Catalysts
Mostrando 25-36 de 901 artigos, teses e dissertações.
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25. Lesões cerebrais multifocais hiperintensas em T2/DWI na COVID-19 não implicam necessariamente em desmielinização
In order to increase the specific surface area of Pt-Rh-Pd / Al2O3 automotive three-way catalyst and improve its low-temperature reduction performance, Ce, Zr, and La were added to the Pt-Rh-Pd / Al2O3 catalyst to prepare the fibrous Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst via an electrospinning technique. The fibrous catalysts were characterized by XRD, F
Arq. Neuro-Psiquiatr.. Publicado em: 2021-01
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26. PREPARATION AND PROPERTIES OF PT-RH-PD / CEO2-ZRO2-LA2O3-AL2O3 FIBROUS CATALYST VIA ELECTROSPINNING
In order to increase the specific surface area of Pt-Rh-Pd / Al2O3 automotive three-way catalyst and improve its low-temperature reduction performance, Ce, Zr, and La were added to the Pt-Rh-Pd / Al2O3 catalyst to prepare the fibrous Pt-Rh-Pd / CeO2-ZrO2-La2O3-Al2O3 catalyst via an electrospinning technique. The fibrous catalysts were characterized by XRD, F
Quím. Nova. Publicado em: 2021-01
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27. An Efficient and Recyclable Sn-Based Phosphotungstic Acid with Tunable Brønsted/Lewis Acidity for Selective Oxidation of Benzyl Alcohol
A series of metal ion (M = Sn2+, Fe3+, Ni2+, Co2+, Ag+, Cu2+) exchanged tungstophosphoric acid (H3PW12O40; TPA) catalysts with tunable Brønsted/Lewis acidity were synthesized and exploited for the oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using hydrogen peroxide (H2O2) as oxidant. The structure of these M-TPA composite salts was also characte
J. Braz. Chem. Soc.. Publicado em: 2021-01
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28. Performance of Water Oxidation by 3D Printed Electrodes Modified by Prussian Blue Analogues
The water oxidation is the limiting step in the water-splitting process. Given this scenario, the development of new catalysts is essential in this field. The emergent demand is the use of Earth-abundant elements and catalysts with high performance under mild conditions. Because of this, catalysts such as Prussian Blue analogues (PBA) have been receiving a l
J. Braz. Chem. Soc.. Publicado em: 2020-11
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29. Theoretical Calculations on the Mechanism of Hydrogenation of Diphenylacetylene over Pdn (n = 1-4) Clusters
Diphenylacetylene (DPA) is a precursor of stilbene and benzil, and reduction of DPA or its derivatives with metallic reagents is both an old and contemporary topic of research. By means of density function theory (DFT) calculations, a detailed investigation of the mechanism of the hydrogenation of DPA over Pd clusters was carried out at the molecular level.
J. Braz. Chem. Soc.. Publicado em: 2020-10
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30. Mechanistic Investigation of DBU-Based Ionic Liquids for Aza-Michael Reaction: Mass Spectrometry and DFT Studies of Catalyst Role
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-based ionic liquids (ILs) has exhibited a high catalytic activity in the aza-Michael reactions compared to conventional catalysts and with imidazole-based ILs. In the present work DBU-based ILs showed high catalytic potential for aza-Michael addition of aromatic amines to 2-cyclohexen-1-one under solvent-free conditio
J. Braz. Chem. Soc.. Publicado em: 2020-09
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31. Catalytic Dehydration of Glycerol to Acrolein over Aluminum Phosphate Catalysts
Gas phase conversion of glycerol to acrolein over a variety of aluminum phosphate (AlP) catalysts synthesized by a simple replacement reaction method with a variation in calcination temperature (300-700 ºC, AlP-300, AlP-400, AlP-500, AlP-600, and AlP-700, respectively) has been investigated. The textural properties, acidities and coke contents of the sample
J. Braz. Chem. Soc.. Publicado em: 2020-08
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32. New Magnetic Fe Oxide-Carbon Based Acid Catalyst Prepared from Bio-Oil for Esterification Reactions
In this work, bio-oil (an organic matrix rich in oxygen functionalities) was used to efficiently dissolve and disperse Fe3+ which upon thermal treatment produced a carbon containing dispersed and encapsulated Fe oxide magnetic nanoparticles. These materials were prepared by dissolution of 8, 16 and 24 wt.% Fe3+ salt in bio-oil followed by treatment at 400, 4
J. Braz. Chem. Soc.. Publicado em: 2020-08
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33. A Comparative Study on the Groebke-Blackburn-Bienaymé Three-Component Reaction Catalyzed by Rare Earth Triflates under Microwave Heating
Over the last twenty years, the Groebke-Blackburn-Bienaymé (GBB) reaction has been emerged as a powerful tool to access different nitrogen-based heterocycles as privileged scaffolds in medicinal chemistry. This multicomponent reaction is usually catalyzed by ordinary Brønsted or Lewis acid catalysts. Herein, we present a comparative study on the catalytic
J. Braz. Chem. Soc.. Publicado em: 2020-07
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34. High Conversion of Palm Olein to Ethyl Esters Using a Strong Anion Exchange Resin: Study of the Operational Parameters
Biodiesel, known as a mixture of fatty acid ethyl/methyl esters, is seen as an alternative, ecofriendly, biodegradable and renewable non-fossil fuel. The use of heterogeneous catalysts for biodiesel synthesis can solve several problems associated with the homogeneous alkaline catalyzed-transesterification. Therefore, this work reports the evaluation of the c
J. Braz. Chem. Soc.. Publicado em: 2020-07
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35. Effect of Growth Parameters on the Photocatalytic Performance of TiO2 Films Prepared by MOCVD
The present study evaluated the main factors that influence the photocatalytic activity of titanium dioxide (TiO2) films grown by metalorganic chemical vapor deposition (MOCVD) at 400 and 500 °C, in different growth times. The photocatalytic behavior was analyzed by measuring the methyl orange dye degradation at different pH values. Structural and morpholog
J. Braz. Chem. Soc.. Publicado em: 2020-06
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36. Easy Epoxidation of Monoterpenes from Common Starting Materials
Epoxidation of monoterpenes, α-pinene, β-pinene, limonene, α-terpinene, and (R)-carvone was carried out by the in situ production of a peroxyacid rather than direct addition of such an expensive and difficult to handle chemical. Previous reports showed use of metal catalysts with high yields, while methodologies without catalysts at high temperature showe
J. Braz. Chem. Soc.. Publicado em: 2020-05