Improved stability of MCM-41 through textural control

Coustel, N.; Renzo, Francesco Di; Fajula, François

doi:10.1039/c39940000967

Cited by 136 publications

(91 citation statements)

References 3 publications

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“…It indicates that the resistance to 4,6-DMDBT is better than that to thiophene. 25 The appearance of the other two weak peaks at 2θ ) 4.383°(110) and 2θ ) 5.031°(200) suggests that the channels are hexagonally organized and the ordered MCM-41 structure is formed. All of the major peaks of Y are identified in the high 2θ region.…”

Section: Materials Characterizationmentioning

confidence: 97%

MCM-41 Overgrown on Y Composite Zeolite as Support of Pd−Pt Catalyst for Hydrogenation of Polyaromatic Compounds

Zhang

Meng

et al. 2007

Ind. Eng. Chem. Res.

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A composite zoelite Y overgrown with a thin layer of mesoporous MCM-41 was prepared as the support of a sulfur-tolerant catalyst for aromatics reduction in diesel cut. This material is different from the mechanical mixture of the two zeolites in many aspects, that is, the FTIR spectra, appearance of particles, distribution of Si and Al, 29 Si MAS NMR spectra, acid strength, and amount of acid sites on the surface. The composite was used as the support of a Pd-Pt catalyst for the hydrogenation of polyaromatic compounds, pyrene and naphthalene. Sulfur tolerance of the catalyst was investigated with naphthalene hydrogenation in the presence of thiophene and 4,6-dimethyldibenzothiophene. It was demonstrated that the introduction of mesopores enhances the activity of pyrene hydrogenation and the sulfur tolerance during naphthalene hydrogenation.

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Section: Materials Characterizationmentioning

confidence: 97%

MCM-41 Overgrown on Y Composite Zeolite as Support of Pd−Pt Catalyst for Hydrogenation of Polyaromatic Compounds

Zhang

Meng

et al. 2007

Ind. Eng. Chem. Res.

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“…The thickness of the MTS walls can be adjusted by changing the alkalinity of the synthesis mixture. [22] The aluminum content, relevant for catalytic applications, can be controlled by either using a silica aluminum oxide as the silica source or by adding the desired amount of sodium aluminate to the reaction mixture. Quite ordered materials were formed with a Si:Al ratio down to 7:1 in the reaction mixture (5.5:1 in the solid formed).…”

mentioning

confidence: 99%

Morphological Control of MCM-41 by Pseudomorphic Synthesis

Martin

Galarneau

Renzo

et al. 2002

Angew. Chem. Int. Ed.

186

167

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The development of micelle-templated silicas (MTS) has represented one of the most original fields of materials research since the seminal papers from the Kresge and Beck groups on MCM-41 and MCM-48. [1,2] The self-assembly of surfactant aggregates and mineral species can be controlled to provide stable mesoporous materials with extremely narrow pore-size distributions. Several recent reviews show the advances in the preparation of ordered porous oxides, [3±5] as well as their applications in catalysis. [6±8] Adsorbents with narrow pore-size distribution at the nanometer scale allow new applications to be devised for the separation of large organic molecules. MCM-41 silicas have been proposed as possible stationary phases for size-exclusion chromatography, [9] normal-phase HPLC, [10] capillary gas chromatography, [11] and enantioselective HPLC. [12,13] The control of the size and shape of the adsorbent particles is an essential condition for any chromatographic application: particle-size scattering affects separation and plate height. Indeed, the preparation of spheres of MTS with predetermined monodispersed size has been the target of several research groups. Positive results have been obtained by introducing surfactant templates in classical preparations of silica gel with controlled grain size. In this way, spheres of MTS have been prepared from water ± alcohol systems, [14,15] by controlled hydrolysis, [16,17] or by spray-drying techniques. [18] A frequent drawback of these methods is the need to simultaneously optimize the conditions for the synthesis of the desired silica ± surfactant mesophase and for the successful formation of monodispersed spheres. This situation restrains the experimental conditions and makes a fine tuning of the properties of MTS, such as, pore size and topology, wall thickness, and aluminum content, difficult. It would be expedient to independently optimize the properties of the particles and the properties of the micelle-templated phase. Herein, a method to achieve this result by transformation of preformed spheres of silica gel into MTS is proposed.The synthesis procedure is directly adapted from the synthesis of MCM-41, [1,2] by using commercial spheres of silica gel as the source of silica. Lichrosphere 100 (Merck) was stirred in an alkaline solution of cetyltrimethylammonium bromide (CTAB), the molar composition of the system being 1 SiO 2 /0.25 NaOH/0.1 CTAB/20 H 2 O. After 30 min stirring at room temperature, the system was put in an autoclave at 388 K for 24 h. The parent silica (Lichrosphere 100) and the recovered solid share the same spherical morphology and granulometric distribution (Figure 1). However, while the parent silica is amorphous, the CTAB-treated solid presents the characteristic X-ray powder diffraction pattern of MCM-41. Figure 1. Pseudomorphic transformation of silica gel to MCM-41. Micrographs (a, b), granulometric distributions; the distribution is given in volume V as a function of particle diameter D p (c, d), and powder diffraction patterns (e, f) fo...

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“…Originally, their hydrothermal stability was poor according to the loss of their mesoporous structure in acid or alkaline solution [7][8][9]. Several methods have been proposed to increase the stability of mesoporous materials, including synthesis of materials with thicker pore walls [10][11][12], silylation [13][14][15][16][17][18], stabilization by tetralkylammonium [19], and salt effect [20,21]. New avenues are explored recently, where templated mesostructured materials have been designed with pore walls with an organic core and an inorganic shell using (EtO) 3 Si-R-Si(OEt) 3 (R = ethane, benzene and thiophene) type of precursors [22,23].…”

Section: Introductionmentioning

confidence: 99%

“…Trimethylsilylation of MCM-41-C and MCM-41-E was done using CTMS in toluene[50] (11,12). FSM-16-C was modified as in c[51] (13).…”

mentioning

confidence: 99%

Surface tailoring control in micelle templated silica

Badiei¹,

Bonneviot²,

Crowther³

et al. 2006

Journal of Organometallic Chemistry

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Improved stability of MCM-41 through textural control

Abstract: Control of silicoaluminate activity during synthesis of MCM-41 leads t o thicker pore walls, and hence to improved thermal and hydrothermal stabilities.

Cited by 136 publications

References 3 publications

MCM-41 Overgrown on Y Composite Zeolite as Support of Pd−Pt Catalyst for Hydrogenation of Polyaromatic Compounds

MCM-41 Overgrown on Y Composite Zeolite as Support of Pd−Pt Catalyst for Hydrogenation of Polyaromatic Compounds

Morphological Control of MCM-41 by Pseudomorphic Synthesis

Surface tailoring control in micelle templated silica

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