JP2000037631A - Preparation of molybdenum - bismuth - iron containing composite oxide catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly active and aimed oxidized product in a high yield by a method wherein after mixing a molybdenum compound and a specific metallic compound are mixed under a specific condition, an iron compound is mixed, and the mixture is dried and burnt to manufacture a catalyst. SOLUTION: In manufacture of a molybdenum containing composite oxide catalyst to be used for oxidizing reaction of an organic compound, an aqueous slurry of 6 or more pH containing a part of a raw material of a molybdenum component, and a part of a raw material of one component selected from nickel, cobalt. magnesium, chromium, manganese and zinc is treated by heating for 10 min or longer within a temperature range of 50 to 120 deg.C. Thereafter, it is mixed in solution containing a raw material for iron component or its slurry, and the mixture is dried and burnt. As raw materials for an iron component, though not especially limited, ferrous oxide, ferric oxide, triiron tetraoxide, etc., can be used, and by allowing ethylenediaminetetraacetate, lactic acid, citric acid, gluconic acid, etc., to coexist together in a solution containing the iron component, a highly active catalyst is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molybdenum-containing composite oxide catalyst used for an oxidation reaction of an organic compound, and more particularly, to nickel, cobalt, magnesium, chromium, manganese and nickel used for a gas phase catalytic oxidation reaction of an organic compound. The present invention relates to a method for producing a molybdenum-bismuth-iron-containing composite oxide catalyst containing at least one element selected from the group consisting of zinc.

[0002]

2. Description of the Related Art Many molybdenum-bismuth-containing composite oxide catalysts are known as catalysts for oxidation reactions of organic compounds. For example, Japanese Patent Publication No. 36-3563, Japanese Patent Publication No. 3
No. 6-5870, Japanese Patent Publication No. 38-17967,
JP-B-39-3670, JP-B-39-10111
JP, JP-B-42-7774, and JP-A-50
No. 64191 is disclosed. These catalysts are subsequently disclosed in JP-B-47-27490, JP-B-Sho-5-27490.
It is improved by adding various additives such as JP-A-4-22795 and JP-B-60-36812, and the yield of the target oxidation product is improved.

On the other hand, efforts have been made to improve the yield of target oxidation products even by improving the preparation method. For example, Japanese Patent Publication No. 43-22746 discloses a method of adding an aqueous solution of bismuth citrate to an aqueous solution of molybdic acid.
No. 387, JP-A-53-10388 and JP-B-55-12298 disclose a method of adding a solid-state bismuth compound to an aqueous molybdic acid solution.
JP-A-51848 discloses a method of simultaneously adding an aqueous solution of bismuth salt and aqueous ammonia to an aqueous solution of molybdic acid having a pH in the range of 6 to 8, and JP-B-59-51849 discloses a method of adding a bismuth salt to a suspension of a molybdenum compound. A method of adding an aqueous solution, JP-A-55-13187, JP-A-55-13187
No. 47144 and Japanese Patent Publication No. 60-29536 disclose a method of forming various molybdates in advance.
JP-A-2-22359 and JP-B-52-47435 disclose a method of forming various bismuth compounds in advance, and JP-A-62-2548 discloses a method of using bismuth oxide or bismuth subcarbonate as a bismuth source. JP-A-2-
No. 59046 discloses a slurry containing at least one of iron, bismuth and tellurium and a molybdenum compound having a pH of 7 or less.
And a method of adjusting to a range exceeding
JP-A-2-251250 discloses a method of adding a chelating agent to a slurry containing a molybdenum compound containing silica to adjust the pH to 6 or more, and JP-A-2-251250 discloses a method of mixing a bismuth compound after the slurry containing molybdenum is adjusted to a pH of 6 or more. Are disclosed.

In order to improve the performance of the catalyst, various methods have been proposed, such as devising a method of mixing an aqueous solution of molybdenum and a bismuth compound, or selecting a raw material of bismuth in particular. However, when these methods are applied to the production of a molybdenum-bismuth-containing composite oxide catalyst containing at least one metal element selected from the group consisting of a divalent metal element and a trivalent metal element, the intended oxidation Product yields were not always satisfactory.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a molybdenum-bismuth-iron-containing composite oxide catalyst useful for various oxidation reactions, which has high activity and provides a desired oxidation product in a high yield. It provides a preparation method.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, when producing a molybdenum-bismuth-iron-containing composite oxide catalyst used for an oxidation reaction of an organic compound, molybdenum was used. When a catalyst is prepared by mixing a compound and a specific metal compound under specific conditions, and then mixing an iron compound to obtain a catalyst, a catalyst can be obtained which has high activity and a high yield of an intended oxidation product. And arrived at the present invention.

