Abstract: Provided is a catalyst for production of unsaturated aldehyde and/or unsaturated carboxylic acid, which shows excellent mechanical strength and low attrition loss and is capable of producing the object product(s) at a high yield. The catalyst comprises a catalytically active component containing molybdenum, bismuth and iron as the essential ingredients, and inorganic fibers, and is characterized in that the inorganic fibers contain at least an inorganic fiber having an average diameter of at least 8 ?m and another inorganic fiber having an average diameter not more than 6 ?m.

Abstract: The invention provides a catalyst for producing acrylic acid at high yield for a long time, in a method for producing acrylic acid by catalytic gas phase oxidation of propane and/or acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas. This catalyst comprises a complex oxide containing molybdenum, vanadium and X component (here the X component is at least one element selected from antimony, niobium and tin) as the essential components, and is characterized in that its main peak as measured by X-ray diffractiometry using K? ray of Cu, d=4.00±0.1 angstrom, and in that the particle size of the X component in the catalyst does not exceed 20 ?m.

Abstract: Provided is a catalyst for production of unsaturated aldehyde and/or unsaturated carboxylic acid, which shows excellent mechanical strength and low attrition loss and is capable of producing the object product(s) at a high yield. The catalyst comprises a catalytically active component containing molybdenum, bismuth and iron as the essential ingredients, and inorganic fibers, and is characterized in that the inorganic fibers contain at least an inorganic fiber having an average diameter of at least 8 ?m and another inorganic fiber having an average diameter not more than 6 ?m.

Abstract: A process which enables production of acrylic acid on an industrial scale at high productivity with stability, comprising production of acrylic acid by oxidation of propane with molecular oxygen, is provided. The process is characterized in characterized by re-use of the gas containing unreacted propane, as obtained after recovering acrylic acid from the gas produced of the reaction, as a recycling gas after removing at least a part of carbon dioxide from the same gas.

Abstract: The invention provides a process which enables, in preparation of acrolein by catalytic gas-phase oxidation of propylene in the presence of molecular oxygen or a molecular oxygen-containing gas or in preparation of acrylic acid by catalytic gas-phase oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, using single kind of catalyst, to suppress occurrence of localized extraordinarily high temperature spots (hot spots) in the catalyst layer and can stably maintain high acrolein or acrylic acid yield for a long time. The process is characterized by use of an oxide catalyst containing molybdenum as an essential component and having relative standard deviation of its particle size in a range of 0.02 to 0.20.

Abstract: The invention provides a process which enables, in preparation of acrolein by catalytic gas-phase oxidation of propylene in the presence of molecular oxygen or a molecular oxygen-containing gas or in preparation of acrylic acid by catalytic gas-phase oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, using single kind of catalyst, to suppress occurrence of localized extraordinarily high temperature spots (hot spots) in the catalyst layer and can stably maintain high acrolein or acrylic acid yield for a long time. The process is characterized by use of an oxide catalyst containing molybdenum as an essential component and having relative standard deviation of its particle size in a range of 0.02 to 0.20.

Abstract: The invention provides a process which enables, in preparation of acrolein by catalytic gas-phase oxidation of propylene in the presence of molecular oxygen or a molecular oxygen-containing gas or in preparation of acrylic acid by catalytic gas-phase oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, using single kind of atalyst, to suppress occurrence of localized extraordinarily high temperature spots (hot spots) in the catalyst layer and can stably maintain high acrolein or acrylic acid yield for a long time. The process is characterized by use of an oxide catalyst containing molybdenum as an essential component and having relative standard deviation of its particle size in a range of 0.02 to 0.20.

Abstract: A process which enables production of acrylic acid on an industrial scale at high productivity with stability, comprising production of acrylic acid by oxidation of propane with molecular oxygen, is provided. The process is characterized in characterized by re-use of the gas containing unreacted propane, as obtained after recovering acrylic acid from the gas produced of the reaction, as a recycling gas after removing at least a part of carbon dioxide from the same gas.

Abstract: A fixed bed reactor for gas-phase catalytic oxidation, the fixed bed reactor, comprising a reaction tube filled with a gas-phase oxidation catalyst, wherein a solid acid is placed in an end portion(s) of the reaction tube or between catalyst layers of the catalyst, or mixed in the catalyst; the solid acid is an oxide or a complex oxide containing at least one kind of element selected from the group consisting of aluminum (Al), silicon (Si), titanium (Ti) and zirconium (Zr), and has a shape of sphere, cylindrical column, cylindrical tube, star, ring, tablet or pellet; the catalyst is a complex oxide containing molybdenum (Mo) and bismuth (Bi) or a complex oxide containing molybdenum (Mo) and vanadium (V); and acid strength(H0) of the solid acid meets an inequality: ?5.6?H0?1.5.

