Active Alumina
Mostrando 13-24 de 32 artigos, teses e dissertações.
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13. Efeito da concentração de irídio sobre as propriedades de catalisadores do tipo Pt-Ge-Ir/Al2O3. / Effect of concentration of iridium on the properties of type catalysts Pt-Ge-Ir/Al2O3.
The effect of iridium content on the activity, selectivity and stability of platinum, germanium and iridium supported in alumina catalysts for oil naphta catalytic reforming was studied in this work. Samples were prepared by the impregnation of the metallic salts (hexachloroplatinic acid, hexachoroiridic acid and germanium chloride) over g-alumina in order t
Publicado em: 2008
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14. Desenvolvimento de nanocamadas e nanocristais de Óxido de Zircônio aplicados a catálise / Development of nanolayers and nanocrystals of Oxide of Zirconium applied the catalysis
This work investigate the synthesis and characterization of a catalytic support of -alumina with a nanolayers and nanocrystals of ZrO2. The incorporation of the platinum began during and after the formation of the catalytic support. The technology is based on the Pechini method. The nanolayer was applied to cover the surface of the γ-alumina, av
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/09/2007
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15. Estudo de adsorção de ácidos naftênicos a partir de correntes de hidrocarbonetos / Study of adsorption of naphthenic acids from hydrocarbon stream
Ácidos naftênicos correspondem à complexa mistura de ácidos carboxílicos presentes no petróleo, responsáveis diretamente pela sua acidez e pela sua corrosividade em fase líquida durante o refino. Tais compostos também estão presentes nas frações destiladas do petróleo, causando diversos problemas na qualidade final do produto. Uma possível form
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/05/2007
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16. Estudo do efeito de fluxos na soldagem ATIG de alumínio
The feasibility of using ATIG (active flux TIG) welding for surface oxide removal in aluminum welding with direct polarity was evaluated. The influence of the flux on different conditions of specimen surface, variations in welding parameters and the effect of metal base composition was also evaluated. Welding trials were performed in a mechanized jig using a
Publicado em: 2007
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17. Síntese, caracterização e aplicação de catalisadores mistos contendo cobalto e cobre
Studies on the use of catalysts have been directed to develop new processes taking into consideration the economic point of view (for example, substitution for cheaper raw materials) as well as the green chemistry aspects. The majority of supported catalysts is prepared by the impregnation method of the metallic salt over a material of high specific surface
Publicado em: 2007
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18. Surface characterization of alumina reinforced with niobium carbide obtained by polymer precursor
Active filler controlled pyrolysis of polymers (AFCOP) is a recent method for obtaining near-net shaped ceramic bodies. Alumina based composites have been developed for use as cutting tools, so knowledge of the surface composition is extremely important because it is directly related to the hardness and wear resistance Samples containing a fixed concentratio
Materials Research. Publicado em: 2006-09
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19. Synthesis of sol-gel aluminas : correlation of the textural, structural, morphological and chemical properties of aluminas with reactivity in the catalytic epoxidation of olefins / Sintese de aluminas sol-gel : correlação das propriedades texturais, estruturais, morfologicas e quimicas da alumina com a reatividade na epoxidação catalitica de olefinas
Epoxidation is a pivotal transformation for organic synthesis of fine and bulk chemicals. The aim of this research is the replacement of stoichiometric oxidative processes or non-environmental friendly catalytic processes by economically sustainable catalytic reactions of oxygen transfer using non-toxic catalysts and oxidants. The alumina/aqueous 70 wt. % H2
Publicado em: 2006
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20. Development, microstructural and mechanical caracterization of SiC ceramics with alumina and rare earth oxides additions / Desenvolvimento, caracterização microestrutural e mecânica de cerâmicas de SiC aditivadas com alumina e óxidos de terras raras
In this work, the mechanical properties are determined at room temperature (hardness and fracture toughness) and high temperatures (compressive creep) of SiC ceramic samples with alumina (Al2O3) and rare earth oxides (REO) additions. The REO is obtained by REC (rare earth concentrate - Nuclemon) calcinations, which contains 76 wt % of yttria (Al2O3). Three c
Publicado em: 2006
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21. Efeito da temperatura de calcinação em catalisadores de platina a base de óxidos de cério e zircônio mássicos e suportados em alumina nas reações de oxidação parcial e reforma autotérmica do metano
The transformation of methane into higher value products became more important in recent years due to the search for new energy sources. The use of partial oxidation and autothermal reforming of methane can give synthesis gas with a H2/CO ratio of 2, that is very adequate for the Fischer-Tropsch synthesis. In order to develop this process, the use of catalys
Publicado em: 2006
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22. Preparação e caracterização de catalisadores de níquel suportado em óxido de zircônio e aluminio.
Alumina-supported nickel has been extensively used to catalyze the methane steam reforming because of its low cost, as compared to noble metal-based catalysts. However, it is not stable during the reaction mainly due to phase transition and sinterization. This calls for the development of new catalysts. An attractive option would be the use of zirconia-based
Publicado em: 2005
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23. Preparation and characterization of alumina-supported Co and Ag/Co catalysts
The effect of silver addition as a promoter in alumina supported cobalt oxide catalysts is investigated in this study. The Co/Al2O3 and Ag/Co/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by inductively-coupled plasma spectrometry, X-ray diffraction (XRD), temperature programmed reduction with hydrogen (TPR
Materials Research. Publicado em: 2003-12
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24. Novos materiais à base de nanofibras de carbono como suporte de catalisador na decomposição da hidrazina
Today satellites propulsion is based on the use of monopropellant and/or bipropellant chemical systems. The maneuvering of satellite is based on the hydrazine decomposition micropropulsors catalyzed by metallic iridium supported on g-alumina. This reaction is a surface reaction and is strongly exothermic and implies that the operation of the micropropulsor i
Química Nova. Publicado em: 2003-10