Catalytic Benzene Alkylation over Mesoporous Zeolite Single Crystals:  Improving Activity and Selectivity with a New Family of Porous Materials

Christensen, Christina Hviid; Johannsen, Kim; Schmidt, Iver; Christensen, Claus H.

doi:10.1021/ja037063c

Cited by 332 publications

(216 citation statements)

References 15 publications

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“…Mesoporous MFI zeolite single-crystal catalyst was shown to be both more active and more selective than conventional MFI with only micropores during the alkylation of benzene with ethylene [121]. Such superior catalytic performances were explained by improved mass transport through the mesoporous channel inside the zeolite crystal.…”

Section: Alkylation and Acylation Reactionsmentioning

confidence: 99%

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

Somorjai

2014

Catal Lett

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The research field of hierarchically nanoporous zeolites has been growing at an enormous pace over the past decades. Hierarchically nanoporous zeolites have versatile structural properties such as high surface area and large pore volume that can alleviate diffusional limitations of conventional zeolites with solely microporous framework. In this review, various synthesis strategies to hierarchically nanoporous zeolites and their structural advantages in catalytic reactions will be reviewed. In the first part, many novel synthetic approaches for hierarchically nanoporous zeolites such as post-demetallation, softtemplating, hard-templating, and dual-pore-generating surfactant-directed methods will be introduced. In the second part, catalytic applications of hierarchically nanoporous zeolites on various chemical reactions involving isomerization, cracking, alkylation and oxidation will be discussed. The present comprehensive review will provide future opportunities and perspectives on the research of hierarchically nanoporous zeolites including their applications to catalytic reactions.

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Section: Alkylation and Acylation Reactionsmentioning

confidence: 99%

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

Somorjai

2014

Catal Lett

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“…34 The world-wide demand for ethylbenzene, which is the raw material for styrene production, is roughly 22 Â 10 6 t per year and is almost exclusively produced by this reaction. The alkylation of benzene with ethene over the H-ZSM-5 catalyst constitutes the heart of the Mobil-Badger process, which was first brought on stream in 1980.…”

Section: Alkylation Of Benzene With Ethenementioning

confidence: 99%

“…Christensen et al showed that the zeolite catalyst with the hierarchical pore architecture is significantly more active than the conventional zeolite catalyst under the reaction conditions employed (T = 583 to 643 K; p = 0.25 MPa), which are sufficiently close to the conditions employed in the industrial process (T = 700 K; p = 2 to 5 MPa). 34 Moreover, the selectivity to ethylbenzene increases by 5 to 10% depending on the benzene conversion. The increased activity is ascribed to the improved mass transport in the mesoporous zeolites which is indicated by an increase of the apparent activation energy from 59 to 77 kJ mol À1 .…”

Section: Alkylation Of Benzene With Ethenementioning

confidence: 99%

Catalytic test reactions for the evaluation of hierarchical zeolites

2016

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Catalytic test reactions for the evaluation of hierarchical zeolitesStudies on the synthesis, characterization and catalytic performance of hierarchical zeolites and related porous materials are currently revitalizing the mature field of zeolite research. This review discusses the challenges in evaluating the catalytic performance of a hierarchical zeolite catalyst compared to its parent zeolite. zeolites and the facilitated access and transport in the additional meso-or macropore system. In this tutorial review, we discuss several test reactions that have been explored to show the benefit of the hierarchical pore system with respect to their suitability to prove the positive effects of hierarchical porous zeolites. It is important to note that positive effects on activity, stability and less frequently selectivity observed for hierarchically structured catalysts not necessarily are only a consequence of the additional meso-or macropores but also the number, strength and location of active sites as well as defects and impurities. With regard to these aspects, the test reaction has to be chosen carefully and potential changes in the chemistry of the catalyst have to be considered as well. In addition to the determination of conversion, yield and selectivity, we will show that the calculation of the activation energy and the determination of the Thiele modulus and the effectiveness factor are good indicators of the presence or absence of diffusion limitations in hierarchical zeolites compared to their parent materials. Key learning pointsHierarchical zeolites are an emerging technology in the mature field of industrial catalysts. Several test reactions are suggested to prove the advantage of their hierarchical structure. In addition to an increase in activity and selectivity suppression of coke formation is often observed. Concept of the Thiele modulus and the effectiveness factor is required to judge the presence of diffusion limitations in hierarchical catalysts.

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“…Especially, the MFI type silicalite-1 (Sil-1) zeolite without cations and silanol defects exhibits high hydrophobic property during the adsorption of volatile organic compounds (VOCs) under wet conditions [4,5]. However, the sole presence of micropores (diameter < 20 Å) limits their use which involves diffusion of bulky molecule [6]. Ordered mesoporous silicates with enlarged pore diameters (20-500 Å) have been developed to overcome these difficulties.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and hydrophobic adsorption properties of microporous/mesoporous hybrid materials

Qiao

et al. 2009

Journal of Hazardous Materials

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a b s t r a c tHybrid materials of silicalite-1 (Sil-1)-coated SBA-15 particles (MSs) have been successfully synthesized by crystallization process under hydrothermal conditions. These MSs materials were characterized by X-ray diffraction, nitrogen adsorption/desorption and TEM techniques, which illustrated that the silicalite-1-coated SBA-15 particles were successfully prepared and had large pore volume and hierarchical pore size distribution. Further experimental studies indicated that longer crystallization time under basic condition caused the mesostructure of SBA-15 materials to collapse destructively and higher calcination temperature tended to disrupt the long-range mesoscopic order while they had little influence on the phase of microcrystalline silicalite-1 zeolite. The resultant MSs materials were investigated by estimating dynamic adsorption capacity under dry and wet conditions to evaluate their adsorptive and hydrophobic properties. The hydrophobicity index (HI) value followed the sequence of silicalite-1 > MSs > SBA-15, which revealed that the SBA-15 particles coated with the silicalite-1 seeds enhanced the surface hydrophobicity, and also were consistent with FTIR results. Our studies show that MSs materials combined the advantages of the ordered mesoporous material (high adsorptive capacity, large pore volume) and silicalite-1 zeolite (super-hydrophobic property, high hydrothermal stability), and the presence of micropores directly led to an increase in the dynamic adsorption capacity of benzene under dry and wet conditions.

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Catalytic Benzene Alkylation over Mesoporous Zeolite Single Crystals: Improving Activity and Selectivity with a New Family of Porous Materials

Cited by 332 publications

References 15 publications

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

Catalytic test reactions for the evaluation of hierarchical zeolites

Synthesis and hydrophobic adsorption properties of microporous/mesoporous hybrid materials

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