JP2005254058A - Method for manufacturing metallic oxide catalyst containing iron, antimony, and tellurium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a metallic oxide catalyst containing iron, antimony, and tellurium, by which the metallic oxide catalyst excellent in physical properties and activity can be manufactured with high reproducibility without necessitating complicated steps nor complicated apparatuses. <P>SOLUTION: This method for manufacturing the metal oxide catalyst containing iron, antimony, and tellurium comprises: a step (1) to prepare a solution or slurry (X) containing an iron component raw material, an antimony component raw material, and a tellurium component raw material; and a step (2) to dry and fire the solution or slurry (X). The step (1) includes: a step (a) to prepare another solution or slurry (Y) of pH≤7 containing the iron component raw material, the antimony component raw material, and a nitrate ion; and a step (b) to heat-treat the solution and slurry (Y) at ≥60°C for ≥30 minutes. The tellurium raw material is divided into two portions so that one of two portions is added to the solution or slurry before the step (b) and the other is added to the solution or slurry after the step (b). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an iron / antimony / tellurium-containing metal oxide catalyst used for producing nitriles by an ammoxidation reaction of an organic compound.

  Antimony-containing metal oxide catalysts are known as catalysts for the production of aldehydes and unsaturated acids by the oxidation reaction of organic compounds, and the production of nitriles by an ammoxidation reaction, and consist of antimony, iron, cobalt, and nickel. A composite metal oxide catalyst with at least one element selected from the group (Patent Document 1), or a composite metal oxide catalyst containing iron, antimony, tellurium, vanadium, molybdenum, tungsten, or the like (Patent Documents 2 to 8) ) Etc. are disclosed. In particular, a catalyst containing iron, antimony, and tellurium as essential components is considered useful.

Regarding a method for producing a general antimony-containing metal oxide catalyst,
(1) A method in which the pH of a slurry containing trivalent or pentavalent antimony, ferric compound, and nitrate radical is adjusted to about 7 or less and heat-treated in a range of about 40 to 150 ° C. (Patent Document 9 and 10),
(2) an antimony-containing metal oxide composition containing antimony and at least one element selected from the group consisting of iron, cobalt, nickel, manganese, cerium, uranium, tin, titanium, and copper, and antimony alone or antimony A method of dry-mixing the compound and heat-treating at about 300 to 1000 ° C. (Patent Document 11),
(3) A method of using antimonic acid, polyantimonic acid, and / or antimonate and antimony trioxide as a mixture of antimony (Patent Document 12),
(4) A method of irradiating an antimony-containing slurry at the time of pH adjustment or after pH adjustment and before heat treatment (Patent Document 13) is disclosed.

However, for the iron / antimony / tellurium-containing catalyst, the above production methods (1) to (4) are difficult because the production reproducibility is poor and it is difficult to stably obtain a catalyst having sufficient strength and activity. Is considered insufficient.
Therefore, as a method for producing an iron / antimony / tellurium-containing catalyst,
(5) At least one metal selected from the group consisting of vanadium, molybdenum, and tungsten in a slurry containing an antimony compound, a polyvalent metal compound, and a silica raw material, having a pH of 7 or less and heat-treated at a temperature of 40 ° C. or higher. A method for preparing a slurry by mixing a tellurium-containing solution obtained by oxidizing metal tellurium with hydrogen peroxide in the presence of an oxide, an oxyacid, or an oxyacid salt (Patent Document 14),
(6) A metal oxide composition containing antimony and at least one element selected from the group consisting of iron, cobalt, nickel, manganese, uranium, tin, and copper is fired at about 500 to 1000 ° C. There has been proposed a method (Patent Documents 15 to 17) in which a solution containing a tellurium component is impregnated and brought into contact with the solution and then refired.
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-A-52-125124 Japanese Patent Laid-Open No. 4-118051 Japanese Examined Patent Publication No. 46-18722 Japanese Patent Publication No. 47-18723 JP 58-11041 A JP-A-60-166037 Japanese Patent Laid-Open No. 60-166039 JP-A-63-209755 Japanese Patent Laid-Open No. 51-17194 Japanese Examined Patent Publication No. 63-47505 JP 58-11041 A

In the prior art (5) in which an iron / antimony / tellurium-containing slurry is prepared, dried and calcined, it is still difficult to reproducibly produce an iron / antimony / tellurium-containing catalyst having good physical properties and activity. The density and strength of the produced catalyst particles may be insufficient, or the target product yield may be insufficient when subjected to the reaction.
The prior art (6) in which a catalyst containing no tellurium component is prepared in advance, brought into contact with it by impregnation with a tellurium component-containing solution, and refired has the above problem greatly improved. However, there are still problems in industrial practical use, such as the need for a large-scale impregnation apparatus and the like.