That is, according to the present invention, (1) molybdenum, (2) bismuth, (3) nickel,
(4) In a method for producing a composite oxide catalyst containing at least one element selected from the group consisting of cobalt, magnesium, chromium, manganese and zinc, and (4) iron as an essential component, at least one of the raw materials of the component (1) is used. And at least a part of the raw material of the component (3), and p
A molybdenum-bismuth-iron-containing composite oxide catalyst comprising mixing an aqueous slurry having H of 6 or more with a solution or slurry containing the raw material of the component (4), and then drying and calcining the mixture. For the preparation of

[0008] An aqueous slurry containing at least a part of the raw material of the component (1) and at least a part of the raw material of the component (3) and having a pH of 6 or more is heated to a temperature of 5 ° C.
After a heat treatment in a range of 0 to 120 ° C. for at least 10 minutes or more, the mixture is mixed with a solution containing the raw material of the component (4) or a slurry thereof, and then the mixture is dried and calcined, whereby higher activity and selectivity are obtained. Is obtained.

[0009] In the method of the present invention, although it is not clear about the mechanism by which high activity and high selectivity are developed, at least a part of the raw material of the component (1) and at least a part of the raw material of the component (3) are used. By adjusting the pH of the aqueous slurry containing the mixture to pH 6 or more, the component (1) and the component (3) are adjusted.
This is presumably because a compound consisting of is preferentially formed, and then a solution containing an iron raw material or a slurry thereof is added to form a preferable catalyst structure. An aqueous slurry containing at least a part of the raw material of the component (1) and at least a part of the raw material of the component (3) and having a pH of 6 or more at a temperature of 50 ° C to 120 ° C for at least 10 minutes. It is considered that the activity and the selectivity are further improved by mixing the solution containing the raw material of the component (4) or a slurry thereof after the heat treatment, because the formation of such a preferable structure is further promoted. .

The catalyst to which the present invention is applied is represented by the general formula: MoaBibFecQdReXfYgOh (where Mo, Bi, Fe and O represent molybdenum, bismuth, iron and oxygen, respectively, and Q is nickel, cobalt, magnesium, chromium, manganese and zinc. At least one element selected from the group consisting of beryllium, phosphorus, boron, arsenic, selenium, lithium, sodium, potassium, rubidium, cesium, thallium and tellurium; X
Is vanadium, tungsten, yttrium, lanthanum, zirconium, hafnium, niobium, tantalum, aluminum, calcium, strontium, barium,
At least one element selected from the group consisting of lead, copper, cadmium, gallium, indium, germanium, tin, antimony and cerium, Y is praseodymium, neodymium, samarium, europium, gadolinium, thorium, uranium, rhenium, ruthenium, rhodium Represents at least one element selected from the group consisting of, palladium, osmium, iridium, platinum, silver and gold. Here, the subscripts a, b, c, d, e, f and g represent the atomic ratios of the respective elements, and when a = 10, 0.1 ≦ b ≦ 5, 0.1 ≦
c ≦ 10, 0.1 ≦ d ≦ 8, 0 ≦ e ≦ 3, 0 ≦ f ≦ 8,
0 ≦ g ≦ 1 and h is the number of oxygen atoms necessary to satisfy the valence of each component. )).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The starting materials for the respective elements constituting the catalyst of the present invention are not particularly limited. For example, the starting materials for the molybdenum component include molybdenum oxides such as molybdenum trioxide, molybdic acid, Molybdic acid or a salt thereof such as ammonium paramolybdate or ammonium metamolybdate, or a heteropoly acid or a salt thereof containing molybdenum such as phosphomolybdic acid or silicomolybdic acid can be used.

As a raw material of the bismuth component, bismuth salts such as bismuth nitrate, bismuth carbonate, bismuth sulfate and bismuth acetate, bismuth trioxide, metal bismuth and the like can be used. These raw materials can be used as a solid or as an aqueous solution or a nitric acid solution, or a slurry of a bismuth compound generated from the aqueous solution.
Alternatively, it is preferable to use the solution or a slurry generated from the solution.

