Structural characterization of organically-modified porous silicates synthesized using CTA+ surfactant and acidic conditions

Babonneau, Florence; Leite, Lorraine; Fontlupt, Stéphanie

doi:10.1039/a805539d

Cited by 103 publications

(93 citation statements)

References 6 publications

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“…In this context, several organo-functionalized mesostructures have been prepared through direct assembly pathways, as well as through grafting reactions of pre-assembled frameworks using different organosilane precursors. [10][11][12][13][14][15][16][17][18] The potential usefulness of these derivatives, as well as other organo-functional derivatives, depends critically on the loading of accessible functional groups in the framework.…”

Section: Functionalized Periodic Mesoporous Organosilicasmentioning

confidence: 99%

“…1a) or by postsynthesis treatment of pre-formed mesoporous silica with an organosilane coupling reagent. [10][11][12][13][14][15][16][17] The mesoporous materials have a microscopically heterogeneous structure composed of an inorganic main framework with an organic layer grafted onto the framework. Generally, they exhibit poorer structural ordering and lower loading of organic content.…”

Section: Introductionmentioning

confidence: 99%

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Highly Ordered Mesoporous Organosilica Hybrid Materials

Kapoor¹,

Inagaki²

2006

Bulletin of the Chemical Society of Japan

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The latest developments in periodic mesoporous organosilicas (PMO) have been compiled. The discovery of mesoporous hybrid organosilicas with molecular scale periodicity resulting from alternating hydrophilic and hydrophobic layers, and a cost effective solution showing the use of allyl derivatives of the bis-silyl precursors are discussed. Relevant uses of the periodic mesoporous materials in diverse applications are summarized. For example, the metal-incorporated periodic mesoporous organic frameworks are likely to offer an advantage in catalytic transformations, while the functionalized PMOs show promise in fascinating catalytic applications via enhancing the physical properties of guest molecules and clusters. In general, the advancement in PMOs have showed great promise and are expected to deliver exciting achievable future findings.

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Section: Functionalized Periodic Mesoporous Organosilicasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Highly Ordered Mesoporous Organosilica Hybrid Materials

Kapoor¹,

Inagaki²

2006

Bulletin of the Chemical Society of Japan

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“…A preparação de silicatos porosos organicamente modificados foi também reportada 70 , utilizando-se para tal síntese alcóxidos do tipo RSi(OEt) 3 com R = -CH 3 , -C 2 H 5 , -C 8 H 17 , -CH= CH 2 ou -C 6 H 5 , sendo que o grupo R exerce influência sobre a porosidade dos materiais calcinados. A organofuncionalização da sílica gel pode também ser conseguida utilizando-se TEOS como precursor, conseguindo-se aumentar a cadeia orgânica ancorada pelo emprego de glutaraldeído 71 .…”

Section: Figura 1 Representação Esquemática Da Natureza Interdisciplunclassified

Alcóxidos como precursores na síntese de novos materiais através do processo sol-gel

