Catalytic selective oxidation of isobutane over Csx(NH4)3−xHPMo11VO40mixed salts

Jing, Fangli; Katryniok, Benjamin; Dumeignil, Franck; Bordes‐Richard, Elisabeth; Paul, Sébastien

doi:10.1039/c4cy00518j

Cited by 30 publications

(25 citation statements)

References 28 publications

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“…The increase of the surface areas with increasing Cs + content is observed for the samples prepared by two different ways, which is consistent with the results reported in the literature [18,19]. 3Cs-E and 3Cs-F are quite similar in chemical and phase compositions according to the characterizations of ICP-AES, FT-IR, XRD and NH 3 -TPD, however there is a remarkable disparity in the surface areas between them.…”

Section: Textural Properties Of the Calcined Compoundssupporting

confidence: 81%

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Zhang

Wang

et al. 2016

Catalysts

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Abstract:The composition, structural evolution and the related property variations of mixed cesium/ammonium acidic salts of heteropolyacids were investigated in detail by tracking and analyzing the initial precipitates, evaporation residues and the calcined products in their preparation process. Results show that V cannot completely enter the heteropolyanions in the initial precipitates when the Cs + added amount is low, and the increase in Cs + adding amount improves the substitution of V for Mo in the heteropolyanions. Both the initial precipitates and the evaporation residues are mixtures of cesium and ammonium salts of heteropolyacids before calcination. Thermal treatment causes the decomposition of the ammonium salts and the formation of single-phase solid solutions from mechanical mixtures. The calcined products of the initial precipitates and the evaporation residues vary greatly in textural properties. The determinants of the catalytic performance for the oxidation of methacrolein to methacrylic acid are acidity and specific surface area of the compounds. The increase in specific surface area mainly improves the conversion of methacrolein, but not the selectivity of methacrylic acid. Insufficient acidity caused by high Cs + content in the compounds is responsible for the low selectivity.

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Section: Textural Properties Of the Calcined Compoundssupporting

confidence: 81%

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Zhang

Wang

et al. 2016

Catalysts

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“…1, all the samples exhibit three strong diffraction peaks at 2q ¼ $10 , 18-26 and 28-36 , which are characteristic of the Keggin structure. 23 vibrations, respectively; these are constant with the Keggin structure of the heteropolyanion. 25 The spectra also have two small absorption peaks at 1416 and 1030 cm À1 , which are respectively attributed to the N-H deformations of the NH 4 + cations and V]O of the vanadyl species of [PMo 11 VO 40 ] Keggin units.…”

Section: Resultsmentioning

confidence: 99%

Deep oxidative desulfurization catalyzed by (NH₄)_xH_4−xPMo₁₁VO₄₀(x = 1, 2, 3, 4) using O₂as an oxidant

Liao

Geng

et al. 2017

RSC Adv.

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“…At room temperature (R.T.), the diffraction lines of the cubic structure typical of Keggin-type heteromolybdates were found at 2θ = 10.8°, 18.8°, 24.3°, 26.6°, 30.9°, 36.3° and 39.6° [21,22]. The presence of (NH4)3HPMo11VO40 was demonstrated by the two characteristic lines, which clearly appeared at 2θ = 15.3° and 21.7° (triangle down in Figure 2).…”

Section: Temperature-programmed Xrd In Airmentioning

confidence: 99%

“…The catalytic selective oxidation of isobutane to methacrolein and methacrylic acid was performed in a fixed-bed reactor at atmospheric pressure [21]. The catalyst (0.8 g), diluted with an equal volume of SiC (0.21 mm particle size), was loaded in a stainless-steel reactor, which was then heated up to the reaction temperature (340 °C) with a ramp of 5 °C /min under airflow (10 mL/min).…”

Section: Catalytic Oxidation Of Isobutanementioning

confidence: 99%

Structural Evolution under Reaction Conditions of Supported (NH4)3HPMo11VO40 Catalysts for the Selective Oxidation of Isobutane

et al. 2015

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When using heteropolycompounds in the selective oxidation of isobutane to methacrolein and methacrylic acid, both the keeping of the primary structure (Keggin units) and the presence of acidic sites are necessary to obtain the desired products. The structural evolution of supported (NH4)3HPMo11VO40 (APMV) catalysts under preliminary thermal oxidizing and reducing treatments was investigated. Various techniques, such as TGA/DTG (Thermo-Gravimetric Analysis/Derivative Thermo-Gravimetry), H2-TPR (Temperature Programed Reduction), in situ XRD (X-Ray Diffraction) and XPS (X-ray Photoelectron Spectroscopy), were applied. It was clearly evidenced that the thermal stability and the reducibility of the Keggin units are improved by supporting 40% APMV active phase on Cs3PMo12O40 (CPM). The partial degradation of APMV takes place depending on temperature and reaction conditions. The decomposition of ammonium cations (releasing NH3) leads to the formation of vacancies favoring cationic exchanges between vanadium coming from the active phase and cesium coming from the support. In addition, the vanadium expelled from the ) to activate isobutane. The increase in reducibility of the supported catalyst is assumed to improve the catalytic performance in comparison with those of unsupported APMV.

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Catalytic selective oxidation of isobutane over Cs_x(NH₄)_3−xHPMo₁₁VO₄₀mixed salts

Cited by 30 publications

References 28 publications

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Deep oxidative desulfurization catalyzed by (NH₄)_xH_4−xPMo₁₁VO₄₀(x = 1, 2, 3, 4) using O₂as an oxidant

Structural Evolution under Reaction Conditions of Supported (NH4)3HPMo11VO40 Catalysts for the Selective Oxidation of Isobutane

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Catalytic selective oxidation of isobutane over Csx(NH4)3−xHPMo11VO40mixed salts

Cited by 30 publications

References 28 publications

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Deep oxidative desulfurization catalyzed by (NH4)xH4−xPMo11VO40(x = 1, 2, 3, 4) using O2as an oxidant

Structural Evolution under Reaction Conditions of Supported (NH4)3HPMo11VO40 Catalysts for the Selective Oxidation of Isobutane

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Catalytic selective oxidation of isobutane over Cs_x(NH₄)_3−xHPMo₁₁VO₄₀mixed salts

Deep oxidative desulfurization catalyzed by (NH₄)_xH_4−xPMo₁₁VO₄₀(x = 1, 2, 3, 4) using O₂as an oxidant