Hierarchically Structured Monolithic Silicalite-1 Consisting of Crystallized Nanoparticles and Its Performance in the Beckmann Rearrangement of Cyclohexanone Oxime

Li, Wen‐Cui; Lu, An‐Hui; Palkovits, Regina; Schmidt, Wolfgang; Spliethoff, Bernd; Schüth, Ferdi

doi:10.1021/ja052693v

Cited by 180 publications

(116 citation statements)

References 31 publications

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“…Several attempts have already been made in this field; [37,38] for example, 3D macroporous monolithic silicalite-1 by using polymer spheres, [39] and hierarchically structured monolithic zeolites by using a carbon template. [40][41][42] In these cases, the organic scaffold templates must be removed by calcination. It would therefore be interesting to develop a more facile and organic scaffold free route to self-supporting well-organized zeolite nanocrystal aggregates with interconnected hierarchically micro-meso-macroporous systems.…”

Section: Introductionmentioning

confidence: 99%

Well‐Organized Zeolite Nanocrystal Aggregates with Interconnected Hierarchically Micro–Meso–Macropore Systems Showing Enhanced Catalytic Performance

Yang

Tian

Chen

et al. 2011

Chemistry A European J

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Preparation and characterization of well‐organized zeolitic nanocrystal aggregates with an interconnected hierarchically micro–meso–macro porous system are described. Amorphous nanoparticles in bimodal aluminosilicates were directly transformed into highly crystalline nanosized zeolites, as well as acting as scaffold template. All pores on three length scales incorporated in one solid body are interconnected with each other. These zeolitic nanocrystal aggregates with hierarchically micro–meso–macroporous structure were thoroughly characterized. TEM images and 29Si NMR spectra showed that the amorphous phase of the initial material had been completely replaced by nanocrystals to give a micro–meso–macroporous crystalline zeolitic structure. Catalytic testing demonstrated their superiority due to the highly active sites and the presence of interconnected micro–meso–macroporosity in the cracking of bulky 1,3,5‐triisopropylbenzene (TIPB) compared to traditional zeolite catalysts. This synthesis strategy was extended to prepare various zeolitic nanocrystal aggregates (ZSM‐5, Beta, TS‐1, etc.) with well‐organized hierarchical micro–meso–macroporous structures.

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Section: Introductionmentioning

confidence: 99%

Well‐Organized Zeolite Nanocrystal Aggregates with Interconnected Hierarchically Micro–Meso–Macropore Systems Showing Enhanced Catalytic Performance

Yang

Tian

Chen

et al. 2011

Chemistry A European J

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“…However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites, [6][7][8][9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials. [17][18][19][20][21][22][23][24][25][26][27][28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized, [29][30][31][32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.Herein, we demonstrate a facile, controllable, and universal route for the synthesis of hierarchical mesoporous zeolites templated from a mixture of small organic ammonium salts and mesoscale cationic polymers. The route involves a one-step hydrothermal synthesis, and the templated mixture is homogeneously dispersed in the synthetic gel.…”

mentioning

confidence: 99%

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

et al. 2006

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Crystals of zeolites with intricate micropores have been widely used in industry as heterogeneous catalysts, in particular as solid acid catalysts in the fields of oil refining and petrochemistry. However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts. [1,2] [19]). However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites, [6][7][8][9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials. [17][18][19][20][21][22][23][24][25][26][27][28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized, [29][30][31][32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.Herein, we demonstrate a facile, controllable, and universal route for the synthesis of hierarchical mesoporous zeolites templated from a mixture of small organic ammonium salts and mesoscale cationic polymers. The route involves a one-step hydrothermal synthesis, and the templated mixture is homogeneously dispersed in the synthetic gel. Importantly, these novel zeolites exhibit excellent catalytic properties compared with conventional zeolites. This work may give an entry to the synthesis of hierarchical mesoporous zeolites that reveal fast mass transport, with potential application in industrial catalysis.Beta zeolite is generally synthesized from a small organic template of tetraethylammonium hydroxide (TEAOH). In the present strategy, hierarchical mesoporous Beta zeolite (Beta-H) was crystallized in the presence of TEAOH and a mesoscale cationic polymer, polydiallyldimethylammonium chloride (PDADMAC). For comparison, conventional Beta zeolite was prepared in the absence of cationic polymer by a similar procedure.The X-ray diffraction (XRD) pattern of calcined Beta-H (Figure 1a) shows well-resolved peaks in the 4-40° range, characteristic for the Beta zeolite structure.

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“…[78] They prepared self-supporting zeolite monoliths in a multi-step synthetic procedure. In the final material, micropores inside the zeolite nanocrystals (30-40 nm) are combined with a mesopore system formed by the packing of the nanoparticles, and a macropore system on the monolith level.…”

Section: Hierarchical Pore Architectures: Combining Microporous and Mmentioning

confidence: 99%

An Overview of Zeolite, Zeotype and Mesoporous Solids Chemistry: Design, Synthesis and Catalytic Properties

Maschmeyer

Water

2006

Catalysts for Fine Chemical Synthesis

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Hierarchically Structured Monolithic Silicalite-1 Consisting of Crystallized Nanoparticles and Its Performance in the Beckmann Rearrangement of Cyclohexanone Oxime

Cited by 180 publications

References 31 publications

Well‐Organized Zeolite Nanocrystal Aggregates with Interconnected Hierarchically Micro–Meso–Macropore Systems Showing Enhanced Catalytic Performance

Well‐Organized Zeolite Nanocrystal Aggregates with Interconnected Hierarchically Micro–Meso–Macropore Systems Showing Enhanced Catalytic Performance

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

An Overview of Zeolite, Zeotype and Mesoporous Solids Chemistry: Design, Synthesis and Catalytic Properties

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