Zeolite UZM-8: Synthesis, Characterization, and Catalytic Properties in Isopropylation of Benzene with 2-Propanol

Hyeok, Seung; Liu, Jin; Shin, Jiho; Hong, Suk Bong

doi:10.1007/s11244-015-0392-y

Cited by 21 publications

(24 citation statements)

References 24 publications

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“…The 2D zeolites are usually made from exfoliation [18][19][20][21][22][23][24] and pillaring [6,15,[25][26][27][28][29][30] of the 2D zeolite precursors that contain stacked zeolite nanosheets of one-to-two unit cell or smaller thickness. The catalytic tests have shown that the delaminated and pillared 2D zeolites have improved activity and lifetime with respect to their 3D microporous counterparts in processing bulky molecules [18,[31][32][33][34][35]. 4 Despite these practices in synthesis and catalytic tests of the unit-cell thick 2D zeolite catalysts, evaluation of acid site locations and the catalytic behaviors of acid sites at each location has not been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

Emdadi

Qin

et al. 2017

Microporous and Mesoporous Materials

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The pillared MWW (PMWW or MCM-36) and pillared MFI (PMFI) zeolites consist of a single-or near single-unit-cell thick two-dimensional (2D) zeolitic layer structure. The concentrations of external surface and pore mouth Brønsted acid sites in these zeolites were quantified by a combined dimethyl ether (DME) titration and methanol dehydration in the presence of 2,6-di-tert-butylpyridine (DTBP) or triphenylphosphine (TPP), respectively. DME can access to all Brønsted acid sites in PMFI and PMWW zeolites and thus determine the total number of acid sites. DTBP cannot access to acid sites in micropores, but on the external surface and at the pore mouth regions. In contrast, TPP can only access to acid sites on external surface. The degree of decrease in methanol dehydration rate in the presence of DTBP or TPP indicates the fraction of the sum of external surface and pore mouth acid sites and the sole fraction of external surface acid sites, respectively. The study shows that PMFI contains ~32% external surface and ~6% pore mouth acid sites, while PMWW consists of ~33% external surface and ~31% pore mouth acid sites. The individual external surface or pore mouth acid site performed distinctively in alkylation of mesitylene by benzyl alcohol reactions.

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Section: Introductionmentioning

confidence: 99%

Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

Emdadi

Qin

et al. 2017

Microporous and Mesoporous Materials

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“…Thus, synthesis protocols offer a large space for further improvements in terms of external surface areas and accessible acid site concentrations. At the same time, all layered MWW zeolites outperformed their 3D counterpart (MCM‐22) with respect to both conversion and selectivity . The presence of mesoporosity between the lamellar MFI nanosheets is behind the observed increase of indole conversion compared to 3D MFI zeolite (from 4 to 97%) and selectivity to 3‐acetylindole (from 30 to 75%) in the indole acylation reaction …”

Section: D Zeolitesmentioning

confidence: 90%

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

et al. 2018

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2D oxide nanomaterials constitute a broad range of materials, with a wide array of current and potential applications, particularly in the fields of energy storage and catalysis for sustainable energy production. Despite the many similarities in structure, composition, and synthetic methods and uses, the current literature on layered oxides is diverse and disconnected. A number of reviews can be found in the literature, but they are mostly focused on one of the particular subclasses of 2D oxides. This review attempts to bridge the knowledge gap between individual layered oxide types by summarizing recent developments in all important 2D oxide systems including supported ultrathin oxide films, layered clays and double hydroxides, layered perovskites, and novel 2D-zeolite-based materials. Particular attention is paid to the underlying similarities and differences between the various materials, and the subsequent challenges faced by each research community. The potential of layered oxides toward future applications is critically evaluated, especially in the areas of electrocatalysis and photocatalysis, biomass conversion, and fine chemical synthesis. Attention is also paid to corresponding novel 3D materials that can be obtained via sophisticated engineering of 2D oxides.