Airoldi¹,

Farias²

2004

Quím. Nova

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Recebido em 17/9/02; aceito em 15/5/03 ALKOXIDE AS PRECURSORS IN THE SYNTHESIS OF NEW MATERIALS THROUGH THE SOL-GEL PROCESS. An overview about the role of alkoxides in the most recent uses of the sol-gel process in the synthesis of new materials is presented. Special attention is focused on the uses of silicon, aluminum, zirconium and titanium alkoxides. This review shows that the alkoxides enable the synthesis of new matrices with controlled surface area, acidity and porosity, as well as some unusual properties. The property associated with the solubility of metal alkoxides opens enormous possibilities of combining them for the synthesis films of powders with a very large range of metal compositions.Keywords: sol-gel; alkoxide; materials. INTRODUÇÃONos últimos anos, os profissionais em Química foram aos poucos se familiarizando com uma nova denominação, corriqueiramente utilizada, a fim de destacar o emprego cada vez mais freqüente de novos compostos químicos para fins tecnológicos, que consiste na Química dos Materiais. Aos poucos o poderio da Química se projetou num espaço interdisciplinar, ou mesmo multidisciplinar. A clás-sica divisão entre as quatro áreas da química, a saber, químicas inorgânica, orgânica, analítica e físico-química, torna-se cada vez menos definida. Tal interpenetração das diferentes sub-áreas faz-se sentir nitidamente na chamada Química supramolecular 1,2 . As inovações que propiciaram o surgimento deste novo campo de pesquisa, consistiram no envolvimento de todos os conhecimentos das áreas antes específicas, na busca de novos compostos, notadamente aqueles com elevado potencial de aplicação tecnológica.Em se tratando de novos materiais, a primeira impressão que se tem é de que existiria uma larga utilização das clássicas rotas da chamada Química do Estado Sólido que, em princípio, deve estar alicerçada no entendimento da termodinâmica da reação. Desta forma, as condições experimentais podem prever a obtenção de compostos estáveis ou metaestáveis. Para o sucesso de muitas destas operações, fatalmente faz-se necessário o uso de uma metodologia que empregue altas temperaturas na obtenção de cristais, vidros ou materiais cerâmicos. Em caso de baixas temperaturas, pode-se obter agregados cristalinos através da preparação de poliânions a partir de soluções, ou mesmo, em processos sintéticos hidrotérmicos. Em quaisquer casos, as propriedades dos materiais sólidos estão altamente governadas pelas leis termodinâmicas, que se traduzem nos diagramas de fases 3 . O panorama assim apresentado contrasta com o crescente interesse que vem surgindo através de uma metodologia aplicada à preparação de materiais, que se baseia na polimerização de compostos inorgânicos simples abrindo um campo na ciência dos materiais, que se direciona à Química macromolecular. O sólido pode não ser o mais estável termodinamicamente, mas resulta de um possível controle da reação química 4 envolvendo, em muitos casos, condições específicas em altas temperaturas.Contrastando com métodos sintéticos clássicos, destacam-se as sí...

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“…This solution was added to another one formed by cetyltrimethylammonium bromide ͑CTAB͒, HCl, and H 2 O ͑CTAB/ H 2 O / HCl/ TEOS= 0.12: 130: 9.2: 1͒ and stirred for 2 h. 16 The resultant product was filtered, washed with water, and dried at 100°C for 24 h. The white solid product was stirred with EtOH for 2 h, then the sample was filtered, washed with EtOH, and vacuum-dried at 100°C. The sample was characterized by TEM ͑JEOL 2000FX electron microscope operating at 200 kV͒, low angle x-ray diffraction ͑Philips X'PERT-MPD diffractometer using Cu K␣ radiation͒, and nitrogen adsorption at 77 K ͑ASAP 2020 analyzer from Micromeritics͒.…”

Section: Experiments Detailsmentioning

confidence: 99%

Collective excitations in liquidD2confined within the mesoscopic pores of a MCM-41 molecular sieve

et al. 2006

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We present a comparative study of the excitations in bulk and liquid D 2 confined within the pores of MCM-41. The material ͑Mobile Crystalline Material-41͒ is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous SiO 2 . Its porosity was characterized by means of adsorption isotherms and found to be composed by a regular array of pores having a narrow distribution of sizes with a most probable value of 2.45 nm. The assessment of the precise location of the sample within the pores is carried out by means of pressure isotherms. The study was conducted at two pressures which correspond to pore fillings above the capillary condensation regime. Within the range of wave vectors where collective excitations can be followed up ͑0.3ഛ Q ഛ 3.0 Å −1 ͒, we found confinement brings forward a large shortening of the excitation lifetimes that shifts the characteristic frequencies to higher energies. In addition, the coherent quasielastic scattering shows signatures of reduced diffusivity.

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Structural characterization of organically-modified porous silicates synthesized using CTA+ surfactant and acidic conditions

Cited by 103 publications

References 6 publications

Highly Ordered Mesoporous Organosilica Hybrid Materials

Highly Ordered Mesoporous Organosilica Hybrid Materials

Alcóxidos como precursores na síntese de novos materiais através do processo sol-gel

Collective excitations in liquidD2confined within the mesoscopic pores of a MCM-41 molecular sieve

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