Abstract: A catalyst for the production of unsaturated aldehyde and unsaturated carboxylic acid by the vapor-phase catalytic oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butanol and methyl-t-butyl ether and a method for the production of unsaturated aldehyde and unsaturated carboxylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo, Bi and Fe as essential components and used for the production of unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene, isobutylene, t-butanol and/or methyl-t-butyl ether and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows unsaturated aldehyde and unsaturated carboxylic acid to be produced stably at a high yield for a long time.

Abstract: A catalyst for the production of unsaturated aldehyde and unsaturated carboxylic acid by the vapor-phase catalytic oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butanol and methyl-t-butyl ether and a method for the production of unsaturated aldehyde and unsaturated carboxylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo, Bi and Fe as essential components and used for the production of unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene, isobutylene, t-butanol and/or methyl-t-butyl ether and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows unsaturated aldehyde and unsaturated carboxylic acid to be produced stably at a high yield for a long time.

Abstract: A catalyst for the production of methacrylic acid by the vapor-phase catalyst oxidation and/or oxidative dehydrogenation of at least one compound selected rom the group consisting of methacrolein, isobutyl aldehyde, and isobutyric acid and a method for the production of methacrylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a composite oxide having Mo and P as essential components and used for the production of methacrylic acid by vapor-phase catalytic oxidation and/or oxidative dehydrogenation of methacrolein, isobutyl aldehyde, and/or isobutyric acid and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows methacrylic acid to be produced stably at a high yield for a long time.

Abstract: The present invention provides a process for producing methacrolein and methacrylic acid by subjecting at least one material selected from isobutylene, t-butanol and methyl t-butyl ether to gas phase catalytic oxidation with molecular oxygen or a molecular oxygen-containing gas using a fixed bed multi-tubular reactor.

Abstract: A method for the production of methacrylic acid comprising the steps of simultaneously introducing at least one compound selected from the group consisting of methacrolein and isobutyl aldehyde and a molecular oxygen-containing gas into a heat exchanger type shell-and-tube reaction vessel packed with an oxide catalyst containing molybdenum and phosphorus thereby effecting catalytic vapor-phase oxidation reaction and/or catalytic vapor-phase oxidative dehydrogenation reaction and consequently forming methacrylic acid, which method is characterized by having the empty space in the gas outlet part of said reaction vessel with a solid filler.

Abstract: A process for producing methacrylic acid, which comprisesfilling a plurality of catalysts of different activities into a plurality of reaction zones which have been formed in each of the reaction tubes of a fixed bed multi-tubular reactor by dividing said reaction tube into two or more portions in the direction of tubular axis, so that the activity of catalyst is higher as the reaction zone is closer to the outlet of the reaction tube, andintroducing into the reaction zones containing the catalysts at least one compound selected from methacrolein, isobutyl aldehyde and isobutyric acid to oxidize the at least one compound with molecular oxygen or a molecular oxygen-containing gas.

Abstract: A catalyst for the production of methacrylic acid composed of an inert carrier and a catalytically active substance. The catalytically active substance layer being composed of oxides represented by the following formula (I)Mo.sub.a P.sub.b a.sub.c B.sub.d C.sub.e D.sub.f O.sub.x (I)where Mo represents molybdenum, P represents phosphorus, A represents at least one element selected from arsenic, antimony, germanium, bismuth, zirconium, cerium and selenium, B is at least one element selected from copper, iron, chromium, nickel, maganese, cobalt, tin, silver, zinc, palladium, rhodium and tellurium, C represents at least one element selected from vanadium, tungsten and niobium, D represents at least one element selected from alkali metals, alkaline earth metals and thallium, and O represents oxygen, a, b, c, d, e, f and x respectively represent the atomic ratios of Mo, P, A, B, C, D and O, and when a=12, b=0.5-4, c=0-5, d=0-3, e=0-4, and f=0.

Abstract: An improved process for producing maleic anhydride which comprises catalytically oxidizing benzene with a molecular oxygen-containing gas in the vapor phase in a multitubular heat-exchanger-type reactor. The process is characterized in thata catalyst-packed layer of the reactor is divided into a gas inlet side layer and a gas outlet side layer,the activity of the gas inlet side layer is controlled by adding at least one component selected from the group consisting of potassium, cesium, thallium and rubidium as a promoter or by decreasing the amount of phosphorus pentoxide (P.sub.2 O.sub.

Abstract: In a method for the preparation of pyromellitic acid or its anhydride by catalytic vapor phase oxidation of a tetra-C.sub.1 -C.sub.4 -alkylbenzene using a catalyst comprising catalytically active material composed of 1 to 20 parts by weight of V.sub.2 O.sub.5, 99 to 80 parts by weight of TiO.sub.2 and/or SnO.sub.2 and/or ZrO.sub.2, and per one hundred parts by weight of V.sub.2 O.sub.5, TiO.sub.2 and/or SnO.sub.2 and/or ZrO.sub.2 0.02 to 10 parts by weight, calculated as P.sub.2 O.sub.5, of a phosphorus compound, 0.01 to 5 parts by weight, calculated as Nb.sub.2 O.sub.5, of a niobium compound, 0 to 1.2 parts by weight, calculated as oxide, of at least one metal selected from the group consisting of potassium, cesium, rubidium and thallium, and 0 to 10 parts by weight, calculated as Sb.sub.2 O.sub.