Efeito de diferentes fontes de sílica nos parâmetros texturais da peneira molecular MCM-41

Fontes, Maria S. B.; Melo, D.M.A.; Costa, Cíntia C.; Braga, Renata Martins; Melo, M. A. F.; Alves, J. A. B. L. R.; Silva, M. L. P.

doi:10.1590/0366-69132016623611966

Cited by 8 publications

(4 citation statements)

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“…Figure 3 reports the FT-IR spectra for all Fe and Co synthesized catalysts in 1800-400 cm -1 range. In all sample's curves, the band in 1640 cm -1 correspond to the O-H vibrations of silanol groups [52], while strong bands around 1230 and 1060 cm -1 correspond to ≡Si-O-Si≡ and Si-O-Si asymmetric stretching, typical for MCM-41. Curves A, C and E, which correspond to Fe5, FeCo5 and Co5 catalyst, have a structure with higher Al content, then this behavior…”

Section: Resultsmentioning

confidence: 97%

“…All catalysts sample presented spherical small crystallites alternating between welldefined structures to greater particle nonuniform clusters. This morphology characteristics is typical for Al-MCM-41 and the more aluminum is inserted into the MCM-41 matrix structure itself, the greater the tendency to observe a more dispersed material containing a less defined morphology [52,[62][63][64].…”

Section: Catalystsmentioning

confidence: 82%

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Glycerol Acetylation with Propionic Acid Using Iron and Cobalt Oxides in Al-MCM-41 Catalysts

Tentor

Dias

Gomes

et al. 2020

Bull. Chem. React. Eng. Catal.

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In this work, Al-MCM-41 molecular sieves were synthesized, containing iron and/or cobalt oxides, impregnated by incipient wetness method, characterized and applied as catalysts in the acetylation reaction of glycerol with propionic acid to produce green glyceryl propionate molecules of high commercial value. According to this, X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Fourier Transform Infra Red (FT-IR), adsorption/desorption N2 isotherms, textural analysis, and Scanning Electron Microscope (SEM) analysis were recorded to evaluate the main characteristics of materials. The presence of Lewis and Brønsted acidic sites and catalysts surface area were observed as important key points to functionalize acetylation reaction. Thus, time reaction, temperature, and glycerol / propionic acid ratio varied to improve the most suitable reaction conditions and behaviors. As a result, glycerol conversion was above 96%, followed by 68% of selectivity to glyceryl monopropionate as well as the formation of glyceryl di- and tri- propionate and a small amount of ethylene glycol dipropionate as an undesired product. Copyright © 2020 BCREC Group. All rights reserved

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Section: Resultsmentioning

confidence: 97%

Section: Catalystsmentioning

confidence: 82%

Glycerol Acetylation with Propionic Acid Using Iron and Cobalt Oxides in Al-MCM-41 Catalysts

Tentor

Dias

Gomes

et al. 2020

Bull. Chem. React. Eng. Catal.

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“…Once the stoichiometric calculations of reagents required to form AlSiM is influenced by the percentage of silicon [52], it is fundamental to know about the chemical composition of the silica precursors. Table 1 shows the XRF (EDX; EDX-700, SHIMADZU, Kyoto, Japan) results.…”

Section: X-ray Fluorescence (Xrf) Studiesmentioning

confidence: 99%

Acetylation of Eugenol on Functionalized Mesoporous Aluminosilicates Synthesized from Amazonian Flint Kaolin

et al. 2020

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The present work was aimed to investigate the catalytic activity of a mesoporous catalyst synthesized from 3-mercaptopropyltrimethoxysilane (MPTS) functionalized Amazonian flint kaolin in the acetylation of eugenol with acetic anhydride. Materials were characterized by thermogravimetry (TGA), N2 adsorption (BET), X-ray dispersive energy spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and acid-base titration. The results presented proved the efficiency of flint kaolin as an alternative source in the preparation of mesoporous materials, since the material exhibited textural properties (specific surface area of 1071 m2 g−1, pore volume of 1.05 cm3 g−1 and pore diameter of 3.85 nm) and structural properties (d100 = 4.35 nm, a0 = 5.06 nm and Wt = 1.21 nm) within the required and characteristic material standards. The catalyst with the total amount of acidic sites of 4.89 mmol H+ g−1 was efficient in converting 99.9% of eugenol (eugenol to acetic anhydride molar ratio of 1:5, 2% catalyst, temperature and reaction time 80 °C and 40 min reaction). In addition, the reused catalyst could be successfully recycled with 92% conversion activity under identical reaction conditions.

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“…Pour la synthèse de MCM-41 on utilise généralement des organosilicates (tetramethylorthosilicate ou tetraethylorthosilicate,…), silice colloïdale ou fumée de silice comme des sources de silice [1][2][3][4][5]. Ces dernières années et pour des considérations économiques et environnementales, les chercheurs étudient la possibilité de remplacer ces sources de silice par des minéraux naturels largement disponibles et peu onéreux.…”

Section: Introductionunclassified

Synthesis of MCM-41 nanomaterial from Algerian bentonite: influence of synthesis pH

Ali-Dahmane¹,

Brahmi²,

Hamacha³

et al. 2017

J. Fundam and Appl Sci.

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Mesoporous materials of the MCM-41 type were synthesized from Algerian bentonite as an aluminosilicate source without the addition of pure silica and aluminum reagents. The samples were synthesized under hydrothermal condition using cetyltrimithylammonium bromide (CTAB) as surfactant. The influence of initial synthesis pH on the material properties of as-synthesis MCM-41 samples was studied at different temperatures of crystallization. The samples were characterized using several techniques e.g. X-ray diffraction (XRD), N 2 adsorption-desorption and transmission electron microscope (TEM). The experimental results showed that bentonite can be used as an aluminosilicate source for the synthesis of Al-MCM-41. By decreasing the synthesis temperature of crystallization, it is necessary to decrease the synthesis pH value to form the best ordered hexagonal phase and eliminate the lamellar phase.

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Efeito de diferentes fontes de sílica nos parâmetros texturais da peneira molecular MCM-41

Cited by 8 publications

References 0 publications

Glycerol Acetylation with Propionic Acid Using Iron and Cobalt Oxides in Al-MCM-41 Catalysts

Glycerol Acetylation with Propionic Acid Using Iron and Cobalt Oxides in Al-MCM-41 Catalysts

Acetylation of Eugenol on Functionalized Mesoporous Aluminosilicates Synthesized from Amazonian Flint Kaolin

Synthesis of MCM-41 nanomaterial from Algerian bentonite: influence of synthesis pH

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