Catalytic applications of mesoporous silica-based materials

Luque, Rafael; Balu, Alina M.; Campelo, J.M.; Gracia, María D.; Losada, Elia; Pineda, Antonio; Romero, Antonio A.; Serrano‐Ruiz, Juan Carlos

doi:10.1039/9781849734776-00253

Cited by 38 publications

(30 citation statements)

References 147 publications

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“…In this sense the SBA-15 type materials, which own a two-dimensional and hexagonal structure (Stuckv et al, 1998;Zhao, 1998;Zhao et al, 2014), is one of the most widely used mesoporous silicates due to their great stability, both thermal and hydrothermal, and the large number of mesoporous channels and thick mesoporous walls (Kresge et al, 1992) that makes them a suitable material in reactions where large molecules participate. However, SBA-15 silicates require heteroatoms and/or the incorporation of different functionalities onto their surface to make them catalytically active (Luque et al, 2012). Such functionalization can be carried out by different methodologies, either direct synthesis or by post-synthesis approaches, which include impregnation, incipient wetness, and other recent methodologies such as mechanochemical grinding (Pineda et al, 2011), which is an efficient procedure that minimizes the use of solvents, which has environmental benefits (Pineda et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Tuneable Acidity in Fluorinated Al-SBA-15 Materials for the Esterification of Valeric Acid to Alkyl Valerates

et al. 2020

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The acidity of Al-SBA-15 materials functionalized by ball milling with several niobium loadings (0. 25-1 wt.%) as well as with several fluorine loadings (by wet impregnation using NH 4 F as a precursor) was characterized and materials investigated in the esterification of valeric acid to alkyl valerates. The parent Al-SBA-15 support as well as the modified materials loaded with Nb and/or F have been catalysts synthesized characterized by X-ray diffraction (XRD), N 2 physisorption measurements, and diffuse reflection infrared spectroscopy (DRIFT) among others. A special interest was paid on the acidity of the materials that was investigated by temperature-programmed desorption of pyridine. Interestingly, the characterization results for the materials containing fluorine showed up an increase in the acidity strength despite of a reduction in the number of acid sites. The catalytic performance of the as-prepared catalysts was investigated in the microwave-assisted esterification reaction of valeric acid to valerate esters. Thus, while the materials modified with niobium exhibited a lower catalytic activity as compared with the catalytic support (Al-SBA-15), the materials loaded with fluorine either onto Al-SBA-15 or on Nb1%/Al-SBA-15 materials presented enhanced conversion values of valeric acid. Therefore, it can be said that the new acid sites with enhanced strength formed by the incorporation of fluorine boost the esterification of valeric acid with alcohols to form the respective valerate ester.

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Section: Introductionmentioning

confidence: 99%

Tuneable Acidity in Fluorinated Al-SBA-15 Materials for the Esterification of Valeric Acid to Alkyl Valerates

et al. 2020

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“…A common and very effective procedure for the synthesis of PMOs relates to the co-condensation of silica with precursors such as tetraalkoxysilane and trialkoxyorganosilane in the presence of a structure-directing agent (templating agent), which determines the structure features of the resulting materials. Consequently, organic groups can easily be incorporated in the pores of these materials via co-condensation [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Highly ordered Nanomaterial Functionalized Copper Schiff Base Framework: Synthesis, Characterization, and Hydrogen Peroxide Decomposition Performance

2017

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An immobilized copper Schiff base tridentate complex was prepared in three steps from SBA-15 supports. The immobilized copper nanocatalyst (heterogeneous catalyst) was characterized by Fourier transform infrared spectroscopy (FT-IR), cross polarization magic angle spinning (CP-MAS), 13-carbon nuclear magnetic resonance ( 13 C-NMR), atomic absorption spectroscopy (AAS), thermogravimetric analysis (TGA), and N 2 -physisorption. Moreover, morphological and structural features of the immobilized nanocatalyst were analyzed using transmission electron microscopy (TEM) and X-ray powder diffraction spectrometry (PXRD). After characterizing the nanocatalyst, the catalytic activity was determined in hydrogen peroxide (H 2 O 2 ) decomposition. The high decomposition yield of H 2 O 2 was obtained for low-loaded copper content materials at pH 7 and at room temperature. Furthermore, the nanocatalyst exhibited high activity and stability under the investigated conditions, and could be recovered and reused for at least five consecutive times without any significant loss in activity. No copper leaching was detected during the reaction by AAS measurements.

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“…Interest in these materials is attributed to their unique properties and potential applications in adsorption and catalytic pro cesses and in materials science for the preparation of new composite materials [1]. The set of textural and acidic characteristics of mesoporous aluminosilicates provides the possibility of using these materials in the reactions of acid-base catalysis for the conversion or production of large organic molecules [2]. The acid sites in Al-MCM 41 mesoporous aluminosilicates are formed owing to the incorporation of Al in the sil ica material of the mesopore walls; this event can occur during both direct synthesis and post synthesis modification.…”

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Physicochemical and catalytic properties of mesoporous aluminosilicates modified with aluminum isopropoxide

et al. 2015

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The effect of alumination on the textural, acidic, and catalytic properties of mesoporous alumi nosilicates with an ordered mesopore system has been studied. It has been found that the aluminizing process is accompanied by the incorporation of Al in the aluminosilicate material of the mesopore walls. It has been shown that, in the phenol methylation process, the composition of products over the original (Si/Al = 12.5) and aluminated aluminosilicates (Si/Al = 2.2 and 0.8) is the same, which is indicative of the identical nature of the active sites. Unlike the original mesoporous aluminosilicate, the aluminated materials have exhibited the same level of activity for 4 h. It has been supposed that the stable activity of the aluminated catalysts is caused by the generation of additional acid sites owing to the interaction of the aluminum enriched material of the mesopore walls with water resulting from the reaction between phenol and methanol.

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Catalytic applications of mesoporous silica-based materials

Cited by 38 publications

References 147 publications

Tuneable Acidity in Fluorinated Al-SBA-15 Materials for the Esterification of Valeric Acid to Alkyl Valerates

Tuneable Acidity in Fluorinated Al-SBA-15 Materials for the Esterification of Valeric Acid to Alkyl Valerates

Highly ordered Nanomaterial Functionalized Copper Schiff Base Framework: Synthesis, Characterization, and Hydrogen Peroxide Decomposition Performance

Physicochemical and catalytic properties of mesoporous aluminosilicates modified with aluminum isopropoxide

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