The solid-state thermal rearrangement of the Dawson anion [P2Mo18O62]6− into a Keggin-type [PMo12O40]3−-containing phase and their reactivity in the oxidative dehydrogenation of isobutyraldehyde

Hu, Jeremy; Burns, Robert C.; Guerbois, J. P.

doi:10.1016/s1381-1169(99)00273-3

Cited by 18 publications

(17 citation statements)

References 21 publications

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“…The use of isobutyraldehyde [15] and isobutyric acid [16,17] as feedstocks rather than isobutane has also been explored; however, the alkane is less expensive and hence preferred. Methacrolein is oxidized by heteropoly compounds to methacrylic acid [18][19][20][21][22][23], which in turn is readily esterified with methanol to yield methyl methacrylate [24].…”

Section: Introductionmentioning

confidence: 99%

Detailed product and kinetic analysis for the low-pressure selective oxidation of isobutane over phosphomolybdic acid

Kendell

Brown

2010

Reac Kinet Mech Cat

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The selective oxidation of isobutane over phosphomolybdic acid has been analyzed using a low-pressure steady-state technique. Observed products are methacrolein, 3-methyl-2-oxetanone (a lactone), acetic acid, carbon dioxide and water. These products form in two distinct fashions designated Categories 1 and 2. Category 1 is exclusively observed with methacrolein and is consistent with a Bulktype (II) process. The lactone and acetic acid are Category 2 products and these form by the Bulk-type (I) mechanism. A kinetic analysis of the distributions shows that the activation energy for Category 1 production (methacrolein) increases with experiment number (varying from 56.9 ± 1.5 to 149 ± 4 kJ mol -1 ) and indicates a temperature-induced structural degradation of phosphomolybdic acid. The Category 2 products are not similarly affected and this suggests that the structural degradation is restricted to the surface of phosphomolybdic acid.

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Section: Introductionmentioning

confidence: 99%

Detailed product and kinetic analysis for the low-pressure selective oxidation of isobutane over phosphomolybdic acid

Kendell

Brown

2010

Reac Kinet Mech Cat

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“…Their excellent thermal stability (Hu et al, 2000;Wu et al, 2005) also makes HPAs good candidates for application in catalysts and sensors that may require extreme environments.…”

Section: Introductionmentioning

confidence: 99%

Catalytic activation of C–H bonds of hydrocarbons by heteropolycompounds

Benlounes

Cheknoun

Mansouri

et al. 2011

Journal of the Taiwan Institute of Chemical Engineers

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“…The use of isobutyraldehyde [13] and isobutyric acid [14] as feedstocks rather than isobutane has also been explored, however the alkane is less expensive and hence preferred. Methacrolein is oxidized by heteropoly compounds to methacrylic acid [15][16][17][18][19][20], which in turn is readily esterified with methanol to yield methyl methacrylate [21].…”

Section: Introductionmentioning

confidence: 99%

Structural and Activity Investigation into Al3+, La3+ and Ce3+ Addition to the Phosphomolybdate Heteropolyanion for Isobutane Selective Oxidation

et al. 2010

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Twelve phosphomolybdate compounds were synthesized via cationic exchange and were of the form: M x H 3-3x [PMo 12 O 40 ] (M = Al, La or Ce; 0 B x B 1). These compounds were analyzed by XRD and adsorption isotherm. Aluminum addition causes a primitive cubic phase, while lanthanum and cerium yield body-centered structures. La and Ce addition reduces surface area of phosphomolybdate structure. Temperature-programmed experiments for the selective oxidation of isobutane yielded methacrolein, 3-methyl-2-oxetanone (lactone), acetic acid (not with aluminous compounds), propene (only with aluminous compounds), carbon dioxide and water. The preference for propene rather than acetic acid formation with Al 3? may be due to the smaller cation size, or primitive cubic structure. These products form via two distinct reaction processes, labeled categories 1 and 2. Category 1 formation is associated with isobutane forming products on the surface, but reaction rate determined by bulk migration of charged particles. Category 2 formation is concerned with isobutane penetrating deep within the bulk of the substrate and forming products which subsequently desorb in a series of bell-shaped humps. Methacrolein forms via both category 1 and 2, whilst all other products form via category 2 exclusively. Kinetic analysis showed apparent activation barriers for category 1 methacrolein formation range from 67 ± 2 kJ mol -1 to [350 kJ mol -1 , and occur in groups with small, medium and large activation barriers. The addition of ?3 metal cations to the phosphomolybdate anion increase thermal stability, significantly decreasing deactivation; IR spectroscopy shows that the Keggin structure remains intact during temperature-programmed experiments with the Al, La and Ce salts.

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The solid-state thermal rearrangement of the Dawson anion [P2Mo18O62]6− into a Keggin-type [PMo12O40]3−-containing phase and their reactivity in the oxidative dehydrogenation of isobutyraldehyde

Cited by 18 publications

References 21 publications

Detailed product and kinetic analysis for the low-pressure selective oxidation of isobutane over phosphomolybdic acid

Detailed product and kinetic analysis for the low-pressure selective oxidation of isobutane over phosphomolybdic acid

Catalytic activation of C–H bonds of hydrocarbons by heteropolycompounds

Structural and Activity Investigation into Al3+, La3+ and Ce3+ Addition to the Phosphomolybdate Heteropolyanion for Isobutane Selective Oxidation

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