Abstract: A catalyst for use in the production of acrylic acid by catalytic gas phase oxidation of acrolein, comprising active substances represented by general formulaMo.sub.(a) V.sub.(b) A.sub.(c) B.sub.(d) C.sub.(e) D.sub.(f) O.sub.

Abstract: A catalyst used for producing, by catalytic gas phase oxidation of a C.sub.3 -C.sub.5 oelfin or tertiary alcohol, the corresponding unsaturated aldehyde and unsaturated carboxylic acid, said catalyst characterized by comprising molybdenum, iron and bismuth and having a specific surface area in the range from 1 to 20 m.sup.2 /gr, a pore volume in the range from 0.1 to 1.0 cc/gr and a pore diameter distribution in which the pore diameters are collectively distributed in the range of each of from 1 to 10 microns and from 0.1 to less than 1 micron; and a process for preparing said catalyst by charging an unfired material power into a centrifugal flow coating device to form particles having the average particle diameter of 2 to 10 mm and then firing the particles.

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.