58834-75-6

Usage

Flammability and Explosibility

Nonflammable

InChI:InChI=1/3H4O7P2.4V/c3*1-8(2,3)7-9(4,5)6;;;;/h3*(H2,1,2,3)(H2,4,5,6);;;;/q;;;4*+3/p-12

Upstream product

• 86119-84-8 phosphoric acid 
• 80937-33-3 oxygen 
• 12054-39-6 oxo orthohydrogenphosphato vanadium (IV) 

Relevant academic research and scientific papers

HREM microstructural studies on the effect of steam exposure and cation promoters on vanadium phosphorus oxides: New correlations with n-butane oxidation reaction chemistry

In situ environmental high-resolution electron microscopy (in situ EHREM) under different gaseous environments and ex situ HREM have been used to directly probe commercially important vanadyl pyrophosphate ((VO)2P2O7) cata

A study of the kinetics and mechanism of the adsorption and anaerobic partial oxidation of n-butane over a vanadyl pyrophosphate catalyst

The interaction of n-butane with a (VO)2P2O7 catalyst was studied by TPD and temperature-programmed reaction. At low temperatures (223 and 423 K), n-butane adsorbed as a butyl-hydroxyl pair. For absorption at 223 K, some of the butyl-hydroxyl species recombined resulting in butane desorption at 260 K upon temperature programming. For adsorption at 423 K, the hydroxyl species of the butyl-hydroxyl pair migrated away from the butyl species, forming water that is detected in the gas phase. Butane did not desorb at 260 K after the temperature was reduced to 223 K under the butane/helium from the adsorption temperature of 423 K before temperature programming from that temperature to 1100 K under a helium stream. Anaerobic temperature-programmed oxidation of n-butane yielded butene and butadiene at a peak maximum temperature of 1000 K, the exact temperature at which, upon programming, oxygen evolves from the lattice and desorbs as O2. This, and the fact that the amount of oxygen desorbing from (VO)2P2O7 at ~ 1000 K is the same as that needed for n-butane oxidation to butene and butadiene, suggested that lattice oxygen as it emerges at the surface is a selective oxidant and that its appearance at the surface is the rate-determining step in the selective oxidation of n-butane. The surface of (VO)2P2O7 on which this selective oxidation occurred had nearly two monolayers of oxygen removed from it by unselective oxidation of n-butane to CO, CO2 and H2O at 550-950 K and had about one monolayer of carbon deposited on it at ~ 1000 K. The anaerobic oxidation of n-butane yielded butene and butadiene instead of maleic anhydride, showing that the mechanism of the n-butane oxidation to maleic anhydride is sequential.

Novel preparation of vanadyl pyrophosphate for selective oxidation of n-butane utilizing intercalation and exfoliation

Intercalation-exfoliation of VOPO4·2H2O crystallites (20 (μm in size) in 2-butanol, followed by reduction with 2-butanol, brought about thin layers of precursor, VOHPO4·O-5H2O, with size of about 2 μm. The obtai

Novel microstructures and reactivity for n-butane oxidation: Advances and challenges in vapor phase alkane oxidation catalysis

The development of novel and improved micro structures was presented for vanadium phosphorus oxide catalysts for the oxidation of n-butane to maleic anhydride (MA) by grafting alkoxides of bismuth and molybdenum on to pre-formed vanadium phosphorus oxide precursor, VO(HPO4)·0.5 H2O. The bismuth/molybdenum grafted catalysts showed no change in selectivity to MA at 40% conversion, when these catalysts were evaluated in an oxygen rich, 2% butane/air mixture. A general decrease in MA selectivity was observed with increasing levels of bismuth and molybdenum for this catalyst both in 2% butane/air and 9% butane/10% O2. The compositional gradient profile and the importance of the formation of a surface region depleted of some bismuth was further supported by the observation that catalysts prepared by co-precipitating the promoter cations with the vanadium phosphate precursor during precursor synthesis did not show a similar enrichment of molybdenum on the catalyst surface. Those systems exhibited smaller performance improvements, as a function of promoter level, than was observed for the supported catalyst systems. For those systems, the largest activity gains required higher levels of promoter cations and were accompanied by some loss in selectivity to MA.