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“…[ 127 ] Similarly, the alkylation of benzene to ethylbenzene and cumene took place more effi cient over the directly-synthesized MCM-56 [ 128,129 ] or the post-modifi ed MCM-56 analogue [ 130 ] than conventional MCM-22 catalyst, and the deactivation rate was quite slow, probably because the active sites on external surface were more open to outside and did not get infl uenced by the micropore blockage. In comparison to the common view that the catalytic reactions mainly occurred inside zeolite channels, the external surfaces of MWW zeolite were highly active for the synthesis of ethylbenzene and cumene.…”

Section: Acid-catalyzed Reactionsmentioning

confidence: 99%

“…Taking advantages of large external surface, the delaminated ITQ‐2 exhibited superior catalytic activity in the alkylation of biphenyl and benzene with propylene . Similarly, the alkylation of benzene to ethylbenzene and cumene took place more efficient over the directly‐synthesized MCM‐56 or the post‐modified MCM‐56 analogue than conventional MCM‐22 catalyst, and the deactivation rate was quite slow, probably because the active sites on external surface were more open to outside and did not get influenced by the micropore blockage. Expected for Friedel‐Crafts alkylation, the delaminated Al‐MWW, prepared by the exfoliation of ERB‐1P and Al substitution, was reported to facilitate the formation of 1‐acetyl‐2‐methoxynaphthalene in the Friedel‐Crafts acylation of 2‐methoxynaphthalene with acetic anhydride .…”

Section: Catalytic Applications Of Layered Zeolite Materialsmentioning

confidence: 99%

Recent Advances in the Synthesis and Application of Two‐Dimensional Zeolites

Sun

2016

Advanced Energy Materials

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traditional hydrothermal syntheses would produce intermediate materials with 2D feature, such as MCM-22P, [ 7,8 ] PREFER, [ 9 ] which are composed of crystalline zeolite layers with the unit-cell thickness stacking on top of each other in ordered or disordered patterns. [10][11][12][13][14][15] Unlike traditional 3D zeolites, the crystal growth of frameworks in 2D layered zeolites is restricted in one particular direction, leaving lots of hydroxyl groups on layer surface. As zeolites are normally defi ned as 3D materials that possess regular micropore systems and consist of TO 4 tetrahedra, layered zeolite precursors containing silanols could not be regarded as zeolites in the strictest sense, but they are broadly included in the family of zeolite materials. Thus, the as-synthesized 2D zeolites are often denoted as layered zeolite precursors (the typical examples are shown in Table 1 ), [7][8][9] which would transform into their 3D order/disorder counterparts after removing organic molecules and condesation of interlayer silanols via calcination. [ 10 ] In the early research stage, the layered zeolite precursors are discovered accidentally in traditional hydrothermal syntheses, because we have limited control over the traditional synthesis process due to the incomplete understanding of crystallization mechanism. At that stage, one of the most attractive features of 2D zeolites is that they could transform into zeolite materials with hierarchical architectures. In some cases, the traditional synthesis produces hierarchical layered material, such as MCM-56, [ 26 ] in which the crystalline zeolite layers disorderly stacked. Furthermore, the recognition that the obtained layered precursors could be modifi ed into various hierarchical zeolite structures (such as delaminated, pillared, interlayer expanded and others) make them signifi cantly different from conventional 3D zeolite materials with rigid structures. Thus, the construction of hierarchical zeolite materials from the perspective of 2D layered zeolite precursors is an important research aspect during the past few years.With the improved synthetic techniques, layered zeolites are not only increasing in number, but also expanding the notion in composition and structure. One remarkable breakthrough in recent years is the discovery of 2D MFI nanosheets with the single unit-cell thickness (about 2 nm), which is achieved by adopting Gemini-type bifunctional surfactants as organic structure-directing agent (OSDA) in hydrothermal synthesis. [ 49 ] The calcined MFI nanosheets become a special kind of hierarchical zeolites Two-dimensional (2D) zeolites, originating from lamellar precursors, are a special kind of porous materials, in which crystalline zeolite nanolayers are weakly assembled in one particular direction. As there is no covalentbond between layers, the stacking sequences could be manipulated and possibly controlled to derive a family of zeolitic materials with structural diversity. The research on 2D zeolites arises from the primary casual discovery during ...

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Zeolite UZM-8: Synthesis, Characterization, and Catalytic Properties in Isopropylation of Benzene with 2-Propanol

Cited by 21 publications

References 24 publications

Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

Quantification of external surface and pore mouth acid sites in unit-cell thick pillared MFI and pillared MWW zeolites

2D Oxide Nanomaterials to Address the Energy Transition and Catalysis

Recent Advances in the Synthesis and Application of Two‐Dimensional Zeolites

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