Phosphoric Acid → Niobium phosphate

Participants

Reaction Conditions

Reaction Steps

A mixture is prepared containing niobic acid, Nb2O5.xH2O, (60.33 g; 0.211 moles; Niobium Products Company, AD-460) and 85% phosphoric acid (602.20 g; 5.22 moles). The mixture is heated to 150° C. with stirring. The niobium oxide dissolves to form a pink solution, and upon heating a precipitate forms. The precipitate is boiled in the phosphoric acid for about 2 hours. The boiled mixture is cooled to room temperature, and the liquid phase is decanted from the precipitate. The precipitate is washed by stirring with 500 ml of water, after which the aqueous mixture is filtered. The washing and filtering cycle is repeated five times. The filtered solid is dried at 110° C. under air for 21/2 days to yield a catalyst of niobium phosphate. The elemental analysis and X-ray diffraction pattern of the catalyst are consistent with the composition NbOPO4. The P/Nb mole ratio, as determined by neutron activation analysis and X-ray fluorescence, is 1.03.

Provenance & Evidence