Microstructures of V-P-O catalysts derived from VOHPO4·0. 5H2O of different crystallite sizes

The influence of crystallite size of precursor VOHPO4·0. 5H2O on the microstructure of a resulting catalyst and selective oxidation of n-butane are investigated. Two kinds of VOHPO4·0. 5H2O, small crystallites (av. 1 μm × 110 nm) and large crystallites (av. 10 μm × 415 nm), were prepared by intercalation-exfoliation-reduction of VOPO4·2H2O in 2-butanol and the direct reduction of VOPO4·2H2O with 2-butanol, respectively. The small VOHPO4·0.5H 2O crystallites transformed into single-phase (VO)2P 2O7 of high specific surface area under the reaction conditions of 1.5% n-butane, 17% O2, and He (balance) at 663 K. In contrast, the catalyst formed from the large VOHPO4·0.5H 2O crystallites assumed the form of particles having a double-layered structure, consisting of peripheral (VO)2P2O7 and internal αII-VOPO4. As compared with the large (VO)2P2O7, the small (VO)2P 2O7 showed high selectivity to maleic anhydride (～78% at 663 K) and higher catalytic activity. Meanwhile, the catalyst with the double-layered structure exhibited moderate selectivity (～70%). Since (VO)2P2O7 is considered to be a selective phase for the selective oxidation of n-butane, the single-phase of (VO) 2P2O7 derived from the small-sized VOHPO 4·0.5H2O crystallites is considered a reason for the high selectivity to maleic anhydride.

Redox features of β-VOPO4 catalyst using 18O tracer and laser Raman spectroscopy

The oxygen ions of the β-VOPO4 catalyst were exchanged with an 18O tracer by a reduction-oxidation method and by a catalytic oxidation of but-1-ene using 18O2. The bands at 992 and 900 cm-1 were more shifted to lower frequencies than those at 1076 and 1002 cm-1. Applying the correlation between the Raman bands and stretching vibrations in the literature, the exchanged oxygen species were estimated. The results suggest that the P-O-V vacancies corresponding to 992 and 900 cm-1 were responsible for reoxidation and the V=O oxygen corresponding to the 1002 cm-1 band of β-VOPO4 was not. The (VO)2P2O7 was oxidized to β-VOPO4 by O2 above 823 K. The insertion position of oxygen was determined at the bands at 992 and 900 cm-1 of β-VOPO4 using 18O2, which is the same as the exchanged position.

The oxygen isotopic exchange reaction on vanadium oxide catalysts

The reactivity of lattice oxygen of vanadium oxide catalysts was studied with the oxygen isotopic exchange reaction. The reactivity of pure V2O5 is compared with the reactivity of Li0.33V2O5, V2

Oxygen stoichiometry and the problem of the growth of (VO)2P2O7 single crystals

The crystal growth of (VO)2P2O7 single crystals is discussed with respect to the formation of a high-temperature nonstoichiometric phase (VO)2P2O7+x. The interaction between vanadyl pyrophosphate and oxygen was investigated in the temperature region 600-900 °C. It was found that the decay of the high-temperature nonstoichiometric phase at lower temperature led to imperfections in crystals grown in an atmosphere with oxygen concentration higher than 0.2%. Two mechanisms for the decay are considered. The oxygen content of the crystals may be reduced at the surface by evolution of gaseous oxygen, whereas in the bulk the formation of an oxygen-enriched solid phase is observed.

Permanent blockade of in situ-generated acid Bronsted sites of vanadyl pyrophosphate catalysts by pyridine during the partial oxidation of toluene

The permanent blockade of in situ-formed Bronsted-acid OH groups and an effective lowering of the catalyst acidity during the partial oxidation of toluene to benzaldehyde is demonstrated by an efficient method using a continuous dosing of pyridine to the feed that leads to drastically increased aldehyde selectivities.

Catalytic dehydration of glycerol over vanadium phosphate oxides in the presence of molecular oxygen

We report the dehydration of glycerol over vanadium phosphate oxide (VPO) catalysts. Catalytic reactions were conducted in a gas-phase fixed-bed reactor at temperatures from 250 to 350 °C with O2/glycerol ratios of 0-13.6. Hemihydrate VOHPOsub