Patent ID: 7595277

Claim:
A catalyst for use in catalytic oxidation or ammoxidation of propane or isobutane in the gaseous phase, which comprises an oxide and a silica carrier having supported thereon said oxide, wherein said silica carrier is present in an amount of from 20 to 60% by weight in terms of SiO 2 , based on the total weight of said oxide and said silica carrier, said oxide being represented by the following formula (1): Mo 1 V a Nb b Sb c O n (1) wherein: a, b, c and n are, respectively, the atomic ratios of vanadium (V), niobium (Nb), antimony (Sb) and oxygen (O), relative to molybdenum (Mo), wherein: 0.1≦a≦1, 0.01≦b≦1, 0.01≦c≦1, and n is the number of oxygen atoms required to satisfy the valence requirements of the other component elements present, said catalyst having a reduction ratio of from 8 to 12% and a specific surface area of from 7 to 30 m 2 /g, said reduction ratio being represented by the following formula (2): reduction ratio (%)=(( n 0 −n )/ n 0 )×100 (2) wherein: n is as defined for formula (1), and n 0 is the number of oxygen atoms required when the other component elements in said oxide of formula (1) respectively exhibit the maximum oxidation numbers of the other component elements.