Abstract: The invention provides a catalyst for producing acrylic acid at high yield for a long time, in a method for producing acrylic acid by catalytic gas phase oxidation of propane and/or acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas. This catalyst comprises a complex oxide containing molybdenum, vanadium and X component (here the X component is at least one element selected from antimony, niobium and tin) as the essential components, and is characterized in that its main peak as measured by X-ray diffractiometry using K? ray of Cu, d=4.00±0.1 angstrom, and in that the particle size of the X component in the catalyst does not exceed 20 ?m.

Abstract: A support for a gas-phase oxidation catalyst, the support including a solid acid, of which acid strength (H0) meets an inequality: ?5.6?H0?1.5; a gas-phase oxidation catalyst including the above support and a complex oxide containing molybdenum and vanadium as essential components, the complex oxide being supported on the support; a process for producing acrylic acid by gas-phase catalytic oxidation of acrolein with molecular oxygen, the process including carrying out the gas-phase catalytic oxidation in a presence of the above gas-phase oxidation catalyst; and a process for producing the above support, the process including controlling an acid strength (H0) of a solid acid so as to meet an inequality: ?5.6?H0?1.5 by adjusting a calcination temperature in a preparation of the solid acid contained in the support.

Abstract: The invention provides a process which enables, in preparation of acrolein by catalytic gas-phase oxidation of propylene in the presence of molecular oxygen or a molecular oxygen-containing gas or in preparation of acrylic acid by catalytic gas-phase oxidation of acrolein in the presence of molecular oxygen or a molecular oxygen-containing gas, using single kind of atalyst, to suppress occurrence of localized extraordinarily high temperature spots (hot spots) in the catalyst layer and can stably maintain high acrolein or acrylic acid yield for a long time. The process is characterized by use of an oxide catalyst containing molybdenum as an essential component and having relative standard deviation of its particle size in a range of 0.02 to 0.20.

Abstract: A fixed bed reactor including a reaction tube filled with a gas-phase oxidation catalyst, wherein a solid acid, of which acid strength (H0) meets an inequality: ?5.6?H0?1.5, is placed in a gas passage containing a starting material compound and/or a produced compound; a process for producing acrolein, the process including using the above fixed bed reactor for production of acrolein by gas-phase catalytic oxidation of propylene with molecular oxygen; a process for producing acrylic acid, the process including using the above fixed bed reactor for production of acrolein by gas-phase catalytic oxidation of propylene with molecular oxygen and for subsequent production of acrylic acid by gas-phase catalytic oxidation of the acrolein with molecular oxygen; and a method for suppressing deposition of a catalyst inhibitor in a fixed bed reactor including a reaction tube filled with a gas-phase oxidation catalyst, the method including placing a solid acid, of which acid strength (H0) meets an inequality: ?5.6?H0?1.

Abstract: A support for a gas-phase oxidation catalyst, the support including a solid acid, of which acid strength (H0) meets an inequality: ?5.6?H0?1.5; a gas-phase oxidation catalyst including the above support and a complex oxide containing molybdenum and vanadium as essential components, the complex oxide being supported on the support; a process for producing acrylic acid by gas-phase catalytic oxidation of acrolein with molecular oxygen, the process including carrying out the gas-phase catalytic oxidation in a presence of the above gas-phase oxidation catalyst; and a process for producing the above support, the process including controlling an acid strength (H0) of a solid acid so as to meet an inequality: ?5.6?H0?1.5 by adjusting a calcination temperature in a preparation of the solid acid contained in the support.

Abstract: The invention provides a method for regenerating with high efficiency a deteriorated catalyst of reduced activity, said catalyst originating from a heteropolyacid catalyst containing heteropolyacid formed of molybdophosphoric acid and/or molybdovanadophosphoric acid, or a salt thereof, to a heteropolyacid catalyst which exhibits approximately equivalent activity level to that of the fresh catalyst. Said method comprises mixing a deteriorated catalyst and a nitrogen-containing heterocyclic compound under the conditions whereunder ammonium ions and nitrate anions are present at such ratio that the amount of total ammonium ions per mol of total nitrate anions does not exceed 1.7 mols, drying the mixture and calcining the same.

Abstract: The invention provides a method for regenerating with high efficiency a deteriorated catalyst of reduced activity, said catalyst originating from a heteropolyacid catalyst containing heteropolyacid formed of molybdophosphoric acid and/or molybdovanadophosphoric acid, or a salt thereof, to a heteropolyacid catalyst which exhibits approximately equivalent activity level to that of the fresh catalyst. Said method comprises mixing a deteriorated catalyst and a nitrogen-containing heterocyclic compound under the conditions whereunder ammonium ions and nitrate anions are present at such ratio that the amount of total ammonium ions per mol of total nitrate anions does not exceed 1.7 mols, drying the mixture and calcining the same.