摘要:
A method for producing a catalyst for the preparation of methacrylic acid comprising a heteropolyacid compound containing phosphorus, molybdenum and an element X selected from the group consisting of potassium, rubidium, cesium and thallium and having an atomic ratio of the element X to molybdenum of 0.5:12 to 2:12, which method comprises the steps of mixing aqueous slurry A containing starting compounds of the heteropolyacid compound in which an atomic ratio of the element X to molybdenum is from 2:12 to 4:12, and aqueous slurry B containing starting compounds of the heteropolyacid compound in which an atomic ratio of the element X to molybdenum is from 0:12 to 0.5:12 to form a slurry mixture; heat-treating the slurry mixture at a temperature of 100° C. or higher; drying the slurry mixture; and calcining the dried mixture.
摘要:
A catalyst for use in the production of an unsaturated aldehyde and/or an unsaturated carboxylic acid, the catalyst comparing (or, preferably, being composed of) a mixed oxide containing molybdenum, bismuth and iron, which has improved mechanical strength, is produced by a method including the steps of (1) drying an aqueous solution or an aqueous slurry containing raw materials of the catalyst and then firstly calcining a dried product in a molecular oxygen-containing gas atmosphere to obtain a calcined product; (2) heating the calcined product obtained in Step (1) in the presence of a reducing material to obtain a reduced product having a mass loss of 0.05 to 6%; and (3) secondly calcining the reduced product obtained in Step (2) in a molecular oxygen-containing gas atmosphere.
摘要:
A catalyst for use in the production of an unsaturated aldehyde and/or an unsaturated carboxylic acid, the catalyst comparing (or, preferably, being composed of) a mixed oxide containing molybdenum, bismuth and iron, which has improved mechanical strength, is produced by a method including the steps of (1) drying an aqueous solution or an aqueous slurry containing raw materials of the catalyst and then firstly calcining a dried product in a molecular oxygen-containing gas atmosphere to obtain a calcined product; (2) heating the calcined product obtained in Step (1) in the presence of a reducing material to obtain a reduced product having a mass loss of 0.05 to 6%; and (3) secondly calcining the reduced product obtained in Step (2) in a molecular oxygen-containing gas atmosphere.
摘要:
A catalyst suited for catalytic vapor-phase oxidation of isobutylene, t-butanol or propylene to produce respectively corresponding unsaturated aldehyde and unsaturated carboxylic acid is provided. Said catalyst consists of ring-formed shaped bodies composed of (i) a catalyst composition containing at least molybdenum and bismuth as the active ingredients and (ii) inorganic fibers. The catalyst excels in mechanical strength, can give the object products at high yield and shows little activity degradation with time.
摘要:
A catalyst for purifying exhaust gas, having deposited on a monolithic honeycomb carrier a catalyst composition comprising an alumina-modified cerium oxide obtained by impregnating a water-insoluble cerium compound with at least one member selected from the group consisting of water-soluble aluminum compounds and alumina hydrates and calcining the product of impregnation, at least one precious metal selected from the group consisting of platinum, palladium, and rhodium, and active alumina.
摘要:
A process is provided for producing a complex oxide catalyst which exhibits superior catalytic activity in a vapor phase catalytic oxidation reaction, particularly in production of unsaturated aldehyde and unsaturated carboxylic acid. The process is characterized by the steps of preparing an aqueous slurry by mixing a complex oxide containing molybdenum and cobalt with an acid and water; drying the aqueous slurry; and calcining the resulting dried solid. Preferably, the complex oxide is obtained as follows: a molybdenum- and cobalt-containing complex oxide catalyst which has been used in a vapor phase catalytic oxidation reaction is mixed with an aqueous extracting solution obtained by dissolving at least one of ammonia and an organic base in water, to thereby extract molybdenum and cobalt into the aqueous phase; and the aqueous phase is dried and is then calcined under an atmosphere of an oxidizing gas.
摘要:
A catalyst for purifying exhaust gas comprises a honeycomb carrier of monolithic structure and a coating layer deposited on the honeycomb carrier and formed with a catalyst composition containing a refractory inorganic oxide in the form of particles possessing and average particle diameter in the range of 0.5 to 20 microns, which refractory inorganic oxide has platinum and/or palladium and rhodium deposited thereon in high concentrations. This catalyst is produced by coating the honeycomb carrier with an aqueous slurry containing the catalyst composition and calcining the coated carrier.
摘要:
A catalyst for use in the production of an unsaturated aldehyde and/or an unsaturated carboxylic acid, the catalyst comparing (or, preferably, being composed of) a mixed oxide containing molybdenum, bismuth and iron, which has improved methanical strength, is produced by a method including the steps of (1) drying an aqueous solution or an aqueous slurry containing raw materials of the catalyst and then firstly calcining a dried product in a molecular oxygen-containing gas atmosphere to obtain a calcined product; (2) heating the calcined product obtained in Step (1) in the presence of a reducing material to obtain a reduced product having a mass loss of 0.05 to 6%; and (3) secondly calcining the reduced product obtained in Step (2) in a molecular oxygen-containing gas atmosphere.
摘要:
A catalyst for the production of methacrylic acid comprising a heteropolyacid compound containing phosphorus and molybdenum is regenerated by a method comprising the steps of heat-treating a mixture containing a deactivated catalyst, water, a nitrate ion and an ammonium ion having a molar ratio to the nitrate ion of 1.3 or less at a temperature of at least 100° C., drying the mixture to obtain a dried catalyst, and calcining the dried catalyst. The regenerated catalyst has substantially the same catalytic activity as a fresh catalyst in a gas phase catalytic oxidation reaction of methacrolein, isobutylaldehyde, isobutane or isobutyric acid to prepare methacrylic acid.
摘要:
A catalyst useful for catalytic vapor-phase oxidation of isobutylene, t-butanol or propylene to produce respectively corresponding unsaturated aldehyde and unsaturated carboxylic acid is provided. The catalyst consists of ring-formed shaped bodies composed of (i) a catalyst composition containing at least molybdenum and bismuth as the active ingredients and (ii) inorganic fibers. The catalyst excels in mechanical strength, can give the object products at high yield and shows little activity degradation with time.