27al Mas Nmr
Mostrando 1-12 de 14 artigos, teses e dissertações.
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1. Influence of Aluminum Addition in the Framework of MCM-41 Mesoporous Molecular Sieve Synthesized by Non-Hydrothermal Method in an Alkali-Free System
Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by
Mat. Res.. Publicado em: 17/08/2017
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2. Synthesis and Characterization of Al-TON Zeolite Using a Dialkylimizadolium as Structure-Directing Agent
In this work, the synthesis of zeolites using 1-butyl-3-methylimidazolium chloride [C4MI]Cl as a structure-directing agent was investigated. The organic cation shows effectiveness and selectivity for the syntheses of TON zeolites under different reaction conditions compared to the traditional structure-directing agent, 1,8-diaminooctane. The 1-butyl-3-methyl
Mat. Res.. Publicado em: 07/11/2016
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3. 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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4. (Síntese de Zeólita A empregando resíduo de caulim amazônico)
Resumo Estudou-se a síntese de zeólita A empregando resíduo de caulim de recobrimento de papel. O resíduo de caulim foi pré-tratado a 550 ºC para 800 ºC. Para fins de comparação, uma amostra de zeólita A foi também preparada utilizando o procedimento IZA. Os materiais obtidos foram caracterizados por 27Al MAS NMR, difração de raios X e microscop
Cerâmica. Publicado em: 2015-12
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5. CARACTERIZAÇÃO E ATIVIDADE CATALÍTICA DE K2CO3/AL2O3 NA TRANSESTERIFICAÇÃO DO ÓLEO DE GIRASSOL COM AQUECIMENTO CONVENCIONAL E MICRO-ONDAS
Commercial and synthetic mesoporous aluminas impregnated with potassium carbonate were characterized by X-ray diffraction (XRD), nitrogen physisorption, infrared spectroscopy and 27Al MAS NMR. The activities in the transesterification reaction of sunflower oil with methanol for biodiesel production were evaluated. 27Al MAS NMR spectra evidenced the presence
Quím. Nova. Publicado em: 2015-02
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6. Síntese e caracterização de vermiculita mesoporosa obtida por modificação com sais complexos de alumínio e lantânio
Os estudos de aumento do espaçamento interplanar basal, distribuição de poros e área superficial de uma argila mesoporosa obtida a partir de vermiculita precursora, foram realizados por intercalação de oligômero poli-hidroxi catiônico Al13 e um misto (La xAl13-x) obtido por dopagem com lantânio, seguida de calcinação para formação dos pilares. A
Cerâmica. Publicado em: 2014-06
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7. Nucleation and growth process of sodalite and cancrinite from kaolinite-rich clay under low-temperature hydrothermal conditions
The synthesis of low-silica zeotypes by hydrothermal transformation of kaolinite-rich clay and the nucleation and growth processes of sodalite and cancrinite in the system Na2O-Al2O3-SiO2-H2O at 100 °C were investigated. The synthesis products were characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier transform infr
Mat. Res.. Publicado em: 01/02/2013
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8. Synthesis, characterization and catalytic activity of mesoporous materials Al-MCM-41 in transesterification reaction of cottonseed oil / Síntese, caracterização e avaliação catalítica do aluminossilicato mesoestruturado AI-MCM-41 na transesterificação de óleos vegetais
Molecular sieves have been applied to the processing of triacylglycerols, to produce biofuels. In this context, the mesoporous catalyst Al-MCM-41 was proposed in this work as an alternative to acid heterogeneous transesterification of cottonseed oil with ethanol. This material was prepared using various Si/Al molar ratios (25, 50, 75 and 100) with reaction t
Publicado em: 2010
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9. Estudo do composto intermetálico GdAl2 via ressonância magnética nuclear em campo magnético externo nulo / Zero-field NMR study of intermetallic compound GdAl2
Recentemente, o Laboratório de Espectroscopia de Alta Resolução por RMN (LEAR), do Instituto de Física de São Carlos - USP, decidiu iniciar pesquisa na área de materiais magnéticos sem a aplicação de campo magnético externo. Por esta razão, montou-se um espectrômetro de RMN em campo zero (RMNz), tendo como componente principal um console de banda
Publicado em: 2009
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10. Efeito de microondas na estrutura cristalina e na atividade catalítica de argilas
The effect of microwave (MW) irradiation on the crystalline structure of two natural clays and one commercial clay, Montmorillonite K10, was analyzed comparing the X-ray diffraction, N2 isotherms, NMR-MAS of 27Al and 29Si spectra of the clays before and after MW irradiation. The preparation of dioxolane ketals of isatin was used to analyze the MW effect on t
Química Nova. Publicado em: 2008
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11. Structural characterization of mullites synthesized by thermal decomposition of topaz
The structure of mullite obtained by thermal decomposition of topaz at 1340 °C and after additional thermal treatment at 1600 °C was characterized by 29Si and 27Al MAS NMR spectroscopy and x ray diffraction. No amorphous phase was detected by these techniques. The 29Si MAS NMR spectra of the mullite samples showed four resonance peaks at -81, -86, -90 and
Materials Research. Publicado em: 2007-03
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12. Influência da razão Al/argila no processo de pilarização de esmectita
As amostras de esmectita do estado do Pará, Amazônia, Brasil foram caracterizadas utilizando XRD, 27Al MAS NMR, FTIR e análise textural por curvas isotérmicas de adsorção-dessorção de nitrogênio. Na produção das argilas pilarizadas foi usado como íon intercalante, o Al13 (o íon de keggin), obtido pela reação das soluções AlC(l3)6H2O/NaOH, co
Cerâmica. Publicado em: 2006-09