Patent ID: 9464039
Filing Date: 2016-10-11
CPC Classification: B01J,C07C,Y02P

Claim Text:
1. A method for producing an unsaturated nitrile, comprising: subjecting propane to a vapor-phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of a composite oxide catalyst, to produce the unsaturated nitrile, wherein a tungsten compound is added into the fluidized bed reactor during the vapor-phase catalytic ammoxidation reaction, to adjust a molar ratio (W/Mo ratio) of a tungsten contained in the tungsten compound to a molybdenum contained in the composite oxide catalyst that exist within the fluidized bed reactor so that the molar ratio is in a range of 0.0001 to 0.1, and the composite oxide catalyst comprises a composite oxide represented by the following composition formula (1): wherein component A represents at least one or more elements selected from Te and Sb; component X represents at least one or more elements selected from W, Bi, and Mn; component Z represents at least one or more elements selected from La, Ce, Pr, Yb, Y, Sc, Sr, and Ba; a, b, c, d, e, and n each represent an atomic ratio of the corresponding element per 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≦d≦1; e is in a range of 0≦e≦1; and n represents a number determined by valences of the component elements; and said method further comprising (1) extracting a mixture of the composite oxide catalyst and the tungsten compound from the fluidized bed reactor during the vapor-phase catalytic ammoxidation reaction; (2) measuring a temporary value of the W/Mo ratio from the mixture obtained by (1); and (3) controlling the W/Mo ratio to fall within the range of 0.0001 to 0.1 based on the temporary value measured in (2).