Influence of layer structure preservation on the catalytic properties of the pillared zeolite MCM-36

Maheshwari, Sudeep; Martı́nez, Cristina; Portilla, M. Teresa; Llopis, Francisco J.; Corma, Avelino; Tsapatsis, Michael

doi:10.1016/j.jcat.2010.04.011

Cited by 74 publications

(72 citation statements)

References 37 publications

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“…22 The corresponding pore size distribution (PSD) was determined using the desorption branches of the isotherms by the Barrett-Joyner-Halenda (BJH) method. The t 1 increment was synchronized with the rotor period, and 16 steps were acquired with a recycle delay of 0.7 s. Solid-state 29 Si MAS NMR experiments were carried out at frequencies of 59.6 MHz, with a pulse width of 10 μs, a pulse delay of 50 s, and a spinning rate of 4 kHz on a Bruker DSX300 NMR spectrometer equipped with a commercial 4 mm MASprobe. The elemental analyses were determined using Electron Probe Micro Analysis (EPMA) in a JEOL JXA-8200 Electron Probe.…”

Section: Characterizationmentioning

confidence: 99%

“…Therefore, the 29 Si and 27 Al MAS NMR results corroborate each other so that the existing CTMABr, TPAOH and HMI agents in the 40Si/Ti-MCM-36ĲP) prevent leaching of the Al f in the T2 and T6 sites, which corresponds to the AP-40Si/Ti-MCM-36Ĳ6 h) having more strong acid sites than A-40Si/Ti-MCM-36Ĳ1 h), as shown in Fig. This is in agreement with the results that the swelling treatment partially dissolves the framework silica, breaks the Si-O-Si bond and generates the silanol groups as the defect sites.…”

Section: View Article Onlinementioning

confidence: 99%

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The influences of Al species and Ti species on the catalytic epoxidation over Si/Ti-pillared MCM-36 synthesized from MCM-22

Jin

Huang

Cheng

et al. 2015

Catal. Sci. Technol.

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A novel mesopore silica-aluminium material, i.e., Si/Ti-MCM-36 derivatives were prepared with Si/Ti mixed oxide as a pillar. The influences of acidity from Al species and the coordination state of Ti species on the catalytic cylcohexene epoxidation with t-butylhydroperoxide (TBHP) as the oxidant were investigated. The mesoporous structures were confirmed by XRD and N 2 ads/desorption experiment. The acidity and surface polarity were characterized by NH 3 -TPD, 27 Al 2D MQ MAS NMR and 29 Si MAS NMR. The Ti coordination state was identified with UV-Vis spectra. By using 27 Al 2D MQ MAS NMR technique, the Al species from the different eight crystallographically T (Si, Al) positions of MWW zeolite were identified, which are associated with bridging hydroxyl groups such as the Brønsted acid site. It was found that the Si/Ti-MCM-36 samples, whether with tetrahedrally (T d ) or octahedrally (O h ) coordinated state Ti species, are all inactive for the cyclohexene epoxidation. A further acid treatment of the Si/Ti-MCM-36 samples can greatly expel Al species from the MWW structure, which largely decrease the acidity and transfer the acid-catalyzed decomposition of t-butylhydroperoxide to Ti catalyzed cyclohexene epoxidation. It shows that not only the amount of Al species but also their framework crystallographic positions have a great influence on the epoxidation activity. Furthermore, the grafting of the tetra-isopropoxide on the acid treated Si/Ti-MCM-36 can increase its hydrophobicity and epoxidation activity. Moreover, the T d TiO 4 in the units has been confirmed to be the most active site for the epoxidation reaction.

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Section: Characterizationmentioning

confidence: 99%

Section: View Article Onlinementioning

confidence: 99%

The influences of Al species and Ti species on the catalytic epoxidation over Si/Ti-pillared MCM-36 synthesized from MCM-22

Jin

Huang

Cheng

et al. 2015

Catal. Sci. Technol.

