Reactivity of molybdovanadophosphoric acids: Influence of the presence of vanadium in the primary and secondary structure

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1280· OSTI ID:5223959

Casarini, D; Centi, G; Lena, V; Tvaruzkova, Z ^[1]; Jiru, P ^[2]

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1. Universita di Bologna (Italy)
2. J. Heyrovsky Institute of Physical Chemistry and Electrochemistry, Prague (Czech Republic)

The catalytic behavior in butadiene and n-butane oxidation of molybdovanadophosphoric acids with vanadium localized inside the primary (oxoanion) and/or the secondary structure is reported. The samples are characterized by infrared, [sup 31]P-NMR, [sup 51]V-NMR, and UV-visible diffuse reflectance spectroscopies in order to obtain information on the nature and localization of vanadium in the samples before reaction and the possible changes occurring during the course of the catalytic reaction. In particular, it is shown that vanadium localized initially in the secondary structure can exchange with the molybdenum atoms of the oxoanion during the catalytic reaction. Introduction of vanadium in the molybdophosphoric acid structure enhances the selective formation of maleic anhydride from the butadiene when vanadium is present both inside the oxoanion or localized in the secondary structure (before the catalytic tests), but the maximum in catalytic performance is found for different amounts of vanadium, depending on where the vanadium is localized initially. However, when present in the secondary structure, vanadium also has a negative influence on the activity of the heteropoly acid. On the contrary, in n-butane oxidation, the presence of vanadium enhances the rate of alkane activation due to the different rate-determining step. The presence of V ions also affects the maximum selectivity and yield to maleic anhydride from butane. V ions in the secondary structure are more selective at low conversion, while V ions inside the oxoanion are more selective at higher conversions and thus allow better maximum yields to maleic anhydride. 40 refs., 11 figs., 2 tabs.

• OSTI ID: 5223959
• Journal Information: Journal of Catalysis; (United States), Vol. 143:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
10 SYNTHETIC FUELS
BUTADIENE
OXIDATION
BUTANE
MOLYBDOPHOSPHORIC ACID
CATALYTIC EFFECTS
VANADIUM COMPOUNDS
ABSORPTION SPECTROSCOPY
CHEMICAL REACTION YIELD
NUCLEAR MAGNETIC RESONANCE
PHOSPHORUS 31
REACTIVITY
VANADIUM 51
ALKANES
CHEMICAL REACTIONS
DIENES
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MOLYBDENUM COMPOUNDS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
POLYENES
REFRACTORY METAL COMPOUNDS
RESONANCE
SPECTROSCOPY
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
VANADIUM ISOTOPES
YIELDS
400201* - Chemical & Physicochemical Properties
100200 - Synthetic Fuels- Production- (1990-)