  The present invention has been made in view of such circumstances, and an iron / antimony / tellurium-containing metal capable of producing a catalyst having good physical properties and activity with good reproducibility and without requiring a complicated process or apparatus. It aims at providing the manufacturing method of an oxide catalyst.

The inventor diligently studied to solve the above-mentioned problems and invented the following production method.
The method for producing an iron / antimony / tellurium-containing metal oxide catalyst of the present invention comprises a step (1) of preparing a solution or slurry (X) containing an iron component raw material, an antimony component raw material, a tellurium component raw material, and a solution or slurry ( X) Drying and firing step (2) In the method for producing an iron / antimony / tellurium-containing metal oxide catalyst, step (1) has a pH of 7 or less containing an iron component raw material, an antimony component raw material, and nitrate ions. A step (a) of preparing a solution or slurry (Y) of the above and a step (b) of heat-treating the solution or slurry (Y) at a temperature of 60 ° C. or higher, and the tellurium component raw material before the step (b) And adding step by step after step (b).

In the production method of the present invention, the addition ratio of the tellurium component before step (b) / after step (b) is preferably 10 to 90:90 to 10 (however, the total amount is 100).
In the present specification, the “addition ratio of tellurium component” means the ratio of the tellurium mole amount added before the step (b) and after the step (b) in the total tellurium mole amount in the catalyst to be produced. .

The present invention can be preferably applied to a catalyst represented by the following composition formula (I).
_{Fe 10 Sb a A b Te c} D d E e O x · (SiO 2) y ··· (I)
(Wherein, A is at least one element selected from the group consisting of vanadium, molybdenum and tungsten, D is magnesium, calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, At least one element selected from the group consisting of copper, silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic, and bismuth, E is lithium, sodium, potassium, rubidium, And at least one element selected from the group consisting of cesium, subscripts a to e, x, and y represent atomic ratios, a = 3 to 100, b = 0.1 to 15, c = 0.1. -12, d = 0 to 50, e = 0 to 5, and y = 10 to 200. x is formed by combining Fe to E. Shows the number of oxygen genus oxide.)

  The present invention can be preferably applied to a catalyst containing iron antimonate as a crystal phase. Further, it can be preferably applied to a catalyst for producing acrylonitrile by an ammoxidation reaction of propylene.

According to the method for producing an iron / antimony / tellurium-containing metal oxide catalyst of the present invention, physical properties (density and strength of catalyst particles, etc.) are good, and activity (target product yield when subjected to reaction) is good. It is possible to produce an iron / antimony / tellurium-containing metal oxide catalyst with good reproducibility.
Further, according to the production method of the present invention, the catalyst prepared by calcination once does not require an operation such as impregnation with a tellurium component-containing solution. A catalyst having various characteristics can be stably produced at low cost.

Hereinafter, the present invention will be described in detail.
The method for producing an iron / antimony / tellurium-containing metal oxide catalyst of the present invention comprises a step (1) of preparing a solution or slurry (X) containing an iron component raw material, an antimony component raw material, a tellurium component raw material, and a solution or slurry ( X) is roughly composed of a step (2) for drying and baking, and the step (1) is characteristic.

"Process (1)"
In the present invention, the step (1) of preparing a solution or slurry (X) containing an iron component raw material, an antimony component raw material, a tellurium component raw material is a solution having a pH of 7 or less containing an iron component raw material, an antimony component raw material, and nitrate ions. The process (a) which prepares a slurry (Y), and the process (b) which heat-processes a solution or slurry (Y) at the temperature of 60 degreeC or more are included.

