Preparation of Catalyst Consisting of Cr₂O₃ and V₂O₅ and Its Characteristics

Abstract

It is known that catalysts prepared from ammonium metavanadate and chromium (III) nitrate contain X- and Y-phases besides vanadium (V) oxide and chromium (III) oxide. No data concerning the crystal structure and the compositions of these two phases have appeared in the literature so far.
In the pres ent work, X- and Y-phases were isolated by an extraction technique using aqueous ammonia and their compositions were determined by chemical analysis to be Cr₂V₁₂0₃₅and Cr₆V₁₈O₄₅, respectively.
It was reported that the catalyst containing Y-phase showed high activity for the oxidation of acrylaldehyde in the liquid phase reaction. Therefore, experiments were further carried out to obtain the favorable conditions for the preparation of the catalyst containing a large amount of Y-phase. The conditions were proposed as follows; NH₄VO₃ and Cr (NO₃)₃⋅9 H₂O are mixed together in water and kneaded at around pH 6.5, and the precipitates obtained are then calcined at 600°C in air.