| 摘要 |
PURPOSE:To enhance durability of activity of a catalyst for producing pyromellitic acid anhydride by blending oxalic acid or the like of the specified amount to vanadium pentoxide and/or ammonium metavanadate and depositing the mixture on a carrier. CONSTITUTION:0.5-1.5mol times oxalic acid and/or tartaric acid for vanadium is added to vanadium pentoxide and/or ammonium metavanadate and the mixture is made to a uniform aq. soln., and a soln. is prepared by adding metallic oxide and metallic salt (ammonium salt, carbonate, etc.,) becoming a promotor to the uniform aq. soln. After depositing this soln. on a carrier having <=1m<2>/g surface area such as melted alumina or silicon carbide, the carrier is calcined at 450-600 deg.C in an air current to obtain a catalyst for producing pyromellitic acid anhydride. This catalyst is excellent in reproducibility of catalytic activity and durable in activity for a long period. |
