Influence of the Generation of Mesopores on the Hydroisomerization Activity and Selectivity of n-Hexane over Pt/Mordenite

Tromp, Moniek; Bokhoven, Jeroen A. van; Oostenbrink, M.T. Garriga; Bitter, Johannes H.; Jong, K.P. de; Koningsberger, D.C.

doi:10.1006/jcat.1999.2778

Cited by 124 publications

(84 citation statements)

References 8 publications

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“…Likely, the dealumination should lead to side pockets enlargement to contain the antibiotic heterocycle, and this can occur assuming a merging of vicinal pockets with part of the main channel [1]. The accessibility of bulky molecules as iso-propylamine or tert-butyl pyridine to mordenite side pockets has been observed after dealumination of mordenite [44,45].…”

mentioning

confidence: 99%

Adsorption and reaction of sulfachloropyridazine sulfonamide antibiotic on a high silica mordenite: A structural and spectroscopic combined study

Martucci

Cremonini

Blasioli

et al. 2013

Microporous and Mesoporous Materials

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a b s t r a c tOwing to their acidic nature, sulfonamide antibiotics concentrate in anionic form in water bodies where they can remain unchanged for long periods of time, accounting for great concern for antibiotic-resistance issues. In this study the removal of sulfachloropyridazine (4-amino-N-(6-Cl-3-pyridazinyl)benzene sulfonamide) antibiotic from water by adsorption on a high silica mordenite with channel window dimension comparable to that of the antibiotic, and with a significant concentration of internal silanol groups due to the dealumination process, was investigated. The adsorption of sulfachloropyridazine by mordenite at room temperature was completed within 4 h with the maximal amount of adsorbed antibiotic of 15.1% zeolite dry weight. The desorption trials elucidated the irreversibility of the adsorption process. The embedding of sulfachloropyridazine into mordenite channels was confirmed by a combined XRPD and FTIR study. Rietveld structure refinement revealed that the incorporation of sulfachloropyridazine molecules caused changes in the dimension of the zeolite channel systems, when compared to the parent zeolite, and a close vicinity of the heterocycle ring nitrogen to the oxygens of mordenite side pocket. FTIR revealed a strong perturbation of the vibrational modes of both the pyridazinyl ring and mordenite silanol groups upon antibiotic adsorption. When the adsorption was conducted at 65°C, an unfavourable temperature effect was highlighted and, interestingly, sulfachloropyridazine transformed with 100% selectivity to 4-amino-N-(6-hydroxyl-3-pyridazinyl)benzene sulfonamide. A nucleophilic aromatic substitution (S N Ar) mechanism was suggested for the formation of the reaction product. It is proposed that the H-bond between mordenite silanol groups and pyridazine nitrogen atom, clearly detected by FTIR, stabilize in the ring partial positive charges favouring the displacement of the chloride leaving group.

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confidence: 99%

Adsorption and reaction of sulfachloropyridazine sulfonamide antibiotic on a high silica mordenite: A structural and spectroscopic combined study

Martucci

Cremonini

Blasioli

et al. 2013

Microporous and Mesoporous Materials

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“…Zeolites with mesoporous structure have a beneficial effect in reactions such as slurry-phase reactions where the diffusion is much slower than for gas-phase reactions. Slurry-phase catalytic cracking and isomerization of n-hexadecane exhibits pronounced activity enhancement using mesoporous zeolite as catalyst than the conventional zeolite [417,434]. Also, an enhancement of cumene cracking was obtained using mesopororous ZSM-5 [435].…”

Section: Crackingmentioning

confidence: 94%

Template-based syntheses for shape controlled nanostructures

Pérez-Page

et al. 2016

Advances in Colloid and Interface Science

130

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A variety of nanostructured materials are produced through template-based synthesis methods, including zerodimensional, one-dimensional, and two-dimensional structures. These span different forms such as nanoparticles, nanowires, nanotubes, nanoflakes, and nanosheets. Many physical characteristics of these materials such as the shape and size can be finely controlled through template selection and as a result, their properties as well. Reviewed here are several examples of these nanomaterials, with emphasis specifically on the templates and synthesis routes used to produce the final nanostructures. In the first section, the templates have been discussed while in the second section, their corresponding synthesis methods have been briefly reviewed, and lastly in the third section, applications of the materials themselves are highlighted. Some examples of the templates frequently encountered are organic structure directing agents, surfactants, polymers, carbon frameworks, colloidal sol-gels, inorganic frameworks, and nanoporous membranes. Synthesis methods that adopt these templates include emulsion-based routes and template-filling approaches, such as self-assembly, electrodeposition, electroless deposition, vapor deposition, and other methods including layer-by-layer and lithography. Templatebased synthesized nanomaterials are frequently encountered in select fields such as solar energy, thermoelectric materials, catalysis, biomedical applications, and magnetowetting of surfaces.

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“…In top-down approaches, mesopores are introduced after the zeolite has been synthesized, and it is usually achieved by extracting either Al or Si atoms from the zeolite framework. Common methods for demetallation include steaming [33][34][35][36][37][38][39][40], acid-leaching [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] and base treatment [47,48]. In bottom-up approaches, the mesopores are introduced in the framework during the synthesis.…”

Section: Introductionmentioning

confidence: 99%

One-pot synthesis of nano-crystalline MCM-22

Tempelman

Portilla

Martínez-Armero

et al. 2016

Microporous and Mesoporous Materials

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Nano-crystalline MCM-22 zeolite was synthesized in a one-pot procedure by the use of an organosilane (dimethyl-octadecyl-(3-trimethoxysilylpropyl)-ammonium chloride, TPOAC) in the zeolite synthesis gel. This crystal growth inhibition procedure introduced mesopores in the MCM-22 crystallites. The lower mechanical stability of the nano-crystalline MCM-22 zeolite compared with bulk MCM-22 can be countered to some extent by pillaring. The increased external surface of the microporous zeolite domains resulted in increased accessibility of the Brønsted acid sites, as followed from the better performance in liquidphase benzene alkylation with propylene as compared with bulk MCM-22. The increased accessibility of the internal acid sites in Mo-loaded hierarchical MCM-22 was also evident from the improved benzene selectivity during methane aromatization. Silylation of hierarchical Mo/MCM-22 was detrimental for the catalytic performance in MDA. The nano-crystalline MCM-22 has physico-chemical and catalytic properties intermediate between those of MCM-22 and ITQ-2 with the benefit over ITQ-2 that it can be synthesized in a single step.

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Influence of the Generation of Mesopores on the Hydroisomerization Activity and Selectivity of n-Hexane over Pt/Mordenite

Cited by 124 publications

References 8 publications

Adsorption and reaction of sulfachloropyridazine sulfonamide antibiotic on a high silica mordenite: A structural and spectroscopic combined study

Adsorption and reaction of sulfachloropyridazine sulfonamide antibiotic on a high silica mordenite: A structural and spectroscopic combined study

Template-based syntheses for shape controlled nanostructures

One-pot synthesis of nano-crystalline MCM-22

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