The raw materials of the iron component include ferrous oxide, ferric oxide, ferric oxide, ferrous nitrate, ferric nitrate, iron sulfate,
Iron chloride, iron organic acid salts, iron hydroxide and the like can be used, and metallic iron may be dissolved in heated nitric acid.
The solution containing the iron component may be used after adjusting the pH with ammonia water or the like. When adjusting the pH, coexistence of a chelating agent in a solution containing an iron component can prevent precipitation of the iron component, and a highly active catalyst can be obtained. Chelating agents that can be used here include ethylenediaminetetraacetic acid, lactic acid, citric acid, tartaric acid and gluconic acid.

The amount of the chelating agent to be added is preferably in the range of 0.1 to 10% by weight, more preferably in the range of 0.5 to 8% by weight, based on the weight of the oxide catalyst to be produced.
If the amount of the chelating agent is less than 0.1% by weight based on the weight of the oxide catalyst, the effect is not sufficiently exhibited, and if it exceeds 10% by weight, many cracks may be formed in the completed catalyst. When preparing a solution containing iron ions and a chelating agent, the chelating agent is used in an amount of 0.1 to 2 per gram of iron.
Gram molecules are preferred.

The raw materials for the other elements are usually oxides or nitrates which can be turned into oxides by heating.
Carbonates, organic acid salts, hydroxides and the like, or mixtures thereof are used.

In the method of the present invention, heat treatment of the aqueous slurry during preparation is not necessarily required, but it is selected from at least a part of the molybdenum raw material and a group consisting of nickel, cobalt, magnesium, chromium, manganese and zinc. By subjecting the aqueous slurry containing at least a part of the raw material of at least one element and having a pH of 6 or more to a temperature of 50 to 120 ° C, preferably 60 to 110 ° C for at least 10 minutes or more, This is desirable in that the properties of the slurry are more stabilized, and the performance, such as the activity and physical properties, of the finally obtained catalyst is improved.

The mixed solution or the aqueous slurry containing the predetermined catalyst component is dried, but the method and the state of the obtained dried product are not particularly limited. For example, a usual spray dryer, slurry dryer, drum dryer or the like is used. A powdery dried product may be obtained, or a block-shaped or flake-shaped dried product may be obtained using an ordinary box-type dryer, tunnel-type firing furnace, or the like. The drying temperature is preferably in the range of 80 to 350C.

There is no particular limitation on the type of firing furnace and the method for firing the obtained dried product.
The dried product may be fired in a stationary state using a normal box-type firing furnace, a tunnel-type firing furnace, or the like, or may be fired while flowing the dried product using a rotary kiln firing furnace or the like. . The firing temperature is 400 to 800 ° C, preferably 5
The range is from 00 to 750 ° C. If the firing is performed at a temperature outside this range, a high-performance catalyst may not be obtained. Also,
There is no particular limitation on the time for which the heat treatment is continued after reaching the predetermined temperature, but if the heat treatment time is too short, a high-performance catalyst may not be obtained. .

Although the catalyst exhibits excellent activity without a carrier,
It may be used by being supported on a suitable carrier. As the carrier used, silica, alumina, zirconia, silica-alumina, silicon carbide, alundum, inorganic silicate and the like can be used. It is particularly preferable to use silica as a carrier for the catalyst in the present invention. The amount of the carrier used is preferably in the range of 10 to 90% of the weight of the catalyst.

The catalyst of the present invention can be used in either a fixed bed or a fluidized bed. The shape and size of the catalyst particles are not particularly limited, and may be in the form of pellets, tablets, spheres, or the like depending on the use conditions. It can be used after being molded into an arbitrary shape and size such as granule and powder.

The catalyst of the present invention is used for an oxidation reaction, an oxidative dehydrogenation reaction and an ammoxidation reaction of an organic compound. Examples of the organic compound subjected to the oxidation reaction using the catalyst of the present invention include propylene, isobutene, methanol, ethanol, tertiary butanol, methyl tertiary butyl ether and the like, and the corresponding aldehyde, nitrile and conjugated diene, respectively. Obtained in high yield. Particularly, a favorable result can be obtained by applying the present invention to the oxidation reaction of propylene, isobutene, and tertiary butanol.

[0022]

EXAMPLES The effects of the present invention will be more specifically described below with reference to examples.

