JP5609254B2 - Method for producing composite oxide catalyst - Google Patents

Description

  The present invention relates to a method for producing a composite oxide catalyst containing iron, antimony, and silica.

Antimony-containing composite oxide catalysts are widely known as catalysts suitable for the production of aldehydes and unsaturated acids by the oxidation reaction of organic compounds and the production of nitriles and hydrocyanic acid by an ammoxidation reaction. In particular, the antimony-containing composite oxide catalyst is useful for an ammoxidation reaction, and is used, for example, for the production of acrylonitrile by an ammoxidation reaction of propylene or for the production of hydrocyanic acid by an ammoxidation reaction of methanol.
Conventionally, many studies have been made on catalysts used in oxidation reactions and ammoxidation reactions, and various catalysts have been proposed so far.

For example, Patent Document 1 discloses a composite oxide catalyst of antimony and at least one element selected from the group consisting of iron, cobalt, and nickel.
For example, Patent Documents 2 to 11 disclose catalysts in which tellurium, vanadium, tungsten, molybdenum, phosphorus, or the like is added to iron or antimony.
Furthermore, investigations for improving the yield of the target product by improving the catalyst preparation method are continued. For example, Patent Documents 12 to 16 disclose a method for adjusting the pH of a slurry containing antimony and a polyvalent metal compound, a method for heat-treating the slurry, and the like.

Japanese Examined Patent Publication No. 38-19111 Japanese Patent Publication No.46-2804 Japanese Patent Publication No. 47-19765 Japanese Patent Publication No. 47-19766 Japanese Patent Publication No.47-19767 JP 50-108219 A JP 58-145617 A JP-A-1-257125 JP-A-3-26342 JP-A-4-118051 JP 2001-114740 A Japanese Patent Publication No.47-18722 JP 49-40288 A Japanese Patent Laid-Open No. 52-140490 JP-A-60-137438 JP-A-1-265068

However, although catalysts produced using the methods disclosed in these patent documents have some effect in improving the yield of the target product, they are not necessarily sufficient as industrial catalysts, and further improvements in catalyst performance Is desired.
This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the composite oxide catalyst which can manufacture a target product with a high yield.

The method for producing a composite oxide catalyst of the present invention is a method for producing a catalyst for producing acrylonitrile , which contains iron, antimony, and silica, and has a composition represented by the following formula (I): , Antimony, and silica are mixed to prepare a mixed slurry, and after the mixed slurry is heat-treated, the element A is mixed, and the ratio of the amount of A element contained in the mixed slurry before the heat treatment is It is characterized in that the molar fraction is 50% or less with respect to the total amount of element A used for the production of the catalyst.
Fe ₁₀ Sb _i A _a D _d E _e G _g O _x (SiO ₂ ) _y (I)

Where Fe, Sb, and SiO ₂ represent iron, antimony, and silica, respectively, A is nickel, copper, aluminum, manganese, zinc, tin, chromium, cobalt, magnesium, calcium, strontium, lead, barium, niobium , At least one element selected from the group consisting of silver, zirconium, gallium, indium, thallium, titanium, and bismuth, D is at least one element selected from the group consisting of vanadium, molybdenum, and tungsten, and E is phosphorus At least one element selected from the group consisting of arsenic, boron, germanium, and tellurium, G represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and O represents oxygen , I, a, d, e, g, x, and y represents the atomic ratio of each element (silicon in the case of silica), and when Fe = 10, i = 3 to 100, a = 0.1 to 20, d = 0 to 15, e = 0 to 20, g = 0 to 3, x = number of oxygen in the metal oxide formed by combining the above components, y = 10 to 200.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the composite oxide catalyst which can manufacture a target product with a high yield can be provided.

Hereinafter, the present invention will be described in detail.
The method for producing a composite oxide catalyst of the present invention (hereinafter sometimes referred to as “the catalyst production method of the present invention”) contains iron, antimony, and silica, and has a composition represented by the following formula (I). A method for producing a catalyst comprising: mixing at least iron, antimony, and silica to prepare a mixed slurry, heat-treating the mixed slurry, and mixing element A, and mixing before heat-treatment The ratio of the amount of A element contained in the slurry is 50% or less in terms of molar fraction with respect to the total amount of A element used for catalyst production.
Fe ₁₀ Sb _i A _a D _d E _e G _g O _x (SiO ₂ ) _y (I)

