Patent ID: 8785675

Claim:
A mixed catalyst for a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction of propane or isobutane, the mixed catalyst comprising: (a) a composite oxide represented by the following composition formula (1): Mo 1 V a Nb b Sb c W d Z e O n (1) wherein Z represents at least one element selected from the group consisting of La, Ce, Pr, Yb, Y, Sc, Sr, and Ba; each of a, b, c, d, e, and n represents an atomic ratio of each element based on Mo atom; a is in a range of 0.01≦a≦1; b is in a range of 0.01≦b≦1; c is in a range of 0.01≦c≦1; d is in a range of 0.001≦d≦1; e is in a range of 0≦e≦1; and n represents a number determined by a valence of a component metal; and (b) a tungsten compound at a ratio of the following formula (2): 0.001<w<0.3 (2) wherein w represents an atomic ratio of tungsten in the tungsten compound as an atomic ratio based on Mo atom in the composite oxide.