Activity test The activity test of the catalyst was carried out as follows, taking the ammoxidation reaction of propylene as a representative example. The catalyst was packed in a fluidized bed reactor having an inner diameter of 25 mmφ and a height of 40 cm so as to have a predetermined contact time, and maintained at a reaction temperature of 430 ° C. 5. In this reactor, a mixed gas of propylene, ammonia, air and water vapor having a molar ratio of propylene: ammonia: oxygen: water of 1: 1.2: 2.1: 0.5 was added for 6 hours.
5 l (in terms of NTP) was supplied. Reaction pressure is 200 kPa
And The ammoxidation product (acrylonitrile) yield and the conversion rate of the starting organic compound (propylene) in the examples are defined by the following formulas. Acrylonitrile yield (%) = (carbon weight of acrylonitrile produced) / (carbon weight of supplied propylene) × 100 propylene conversion (%) = (carbon weight of propylene consumed) / (propylene supplied Carbon weight) ×
100

Example 1 The composition was Mo.₁₀Bi₁Fe₂Ni_6.5K_0.4P
_0.2O_x-(SiO2) ₆₀(X is the valence of another element
In the following examples and comparisons
In the examples, the description of oxygen in the catalyst composition is omitted. )
The resulting catalyst was prepared in the following manner. 20% silica
To 1745.3 g of the sol, 3.9 g of potassium nitrate was added to pure water 2
A solution dissolved in 0 g was added. Add the solution to this solution with stirring.
171.0 g of ammonium molybdate was added to 510 g of pure water.
Was added. Subsequently, nickel nitrate 183.
0 g dissolved in 190 g pure water, bismuth nitrate 4
A solution of 7.0 g in 48 g of 10% nitric acid and 85%
2.2 g of a phosphoric acid aqueous solution was sequentially added. 1 to this slurry
After adjusting the pH to 8.0 by adding 5% aqueous ammonia,
20 g of enic acid and 78.2 g of ferric nitrate were added to 100 g of pure water.
Was added. Spin the obtained slurry on a rotating disk
320 ° C inlet temperature and 160 ° C outlet temperature using a spray dryer
Controlled and spray dried. The obtained spherical particles
Heat at 50 ° C., followed by 400 ° C. for 2.5 hours, then 6
It was baked at 20 ° C. for 3 hours.

Example 2 The composition is Mo ₁₀ Bi ₁ Fe _0.5 Ni _6.5 Cr ₁ K
_0.4 - _(SiO2) a catalyst represented by _{6 0} was prepared in the following manner. A solution of 5.5 g of potassium nitrate dissolved in 30 g of pure water was added to 2429.3 g of a 20% silica sol. Under stirring, add ammonium paramolybdate 2
A solution in which 38.0 g was dissolved in 650 g of pure water was added. Subsequently, 254.8 g of nickel nitrate and 20.5 g of chromium nitrate were used.
g in 300 g of pure water and bismuth nitrate 6
A solution of 5.4 g dissolved in 66 g of 10% nitric acid was sequentially added. To this slurry was added 15% aqueous ammonia to adjust the pH to 9.
After adjusting the slurry to 5, the slurry was heated under reflux at 100 ° C. for 2 hours, and then a solution of 7 g of citric acid and 27.2 g of ferric nitrate dissolved in 40 g of pure water was added. The obtained slurry was subjected to an inlet temperature of 320 with a rotating disk type spray dryer.
℃, the outlet temperature was controlled at 160 ℃, spray-dried. The spherical particles obtained are heated at 250 ° C.
Baking was performed at 0 ° C. for 2.5 hours and further at 600 ° C. for 3 hours.

Example 3 The composition is Mo ₁₀ Bi ₂ Fe ₂ Co _6.5 K _0.2 Te
_{0.2 - (SiO2)} a catalyst represented by _{6 0,} the next ammonium paramolybdate using cobalt nitrate as a cobalt raw material, in addition to the following potassium nitrate with telluric acid as tellurium material, the final firing temperature 550 ° C. Except having been described, it was prepared in the same manner as in Example 2.

