients

Tailored N-containing carbons as catalyst supports in alcohol oxidation

The introduction of N-containing functionalities in carbon-based materials is brought to stable and highly active metal-supported catalysts. However, up to now, the role of the amount and the nature of N-groups have not been completely clear. This study aims to clarify these aspects by preparing tailored N-containing carbons where different N-groups are introduced during the synthesis of the carbon material. These materials were used as the support for Pd nanoparticles. Testing these catalysts in alcohol oxidations and comparing the results with those obtained using Pd nanoparticles supported on different N-containing supports allowed us to obtain insight into the role of the different N-containing groups. In the cinnamyl alcohol oxidation, pyridine-like groups seem to favor both activity and selectivity toward cinnamaldehyde

From renewable to fine chemicals through selective oxidation: The case of glycerol

Catalytic selective oxidation of glycerol is presented in terms of catalytic systems and experimental conditions. Unsupported gold nanoparticles (AuNPs), AuNPs on carbon and on TiO2 were employed and compared in terms of reaction selectivity and activity. The role of the base and the formed hydrogen peroxide has been considered. Gold based catalysts showed selectivity that is strongly dependent of the reaction conditions. In particular C-C scission products increases by increasing the reaction temperature but correlated only partially with the rate of degradation of the H 2O2 formed under the operative conditions. Moreover, under neutral/acidic conditions glycerol can be oxidised also by increasing the temperature slightly, but it leads to a detrimental effect on selectivity and catalyst life

Microgel-stabilised gold nanoclusters: powerful "quasi-homogeneous" catalysts for the aerobic oxidation of alcohols in water

Gold nanoclusters of small size (2.5 nm) and narrow size distribution were synthesized in solution using tailor-made soluble cross-linked polymers (microgels) as exotemplates and stabilizers. The resulting microgel-stabilized nanoclusters could be conveniently isolated by precipitation, stored in the solid state, and redispersed in water and polar organic solvents. They were found to exhibit remarkable catalytic activity (average TOF up to 960 h(-1)) in the aerobic oxidation of benzylic and aliphatic alcohols and also of polyols in water under mild conditions (50-70 degrees C, 1-3 atm O2)

Microgel-stabilized gold nanoclusters: powerful "quasi homogeneous" catalysts for the aerobic oxidation of alcohols in water

Gold nanoclusters of small size (2.5 nm) and narrow size distribution were synthesized in solution using tailor-made soluble cross-linked polymers (microgels) as exotemplates and stabilizers. The resulting microgel-stabilized nanoclusters could be conveniently isolated by precipitation, stored in the solid state, and redispersed in water and polar organic solvents. They were found to exhibit remarkable catalytic activity (average TOF up to 960 h(-1)) in the aerobic oxidation of benzylic and aliphatic alcohols and also of polyols in water under mild conditions (50-70 degrees C, 1-3 atm O-2)

In Situ Formation of Au-Pd Alloyed Nanoparticles during Liquid Phase Oxidation of Alcohols

The catalytic oxidation of alcohols with molecular oxygen on supported nanometallic catalysts represents one of the green methods in a crucial process for the synthesis of fine chemicals. We have designed an experiment using physically mixed Au/AC and Pd/AC (AC=activated carbon) as the catalyst in the liquid-phase oxidation of benzyl alcohol by aerobic oxygen. The evolution of the physically mixed catalyst structures at different stages in the catalytic reaction was investigated by aberration-corrected high-resolution transmission electron microscopy and spatially resolved element mapping techniques at the nanometre scale, and they were also compared with the structure of the bimetallic alloy. For the first time we show the formation of surface Au\u2013Pd bimetallic sites by reprecipitation of Pd onto Au nanoparticles. Negligible Au leaching was observed. The in situ structural evolution can be directly correlated to the great enhancement of the catalyst activity. Moreover, we distinguish the different behaviours of Au and Pd, thus suggesting an oxygen differentiating mechanism for Au and Pd sites. The findings are of great importance to both the understanding of the structure\u2013activity correlation and the design of highly active catalysts in green chemistr