| 摘要 |
PURPOSE:To obtain a catalyst for a fluidized bed generating no lowering of activity in spite of long-term use by adding oxide of iron or phosphorus to titanium oxide, a vanadium compound, an alkali metal compound and a sulfate compound being essential components in a specific ratio. CONSTITUTION:About 40-90wt.% of titanium oxide, about 5-13wt.% of a vanadium compound, about 2.7-43wt.% of an alkali metal compound and about 1.5-4.5wt.% of a sulfate compound are used as essential components on an oxide basis. 0.3-15wt.% of oxide of an element selected from Fe, P, W and Ba is added to said components. The obtained catalyst shows no lowering of activity even if it is used for a long period of time when phthalic anhydride or pyromellitic anhydride is prepared by the vapor phase oxidation of an aromatic hydrocarbon raw material such as o-xylene or naphthalene. |
