Preparation, Solid‐state Characteristics, and Catalytic Properties of Promoted Vanadium Phosphate Materials

Narayana, K.V.; Martin, Andreas; Lcke, B.; Belmans, Marc; Boers, F.; Deynse, D. van

doi:10.1002/zaac.200400246

Cited by 15 publications

(13 citation statements)

References 27 publications

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“…[5] should be used; a comparison of eqs. [4] and [5] shows that the second moment of an A 2 spin system is 9/4 times greater than that of an AX spin system. In Table 2, we have collected various second moments calculated from the structure of b-VOPO 4 .…”

Section: ½4mentioning

confidence: 95%

“…For the homonuclear case, eq. [4] is only strictly valid if the spins in the pair-wise summation behave as an A 2 spin system; otherwise, if the chemical shift difference becomes greater than the dipolar coupling, the spin system may behave similarly to a heteronuclear spin pair and eq. [5] should be used; a comparison of eqs.…”

Section: ½4mentioning

confidence: 98%

“…39,40 As part of our efforts to investigate the VPO system via solid-state NMR methods, the objective of the present study is the 31 P solid-state NMR characterization of b-VOPO 4 as a prototype of diamagnetic vanadyl phosphates. This is the most stable phase of VOPO 4 , and its presence in catalyst systems has been detected by several groups. 9,41-46 The 31 P NMR properties of b-VOPO 4 have been investigated by other workers in the field, but the spectra were partly misinterpreted or obtained under conditions inappropriate to reveal NMR spectroscopic details.…”

Section: Introductionmentioning

confidence: 96%

“…This is the most stable phase of VOPO 4 , and its presence in catalyst systems has been detected by several groups. 9,41-46 The 31 P NMR properties of b-VOPO 4 have been investigated by other workers in the field, but the spectra were partly misinterpreted or obtained under conditions inappropriate to reveal NMR spectroscopic details. 13,14,[47][48][49] Using 31 P spin-echo mapping, Li et al 49 reported for a static powder sample of b-VOPO 4 a peak centered near 0 ppm, with a width of about 100 ppm (B 0 = 7.05 T), corresponding to ca.…”

Section: Introductionmentioning

confidence: 96%

“…Amongst them, vanadyl phosphates (VPOs) found industrial applications as selective and efficient heterogeneous catalysts in the mild oxidation of alkanes or alkenes or in ammoxidation reactions. [2][3][4] One of the most striking reactions catalyzed by VPOs, dubbed the "Butox" process, 5 is the oxidation of n-butane to maleic acid anhydride, recognized as probably the most complex selective oxidation reaction used in industry. 2,[6][7][8] In light of its technical importance, it is no surprise that a manifold of analytical methods, including theoretical investigations, has been employed to study partial aspects of this process such as the actual catalyst materials or the reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions

Eichele

GrimmerArnd-Rüdiger

2011

Can. J. Chem.

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Field-dependent 31 P solid-state NMR studies demonstrate that the line shape in spectra of b-VOPO4 depends on 51 V-31 P direct and indirect spin-spin interactions (M 2 ( 51 V, 31 P) = 101(23) × 10 6 rad 2 s -2 , 2 J iso ( 51 V, 31 P) = 48(5) Hz) and, to a lesser extent, on 31 P chemical shift anisotropy (d iso = -10.4(2), U = d 11 -d 33 = 22(2) ppm) and 31 P-31 P interactions (M 2 ( 31 P, 31 P) = 6.7(1) × 10 6 rad 2 s -2 ). In contrast, homonuclear dipolar interactions play an important role for the field and spinning rate dependent 31 P spin-lattice relaxation via paramagnetic impurities (T 1 = 20-60 s). Vanadium-51 magic-angle spinning NMR spectra indicate a sizeable chemical shift anisotropy (d iso = -754(1), d 11 = -336(10), d 22 = -344(6), d 33 = -1581(8) ppm) and nuclear quadrupole interaction (c = 1.5(1) MHz, h = 0.35 (5)); the principal axis systems of both interactions are clearly not coincident, with an angle of 35(5)°between the greatest component of the electric field gradient tensor and d 33 .Résumé : Des études RMN du 31 P à l'état solide et dépendant du champ démontrent que la forme des raies dans les spectres du b-VOPO 4 dépend des interactions spin-spin directes et indirectes (M 2 ( 51 V, 31 P) = 101(23) × 10 6 rad 2 s -2 , 2 J iso ( 51 V, 31 P) = 48(5) Hz) et, à un degré moindre, sur l'anisotropie du déplacement chimique du 31 P (d iso = -10,4(2); U = d 11 -d 23 = 22(2) ppm) et aux interactions 31 P-31 P (M 2 ( 31 P, 31 P) = 6,7(1) × 10 6 rad 2 s -2 ). Par ailleurs, les interactions dipolaires homonucléaires jouent un rôle important pour la relaxation spin-réseau du 31 P qui varie avec le champ et la vitesse de rotation par le biais d'impuretés paramagnétiques (T 1 = 20-60 s). Les spectres RMN du vanadium à l'angle magique de rotation indiquent qu'il existe une anisotropie importante du déplacement chimique (d iso = -754(1), d 11 = -336(10), d 22 = -344(6), d 33 = -1581(8) ppm) et une interaction quadripolaire nucléaire (c = 1,5(1) MHz, h = 0,35(5)); il est clair que les axes principaux des systèmes des deux interactions ne coïncident pas, avec un angle de 35(5)°entre la composante principale du tenseur du gradient de champ électrique et d 33 .Mots-clés : spectroscopie RMN à l'état solide, RMN du 31 P, RMN du 51 V, relaxation spin-réseau, couplage spin-spin nucléaire indirect, anisotropie du déplacement chimique, tenseur du gradient de champ électrique, phosphate de vanadyle.[Traduit par la Rédaction]