Furthermore, in the step (1), the tellurium component raw material is added separately before the step (b) (that is, during the step (a)) and after the step (b). In the step (a), the timing of adding a part of the tellurium component raw material may be before pH adjustment or after adjustment. Further, the tellurium component raw material added first and the tellurium component raw material added later may be the same or non-identical.
Regarding the component raw materials other than tellurium, the whole amount may be added at the time of preparing the solution or slurry (Y), or may be added separately in the step (a) and other optional steps. When the raw materials are added separately, the raw material added first and the raw material added later may be the same or non-identical as in the tellurium component raw material.

The iron component raw material is not particularly limited as long as it can be easily converted into an oxide, but iron is preferably present as trivalent ions in the solution or slurry, and ferric nitrate, ferric sulfate. An inorganic acid salt such as iron acetate, an organic acid salt such as iron acetate, or a metal iron such as electrolytic iron powder dissolved in nitric acid is preferably used.
The amount of iron ion in the solution or slurry (Y) is not particularly limited, but 0.1 gram ion or more, particularly 0.15 to 2 gram ion is preferable with respect to 1 gram atom of antimony. If the amount of iron ions is less than the lower limit, the reaction rate of nitric acid oxidation of antimony trioxide in step (b) becomes too small, which is not practical.

  Although it does not specifically limit as an antimony component raw material, A trivalent compound is preferable as the antimony component raw material added at least when preparing a solution or slurry (Y), and a compound obtained by oxidizing antimony trioxide or metal antimony with nitric acid is preferably used. . In step (b), the trivalent antimony component is oxidized to a pentavalent antimony component to produce iron antimonate.

  Nitrate ions function as an oxidizing agent for nitric acid oxidation of antimony in step (b). The amount of nitrate ion in the solution or slurry (Y) is not particularly limited, but 0.5 gram ion or more, particularly 1 to 5 gram ion is preferable with respect to 1 gram atom of antimony. The nitrate ion source is not particularly limited, and a nitrate ion equivalent or nitric acid contained in ferric nitrate can be used.

  There is no restriction | limiting in particular as a tellurium component raw material, The solution etc. which melt | dissolved tellurium dioxide, telluric acid, metal tellurium in nitric acid can be used. In addition, an oxide of at least one metal selected from the group consisting of vanadium, molybdenum, and tungsten, oxygen acid, or the like, as described in Patent Document 14 listed in the section “Background Art”, or A tellurium-containing solution obtained by hydrogen peroxide oxidation in the presence of an oxyacid salt can also be used.

In the present invention, it is described that the tellurium raw material component is added separately before step (b) (in step (a)) and after step (b). In the present invention, it is particularly preferable that the addition ratio before step (b) (during step (a)) / after step (b) is 10 to 90:90 to 10 (where the total amount is 100). By separately adding the tellurium component at such an addition ratio, a catalyst having particularly good physical properties and activity can be produced with good reproducibility.
The lower limit of the amount of tellurium component added before the step (b) (during step (a)) relative to the total amount of tellurium added is more preferably 15, particularly preferably 20, and the upper limit is more preferably 85, particularly preferably 80. is there.

  In addition to the iron component raw material, the antimony component raw material, the tellurium component raw material, and the nitrate ion source, other components may be added to the solution or slurry (Y) prepared in the step (a) as necessary. However, since a chelating agent or the like may inhibit the nitric acid oxidation reaction of the antimony component in the subsequent step (b), it is preferable to design the component to be added and the amount thereof within a range where there is no such risk.

As described above, in the step (a), a solution or slurry (Y) having a pH of 7 or less is prepared. The upper limit of the pH is preferably 6, particularly preferably 5.
When the pH of the solution or slurry prepared in step (a) exceeds the above upper limit, the iron component settles in the form of hydroxide or the like in the solution or slurry, and nitric acid oxidation reaction of trivalent antimony in step (b) Does not proceed, or the reaction rate is extremely slow, which is not realistic.
The lower limit of the pH is not particularly limited, but it is preferable that the pH be 1 or more, particularly preferably 1.2 or more, because the nitric acid oxidation reaction of trivalent antimony in the step (b) can be promoted.

