| abstract |
This composite oxide catalyst is used for a vapor-phase catalytic oxidation reaction or vapor-phase catalytic ammoxidation reaction of propane or isobutane, and contains a composite oxide that is represented by a composition formula Mo1VaSbbNbcWdZeOn (wherein component Z represents one or more elements selected from among La, Ce, Pr, Yb, Y, Sc, Sr and Ba; and a, b, c, d, e and n represent the atomic ratios of respective elements and satisfy 0.1 ≤ a < 0.2, 0.15 ≤ b ≤ 0.5, 0.01 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.4, 0 ≤ e ≤ 0.2 and 0.60 < a/b < 1.00.) By using this composite oxide catalyst in the above-mentioned reactions, the yield of an unsaturated nitrile can be increased by suppressing the production of CO2 and CO. |