Catalysts Deactivation
Mostrando 1-12 de 38 artigos, teses e dissertações.
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1. Metal-Supported Niobium Catalysts Investigation for Conversion of Bio-Renewable Glycerol to Organic Compounds
The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Oxidative Dehydration of Glycerol over Molybdenum- and Vanadium-Based Catalysts
Surplus of glycerol production from the biodiesel industry has led to the search for glycerol conversion routes, the most common of which are dehydration and oxidative dehydration. Vanadium and molybdenum oxides were supported on γ-Al2O3 and their properties were analyzed through several characterization techniques, showing that the acidity increases after
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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3. LEWIS ACID SITES OF Mg2+-MODIFIED POLYSTYRENE SULFONIC ACID RESIN CATALYSYS FOR SYNTHESIS OF DIBUTYL SUCCINATE
The polystyrene sulfonic acid resin catalysts were fabricated, containing elements of Cl and Mg through oxidization and impregnation, and they were characterized by EDS, FT-IR spectra, Py-IR spectra, UV spectra, XPS and TGA to investigate their physiochemical properties. The catalytic performances of these catalysts were examined in the esterification reacti
Quím. Nova. Publicado em: 2018-06
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4. MORE ACTIVE AND SULFUR RESISTANT BIMETALLIC Pd-Ni CATALYSTS
The influence of the kind of metal precursor and the sequence of impregnation on the properties of Pd-Ni catalysts was evaluated during the test reaction of selective hydrogenation of styrene to ethylbenzene by means of physicochemical characterization. The focus was put on the final hydrogenating activity and the resistance to deactivation by sulfided compo
Quím. Nova. Publicado em: 2018-02
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5. Electroremediation of deactivated catalysts from fluidised catalytic cracking for vanadium removal - the effect of a dual cathode chamber reactor
Abstract The aim of this study was to evaluate the quantity of vanadium removed through electrokinetic remediation applied to catalyst waste used in a fluid catalytic cracking process. In excess, vanadium affects process efficiency by reducing the catalyst’s activity, causing deactivation and reducing its useful life in petroleum cracking during refining.
Braz. J. Chem. Eng.. Publicado em: 2018-01
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6. SELECTIVE HYDROGENOLYSIS OF GLYCEROL TO PROPYLENE GLYCOL IN A CONTINUOUS FLOW TRICKLE BED REACTOR USING COPPER CHROMITE AND Cu/Al2O3 CATALYSTS
The glycerol hydrogenolysis reaction was performed in a continuous flow trickle bed reactor using a water glycerol feed and both copper chromite and Cu/Al2O3 catalysts. The commercial copper chromite had a higher activity than the laboratory prepared Cu/Al2O3 and was used for most of the tests. Propylene glycol was the main product with both catalysts, aceto
Quím. Nova. Publicado em: 2017-05
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7. A importância do estado excitado 3MLCT de compostos de Ru(II), Re(I) e Ir(III) no desenvolvimento de fotossensores, oleds e fotorredução de CO2
The photochemistry and photophysics of coordination compounds have been extensively investigated not only because their structure, stability, reactivity dependence on the metal center oxidation state and the coordinated ligand; but also for their electronic transitions in a wide range of visible radiation. The knowledge of light absorption, excited state dea
Quím. Nova. Publicado em: 2017-02
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8. Gas-Phase Conversion of Glycerol to Acetol: Influence of Support Acidity on the Catalytic Stability and Copper Surface Properties on the Activity
Mesoporous mixed copper-aluminum oxides and copper-silicon oxides were synthesized with polymeric precursors route in order to evaluate the effect of the support acidity on the catalytic stability due to the carbon deposit and the copper surface characteristics on the catalytic activity for the gas-phase conversion of glycerol to acetol. The samples were cha
J. Braz. Chem. Soc.. Publicado em: 2016-12
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9. SYNTHESIS OF PROPYLENE FROM ETHANOL USING PHOSPHORUS-MODIFIED HZSM-5
Abstract Effects of phosphorus addition to HZSM-5 on ethanol conversion to propylene were evaluated. Catalysts were characterized by XRF, XRD, nitrogen adsorption, 27Al and 31P MAS NMR, n-propylamine and ammonia TPD. Increasing P content decreased the strength and density of acid total sites. Ethanol dehydration was carried out in a fixed bed reactor operati
Braz. J. Chem. Eng.. Publicado em: 2016-09
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10. Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al2O3 Catalyst
A series of highly dispersed Pd/Al2O3 catalysts were prepared via the polyol method. The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), UV-Vis spectrophotometry, temperature programmed reduction (TPR) and transmission electron microscopy (TEM). The influence of Pd particle size on the hydrogenation of 2-amyl anthraquinone (AAQ)
J. Braz. Chem. Soc.. Publicado em: 2016-06
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11. NANOPARTICLES OF TUNGSTEN AS LOW-COST MONOMETALLIC CATALYST FOR SELECTIVE HYDROGENATION OF 3-HEXYNE
Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surface. The eff
Quím. Nova. Publicado em: 2016-01
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12. The role of zeolites in the deactivation of multifunctional fischer-tropsch synthesis catalysts: the interaction between HZSM-5 and Fe-based Ft-catalysts
In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized u
Braz. J. Chem. Eng.. Publicado em: 2013-12