Where Fe, Sb, and SiO ₂ represent iron, antimony, and silica, respectively, A is nickel, copper, aluminum, manganese, zinc, tin, chromium, cobalt, magnesium, calcium, strontium, lead, barium, niobium , At least one element selected from the group consisting of silver, zirconium, gallium, indium, thallium, titanium, and bismuth, D is at least one element selected from the group consisting of vanadium, molybdenum, and tungsten, and E is phosphorus At least one element selected from the group consisting of arsenic, boron, germanium, and tellurium, G represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and O represents oxygen , I, a, d, e, g, x, and y represents the atomic ratio of each element (silicon in the case of silica), and when Fe = 10, i = 3 to 100, a = 0.1 to 20, d = 0 to 15, e = 0 to 20, g = 0 to 3, x = number of oxygen in the metal oxide formed by combining the above components, y = 10 to 200.

In the catalyst production method of the present invention, first, a catalyst raw material containing at least iron, antimony, and a silica component is mixed to prepare a mixed slurry before heat treatment.
There are no restrictions on the mixing conditions and mixing order of the catalyst raw materials when preparing the mixed slurry before the heat treatment.

In addition, the mixed slurry before the heat treatment may or may not contain raw materials for the D element, E element, and / or G element component. However, the amount of element A contained in the mixed slurry before the heat treatment is limited.
It is important that the ratio of the amount of A element contained in the mixed slurry before the heat treatment is 50% or less in terms of molar fraction with respect to the total amount of A element used for catalyst production. When the ratio of the amount of A element in the mixed slurry before the heat treatment is 50% or less in terms of molar fraction with respect to the total amount of A element, a catalyst capable of producing the target product in high yield can be obtained. Although the mechanism by which the target product is produced in a high yield is not clear, it is advantageous for producing the target product by controlling the ratio of the amount of element A contained in the mixed slurry during the heat treatment. This is thought to be due to the iron-antimony crystal structure being obtained. The ratio of the amount of element A in the mixed slurry before the heat treatment is preferably 40% or less, and more preferably 30% or less.
In the present invention, the “ratio of the amount of element A” means the ratio of the raw material of the A element component contained in the mixed slurry before the heat treatment to the mole fraction of all the raw materials of the A element component used for catalyst production. It is a converted value.

Although it does not restrict | limit especially about the catalyst raw material of each component used for a catalyst manufacturing method, What is shown below is mentioned.
Examples of the raw material for the iron component include ferrous oxide, ferric oxide, ferrous nitrate, ferric nitrate, iron sulfate, iron chloride, iron organic acid salt, and iron hydroxide. In addition, metallic iron may be dissolved in heated nitric acid.

  As the raw material of the antimony component, for example, oxides such as antimony trioxide and antimony pentoxide, antimony chloride, antimony sulfate and the like can be used.

As a raw material for the silica component, silica sol is preferable, which can be appropriately selected from commercially available ones.
The size of the silica particles in the silica sol is not particularly limited, but the average particle diameter is preferably 2 to 100 nm, more preferably 5 to 75 nm. The silica sol may have a uniform silica particle size or may be a mixture of silica particles of several sizes. Further, a plurality of types of silica sols having different average particles and pH may be mixed and used.
The average particle diameter of the silica particles is a value obtained from the amount of nitrogen adsorbed on the surface of the silica particles by the BET method.

  There are no particular restrictions on the raw materials of the components other than the iron component, antimony component, and silica component, that is, the A element, D element, E element, and G element. Oxidation of each element or easy oxidation by heating Chlorides, sulfates, nitrates, ammonium salts, carbonates, hydroxides, organic acid salts, oxyacids, oxyacid salts, heteropolyacids, heteropolyacid salts, or a mixture thereof can be used. . Moreover, you may use these in combination of multiple types.

  There is no restriction | limiting about the solvent used when preparing a mixing slurry, For example, water, ethyl alcohol, acetone, etc. are mentioned, However, It is preferable to use water. Further, an acid such as nitric acid, sulfuric acid or hydrochloric acid, or an alkaline solution such as aqueous ammonia may be added to the solvent.

Next, the mixed slurry is heated.
The lower limit of the heat treatment temperature is preferably 80 ° C. or higher, more preferably 85 ° C. or higher, and further preferably 90 ° C. or higher. The upper limit is not particularly limited, and is preferably 120 ° C. or lower. If the lower limit of the heat treatment temperature is less than 80 ° C., the formation of an iron-antimony crystal phase that is advantageous for producing the target product tends to be insufficient, and the yield of the target product may be reduced.
The heat treatment time can be performed in the range of 30 minutes to 72 hours. When the heat treatment time is less than 30 minutes, the formation of an iron-antimony crystal phase advantageous for producing the target product tends to be insufficient, and the heat treatment effect cannot be sufficiently obtained. On the other hand, even if the heat treatment time exceeds 72 hours, the obtained effect reaches a peak.
The pressure during the heat treatment is usually performed under normal pressure, but is not particularly limited. If necessary, the heat treatment may be performed under pressure.