As described above, the heat treatment temperature in step (b) is 60 ° C. or higher. The lower limit is preferably 70 ° C., particularly preferably 80 ° C. When the heat treatment temperature is less than the lower limit, the production of iron antimonate does not proceed, or the reaction rate is extremely slow, which is not realistic.
The upper limit of the heat treatment temperature is not particularly limited, and it is generally performed at a boiling point or lower at normal pressure of the solution or slurry (Y), for example, 120 ° C. or lower. Processing can also be performed.

  Although the heat processing time in a process (b) is not specifically limited, 30 minutes or more are preferable. The lower limit is more preferably 45 minutes, particularly preferably 60 minutes. If the heat treatment time is too short, the production reaction of iron antimonate is not completed, and the physical properties and activity of the resulting catalyst may be poor. The upper limit of the heat treatment time is not particularly limited, but is usually set within 10 hours. Even if the time is prolonged, the performance of the obtained catalyst is hardly changed, and only the production efficiency is lowered.

After the step (b), the remaining tellurium component raw materials and other component raw materials are added as necessary to obtain a solution or slurry (X) before drying and firing.
The method for preparing the solution or slurry (Y) to be subjected to the heat treatment and the solution or slurry (X) to be subjected to drying and firing is not particularly limited, and contains iron and antimony described in the patent document cited in the section of “Background Technology”. A method for preparing a metal oxide catalyst can be applied.

"Process (2)"
In step (2), the solution or slurry (X) prepared in step (1) is dried and calcined to complete the catalyst.
Drying conditions are not particularly limited. The present invention can be applied to either a fixed bed catalyst or a fluidized bed catalyst, but is particularly preferably applicable to a fluidized bed catalyst. When producing a fluidized bed catalyst, it is preferable to dry the solution or slurry (X) by spray drying. As the spray drying apparatus, known ones such as a rotary disk type and a nozzle type can be used, and the spray drying conditions are appropriately adjusted so as to obtain a catalyst having a preferable particle size as the fluidized bed catalyst.
By firing the dried particles, the activity as a catalyst is expressed. The firing conditions are not particularly limited, but the firing temperature is preferably 200 to 1000 ° C., and the firing time is preferably 0.5 to 20 hours. By carrying out the firing twice or more times, the physical properties and activity of the catalyst may be improved.

In the method for producing a catalyst of the present invention, physical properties (such as the density and strength of the catalyst particles) and activity (subjected to the reaction) are devised by preparing the step (1) for preparing a solution or slurry (X) to be dried and calcined. The production of iron-antimony-tellurium-containing metal oxide catalysts with good yield of the desired product was achieved with good reproducibility.
Furthermore, since the present invention is a devised step (1) for preparing a solution or slurry (X) to be dried and calcined, the catalyst once calcined is further impregnated with a tellurium component-containing solution. No operation is required. Therefore, a catalyst having good characteristics can be stably produced at low cost without requiring a complicated process or apparatus.

The production method of the present invention can be applied to a catalyst having any composition as long as it is an iron / antimony / tellurium-containing metal oxide catalyst, but is particularly preferably applied to a catalyst represented by the following composition formula (I). it can.
_{Fe 10 Sb a A b Te c} D d E e O x · (SiO 2) y ··· (I)
However, in the formula, A is at least one element selected from the group consisting of vanadium, molybdenum and tungsten, D is magnesium, calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, copper At least one element selected from the group consisting of silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic, and bismuth, E is lithium, sodium, potassium, rubidium, and It represents at least one element selected from the group consisting of cesium.

  Subscripts a to e, x, and y represent atomic ratios. The lower limit of a is 3, preferably 5, and the upper limit is 100, preferably 90. The lower limit of b is 0.1, preferably 0.2, and the upper limit is 15, preferably 12. The lower limit of c is 0.1, preferably 0.2, and the upper limit is 12, preferably 10. The lower limit of d is 0, and the upper limit is 50, preferably 40. The lower limit of e is 0, and the upper limit is 5, preferably 4.5. The lower limit of y is 10, preferably 20, and the upper limit is 200, preferably 180. x represents the oxygen number of the metal oxide formed by combining Fe to E, and is naturally determined according to the metal composition.

