Synthesis of high-silica CHA type zeolite by interzeolite conversion of FAU type zeolite in the presence of seed crystals

The influence of seed crystals on the interzeolite conversion of FAU type zeolite into CHA type zeolite was investigated in the presence of benzyltrimethylammonium hydroxide as a structure-directing agent under various hydrothermal synthesis conditions. Pure and highly crystalline CHA type zeolites with a wide range of Si/Al ratios were obtained in a shorter crystallization time as compared with those obtained without seed crystals. Furthermore, we achieved the first successful synthesis of high-silica CHA type zeolite in the absence of Na(+) cations by increasing the seed content. The protonated CHA type zeolite with a Si/Al ratio of ca. 15 yielded the highest propylene yield of ca. 48 C-% in ethanol conversion into light olefins

Association of airway obstruction with first-pass success and intubation-related adverse events in the emergency department: multicenter prospective observational studies

BackgroundAirway obstruction is a relatively rare but critical condition that requires urgent intervention in the emergency department (ED). The present study aimed to investigate the association of airway obstruction with first-pass success and intubation-related adverse events in the ED.MethodsWe analyzed data from two prospective multicenter observational studies of ED airway management. We included adults (aged ≥18 years) who underwent tracheal intubation for non-trauma indications from 2012 through 2021 (113-month period). Outcome measures were first-pass success and intubation-related adverse events. We constructed a multivariable logistic regression model adjusting for age, sex, modified LEMON score (without airway obstruction), intubation methods, intubation devices, bougie use, intubator’s specialty, and ED visit year with accounting for patients clustering within the ED.ResultsOf 7,349 eligible patients, 272 (4%) underwent tracheal intubation for airway obstruction. Overall, 74% of patients had first-pass success and 16% had intubation-related adverse events. The airway obstruction group had a lower first-pass success rate (63% vs. 74%; unadjusted odds ratio [OR], 0.63; 95% CI, 0.49–0.80), compared to the non-airway obstruction group. This association remained significant in the multivariable analysis (adjusted OR 0.60, 95%CI 0.46–0.80). The airway obstruction group also had a significantly higher risk of adverse events (28% vs. 16%; unadjusted OR, 1.93; 95% CI, 1.48–2.56, adjusted OR, 1.70; 95% CI, 1.27–2.29). In the sensitivity analysis using multiple imputation, the results remained consistent with the main results: the airway obstruction group had a significantly lower first-pass success rate (adjusted OR, 0.60; 95% CI, 0.48–0.76).ConclusionBased on these multicenter prospective data, airway obstruction was associated with a significantly lower first-pass success rate and a higher intubation-related adverse event rate in the ED

Reverse water gas shift reaction using supported ionic liquid phase catalysts

The reverse water gas shift reaction (RWGSR) using a supported ionic liquid-phase (SILP) catalyst consisting of Ru catalyst, ionic liquid (1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl)), and porous silica gel support, was investigated. The catalytic activity of the SILP catalyst toward RWGSR strongly depends on the kind of Ru catalyst and amount of IL. Among the three kinds of Ru catalysts ([RuCl2(CO)(3)](2), Ru-3(CO)(12), and RuC13), [RuCl2(CO)(3)](2) exhibits the best catalytic activity. Brunauer Emmett Teller (BET) surface area analysis and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses of the SILP catalyst based on [RuCl2(CO)(3)](2) and [C(4)mim]Cl revealed that both the solvation of the active catalytic Ru species and the surface area of the ionic liquid phase strongly affect catalytic activity. Hence, these factors help to determine the optimum amount of [C(4)mim]Cl in the SILP catalyst. The resulting SILP catalyst, with an optimum constitution, exhibited greater catalytic activity than the homogeneous system in which the same amounts of [RuCl2(CO)(3)](2) and [C(4)mim]Cl were employed. Catalytically active Ru species during RWGSR in both systems were investigated by means of electrospray ionization-mass spectrometry (ESI-MS). Interestingly, the rate-determining step in the two systems was different, implying that the silica support lowers the activation energy of the protonation reaction in the catalytic cycle. Therefore, the facilitation of the RWGSR by a SILP catalyst system can be realized by good mass transport, derived from the large surface area, as well as the effect of the silica support on activation energy. Furthermore, 20 cycles of the RWGSR using the SILP catalyst were accomplished

Liquid phase oxidation of glycerol in batch and flow-type reactors with oxygen over Au–Pd nanoparticles stabilized in anion-exchange resin

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Impacts of Ni-Loading Method on the Structure and the Catalytic Activity of NiO/SiO₂-Al₂O₃ for Ethylene Oligomerization

To clarify the Ni species of NiO/SiO2-Al2O3 catalysts that are active for ethylene oligomerization, 18 types of NiO/SiO2-Al2O3 were prepared using three Ni-loading methods (i.e., ion-exchange, impregnation, and homogeneous precipitation), with different Ni-loadings (1–20 wt%), and examined with respect to their structure and catalytic activity for ethylene oligomerization. Characterized by N2 adsorption, powder XRD, FE-SEM, H2-TPR, NH3-TPD, and C2H4-TPD showed that Ni species in the catalysts prepared by ion-exchange were mainly ion-exchanged Ni cations. In contrast, Ni species in the catalysts prepared by impregnation were a mixture of ion-exchanged Ni cations and NiO particles, and those in the catalysts prepared by homogeneous precipitation were all NiSiO3 particles. Catalytic-reaction tests at 300 °C and 0.1 MPa revealed the following: the ion-exchanged Ni cations showed the highest C2H4 conversion rate; the NiSiO3 particles showed a moderate reaction rate; and the NiO particles were not active for ethylene oligomerization. We concluded that the high catalytic activity of the ion-exchanged Ni cations was a result of their high dispersion and medium-strength acidity, which together promoted the adsorption and activation of ethylene on, and the desorption of oligomerization products from, the catalyst