One-Step Synthesis of Mesoporous Hybrid Titania−Silica Xerogels for the Epoxidation of Alkenes

Lorret, O.; Lafond, Vincent; Mutin, P. Hubert; Vioux, André

doi:10.1021/cm061478q

Cited by 44 publications

(41 citation statements)

References 26 publications

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“…Finally, an abrupt decrease in homogeneity was or ZrCl 4 were reacted with MeSiCl 3 and diisopropylether, no Si-O-M bonds were observed in the 29 Si cross-polarization magic angle spinning (CPMAS) NMR spectra [69]. High homogeneity in this type of hybrid material was later achieved when MeSiCl 3 or Me 3 SiCl were used along with SiCl 4 and reacted with TiCl 4 and diisopropylether [70].…”

Section: X + M´(or)mentioning

confidence: 99%

“…It is noteworthy that even in the absence of templates the pore size distributions were relatively narrow with maxima in the mesoporous region. Interestingly these remarkable porosity properties were not adversely affected by the introduction of organic groups (SiCl 4 partially substituted with MeSiCl 3 or Me 3 SiCl in the synthesis) affording mesoporous silica-titania hybrids with surface areas around 1000 m 2 ·g −1 [70].…”

Section: Without Templatesmentioning

confidence: 99%

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The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described.

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Section: X + M´(or)mentioning

confidence: 99%

Section: Without Templatesmentioning

confidence: 99%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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“…A less energy intensive method for the preparation of oxide materials is by drying the solvent under ambient conditions to produce xerogels. Several synthetic procedures have been reported for their preparation, but the most common methods usually result in non-porous materials (Erdem et al, 2001;Fernandez et al, 2007;Handy et al, 1992;Holland et al, 2000;Lorret et al, 2006). This is because the drying of the solvents under ambient conditions cause collapse of the pores due to the differential capillary pressure developed.…”

Section: Introductionmentioning

confidence: 99%

An investigation into the effect of porosities on the adsorption of rhodamine B using titania–silica mixed oxide xerogels

Rasalingam

Peng

Koodali

2013

Journal of Environmental Management

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“…In order to circumvent the deactivation of the amorphous and mesoporous TiO2-SiO2 catalyst prepared by NHSG, we investigated the effect of surface hydrophobization on the catalyst activity in the presence of water for the epoxidation of cyclohexene [24,25]. The surface functionalization was achieved either in one-pot during the gel synthesis or by postsynthesis silanization with a methylated precursor.…”

Section: Introductionmentioning

confidence: 99%

Mesoporous SiO2–TiO2 Epoxidation Catalysts: Tuning Surface Polarity to Improve Performance in the Presence of Water

Smeets¹,

Mustapha²,

Schnee³

et al. 2018

Preprint

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Herein, we present the preparation by the non-hydrolytic sol-gel route of a mesoporous SiO2-TiO2 epoxidation catalyst with high specific surface area and large pores. This catalyst is active in the catalytic epoxidation of cyclohexene with H2O2 in acetonitrile, showing performances comparable to a TS-1 catalyst. Yet, it is dramatically deactivated when water is used as a cosolvent, which represents an important limitation for the applicability of this catalyst. In order to circumvent the deactivation of the catalyst in the presence of water, we investigate the effect of surface hydrophobization with methyl groups on the catalytic activity and selectivity. Two functionalization methods are investigated: one-pot synthesis with methyltrichlorosilane and post-synthesis silanization with methyltrimethoxysilane. The catalytic performance of the materials are compared to the pristine catalyst and to TS-1 in the presence of an excess of water in the medium. On the one hand, we show that the one-pot methylation does not increase water resistance, in spite of an increased surface hydrophobicity. We interpret this result in the light of a poorer Ti dispersion and lower Ti 4+ surface content in these catalysts. On the other hand, post-synthesis grafting significantly improves the catalytic performances because it combines a hydrophobic surface with a high active site content. At the molecular level, we show that the direct epoxidation pathway is restored thanks to the surface functionalization.

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One-Step Synthesis of Mesoporous Hybrid Titania−Silica Xerogels for the Epoxidation of Alkenes

Abstract: Highly active and selective titania−silica epoxidation catalysts modified by MeSiO1.5 and Me3SiO0.5 groups were obtained in one step by a nonhydrolytic sol−gel process using low-cost chloride precursors and routine evaporative drying.

Cited by 44 publications

References 26 publications

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

An investigation into the effect of porosities on the adsorption of rhodamine B using titania–silica mixed oxide xerogels

Mesoporous SiO2–TiO2 Epoxidation Catalysts: Tuning Surface Polarity to Improve Performance in the Presence of Water

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