Selective catalytic oxidation of lower alkanes

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A new preparation method to introduce promoter ions into the (VO)_2P_2O_7 crystal lattice was developed. A precipitate was obtained by the addition of a small amount of water to a blue isobutanol refluxing solution which contained reduced and dissolved V_2O_5 and the acetylacetonate of a promoter element. The catalyst which was prepared by the calcination of this precipitate, has the same composition as that of a starting solution. No evidence showing localization of the added promoter element, was obtained by the observation of the catalyst using EDX and WDX. ESCA depth profile of the component elements suggested the homogeneity between the surface and the bulk of the catalyst. There is a linear relationship between the activity of the catalysts for MA formation and position of IR V=O absorption bands of the catalysts containing promoter elements. The active sites of the catalysts for the oxidation are thought to be the surface V=O.It was found that metal pyrophosphates are effective for the partial oxidation of propane and iso-butane. Iso-butane was oxidized into iso-butane with the selectivity of >80% at 500-550ﾟC over Ni_2P_2O_7.