Heteropoly compounds in ammoxidation of methylpyrazine

Бондарева, В. М.; Андрушкевич, Т. В.; Detusheva, L. G.; Litvak, G. S.

doi:10.1007/bf00814475

Cited by 27 publications

(14 citation statements)

References 13 publications

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“…Interestingly, dehydration of Keggin-type HPA at elevated temperature and formation of PW 12 O 38.5 have previously been reported [31,32]. Such behavior has also been observed for H 3 PMo 12 O 40 and ascribed to the loss of lattice oxygen and formation of PMo 12 O 38.5 species [33]. The exothermic peak at 730 • C is attributed to decomposition of HPA to phosphorus and tungsten oxides in accordance with XRD analysis.…”

Section: Properties Of Bulk Hpasupporting

confidence: 62%

Adsorption of Wells–Dawson tungsten heteropolyacid on sol–gel alumina: Structural features and thermal stability

Tarlani

Abedini

Khabaz

et al. 2005

Journal of Colloid and Interface Science

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Section: Properties Of Bulk Hpasupporting

confidence: 62%

Adsorption of Wells–Dawson tungsten heteropolyacid on sol–gel alumina: Structural features and thermal stability

Tarlani

Abedini

Khabaz

et al. 2005

Journal of Colloid and Interface Science

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“…These bands being the characteristic bands of AMPA could be assigned to NH + 4 , P=O, Mo-O t groups, respectively. 13 The main feature of FTIR spectra of these catalysts was increase in intensity of all the bands upon increase in loading from 5 to 25 wt%. It is worth mentioning here that in the spectra of catalysts with low AMPA loading (5-15 wt%), bands corresponding to P=O and Mo=O were seen as broad humps.…”

Section: Fourier Transform Infrared Spectramentioning

confidence: 95%

“…However, these catalysts required high reaction temperatures (close to 430 • C), for this reaction which normally leads to thermal runaway since the highly exothermic oxidation of ammonia starts dominating under these conditions. In order to moderate the reaction conditions, Bondareva et al 13 employed vanadium-containing MPA as catalyst at lower reaction temperatures (380-390 • C) and achieved about 75% CP yield. They reported the formation of AMPA in the catalysts after the reaction, even though the fresh catalysts were in the acid form.…”

Section: Introductionmentioning

confidence: 99%

Ammoxidation of 2-methyl pyrazine on supported ammonium salt of 12-molybdophosphoric acid catalysts: The influence of nature of support

et al. 2014

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Influence of the nature of support on the formation of catalytically active species was investigated to clarify the key factor for the synthesis of supported ammonium salt of 12-molybdophosphoric acid (AMPA) catalyst which maintains the activity of ammoxidation during 2-methylpyrazine reaction. With this aim, different loadings of niobia-, silica-and alumina-, supported AMPA catalysts were prepared. The AMPA loading was varied in the range of 5-25 wt%. The synthesized solids were characterized by nitrogen adsorption for BET surface area, XRD and 31 P MAS NMR techniques. All the AMPA-supported samples are poorly crystalline even after 25 wt% AMPA loading. Investigations using 31 P MAS NMR spectroscopy of samples revealed that Keggin ion existed as at least five different species on the supports. The investigated properties were acidity of the support and amount of AMPA loading on the support. Active sites for the ammoxidation of MP on supported AMPA catalysts seem to be the interacted and/or the lacunary species. Maximum catalytic activity could be obtained at lower loadings with AMPA deposited on acidic supports whereas the less acidic supports require higher loading. It was found that in order to efficiently generate the active interactive species, the support must have an acidity which promotes the formation of support-AMPA interactive species. It is possible to enhance the catalytic activity of the supported AMPA catalyst for ammoxidation of 2-methylpyrazine by controlling the acidity of the support and AMPA loading on the support.

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“…The second and the new class of low temperature ammoxidation catalysts includes the 12-molybdophosphoric acid and its ammonium salt. Bondareva et al [33] have suggested the use of V-containing heteropoly compounds as catalysts for the ammoxidation of MP and obtained a maximum CP selectivity of ca. 70% at 90% conversion.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Ammoxidation Functionality of Silica Supported Vanadium Incorporated Ammonium Salt of 12-Molybdophosphoric Acid Catalyst

et al. 2007

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A series of silica supported vanadium incorporated ammonium salts of 12-molybdophosphoric acid (AMPV) catalysts, with 5-25 wt% of active component were prepared. These catalysts were characterized by XRD, FTIR, BET-Surface Area, TGA/DTA and acidity by potentiometry techniques. The characterization data derived from XRD, FT-IR techniques reveal that the AMPV on silica support exists in the form of Keggin structure. These catalysts are studied for the vapor phase ammoxidation of 2-methyl pyrazine (MP) to cyanopyrazine (CP). The conversion of methyl pyrazine increased with increase in loading on silica showing a maximum value of conversion at 20 wt% AMPV loading. The ammoxidation activity of these catalysts with and without vanadium is studied and the vanadium incorporation led to substantial improvement in the cynopyrazine selectivity.

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Heteropoly compounds in ammoxidation of methylpyrazine

Cited by 27 publications

References 13 publications

Adsorption of Wells–Dawson tungsten heteropolyacid on sol–gel alumina: Structural features and thermal stability

Adsorption of Wells–Dawson tungsten heteropolyacid on sol–gel alumina: Structural features and thermal stability

Ammoxidation of 2-methyl pyrazine on supported ammonium salt of 12-molybdophosphoric acid catalysts: The influence of nature of support

Synthesis, Characterization and Ammoxidation Functionality of Silica Supported Vanadium Incorporated Ammonium Salt of 12-Molybdophosphoric Acid Catalyst

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