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Section: ½4mentioning

confidence: 95%

Section: ½4mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions

Eichele

GrimmerArnd-Rüdiger

2011

Can. J. Chem.

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Heterogeneously Catalyzed Ammoxidation: A Valuable Tool for One‐Step Synthesis of Nitriles

2010

Self Cite

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Ammoxidation is a partial oxidation with selective insertion of nitrogen into a methyl group (aldehyde or alcoholic groups are also able to react) that is in the α‐position to double bonds of olefinic, aromatic or heteroaromatic hydrocarbons to produce corresponding nitriles. The reaction is accelerated by heterogeneous catalysis and carried out in continuous process, in general. The heterogeneously catalyzed ammoxidation of various hydrocarbons to synthesize a wide range of industrially important nitriles has been the subject of great interest in recent times because nitriles are very useful basic chemicals (e.g. acrylonitrile) and organic intermediates (e.g. nicotinonitrile) used in the manufacture of numerous value‐added fine chemicals. The reaction proceeds with H abstraction from the methyl group, leading to an allylic or benzylic intermediate that reacts with catalyst lattice oxygen to form an oxygen‐containing intermediate through the Mars–van Krevelen mechanism. Nitrogen insertion seems to be due to adsorbed N species. Finally, nitrile formation occurs via an imine intermediate. Alkanes could be converted in a similar way, albeit with catalysts that possess a dehydrogenation function to give rise to the intermediate allylic species. Furthermore, ammoxidation is a very “green” reaction because oxygen or air is used as oxidant and water is generally the only byproduct. The ammoxidation reaction is used in the production of large‐scale chemicals, such as acrylonitrile, as well as that of intermediates, specialty chemicals, and fine chemicals in the agrochemical, health, and nutrition industries. The reaction is mostly carried out in the gas phase using supported transition metal oxides as catalysts. The most important advantage is that the ammoxidation is a simple, single‐step, eco‐friendly reaction. Nevertheless, one bottleneck is that only less‐functionalized reactants can be converted; that is, higher substituted molecules are often subject to side‐reactions. However, at present, ammoxidation is indeed a lucrative field of study, which has recently found much wider application in industry and hence will in years to come continue to offer exceptional commercial rewards for the production of industrially important nitriles.

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Neues Zentrum für Angewandte Katalyseforschung: Institute aus Berlin und Rostock fusionieren zum Leibniz‐Institut für Katalyse e. V. an der Universität Rostock

Zapf

Rosenthal

2006

Chemie Ingenieur Technik

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Preparation, Solid‐state Characteristics, and Catalytic Properties of Promoted Vanadium Phosphate Materials

Cited by 15 publications

References 27 publications

Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions

Phosphorus-31 and vanadium-51 solid-state nuclear magnetic resonance spectroscopy of β-vanadyl phosphate — Effects of homo- and heteronuclear spin-spin, electrostatic, and paramagnetic interactions

Heterogeneously Catalyzed Ammoxidation: A Valuable Tool for One‐Step Synthesis of Nitriles

Neues Zentrum für Angewandte Katalyseforschung: Institute aus Berlin und Rostock fusionieren zum Leibniz‐Institut für Katalyse e. V. an der Universität Rostock

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