Composite oxide catalyst
Disclosed is a complex oxide catalyst composed of catalyst particles containing Mo, V, a component X and a silica-containing carrier. The component X is at least one element selected from alkaline earth metal elements and rare earth elements. The complex oxide catalyst is supported by the carrier, and the component X is uniformly distributed in the catalyst particles.
1. A vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction of propane or isobutane with a composite oxide catalyst,
wherein said composite oxide catalyst comprises a catalyst particle of the following formula (1) and a carrier containing silica,
Mo 1 V a Nb b Y c X d O n (1)
wherein a, b, c, d and n each represent an atomic ratio per Mo atom, in which
a is in the range of 0.01≦a≦1;
b is in the range of 0.01≦b≦1;
c is in the range of 0.01≦c≦1;
a/c as a ratio of a to c is in the range of 0<a/c<1;
d is in the range of 0.002≦d<0.01; and
n is the number determined by an atomic valence of a component metal;
X is at least one selected from the group consisting of Sr, Ba, Sc, yttrium, La, Ce, Pr and Yb; and
Y is at least one selected from the group consisting of Te and Sb:
wherein the composite oxide catalyst is carried by the carrier,
wherein the component X is uniformly distributed in the catalyst particle, and
wherein a dispersion value D X of a signal intensity ratio as measured by EPMA of the component X to Si, at the time of composition analysis of a cross-section of the catalyst particle, is 0<D X <0.5:
wherein said composite oxide catalyst is prepared in a method comprising,
mixing a silica and an Nb compound into a mixture containing an Mo compound, a V compound, a Y compound and an X compound to prepare a raw material mixture,
spray-drying the raw material mixture to prepare a dry powder, and calcining the dry powder:
wherein the vapor-phase catalytic oxidation reaction or the vapor-phase catalytic ammoxidation reaction of propane or isobutane comprises a step of contacting said composite oxide catalyst with propane or isobutane.
2. The method according to claim 1 , which is a vapor-phase catalytic oxidation of propane or isobutane with the composite oxide catalyst to prepare an unsaturated acid.
3. The method according to claim 1 , which is a vapor-phase catalytic ammoxidation of propane or isobutane to prepare an unsaturated nitrile.
4. A method for producing a composite oxide catalyst comprising a catalyst particle of the following formula (1) and a carrier containing silica,
Mo 1 V a Nb b Y c X d O n (1)
wherein a, b, c, d and n each represent an atomic ratio per Mo atom, in which
a is in the range of 0.01≦a≦1;
b is in the range of 0.01≦b≦1;
c is in the range of 0.01≦c≦1;
a/c as a ratio of a to c is in the range of 0<a/c<1;
d is in the range of 0.002≦d<0.01; and
n is the number determined by an atomic valence of a component metal;
X is at least one selected from the group consisting of Sr, Ba, Sc, yttrium, La, Ce, Pr and Yb; and
Y is at least one selected from the group consisting of Te and Sb:
wherein the composite oxide catalyst is carried by the carrier,
wherein the component X is uniformly distributed in the catalyst particle, and
wherein a dispersion value D X of a signal intensity ratio as measured by EPMA of the component X to Si, at the time of composition analysis of a cross-section of the catalyst particle, is 0<D X <0.5:
said method comprising,
mixing a silica and an Nb compound into a mixture containing an Mo compound, a V compound, a Y compound and an X compound to prepare a raw material mixture,
spray-drying the raw material mixture to prepare a dry powder, and calcining the dry powder.
5. The method according to claim 4 ,
wherein the component X is at least one element selected from Sc, Y (yttrium), La, Ce, Pr and Yb.
6. The method according to claim 4 ,
wherein the composite oxide catalyst is carried by 20 to 60% by weight of silica as SiO 2 equivalent.
7. The method according to claim 4 ,
wherein 80 wt % or more of oxide particles containing the component X are present in the catalyst particle as particles each having a particle diameter of 1 μm or less.
8. The method according to claim 4 ,
wherein the atomic ratios of a to c per Mo atom are 0.1≦a≦0.4, 0.01≦b≦0.2 and 0.1≦c≦0.5.
9. The method according to claim 4 ,
wherein X is Ce and Y is Sb.
10. The method according to claim 4 ,
wherein the c which is an atomic ratio of the component Y per Mo atom is 0.01≦c≦0.6.