| abstract |
PROBLEM TO BE SOLVED: To provide a heteropolyacid catalyst comprising a heteropolyacid comprising molybdophosphoric acid and / or molybdovanadophosphoric acid or a salt thereof, which is more excellent in performance, life and strength. And a method for producing the same. SOLUTION: When producing the heteropolyacid catalyst in the presence of a nitrogen-containing heterocyclic compound, all the catalyst constituent element raw materials and the nitrogen-containing heterocyclic compound are mixed in the presence of water, (1) It contains a nitrogen-containing heterocyclic compound, a nitrate group and an ammonium group, (2) the total ammonium group amount does not exceed 1.7 mol per 1 mol of the total nitrate group, and (3) the total ammonium group amount is After preparing a mixture that does not exceed 10 moles per 12 moles of molybdenum atoms, the mixture is dried and fired. |