FIELD: chemistry.
SUBSTANCE: invention relates to a mixed catalyst for catalytic vapour-phase oxidation or catalytic vapour-phase ammoxidation of propane or isobutane. The disclosed mixed catalyst contains: (a) a composite oxide of formula Mo1VaNbbSbcWdZeOn (1), where Z is at least one element selected from a group consisting of La, Ce, Pr, Yb, Y, Sc, Sr and Ba; each of the indices a, b, c, d, e and n is the atomic fraction of each element with respect to an atom of Mo; a is in the range 0.01≤a≤1; b is in the range 0.01≤b≤1; c is in the range 0.01≤c≤1; d is in the range 0.001≤d≤1; e is in the range 0≤e≤1; and n is a number defined by the valence of metal components; and (b) a tungsten compound in a ratio which satisfies the condition 0.001<w<0,3 (2), where w is the atomic fraction of tungsten in the tungsten compound as an atomic fraction with respect to the atom of Mo in the composite oxide. Elementary tungsten from said tungsten compound (b) diffuses onto the surface of the composite oxide (a) and is fixed on said surface of the composite oxide (a) during catalytic vapour-phase oxidation of propane or isobutane with oxygen or during catalytic vapour-phase ammoxidation of propane or isobutane with oxygen and ammonia. The invention also relates to a method of producing an unsaturated acid or unsaturated nitrile using said mixed catalyst.
EFFECT: disclosed mixed catalyst has high heat resistance and redox resistance.
5 cl, 12 ex