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“…The MCM-41 can be synthesized by a variety of techniques, although the most common is the sol-gel hydrothermal method [28][29][30][31], using surfactants in the selfassembly processes that form the mesoporous materials [32][33][34]. In recent years, inorganic-organic hybrid materials have been attracted great interest because they have excellent properties [35].…”

Section: Introductionmentioning

confidence: 99%

Applications of inorganic–organic mesoporous materials constructed by self-assembly processes for removal of benzo[k]fluoranthene and benzo[b]fluoranthene

Costa

Garcia

Santos

et al. 2015

J Sol-Gel Sci Technol

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The mesoporous materials MCM-41 and the functionalized inorganic-organic material p-aminobenzoic acid-MCM-41 (PABA-MCM-41) were used as adsorbents to remove the PAHs benzo[k]fluoranthene and benzo[b]fluoranthene from aqueous media. Both MCM-41 and PABA-MCM-41 exhibited the hexagonal mesostructures typical of the M41S family, as confirmed by SAXS, with type IV isotherms and type H1 hysteresis. The materials showed uniform mesopore size distributions, high surface areas, and thermal stability. Adsorption tests showed that for both mesoporous materials, the quantity adsorbed (q e ) increased for higher initial PAH concentrations, and adsorption equilibrium was reached in around 90 min. The experimental kinetic data were fitted using the pseudosecond-order model, and the adsorption process could be described by the Langmuir isotherm. At higher temperatures, there were increases in the initial rates of adsorption and the kinetic constants for adsorption of the PAHs by PABA-MCM-41. The thermodynamic parameters indicated that the process was spontaneous, endothermic, and with a tendency toward disorder of the system at the adsorbent/adsorbate interface. The functionalization of MCM-41 increased the efficiency of adsorption of the PAHs by 44.5 and 32.0 % for benzo[k]fluoranthene and benzo[b]fluoranthene, respectively. Graphical Abstract Effect of contact time on adsorption of (a) B[k]F and (b) B[b]F by PABA-MCM-41. Conditions: 0.05 g of PABA-MCM-41, 5 mL of each PAH solution (concentration 200 lg L -1 ), temperature of 25°C, contact time of 300 min, and agitation at 150 rpm. 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 22.2 22.3 22.4 22.5 26.5 PAH (a) Benzo[k]fluoranthene (b) Benzo[b]fluoranthene Time (min) q e (µg g -1 )

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“…Among the resulting materials, pillared layered silicates are expected for the application of adsorption, catalysts, support of catalysts, molecular sieves, etc. Pillaring with polymeric silica or metal oxides such as titania, alumina and zirconia has been reported for various layered silicates, such as magadiite [2][3][4][5][6], kenyaite [7,8], octosilicate [9], MCM-22 [10][11][12][13], kanemite [14], kenyaite [15] and potassium layered silicate with kenyaitelike structure [16]. These pillared layered silicates are usually obtained by intercalation of polycations as precursors of pillars into interlayered regions of layered silicates and subsequent calcinations of the resulting materials.…”

Section: Introductionmentioning

confidence: 99%

Preparation of microporous pillared magadiite from silylated magadiite and their unique inclusion behaviors of organic molecules

Matsuo

Yamauchi

2013

Microporous and Mesoporous Materials

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Influence of layer structure preservation on the catalytic properties of the pillared zeolite MCM-36

Cited by 74 publications

References 37 publications

The influences of Al species and Ti species on the catalytic epoxidation over Si/Ti-pillared MCM-36 synthesized from MCM-22

The influences of Al species and Ti species on the catalytic epoxidation over Si/Ti-pillared MCM-36 synthesized from MCM-22

Applications of inorganic–organic mesoporous materials constructed by self-assembly processes for removal of benzo[k]fluoranthene and benzo[b]fluoranthene

Preparation of microporous pillared magadiite from silylated magadiite and their unique inclusion behaviors of organic molecules

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