The thermal decomposition of ammonium heptamolybdate

Hanafi, Z. M.; Khilla, M. A.; Askar, Mustapha

doi:10.1016/0040-6031(81)85083-6

Cited by 43 publications

(15 citation statements)

References 6 publications

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“…In Figure 3, the IR absorption spectrum of AHM is shown. It is very similar to those previously reported for AHM and related compounds 9,23,39,40. An assignment of the absorption bands is given in Table 2.…”

Section: Resultssupporting

confidence: 87%

Structural Investigation of the Thermal Decomposition of Ammonium Heptamolybdate by in situ XAFS and XRD

2003

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The decomposition of ammonium heptamolybdate (AHM, (NH4)6Mo7O24*4H2O) was studied in situ by X-ray diffraction and X-ray absorption spectroscopy as well as by thermal analysis (TG/DTA). Decomposition conditions such as reactant atmospheres, (20% oxygen, 5% propene, 5% hydrogen, pure helium, and static air), heating rates and gas flow rates are varied to reveal their influence on the decomposition. The results obtained show that the reaction pathway is influenced by the partial pressure of the decomposition products in the gas phase. The partial pressure of the decomposition products, water and ammonia, at a given temperature, is influenced mainly by the reactant gas flow rate and the heating rate. Lowering the partial pressure of ammonia and water inhibits the crystallization of the intermediate ammonium tetramolybdate (ATM) and promotes the formation of the intermediate hexagonal

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Section: Resultssupporting

confidence: 87%

Structural Investigation of the Thermal Decomposition of Ammonium Heptamolybdate by in situ XAFS and XRD

2003

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“…1 26.722. The crystalline structure of the precursor was thus similar to that of ammonium paramolybdate [40], with a high proportion of Mo atoms. MoO 3 (Fig.…”

Section: Preparation Of the Catalystsmentioning

confidence: 90%

Investigation of a molybdenum-containing silica catalyst synthesized by the sol–gel process in heterogeneous catalytic esterification reactions using methanol and ethanol

Bail

Santos

Freitas

et al. 2013

Applied Catalysis B: Environmental

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“…The thermal decomposition of crystalline cobalt nitrate follows the scheme Ammonia is released and ammonium tetramolydate is formed in the second stage of the process (temperature range, 200-240°C). The third stage of the process (240-280°C) is associated with the formation of (NH 4 ) 2 O · 22MoO 3 intermediate [30]. A further rise in temperature to 370°C leads to the formation of molybdenum oxide(VI).…”

Section: Thermal Analysis Of the Samplesmentioning

confidence: 99%

Hydrocracking of vegetable oil on boron-containing catalysts: Effect of the nature and content of a hydrogenation component

et al. 2016

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Catalysts based on metals (Pt, Pd) and metal oxides (NiO, Co 3 O 4 , MoO 3 , WO 3 ), supported on the surface of borate containing aluminum oxide (B 2 O 3 -Al 2 O 3 ), in the hydrocracking of sunflower oil at a tem perature of 400°C, a pressure 4.0 MPa and a mass hourly space velocity MHSV 5.0 h -1 are compared. H 2 TPR and IR spectroscopy of adsorbed CO and ESDR show that the hydrogenation catalyst components are Pt 0 and Pd 0 , a mixture of Ni 2+ + Ni 0 , Co 2+ + Co 0 , or a mixture of the highest and partially reduced oxides of Mo and W. It is established that catalysts containing Pt, Pd, NiO and Co 3 O 4 , ensure complete oil hydrode oxygenation. The main oxygen removal reactions in Pt and Pd systems are decarboxylation and hydrode carbonylation. For catalysts with NiO and Co 3 O 4 , characteristic reactions are reduction and methanation. The highest yield of the diesel fraction was obtained on Pt/B 2 O 3 Al 2 O 3 catalysts with metal contents of 0.3-1.0 wt %. Along with n alkanes, the diesel fractions obtained on these catalysts include cycloalkanes and iso alkanes (up to around 40 wt %) and aromatic hydrocarbons present in trace amounts. Hydrocracking on the Pt system at 400°C for 20 h with MHSV of 1.0 h -1 produces a diesel fraction with a yield of at least 82.0 wt % and the content of iso alkanes at least 76.1 wt %.

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The thermal decomposition of ammonium heptamolybdate

Cited by 43 publications

References 6 publications

Structural Investigation of the Thermal Decomposition of Ammonium Heptamolybdate by in situ XAFS and XRD

Structural Investigation of the Thermal Decomposition of Ammonium Heptamolybdate by in situ XAFS and XRD

Investigation of a molybdenum-containing silica catalyst synthesized by the sol–gel process in heterogeneous catalytic esterification reactions using methanol and ethanol

Hydrocracking of vegetable oil on boron-containing catalysts: Effect of the nature and content of a hydrogenation component

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