| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite oxide catalyst which gives high conversion ratio of raw material unsaturated aldehyde and high selectivity of unsaturated carboxylic acid and indicates stable performance over a long period of time, when manufacturing the unsaturated carboxylic acid by subjecting unsaturated aldehyde to gas-phase catalytic oxidation by a molecular oxygen-containing gas.SOLUTION: A composite oxide catalyst having a prescribed component is used when manufacturing corresponding unsaturated carboxylic acid by subjecting unsaturated aldehyde to gas-phase catalytic oxidation by a molecular oxygen-containing gas. The surface area of the composite oxide catalyst is turned to 0.5-10 m2/g, a pore volume is turned to 0.1-0.9 cc/g, and among the pores of the composite oxide catalyst, the pore volume occupied by the pores whose pore diameter is less than 0.1 μm is turned to at least 20% of the entire pore volume, the pore volume occupied by the pores whose pore diameter is 0.1 μm or larger and smaller than 1 μm is turned to at least 10% of the entire pore volume, the pore volume occupied by the pores whose pore diameter is 1 μm or larger and smaller than 10 μm is turned to 80% or less of the entire pore volume, and the pore volume occupied by the pores whose pore diameter is 10 μm or larger is turned to 10% or less of the entire pore volume. |
