Abstract: Disclosed is an ammoxidation catalyst composition for use in producing acrylonitrile from propylene, or methacrylonitrile from isobutylene, by ammoxidation of the propylene or of the isobutylene, comprising an oxide catalyst and a silica carrier having the oxide catalyst supported thereon, wherein the silica carrier is present in an amount of from 40 to 60% by weight, based on the total weight of the oxide catalyst and the silica carrier. The oxide catalyst comprises oxides of molybdenum, bismuth, iron, and component A which is at least one element selected from potassium, rubidium and cesium, wherein bismuth, iron and component A are, respectively, present in amounts of from 0.1 to 6, from 0.1 to 8 and from 0.01 to 0.5 in terms of atomic ratios relative to twelve atoms of molybdenum.

Abstract: Disclosed is an ammoxidation catalyst composition for use in producing acrylonitrile from propylene, or methacrylonitrile from isobutene or tert-butanol, by ammoxidation of the propylene or of the isobutene or tert-butanol, comprising an oxide catalyst composition represented by the formula:Mo.sub.12 (Bi.sub.1-a A.sub.a).sub.b Fe.sub.c Ni.sub.d X.sub.e Y.sub.f O.sub.g,whereinA is at least one rare earth element,X is at least one element selected from magnesium and zinc,Y is at least one element selected from potassium, rubidium and cesium,a is a number of from 0.6 to 0.8,b is a number of from 0.5 to 2,c is a number of from 0.1 to 3,d is a number of from 4 to 10,e is a number of from 0 to 3,f is a number of from 0.01 to 2, andg is a number determined by the valence requirements of the other elements present.

Abstract: In the preparation of acrylonitrile or methacrylonitrile by ammoxidation of propylene or isobutylene with ammonia and molecular oxygen in the vapor phase in the presence of a catalyst comprising silica and supported thereon oxides of molybdenum, bismuth and iron, the yield of acrylonitrile or methacrylonitrile based on ammonia is improved without sacrificing the yield based on propylene or isobutylene by the use of a novel catalyst having, incorporated therein, 0.002 to 0.2 atom, based on 12 atoms of molybdenum, of an oxide of at least one element selected from the group consisting of palladium, platinum, osmium and iridium.

Abstract: A catalyst composition having a composition represented by the formula:A.sub.0.1-4 B.sub.0.02-1 Mo.sub.12 Bi.sub.0.5-10 Fe.sub.0.5-10 Na.sub.0-3 P.sub.0-2 O.sub.gwherein A is at least one element selected from the group consisting of cerium, lanthanum, neodium, praseodium, samarium, europium and gadrinium, B is at least one element selected from the group consisting of potassium, rubidium and cesium, and g is the number of oxygen atoms required to satisfy the valence requirements of the other elements present, and supported on silica.

Abstract: A process for the preparation of acrylonitrile by the ammoxidation reaction of propylene, characterized by using an oxide type catalyst which contains, as active ingredients, molybdenum, bismuth, iron and at least one element selected from potassium, rubidium and cesium in specifically limited proportions and which may further contain sodium and/or phosphorus. By the use of such a specific catalyst, the selectivity for the desired acrylonitrile is remarkably improved, and there can be attained high yield of the product. In the process of the present invention, the catalyst can maintain a high activity and a high selectivity for a long time, without undergoing attrition. The catalyst is well prevented from sublimation-escaping of the ingredient molybdenum therefrom.