Simultaneous Quantification of Brønsted- and Lewis-Acid Sites in a USY Zeolite

Sutovich, Kevin J.; Peters, Alan W.; Rakiewicz, Edward F.; Wormsbecher, Richard F.; M, Mattingly, Susan; Mueller, Karl T.

doi:10.1006/jcat.1998.2379

Cited by 46 publications

(40 citation statements)

References 8 publications

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“…94 Trimethylphosphine oxide (TMPO) was used by Mueller's group to direct and simultaneous quantification of the Brønsted and Lewis-acid site content in USY zeolite via 31 P MAS NMR spectroscopy. 94,95 Zhao et al reported an approach to qualitatively and quantitatively characterize the internal and external acidic sites in zeolites using different adsorbed probe molecules namely TMP oxide (TMPO) and tributylphosphine oxide (TBPO) by the combination of MAS NMR spectroscopy and elemental analysis. 96,97 Although there are many factors that influence the 31 P chemical shift in these complexes, one primary source is due to electronic changes in the probe molecule leading to a change in the local magnetic field around the nucleus.…”

Section: Trimethylphosphine Oxidementioning

confidence: 99%

“…Since our laboratory 110 first reported that methane can be transformed into aromatics and H 2 on the MoO 3 /HZSM-5 catalyst in the absence of oxygen in 1993, the methane dehydroaromatization (MDA) reaction has been extensively investigated. [111][112][113] Our work on the applications of solid-state NMR in this reaction can be summarized as follows: (a) interaction between Mo species and zeolite support, (b) direct observation of the active site by ultrahigh field 95 Mo NMR, (c) investigation of the catalytic process. H MAS NMR demonstrated that the Mo species might migrate into the lattice channels of HZSM-5 zeolite during the impregnation and subsequent treatment.…”

Section: 24mentioning

confidence: 99%

“…66,[115][116][117] However, it is unclear whether the active molybdenum species are small crystallites or isolated exchanged species. Zheng et al employed ultrahigh-field 95 Mo NMR spectroscopy at 21.1 T to recognize different types of molybdenum species on the Mo/HZSM-5 catalyst. 118,119 The left side of Fig.…”

Section: 24mentioning

confidence: 99%

“…118,119 The left side of Fig. 6 shows the static 95 Mo NMR spectra of MoO 3 and the activated catalyst. Compared with MoO 3 , the spectrum of 2Mo/HZSM-5 has a much broader peak centered at about À250 ppm, spanning from about À639 to 168 ppm (Fig.…”

Section: 24mentioning

confidence: 99%

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In situsolid-state NMR for heterogeneous catalysis: a joint experimental and theoretical approach

et al. 2012

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In situ solid-state NMR is a well-established tool for investigations of the structures of the adsorbed reactants, intermediates and products on the surface of solid catalysts. The techniques allow identifications of both the active sites such as acidic sites and reaction processes after introduction of adsorbates and reactants inside an NMR rotor under magic angle spinning (MAS). The in situ solid-state NMR studies of the reactions can be achieved in two ways, i.e. under batch-like or continuous-flow conditions. The former technique is low cost and accessible to the commercial instrument while the latter one is close to the real catalytic reactions on the solids. This critical review describes the research progress on the in situ solid-state NMR techniques and the applications in heterogeneous catalysis under batch-like and continuous-flow conditions in recent years. Some typical probe molecules are summarized here to detect the Brønsted and Lewis acidic sites by MAS NMR. The catalytic reactions discussed in this review include methane aromatization, olefin selective oxidation and olefin metathesis on the metal oxide-containing zeolites. With combining the in situ MAS NMR spectroscopy and the density functional theoretical (DFT) calculations, the intermediates on the catalyst can be identified, and the reaction mechanism is revealed. Reaction kinetic analysis in the nanospace instead of in the bulk state can also be performed by employing laser-enhanced MAS NMR techniques in the in situ flow mode (163 references).

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Section: Trimethylphosphine Oxidementioning

confidence: 99%

Section: 24mentioning

confidence: 99%

Section: 24mentioning

confidence: 99%

Section: 24mentioning

confidence: 99%

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In situsolid-state NMR for heterogeneous catalysis: a joint experimental and theoretical approach

et al. 2012

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“…A novel solid-state 31 P MAS-NMR technique developed recently reveals the potency in simultaneous determination of the types and strengths of acid sites in solid acid catalysts using trimethylphosphine (TMP) [12][13][14][15] or trimethylphosphine oxide [16][17][18] as probes. From the viewpoint of NMR applications, since the 31 P nucleus possesses a higher sensitivity and a wider chemical shift range (>300 ppm) compared to 13 C and 15 N, thus these phosphorus molecules are advantageous over other conventional NMR probes, such as pyridine or methyl amine [19,20].…”

Section: Introductionmentioning

confidence: 99%