The composition of the present invention can be preferably applied to a catalyst containing iron antimonate as a crystal phase. There are several compositions of iron antimonate (see, for example, Patent Document 8 listed in the section of “Background Art”), but FeSb ₄ is the most common, and its crystal phase can be confirmed by X-ray diffraction. it can. In this specification, “iron antimonate” includes not only pure iron antimonate but also various elements dissolved therein.

  The present invention is preferably applied to catalysts for the production of aldehydes and unsaturated acids by the oxidation reaction of organic compounds, the production of nitriles by an ammoxidation reaction, especially catalysts for the production of nitriles by an ammoxidation reaction. it can.

  The raw material organic compounds of nitriles include olefins, alcohols, ethers, aromatic compounds, heteroaromatic compounds, etc., specifically propylene, isobutene, methanol, ethanol, tertiary butanol, methyl tertiary butyl ether, toluene , Xylene, picoline, quinaldine and the like. The present invention can be preferably applied particularly to a catalyst for producing acrylonitrile by ammoxidation reaction of propylene.

  In the ammoxidation reaction, the composition of the feed gas is usually made from raw material organic compound / ammonia / air = 1 / 0.1 to 5/8 to 20 (molar ratio), the reaction temperature is 370 to 500 ° C., and the reaction pressure is normal pressure. It is carried out with an apparent contact time of 0.1 to 20 seconds between ˜500 kPa and the catalyst and the supply gas. Air is preferably used as the oxygen source, but it can also be diluted with water vapor, nitrogen, carbon dioxide, saturated hydrocarbon, etc., or enriched with oxygen.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited at all by the following example.
(Example 1-1)
A catalyst represented by the composition formula Fe ₁₀ Sb ₂₅ W _0.5 Mo _1.2 Te ₃ Co ₂ Cu ₂ B _0.5 O _x. (SiO ₂ ) ₆₀ was prepared by the following procedure.
13.6 g of copper powder was dissolved in 761 g of 63 mass% nitric acid. After adding 740 g of pure water to this solution, the solution was heated to 60 ° C., and 59.8 g of electrolytic iron powder and 20.5 g of tellurium powder were added little by little and dissolved. After confirmation of dissolution, 3.3 g of boric acid and 62.3 g of cobalt nitrate were sequentially added and dissolved (solution A).
Separately, 14.0 g of ammonium paratungstate was dissolved in 680 g of pure water (Liquid B).
Separately, 22.7 g of ammonium paramolybdate and 20.5 g of tellurium powder were suspended in 130 g of pure water, heated to 80 ° C., and then dissolved by dropping 62 g of 35% by mass hydrogen peroxide (liquid C). .
While stirring, 1929.5 g of 20% by mass silica sol, 390.1 g of antimony trioxide powder, and B solution were sequentially added to the A solution. 15 mass% ammonia water was dripped at this slurry, and pH was adjusted to 2.0 (above, process (a)). The slurry (Y) after pH adjustment was subjected to heat treatment at 99 ° C. under reflux for 3 hours (step (b)). The slurry after the heat treatment was cooled to 80 ° C., and liquid C was added (step (1) above).
The obtained slurry (X) was spray-dried with a rotary disk spray dryer at an inlet temperature of 330 ° C. and an outlet temperature of 160 ° C., and the obtained dried particles were heated at 250 ° C. for 2 hours and at 400 ° C. for 2 hours. It heat-processed and finally carried out the flow baking for 3 hours at 700 degreeC (process (2)).

(Examples 1-2 and 1-3)
In order to confirm reproducibility, a catalyst having the same composition as in Example 1-1 was prepared by the same method.