Next, the mixed slurry after the heat treatment and the raw material for the element A component are mixed. There are no restrictions on the mixing conditions and mixing order in mixing the mixed slurry after the heat treatment and the raw material of the A element component.
When using the raw material of multiple types of A element component, you may add separately to the mixed slurry after heat processing, and may add together. The raw material for the A element component may be added directly to the mixed slurry after the heat treatment as it is, but it is preferably added as a solution after being dissolved in a liquid such as water.

Further, when the mixed slurry after the heat treatment and the raw material for the A element component are mixed, the raw materials for the D element, the E element, and the G element component may be mixed. There are no restrictions on the mixing conditions and order.
The mixed slurry is not necessarily required to contain all the elements constituting the catalyst, and the raw materials of the element components not contained in the mixed slurry are added in each step until the drying step described later. Alternatively, it may be added by a method such as impregnating the dried catalyst.

Next, in the drying step, the mixed slurry after the heat treatment in which the raw materials for the element A component are mixed is dried to obtain a dried product (catalyst precursor).
The composite oxide catalyst produced by the catalyst production method of the present invention is preferably used as a fluidized bed catalyst, and in that case, it is preferred to form spherical particles by spray drying. At the time of spray drying, a spray dryer such as a pressure nozzle type, a two-fluid nozzle type, and a rotary disk type is used.

At the time of spray drying, the temperature of the hot air circulated in the drying chamber of the spray dryer is preferably 130 ° C. or higher, more preferably 140 ° C. or higher, and preferably the upper limit of the temperature in the vicinity of the inlet to the drying chamber. Is 400 ° C. or lower, more preferably 350 ° C. or lower. Further, the lower limit of the temperature in the vicinity of the drying chamber outlet is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and the upper limit is preferably 220 ° C. or lower, more preferably 200 ° C. or lower. Furthermore, the difference between the temperature in the vicinity of the inlet and the temperature in the vicinity of the drying chamber outlet is preferably maintained at 20 to 220 ° C, more preferably 30 to 210 ° C.
When each of the above temperatures is not within the predetermined range, there may be a problem such that the activity of the obtained catalyst and the yield of the target product are reduced, or the bulk density and particle strength of the catalyst are reduced. There is.

Next, in the firing step, the dried product (catalyst precursor) is fired to obtain a composite oxide catalyst containing iron, antimony, and silica.
In the present invention, the firing is preferably carried out in two or more times. By performing the baking in two or more times, the target product yield is more likely to be improved.
When the final firing is the final firing, and the preliminary firing is performed prior to the final firing, the lower temperature limit of the final firing is preferably 550 ° C. or higher, more preferably 570 ° C. or higher, and the upper limit is preferably It is 1100 degrees C or less, More preferably, it is 1000 degrees C or less. If the temperature is lower than the lower limit, sufficient catalytic performance may not be exhibited, and the target product yield may be reduced. On the other hand, if it is higher than the upper limit, the yield of the target product may be reduced, or the activity of the catalyst may be excessively low. Further, in the ammoxidation reaction, ammonia combustibility is remarkably increased, and the ammonia basic unit may be lowered, which is not preferable.

  Further, the lower limit of the final firing time is preferably 0.1 hour or longer, more preferably 0.5 hour or longer. If the calcination time is shorter than the lower limit, sufficient catalyst performance may not be exhibited, and the target product yield may decrease. The upper limit is not particularly limited, but the effect obtained even if the time is extended more than necessary does not become a certain level, and is usually within 20 hours.

On the other hand, the temperature for temporary baking is preferably in the range of 200 to 490 ° C.
A general-purpose firing furnace can be used for final firing and temporary firing, but a rotary kiln, fluidized firing furnace, and the like are particularly preferably used. The gas atmosphere used at this time may be an oxidizing gas atmosphere containing oxygen or an inert gas atmosphere such as nitrogen, but it is convenient to use air.

The average particle size of the catalyst thus produced is preferably in the range of 5 to 200 μm, more preferably in the range of 10 to 150 μm. In order to make the particle size distribution of the resulting catalyst within a desired range, the spray drying conditions may be adjusted as appropriate.
The average particle diameter of the catalyst is a value (average median diameter) measured by a laser diffraction / scattering method.