Example 4 The composition was Mo ₁₀ Bi ₁ Fe ₂ Ni ₅ Mg _1.5 K _0.2
Te _0.2 - _(SiO2) a catalyst represented by ₆₀ was prepared in the following manner. To 2438.9 g of a 20% silica sol,
A solution in which 2.7 g of potassium nitrate was dissolved in 30 g of pure water was added. Under stirring, a solution of 238.9 g of ammonium paramolybdate dissolved in 650 g of pure water was added to this solution.
Subsequently, a solution of 196.7 g of nickel nitrate and 52.0 g of magnesium nitrate in 300 g of pure water, a solution of 65.6 g of bismuth nitrate in 66 g of 10% nitric acid, and a solution of 6.2 g of telluric acid in 20 g of pure water Were sequentially added. To this slurry was added 15% aqueous ammonia to adjust the pH to 8.
After adjusting the slurry to 0, the slurry was heated at 100 ° C. for 2 hours under reflux. Separately, citric acid 20 in 150 g of pure water
g, and ferric nitrate (109.3 g) were dissolved, and 15% aqueous ammonia was added to adjust the pH to 7.0. This solution was mixed with the previously heated slurry under stirring. The obtained slurry was spray-dried by controlling the inlet temperature to 320 ° C. and the outlet temperature to 160 ° C. using a rotating disk type spray dryer. The spherical particles obtained are heated at 250 ° C. and subsequently at 400 ° C. for 2.5
Baked at 575 ° C. for 3 hours.

Example 5 The composition is Mo ₁₀ Bi ₂ Fe ₂ Ni ₅ Zn _1.5 K _0.2
A catalyst represented by Ce _0.2- (SiO 2) ₆₀ was added sequentially after nickel nitrate using zinc nitrate as a zinc raw material and cerium nitrate as a cerium raw material to adjust the pH to 8.5 and the final firing temperature to 575 ° C. Except having been described, it was prepared in the same manner as in Example 2.

Example 6 The composition is Mo ₁₀ Bi _1.5 Fe _1.5 Ni ₆ Mn ₁ K
A catalyst represented by _0.5 P _0.2- (SiO 2) ₆₀ is
Manganese nitrate was used as a manganese raw material, and it was prepared in the same manner as in Example 2 except that the pH was adjusted to 8.5 after addition to nickel nitrate.

Example 7 The composition is Mo ₁₀ Bi ₁ Fe ₁ Ni _6.5 K ₁ B _0.5 S
A catalyst represented by m _0.2- (SiO 2) ₉₀ is added to boric acid as a boron raw material, followed by paramolybdic acid, and then samarium nitrate to bismuth nitrate as a samarium raw material, and the final firing temperature is 620 ° C. Except having been described, it was prepared in the same manner as in Example 2.

Example 8 The composition was Mo ₁₀ Bi ₁ Fe ₁ Ni _6.5 K _0.2 Te.
_0.2 W _0.5- (SiO 2) ₄₀
Using ammonium paratungstate as a tungsten raw material and ammonium paramolybdate followed by potassium nitrate using telluric acid as a tellurium raw material, p
It was prepared in the same manner as in Example 2 except that H was changed to 8.5.

Example 9 The composition is Mo ₁₀ Bi ₁ Fe ₁ Ni _6.5 K _0.1 Cs
_0.05 V _0.5- (SiO 2) ₄₀
Cesium nitrate was used as a cesium raw material, and potassium nitrate was used. Then, a solution of ammonium metavanadate dissolved in hydrogen peroxide was used as a vanadium raw material, followed by ammonium paramolybdate, and the pH was adjusted to 8.5. Prepared in a manner similar to Example 1.

Example 10 The composition was Mo ₁₀ Bi ₁ Fe ₁ Ni _6.5 K _0.4 Sn.
A catalyst represented by _0.5 Sb _1- (SiO 2) ₆₀ was added sequentially after ammonium paramolybdate using stannic oxide as a tin material and antimony trioxide as an antimony material, and the pH was adjusted to 9.5. It was prepared in the same manner as in Example 1 except that the pH was adjusted.

Comparative Example 1 Example 1 except that ferric nitrate was added next to nickel nitrate.
A catalyst having the same composition as in Example 1 was prepared in the same manner as in Example 1.

Comparative Example 2 Example 2 except that ferric nitrate was added next to nickel nitrate.
A catalyst having the same composition as in Example 2 was prepared in the same manner as in Example 2.

Comparative Example 3 A catalyst having the same composition as in Example 3 was prepared in the same manner as in Example 3 except that the ferric nitrate solution was added after the cobalt nitrate solution.

