Abstract: An object of the present invention is to provide a method for regenerating a catalyst for butadiene production, for removing a coke-like substance which is generated by oxidative dehydrogenation of n-butene in the presence of a catalyst for butadiene production and which is attached to the catalyst and the inside of a reactor. After the catalyst is used in oxidative dehydrogenation of butenes, the catalyst regeneration method of the present invention removes a coke-like substance in a reactor which is charged with the catalyst for butadiene production, the catalyst having a prescribed composition before being used in the oxidative dehydrogenation.

Abstract: Provided are a catalyst that suppresses production of a coke-like material and improves the long-term stability of the reaction, and a method for producing the catalyst. A composite metal oxide catalyst for conjugated diolefin production is used for producing a conjugated diolefin from a mixed gas including a monoolefin having 4 or more carbon atoms and molecular oxygen by a catalytic oxidative dehydrogenation reaction, the catalyst having a relative intensity ratio of X-ray diffraction peaks represented by the following Formula (A): 0.9<Pr<3.0 Pr=Pi1/Pi2??(A) (in the formula, Pi1 represents the maximum peak height at a 2? value in the range of 26.4°±0.3° in the X-ray diffraction peaks; Pi2 represents the maximum peak height at a 2? value in the range of 28.5°±0.3° in the X-ray diffraction peaks; and Pr represents the relative intensity ratio of Pi1 with respect to Pi2).

Abstract: A supported molded catalyst having increased hardness, the supported molded catalyst being capable of improving the long-term stability of a reaction for producing a conjugated diolefin by catalytic oxidative dehydrogenation from a mixed gas including a monoolefin having 4 or more carbon atoms and molecular oxygen; and a method for producing the catalyst is provided. A molded catalyst for conjugated diolefin production, the molded catalyst being a catalyst for producing a conjugated diolefin by a catalytic oxidative dehydrogenation reaction from a mixed gas including a monoolefin having 4 or more carbon atoms and molecular oxygen, and being produced by molding a composite metal oxide and a glass fiber-like inorganic auxiliary agent.

Abstract: The present invention relates to a method for producing acrylic acid through vapor-phase contact oxidation of acrolein, wherein a reactor tube is divided into at least two catalyst layers, and catalysts having a higher activity are charged in the reactor tube sequentially toward an outlet port side from a material source gas inlet port side for a reaction therein to give acrylic acid, and wherein a catalyst activity-controlling method is a method comprising: a step of mixing a molybdenum-containing compound, a vanadium-containing compound, a copper-containing compound and an antimony-containing compound with water, then drying and calcining a resulting mixture, in which a catalytically-active element composition is kept constant but material source compounds are made to vary in type to give composite metal oxides having a different activity.

Abstract: The present invention relates to a method for producing acrylic acid through vapor-phase contact oxidation of acrolein, wherein a reactor tube is divided into at least two catalyst layers, and catalysts having a higher activity are charged in the reactor tube sequentially toward an outlet port side from a material source gas inlet port side for a reaction therein to give acrylic acid, and wherein a catalyst activity-controlling method is a method comprising: a step of mixing a molybdenum-containing compound, a vanadium-containing compound, a copper-containing compound and an antimony-containing compound with water, then drying and calcining a resulting mixture, in which a catalytically-active element composition is kept constant but material source compounds are made to vary in type to give composite metal oxides having a different activity.