  The composition of the catalyst can be confirmed by conducting elemental analysis by ICP (inductively coupled radio frequency plasma) emission analysis, fluorescent X-ray analysis, atomic absorption analysis or the like. In the case where an extremely volatile element is not used, it may be calculated from the amount of each raw material used at the time of catalyst production.

  According to the method for producing a catalyst of the present invention, a composite oxide catalyst capable of producing a target product in a high yield is obtained by defining the ratio of the amount of element A in the mixed slurry before heat treatment within a specific range. It is done. This composite oxide catalyst can be suitably used for producing nitriles and the like by an ammoxidation reaction of an organic compound. Among the ammoxidation reactions, it is suitable for the production of acrylonitrile by the ammoxidation reaction of propylene and the production of hydrogen cyanide by the ammoxidation reaction of methanol. Particularly, when used for the production of acrylonitrile, a high acrylonitrile yield is obtained.

  In order to produce nitriles and the like by an ammoxidation reaction of an organic compound using the composite oxide catalyst produced according to the present invention, it is preferable to use a fluidized bed reactor. This can be carried out by filling the fluidized bed reactor with a composite oxide catalyst and supplying a raw material gas containing a raw material organic compound, ammonia, and oxygen to the catalyst layer.

Although it does not specifically limit as source gas, The source gas of the range whose organic compound / ammonia / oxygen is 1 / 1.1-1.5 / 1.5-3 (molar ratio) is preferable.
It is convenient to use air as the oxygen source. The source gas may be used after being diluted with an inert gas such as water vapor, nitrogen or carbon dioxide, saturated hydrocarbon or the like, or may be used with an increased oxygen concentration.
The reaction temperature of the ammoxidation reaction is preferably 370 to 500 ° C., and the reaction pressure is preferably within the range of normal pressure to 500 kPa.
The apparent contact time is preferably 0.1 to 20 seconds.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to an Example.
In the following examples and comparative examples, “parts” means parts by mass.
In addition, the composition of the catalyst obtained by the Example and the comparative example was calculated | required from the preparation amount of each raw material used for manufacture of a catalyst.
Moreover, the activity test of the catalyst obtained in each example was implemented in the following procedures.

[Catalyst activity test]
In order to evaluate the activity of the catalyst, acrylonitrile was produced by ammoxidation of propylene in the following manner.
A fluidized bed reactor having an inner diameter of 55 mm and a height of 2000 mm in the catalyst fluidized part was filled with the catalyst so that the apparent contact time between the catalyst and the raw material gas was as shown in Table 1. The contact time in that case was calculated | required by the following formula.
Contact time (seconds) = apparent volume density based catalyst volume (mL) / feed gas amount converted to reaction conditions (mL / second)

Air was used as an oxygen source, and a raw material gas having a composition of propylene: ammonia: oxygen = 1: 1.1: 2.3 (molar ratio) was fed into the catalyst layer at a gas linear velocity of 17 cm / sec. The reaction pressure was 200 kPa, and the reaction temperature was 460 ° C.
Gas chromatography was used to quantify the reaction product, and the propylene conversion rate and acrylonitrile yield 4 hours after the start of the reaction were determined. The propylene conversion rate and acrylonitrile yield at that time were determined by the following formula.
Propylene conversion rate (%) = {(carbon mass of supplied propylene−carbon mass of unreacted propylene) / carbon mass of supplied propylene} × 100
Acrylonitrile yield (%) = (carbon mass of produced acrylonitrile / carbon mass of supplied propylene) × 100

  In each example and comparative example, the ratio of the amount of element A in the mixed slurry before the heat treatment, the final calcination conditions (temperature, time) in the calcination process, and the conditions and results of the activity test of the catalyst obtained in each example Table 1 shows.