Comparative Example 4 A catalyst having the same composition as in Example 4 was prepared by the following method. 2
2438.9 g of 0% silica sol was added to 2.7 kg of potassium nitrate.
g was dissolved in 30 g of pure water. Under stirring, a solution of 238.9 g of ammonium paramolybdate dissolved in 650 g of pure water was added to this solution. Subsequently, a solution in which 65.6 g of bismuth nitrate was dissolved in 66 g of 10% nitric acid and a solution in which 6.2 g of telluric acid was dissolved in 20 g of pure water were sequentially added. To this slurry was added 15% aqueous ammonia to adjust the pH to 8.
After adjusting the slurry to 0, the slurry was heated at 100 ° C. for 2 hours under reflux. Separately, citric acid 20 in 450 g of pure water
g, ferric nitrate 109.3 g, nickel nitrate 196.7
g and magnesium nitrate 52.0 g were dissolved, and 15% aqueous ammonia was added to adjust the pH to 7.0. This solution was mixed with the previously heated slurry under stirring. The obtained slurry was subjected to a rotating disk type spray dryer at an inlet temperature of 320 ° C.
The outlet temperature was controlled at 160 ° C., and spray drying was performed. The obtained spherical particles were heated at 250 ° C., and subsequently calcined at 400 ° C. for 2.5 hours and further at 600 ° C. for 3 hours.

Table 1 shows the results of the activity tests of the catalysts obtained in the examples and comparative examples.

[Table 1]

[0039]

The molybdenum-bismuth-iron-containing composite oxide catalyst prepared by the method of the present invention has high activity,
In addition, the selectivity and yield of the target compound are high, and acrylonitrile can be obtained with good yield by, for example, ammoxidation of propylene.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C07C 253/26 C07C 253/26 255/08 255/08 (72) Inventor Tomi Sasaki 10 Ogurocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture No. 1 Inside the Chemical Development Laboratory, Mitsubishi Rayon Co., Ltd.

Claims (3)

[Claims] 1. A catalyst component comprising (1) molybdenum,
A method for producing a composite oxide catalyst comprising (2) bismuth, (3) at least one element selected from the group consisting of nickel, cobalt, magnesium, chromium, manganese and zinc, and (4) iron as an essential component, An aqueous slurry containing at least a part of the raw material of the component (1) and at least a part of the raw material of the component (3) and having a pH of 6 or more, and a solution or slurry containing the raw material of the component (4) And then drying and calcining the mixture to prepare a molybdenum-bismuth-iron-containing composite oxide catalyst. 2. A catalyst component comprising (1) molybdenum,
A method for producing a composite oxide catalyst comprising (2) bismuth, (3) at least one element selected from the group consisting of nickel, cobalt, magnesium, chromium, manganese and zinc, and (4) iron as an essential component, An aqueous slurry containing at least a part of the raw material of the component (1) and at least a part of the raw material of the component (3) and having a pH of 6 or more at a temperature of 50 to 120 ° C. for at least 10 minutes or more. The molybdenum-bismuth-iron-containing composite oxide according to claim 1, wherein after the heat treatment, the mixture is mixed with a solution containing the raw material of the component (4) or a slurry thereof, and then the mixture is dried and calcined. Preparation of catalyst. 3. The composite oxide catalyst has a general formula: MoaBibFecQdReXfYgOh (wherein Mo, Bi, Fe and O represent molybdenum, bismuth, iron and oxygen, respectively, and Q is nickel, cobalt, magnesium, chromium, manganese and zinc. At least one element selected from the group consisting of beryllium, phosphorus, boron, arsenic, selenium, lithium, sodium, potassium, rubidium, cesium, thallium and tellurium; X
Is vanadium, tungsten, yttrium, lanthanum, zirconium, hafnium, niobium, tantalum, aluminum, calcium, strontium, barium,
At least one element selected from the group consisting of lead, copper, cadmium, gallium, indium, germanium, tin, antimony and cerium, Y is praseodymium, neodymium, samarium, europium, gadolinium, thorium, uranium, rhenium, ruthenium, rhodium Represents at least one element selected from the group consisting of, palladium, osmium, iridium, platinum, silver and gold. Here, the subscripts a, b, c, d, e, f and g represent the atomic ratios of the respective elements, and when a = 10, 0.1 ≦ b ≦ 5, 0.1 ≦
c ≦ 10, 0.1 ≦ d ≦ 8, 0 ≦ e ≦ 3, 0 ≦ f ≦ 8,
0 ≦ g ≦ 1 and h is the number of oxygen atoms necessary to satisfy the valence of each component. 3. The method for preparing a molybdenum-bismuth-iron-containing composite oxide catalyst according to claim 1, wherein the catalyst has a composition represented by the following formula: