Phosphoric Acid → Niobium phosphate

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Reaction Steps

Niobic acid, Nb2O5.xH2O (60.0 g) is stirred in 85 percent phosphoric acid (600.0 g) at 150° C. The niobium oxide dissolves to form a solution, and upon further heating a precipitate forms. The precipitate is boiled in the phosphoric acid solution for about 2 hours with stirring. The mixture is cooled to room temperature, and the liquid is decanted from the precipitate. Water (500 ml) is added to the precipitate with stirring, and the precipitate is filtered. The washing and filtering cycle is repeated three times. The filtered solid is dried at 150° C. under air, then heated overnight at 300° C. to yield a niobium phosphate catalyst. The elemental analysis of the catalyst is consistent with the composition NbOPO4.

Provenance & Evidence