[Example 1]
The catalyst was produced by the following procedure.
376.6 parts of iron powder was dissolved in 4000 parts of 63% by mass nitric acid. To this solution, 3000 parts of pure water was added with stirring. After heating this solution to 60 ° C., 6751.5 parts of 30% by mass silica, 1769.0 parts of antimony trioxide powder, and a molybdenum solution prepared by dissolving 83.3 parts of ammonium paramolybdate in 200 parts of pure water were sequentially added. A mixed slurry was prepared. The ratio of the amount of A element contained in the mixed slurry before the heat treatment was 0% in terms of molar fraction with respect to the total amount of A element.
15% by mass aqueous ammonia was added to the mixed slurry to adjust to pH 2.2, and the resulting mixed slurry was heated at 98 ° C. for 4 hours under reflux.
Next, the mixed slurry after the heat treatment is cooled to 80 ° C., 101.2 parts of aluminum nitrate nonahydrate, 117.6 parts of nickel nitrate hexahydrate, 488.7 parts of copper nitrate trihydrate Then, 6.57 g of cesium nitrate, 41.7 parts of boric acid, and 387.1 parts of telluric acid were sequentially added. The mixed slurry was atomized using a homogenizer.
The mixed slurry after the atomization treatment was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dry particles were calcined at 250 ° C. for 2 hours and at 450 ° C. for 2 hours, and finally fluidly calcined at 750 ° C. for 4 hours using a fluidized calciner to obtain a catalyst.
The obtained catalyst was subjected to an activity test. In addition, the composition of the obtained catalyst was as follows.
Fe ₁₀ Sb ₁₈ Al _0.4 Ni _0.6 Cu ₃ Mo _0.7 Te _2.5 B ₁ Cs _0.05 O _x (SiO ₂ ) ₅₀
Here, x is the number of oxygen in the metal oxide formed by combining the above components.

[Example 2]
In Example 1, after adding 101.2 parts of aluminum nitrate nonahydrate to the mixed slurry cooled to 80 ° C. after the heat treatment, the iron powder was dissolved in nitric acid and further diluted with pure water. A catalyst was produced in the same manner as in Example 1 except that it was added, and an activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 10% in terms of mole fraction with respect to the total amount of A element.

[Example 3]
In Example 1, 117.6 parts of nickel nitrate hexahydrate were not added after aluminum nitrate, but were added after dissolving iron powder in nitric acid and further diluting with pure water. The catalyst was produced in the same manner as in Example 1 and the activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 15% in terms of mole fraction with respect to the total amount of A element.

[Example 4]
In Example 1, 101.2 parts of aluminum nitrate nonahydrate and 117.6 parts of nickel nitrate hexahydrate were added to nitric acid instead of being added to the mixed slurry cooled to 80 ° C. after the heat treatment. A catalyst was produced in the same manner as in Example 1 except that iron powder was dissolved and further diluted with pure water and then added, and an activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 25% in terms of molar fraction with respect to the total amount of A element.

[Example 5]
The catalyst was produced by the following procedure.
A nitric acid solution was prepared by adding 3000 parts of 63 mass% nitric acid to 3000 parts of pure water being stirred. After heating this nitric acid solution to 60 ° C., 2856.1 parts of ferric nitrate nonahydrate was added and dissolved. In this solution, 4778.4 parts of 40% by mass silica, 1906.4 parts of antimony trioxide powder, molybdenum solution obtained by dissolving 56.2 parts of ammonium paramolybdate in 200 parts of pure water, 180% by mass of ammonium metatungstate solution 180%. .3 parts were added sequentially to prepare a mixed slurry. The ratio of the amount of A element contained in the mixed slurry before the heat treatment was 0% in terms of molar fraction with respect to the total amount of A element.
15% by mass aqueous ammonia was added to the mixed slurry to adjust the pH to 2.2, and the resulting slurry was heated at 98 ° C. for 4 hours under reflux.
Next, the mixed slurry after the heat treatment was cooled to 80 ° C., 6.17 parts of nickel nitrate hexahydrate, 85.4 parts of copper nitrate trihydrate, 46.8 parts of lead nitrate, 85 mass% phosphorus 146.7 parts of acid and 324.7 parts of telluric acid were sequentially added. The mixed slurry was atomized using a homogenizer.
The mixed slurry after the atomization treatment was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dry particles were calcined at 250 ° C. for 2 hours and 450 ° C. for 2 hours, and finally fluidly calcined at 800 ° C. for 4 hours using a fluid calcining furnace to obtain a catalyst.
The obtained catalyst was subjected to an activity test. In addition, the composition of the obtained catalyst was as follows.
Fe ₁₀ Sb _18.5 Ni _0.03 Cu _0.5 Pb _0.2 Mo _0.45 W _0.55 Te ₂ P _1.8 O _x (SiO ₂ ) ₄₅
Here, x is the number of oxygen in the metal oxide formed by combining the above components.

