Butane Selective Oxidation to Maleic Anhydride Over VPO

1 n-Butane Selective Oxidation to Maleic Anhydride Over VPO 

Maleic anhydride (MA) is an important intermediate in the production of chemicals such as unsaturated polyester resins, lube oil additives, maleic copolymers and others [124]. Currently, MA is predominantly produced by the oxidation of butane, and all industrial catalysts for this reachon are based on vanadium phos- 

0 ) and the role of phosphorus enrichment remain under discussion [126, 128, 146-150]. 

Being relatively surface sensitive, XPS can contribute to an understanding of this catalytic system, and has already done so. It gives valuable information on the formal oxidation state and the stoichiometry of the constituents in the sampling depth of the technique. However, XPS investigations reported in the literature are 

This equation has been extensively accepted and applied, and thus comparison of various VPO materials in different publications has been possible (see Table 6.3). Although calculating the mean oxidation state of vanadium is exceptionally valuable (especially with spectra lacking resolution), it allows determination of the fraction of different contributions if only two oxidation states are present in the sample (i.e. it is not useful if V / V / V are simultaneously present). Furthermore, with a significantly high E contribution in the O Is line (from adsorbed water, OH groups and carbon-related O) the equahon will overeshmate the degree of reduchon of the formal vanadium valence. 

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