Hydrogenation of Acetophenone on Pd/Silica–Alumina Catalysts with Tunable Acidity: Mechanistic Insight by In Situ ATR-IR Spectroscopy

Understanding the cooperative action of metal and acid sites of bifunctional catalysts is essential for developing more efficient catalysts for greener chemical processes. We used in situ ATR-IR spectroscopy in tandem with modulation excitation spectroscopy (MES) and phase-sensitive detection (PSD) to examine the functioning of Pd/silica–alumina (Pd/SA) catalysts with different acidity of the support in the liquid-phase hydrogenation of acetophenone (AP). The spectroscopic studies revealed that AP was adsorbed on the Pd surface in η¹ (O) configuration and initially hydrogenated to 1-phenylethanol (PE) on the metallic Pd sites. On the Pd surface, PE was less strongly adsorbed than AP. PE was preferentially adsorbed on the acidic silica–alumina support via the C–OH group and subsequently dehydrated to styrene on the acidic sites. Hydrogen originating from dissociative adsorption on Pd sites is proposed to hydrogenate part of the formed styrene to ethylbenzene (EB). The intermediate styrene had a short lifetime under hydrogenation conditions. Increasing the support acidity by raising the atomic fraction of aluminum (Al × 100%/(Al + Si)) in SA from 0 to 70% promoted the styrene production, which in turn strongly enhanced the EB yield from 17.3% on Pd/silica to 54.3% on Pd/SA-70, respectively

Molecular Insight into Pt-Catalyzed Chemoselective Hydrogenation of an Aromatic Ketone by In Situ Modulation–Excitation IR Spectroscopy

Chemoselective platinum-catalyzed liquid-phase hydrogenation of aromatic ketones is an important reaction in the production of fine chemicals and pharmaceuticals. A typical example of this class of reactions is the hydrogenation of acetophenone (AP) over a Pt/Al₂O₃ catalyst. We investigated the adsorption behavior of the different reaction components and their reaction pathways using in situ attenuated total reflection infrared spectroscopy in combination with modulation excitation spectroscopy and phase sensitive detection. AP adsorbed on both Pt and the alumina support. On Pt, AP adsorbed in the η¹ (O) configuration prevailed, whereas on alumina, AP bound to Lewis acid sites was predominant. In the presence of hydrogen, η¹ (O) AP adsorbed on Pt was hydrogenated to the main product, 1-phenylethanol (PE), with high selectivity (82.5%). The produced PE was more strongly adsorbed on the alumina support than on Pt, leading to replacement of AP and accumulation of PE on alumina. Co-adsorption experiments of AP with its products PE, 1-cyclohexylethanol, and ethylbenzene revealed that AP adsorbed in the η¹ (O) configuration was always the prevalent adsorption mode of AP on Pt, which may partly explain the high selectivity to PE observed. Co-adsorption of AP and CO did not significantly affect the adsorption of AP; however, CO adsorption strongly suppressed the adsorption and dissociation of H₂. The studies revealed a striking difference in the selectivity behavior between the gas-phase and liquid-phase hydrogenation. Although in the gas-phase hydrogenation of AP, a significant effect of decomposition/hydrogenolysis products on the chemoselectivity of AP hydrogenation was reported, these fragmentation reactions were barely observed in the liquid phase

Additional file 1 of Development and application of emotion recognition technology — a systematic literature review

Supplementary Material

Novel β-lactam/β-lactamase inhibitors versus alternative antibiotics for the treatment of complicated intra-abdominal infection and complicated urinary tract infection: a meta-analysis of randomized controlled trials

<p><b>Introduction</b>: The aim of this study is to compare the efficacy and safety of novelBL/BLIs with alternative antibiotics for the treatment of cIAI and cUTI.</p> <p><b>Area covered</b>: We performed a systematic review and meta-analysis of all randomized controlled trials comparing novel BL/BLIs with other antibiotics for the treatment of cIAI and cUTI. The primary outcome included clinical and microbiological treatment success.</p> <p><b>Expert commentary</b>: We found that novel BL/BLIs obtained a similar clinical outcome with other antibiotics in CE population (OR = 1.07, 95%CI = (0.80, 1.44), P = 0.64). However, novel BL/BLIs had better clinical treatment success in the cUTI subgroup (OR = 2.14, 95%CI = (1.06, 4.31), P = 0.03). Furthermore, novel BL/BLIs achieved significant microbiological treatment success in patie nts with cUTI (OR = 1.70, 95%CI = (1.29, 2.25), P  =  0.0002) and had higher eradication rates for Gram-negative pathogens (OR = 1.82, 95%CI = (1.26, 2.64), P = 0.001) including <i>E.coli</i> and <i>K.pneumoniae</i>. No difference was observed concerning the incidence of mortality and adverse events between the two groups. Therefore, we concluded that novel BL/BLIs are not inferior to other available antibiotics for the treatment of cIAI, and they have advantages in patients with cUTI. Simultaneously, they are sensitive to Gram-negative pathogens, especially for <i>E.coli</i> and <i>K.pneumoniae</i>.</p

Primer sequences used in this study for real-time PCR in pigs.

<p>Primer sequences used in this study for real-time PCR in pigs.</p

Oxidative Polyoxometalates Modified Graphitic Carbon Nitride for Visible-Light CO₂ Reduction

Developing a photocatalysis system for converting CO₂ to valuable fuels or chemicals is a promising strategy to address global warming and fossil fuel consumption. Exploring photocatalysts with high-performance and low-cost has been two ultimate goals toward photoreduction of CO₂. Herein, noble-metal-free polyoxometalates (<b>Co4</b>) with oxidative ability was first introduced into g-C₃N₄ resulted in inexpensive hybrid materials (Co4@g-C₃N₄) with staggered band alignment. The staggered composited materials show a higher activity of CO₂ reduction than bare g-C₃N₄. An optimized Co4@g-C₃N₄ hybrid sample exhibited a high yield (107 μmol g^–1 h^–1) under visible-light irradiation (λ ≥ 420 nm), meanwhile maintaining high selectivity for CO production (94%). After 10 h of irradiation, the production of CO reached 896 μmol g^–1. Mechanistic studies revealed the introduction of <b>Co4</b> not only facilitate the charge transfer of g-C₃N₄ but greatly increased the surface catalytic oxidative ability. This work creatively combined g-C₃N₄ with oxidative polyoxometalates which provide novel insights into the design of low-cost photocatalytic materials for CO₂ reduction

PCV2 infection in piglet lymphocytes.

<p>Control lymphocyte cultures (A) and lymphocytes incubated with PCV2 for 6, 12, 24 and 48 h (B–E) were stained with anti-PCV2 antibody (green) by indirect immunofluorescence. DAPI was used to visualize the nuclei (blue). (F) The percentage of infected lymphocytes at each time point was quantified by flow cytometry. The numbers of infected cells increased with incubation time.</p

Changes in p-IκBα protein expression after PCV2 infection.

<p>Western blotting was used to measure expression of p-IκBα protein in the cytoplasm at 6, 12, 24 and 48 h in each group of lymphocytes. Levels of p-IκBα increased after PCV2 infection relative to controls, and this effect was abrogated by the NF-κB inhibitor BAY11-7082. Expression of GADPH was used as a positive control. * <i>P</i><0.05, ** <i>P</i><0.01.</p

Changes in IL-4 and IL-12 levels after PCV2 infection.

<p>Supernatants from control cultures and lymphocytes cultured with PCV2, NF-κB inhibitor BAY11-7082, or a combination of both, were sampled after 6, 12, 24 and 48 h and tested by ELISA to determine the concentration of (A) IL-4 and (B) IL-12. PCV2 induced a decrease in IL-4 and an increase in IL-12 concentration, and these effects were abrogated by BAY11-7082. * <i>P</i><0.05, ** <i>P</i><0.01.</p

Changes in NF-κB p65 protein expression after PCV2 infection.

<p>Western blotting was used to measure expression of NF-κB p65 protein in the nucleus at 6, 12, 24 and 48 h in each group of lymphocytes. Levels of p65 increased after PCV2 infection and this effect was abrogated by the NF-κB inhibitor BAY11-7082. Expression of histone H3 was used as a positive control. ** <i>P</i><0.01.</p