[Example 6]
In Example 5, instead of adding 6.17 parts of nickel nitrate hexahydrate to the mixed slurry cooled to 80 ° C. after the heat treatment, the molybdenum solution was added after the ammonium metatungstate solution and three times. A catalyst was produced in the same manner as in Example 5 except that it was added to each of the mixed slurries cooled to 80 ° C. after the heat treatment instead of being added after the antimony oxide powder, and an activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 4% in terms of mole fraction with respect to the total amount of A element.

[Comparative Example 1]
In Example 1, 488.7 parts of copper nitrate trihydrate was not added after nickel nitrate hexahydrate, but was added after dissolving iron powder in nitric acid and further diluting with pure water. Except for the above, a catalyst was produced in the same manner as in Example 1, and an activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 75% in terms of molar fraction with respect to the total amount of A element.

[Comparative Example 2]
In Example 1, 101.2 parts of aluminum nitrate nonahydrate, 117.6 parts of nickel nitrate hexahydrate, and 488.7 parts of copper nitrate trihydrate were cooled to 80 ° C. after the heat treatment. The catalyst was produced in the same manner as in Example 1 except that the iron powder was dissolved in nitric acid and then diluted with pure water and then added, and the activity test was conducted.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 100% in terms of mole fraction with respect to the total amount of A element.

[Comparative Example 3]
In Example 5, 85.4 parts of copper nitrate trihydrate was not added after nickel nitrate hexahydrate, but after the molybdenum solution and 180.3 parts of ammonium metatungstate solution. The catalyst was produced in the same manner as in Example 5 except that it was added to the mixed slurry cooled to 80 ° C. after the heat treatment instead of being added after the molybdenum solution, and the activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 68% in terms of mole fraction with respect to the total amount of A element.

[Comparative Example 4]
In Example 5, 6.17 parts of nickel nitrate hexahydrate, 85.4 parts of copper nitrate trihydrate, and 46.8 parts of lead nitrate were mixed into a mixed slurry cooled to 80 ° C. after the heat treatment. A catalyst was produced in the same manner as in Example 5 except that the catalyst was added after the ferric nitrate.9 hydrate instead of sequentially, and the activity test was performed.
In the production of this catalyst, the ratio of the amount of A element contained in the mixed slurry before the heat treatment was 100% in terms of mole fraction with respect to the total amount of A element.

As can be seen from Table 1, all of the composite oxide catalysts obtained in Examples 1 to 6 were able to produce acrylonitrile in a high yield.
On the other hand, although the composite oxide catalysts obtained in Comparative Examples 1 and 2 have the same composition as the composite oxide catalysts obtained in Examples 1, 2, 3, and 4, Examples 1 and 2 The acrylonitrile yield was low compared to the catalysts obtained in 3, and 4.
Similarly, the composite oxide catalysts obtained in Comparative Examples 3 and 4 were obtained in Examples 5 and 6 even though they had the same composition as the composite oxide catalysts obtained in Examples 5 and 6. The acrylonitrile yield was low compared to the catalyst.

The composite oxide catalyst produced according to the present invention can produce the target product in high yield in the production of aldehydes and unsaturated acids by the oxidation reaction of organic compounds and in the production of nitriles and hydrocyanic acid by the ammoxidation reaction. . Therefore, its industrial value is great.

Claims (1)

A method for producing a catalyst for producing acrylonitrile , comprising iron, antimony, and silica, and having a composition represented by the following formula (I):
At least iron, antimony, and silica are mixed to prepare a mixed slurry, and the mixed slurry is heated and then mixed with element A,
The ratio of the amount of A element contained in the mixed slurry before heat treatment is 50% or less in terms of molar fraction with respect to the total amount of A element used for catalyst production, .
Fe ₁₀ Sb _i A _a D _d E _e G _g O _x (SiO ₂ ) _y (I)
(Wherein Fe, Sb, and SiO ₂ represent iron, antimony, and silica, respectively, and A represents nickel, copper, aluminum, manganese, zinc, tin, chromium, cobalt, magnesium, calcium, strontium, lead, barium, At least one element selected from the group consisting of niobium, silver, zirconium, gallium, indium, thallium, titanium, and bismuth, D is at least one element selected from the group consisting of vanadium, molybdenum, and tungsten, E is At least one element selected from the group consisting of phosphorus, arsenic, boron, germanium, and tellurium, G is at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and O is oxygen. I, a, d, e, g, x, and Y represents the atomic ratio of each element (silicon in the case of silica), and when Fe = 10, i = 3 to 100, a = 0.1 to 20, d = 0 to 15, e = 0 to 20, (g = 0-3, x = number of oxygen in the metal oxide produced by combining the above components, y = 10-200)