(Example 2)
A catalyst represented by the composition formula Fe ₁₀ Sb ₂₀ W _0.3 Mo _0.4 Te ₁ Ni _0.5 Cu ₂ Mg _0.3 P _0.1 Li _0.1 Cs _0.1 · (SiO ₂ ) ₄₅ was prepared by the following procedure.
17.9 g of copper powder was dissolved in 928 g of 63% by mass nitric acid. After adding 900 g of pure water to this solution, it was heated to 60 ° C., and 78.2 g of electrolytic iron powder and 5.4 g of tellurium powder were added little by little and dissolved. After confirmation of dissolution, 10.8 g of magnesium nitrate, 20.5 g of nickel nitrate, 1.0 g of lithium nitrate, and 2.8 g of cesium nitrate were sequentially added and dissolved (solution D).
Separately, 11.0 g of ammonium paratungstate was dissolved in 540 g of pure water (solution E).
Separately, 10.0 g of ammonium paramolybdate and 22.7 g of telluric acid were dissolved in 200 g of pure water (F solution).
While stirring, 1905.2 g of 20% by mass silica sol, 410.9 g of antimony trioxide powder, and E solution were sequentially added to D solution. 15 mass% ammonia water was dripped at this slurry, and pH was adjusted to 1.8 (above, process (a)). The slurry (Y) after pH adjustment was heat-treated at 99 ° C. for 3 hours under reflux (step (b)). The slurry after the heat treatment was cooled to 80 ° C., and 1.6 g of 85 mass% phosphoric acid and liquid F were sequentially added (step (1)).
The obtained slurry (X) was spray-dried in the same manner as in Example 1-1, and the obtained dried particles were heat-treated at 250 ° C. for 2 hours and at 400 ° C. for 2 hours, and finally flowed at 800 ° C. for 3 hours. Firing was performed (step (2)).

(Example 3)
A catalyst represented by the composition formula Fe ₁₀ Sb ₆₀ W _0.5 Mo _0.5 V _0.2 Te ₂ Zn ₃ Cu ₁ K _0.1 · (SiO ₂ ) ₃₀ was prepared by the following procedure.
Copper powder 5.0g was melt | dissolved in 470g of 63 mass% nitric acid. After adding 460 g of pure water to this solution, the solution was heated to 60 ° C., and 43.9 g of electrolytic iron powder and 12.0 g of tellurium powder were added little by little and dissolved. After confirmation of dissolution, 0.8 g of potassium nitrate and 70.2 g of zinc nitrate were sequentially added and dissolved (solution G).
Separately, 10.3 g of ammonium paratungstate was dissolved in 500 g of pure water (liquid H).
Separately, 6.9 g of ammonium paramolybdate, 8.0 g of tellurium powder, and 1.8 g of ammonium metavanadate were suspended in 54 g of pure water, heated to 80 ° C., and then 25 g of 35% by mass hydrogen peroxide solution was dropped. Dissolved (Liquid I).
While stirring, 708.4 g of 20% by mass silica sol, 687.4 g of antimony trioxide powder, and H liquid were sequentially added to G liquid.
15 mass% ammonia water was dripped at the obtained slurry, and pH of the slurry was adjusted to 2.2 (above, process (a)). The slurry (Y) after pH adjustment was heat-treated at 99 ° C. for 3 hours under reflux (step (b)).
The slurry after the heat treatment was cooled to 80 ° C., and the liquid I was added (step (1) above).
The obtained slurry (X) was spray-dried in the same manner as in Example 1-1, and the obtained dried particles were heat-treated at 250 ° C. for 2 hours and 400 ° C. for 2 hours, and finally flowed at 750 ° C. for 3 hours. Firing was performed (step (2)).

Example 4
A catalyst represented by the composition formula Fe ₁₀ Sb ₂₅ Mo ₂ Te ₄ Ni ₂ Cu ₂ Cr _0.1 Al _0.2 Rb _0.05 · (SiO ₂ ) ₅₀ was prepared by the following procedure. .
14.3 g of copper powder was dissolved in 787.1 g of 63% by mass nitric acid. After adding 760 g of pure water to this solution, the solution was heated to 60 ° C., and 62.7 g of electrolytic iron powder and 35.8 g of tellurium powder were added little by little and dissolved. After confirmation of dissolution, 65.3 g of nickel nitrate, 4.5 g of chromium nitrate, 8.4 g of aluminum nitrate, and 0.8 g of rubidium nitrate were sequentially added and dissolved (solution J).
Separately, 39.7 g of ammonium paramolybdate and 38.7 g of telluric acid were dissolved in 400 g of pure water (solution K).
While stirring, 1686.9 g of 20 mass% silica sol and 409.3 g of antimony trioxide powder were sequentially added to the J liquid. 15 mass% ammonia water was dripped at the obtained slurry, and pH of the slurry was adjusted to 2.4 (above, process (a)). The slurry (Y) after pH adjustment was heat-treated at 99 ° C. under reflux for 3 hours (step (b)). The slurry after the heat treatment was cooled to 80 ° C., and liquid K was added (step (1) above).
The obtained slurry (X) was spray-dried in the same manner as in Example 1-1, and the obtained dried particles were heat-treated at 250 ° C. for 2 hours and 400 ° C. for 2 hours, and finally flowed at 740 ° C. for 3 hours. Firing was performed (step (2)).

(Example 5)
A catalyst represented by the composition formula Fe ₁₀ Sb ₃₀ Mo _0.3 V _0.1 Te _1.5 Cu ₂ Mn _0.2 P _0.2 · (SiO ₂ ) ₈₀ was prepared by the following procedure.
10.7 g of copper powder was dissolved in 564.7 g of 63% by mass nitric acid. After adding 550 g of pure water to this solution, the solution was heated to 60 ° C., and 46.9 g of electrolytic iron powder and 10.7 g of tellurium powder were added little by little and dissolved. After confirming dissolution, 4.8 g of manganese nitrate was added (Liquid L).
Separately, 4.5 g of ammonium paramolybdate, 1.0 g of ammonium metavanadate, and 5.4 g of tellurium powder are suspended in 50 g of pure water, heated to 80 ° C., and 35% by mass hydrogen peroxide is added dropwise to dissolve. (M solution).
While stirring, 2019.2 g of 20 mass% silica sol and 367.4 g of antimony trioxide powder were sequentially added to the L liquid. 15 mass% ammonia water was dripped at the obtained slurry, and pH of the slurry was adjusted to 1.7 (above, process (a)). The slurry (Y) after pH adjustment was heat-treated at 99 ° C. for 3 hours under reflux (step (b)). The slurry after the heat treatment was cooled to 80 ° C., and liquid M was added (step (1) above).
The obtained slurry (X) was spray-dried in the same manner as in Example 1-1, and the obtained dried particles were heat-treated at 250 ° C. for 2 hours and 400 ° C. for 2 hours, and finally flowed at 780 ° C. for 3 hours. Firing was performed (step (2)).

(Comparative Example 1-1)
A catalyst was prepared in the same manner as in Example 1-1 except that the tellurium powder of the tellurium component raw material was added all at once to the liquid A.
(Comparative Examples 1-2, 1-3)
In order to confirm reproducibility, a catalyst was prepared by the same method as Comparative Example 1-1.
(Comparative Example 2)
A catalyst was prepared in the same manner as in Example 2 except that telluric acid was used as a tellurium component raw material and all the components were added to the F solution at once.
(Comparative Example 3)
A catalyst was prepared in the same manner as in Example 1-1 except that the pH was adjusted to 8.0 when adjusting the pH with aqueous ammonia.

  Composition of catalyst prepared in each example, and catalyst preparation conditions (addition ratio of tellurium (Te) before / after heat treatment of solution or slurry in step (1), pH of solution or slurry adjusted with aqueous ammonia, The firing temperature is summarized in Table 1.

(Evaluation items and evaluation methods)
Evaluation items and evaluation methods were as follows.
<Compressive strength of catalyst particles>
The compressive strength of the catalysts obtained in Examples 1-1 to 1-3 and Comparative Example 3 was measured.
Particles having a particle size of 45 to 50 μm were collected using Micromesh High Precision Sieves, and the compressive strength (g · weight / particle) was measured with “MCTM-200” manufactured by Shimadzu Corporation. In each example, measurement was performed with 30 samples, and an average value was obtained. The measurement conditions were as follows. The results are shown in Table 2.
Upper pressure indenter Diamond 500μm flat indenter Lower pressure plate SUS plate Load speed 0.72g weight / sec

<Activity of catalyst>
Using the catalyst prepared in each example except Comparative Example 3, acrylonitrile was synthesized by ammoxidation of propylene.
The catalyst was packed in a fluidized bed reactor having an inner diameter of 25 mm and a height of 400 mm. To this, air was used as an oxygen source, and a supply gas having a composition of propylene / ammonia / oxygen = 1 / 1.1 / 2.2 (molar ratio) was fed at a gas linear velocity of 4.5 cm / sec. The reaction pressure was 200 kPa. The reaction temperature and the apparent contact time between the catalyst and the feed gas defined by the following formula were as shown in Table 2. Four hours after the start of the reaction, the propylene conversion rate and the acrylonitrile yield defined by the following formulas were determined.
Contact time (sec) = catalyst volume based on apparent bulk density (ml) / feed gas flow rate converted to reaction conditions (ml / sec)
Propylene conversion rate (%) = (number of moles of propylene consumed in reaction / number of moles of propylene supplied) × 100
Acrylonitrile yield (%) = (number of moles of acrylonitrile produced / number of moles of propylene fed) × 100

(result)
The results are shown in Table 2.
As shown in Tables 1 and 2, in the examples where the catalyst was produced by the production method of the present invention, a catalyst having good compressive strength and activity was obtained. When acrylonitrile was synthesized, the propylene conversion rate was 97. A good acrylonitrile yield of 81.4% or higher was obtained. Moreover, as shown in Examples 1-1 to 1-3, a catalyst having the same characteristics could be stably produced with good reproducibility.

On the other hand, in Comparative Examples 1-1 to 1-3 and 2 in which tellurium component raw materials were added all at once, the obtained catalyst was compared with the example in which the catalyst having the same composition was prepared in the synthesis of acrylonitrile. The propylene conversion rate and the acrylonitrile yield were inferior. In addition, as shown in Comparative Examples 1-1 to 1-3, even when the catalyst was prepared under the same conditions, the activity varied, and it was difficult to produce a catalyst having equivalent characteristics with good reproducibility.
Further, in Comparative Example 3 in which the pH of the solution or slurry immediately before the heat treatment was more than 7, the obtained catalyst had a result that the compressive strength was remarkably inferior to the Examples.

  The technique of the present invention can be preferably applied to an iron / antimony / tellurium-containing metal oxide catalyst used for the production of aldehydes and unsaturated acids by oxidation reaction of organic compounds and the production of nitriles by ammoxidation reaction.

Claims (5)

Iron, antimony, and step (1) of preparing a solution or slurry (X) containing an iron component raw material, an antimony component raw material, a tellurium component raw material, and a step (2) of drying and firing the solution or slurry (X) In the method for producing a tellurium-containing metal oxide catalyst,
Step (1) is a step (a) of preparing a solution or slurry (Y) having a pH of 7 or less containing an iron component raw material, an antimony component raw material, and nitrate ions, and the solution or slurry (Y) at a temperature of 60 ° C. or higher. Including a step (b) of heat treatment,
A method for producing an iron / antimony / tellurium-containing metal oxide catalyst, wherein the tellurium component raw material is added separately before step (b) and after step (b).   The ratio of the tellurium component before step (b) / after step (b) is set to 10 to 90:90 to 10 (provided that the total amount is 100). A method for producing an antimony and tellurium-containing metal oxide catalyst. The method for producing an iron / antimony / tellurium-containing metal oxide catalyst according to claim 1, wherein the catalyst is represented by the following composition formula (I).
_{Fe 10 Sb a A b Te c} D d E e O x · (SiO 2) y ··· (I)
(Wherein, A is at least one element selected from the group consisting of vanadium, molybdenum and tungsten, D is magnesium, calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, At least one element selected from the group consisting of copper, silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic, and bismuth, E is lithium, sodium, potassium, rubidium, And at least one element selected from the group consisting of cesium, subscripts a to e, x, and y represent atomic ratios, a = 3 to 100, b = 0.1 to 15, c = 0.1. -12, d = 0 to 50, e = 0 to 5, and y = 10 to 200. x is formed by combining Fe to E. Shows the number of oxygen genus oxide.)   The method for producing an iron / antimony / tellurium-containing metal oxide catalyst according to claim 1, wherein the catalyst contains iron antimonate as a crystal phase.   The method for producing an iron / antimony / tellurium-containing metal oxide catalyst according to claim 1, wherein the catalyst is for producing acrylonitrile by an ammoxidation reaction of propylene.