Method for producing catalyst

Abstract

Provided is a method for producing a catalyst for producing 1,3-butadiene from a starting material that contains ethanol, the method comprising: a heat treatment step for fixing an element (A) which is selected from the group consisting of group 4 elements and group 5 elements of the periodic table on a carrier by subjecting a mixture that contains a water-soluble adjustment material of the element (A) which is prepared to be water-soluble, the carrier, and water to a heat treatment under the conditions where the heat treatment temperature is 80°C or higher and the heat treatment temperature is equal to or lower than the boiling point of water; and a drying and firing step for drying and firing the mixture after the heat treatment step.

Description

Catalyst manufacturing method

[0001] The present invention relates to a method for producing a catalyst for producing 1,3-butadiene from a raw material containing ethanol.

[0002] The ETB (Ethanol to Butadiene) process for producing 1,3-butadiene from raw materials containing ethanol includes a single-stage process (Lebedev process) in which ethanol is converted to butadiene in one stage, and a two-stage process (Ostromislensky process) in which ethanol is first dehydrogenated to synthesize acetaldehyde, and then butadiene is synthesized from the ethanol and acetaldehyde. Catalysts in which elements of Groups 4 and 5 of the periodic table are supported on silica are known as ETB catalysts used in the ETB process (Patent Documents 1 and 2).

[0003] Japanese Patent No. 6803289 Japanese Patent No. 7227209

[0004] The present invention provides a novel method for producing a catalyst that provides high 1,3-butadiene selectivity.

[0005] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have completed the present invention with the following configuration. [1] A method for producing a catalyst for producing 1,3-butadiene from a raw material containing ethanol, the method comprising: a heat treatment step of heat-treating a mixture containing a water-soluble preparation of an element (A) selected from Groups 4 and 5 of the periodic table, a support, and water, at a heat treatment temperature of 80°C or higher under conditions that are equal to or lower than the boiling point of water, thereby immobilizing the element (A) on the support; and a drying and calcining step of drying and calcining the mixture after the heat treatment step. [2] The method for producing the catalyst according to [1], wherein the heat treatment step is performed in the presence of liquid water. [3] The method for producing the catalyst according to [1] or [2], wherein the heat treatment temperature is higher than 100°C. [4] The method for producing the catalyst according to [1] or [2], wherein the heat treatment temperature is higher than 100°C. [5] The method for producing the catalyst according to [1] or [2], wherein the heat treatment step is performed at a temperature in the range of 120°C to 200°C. [5] The method for producing a catalyst according to [1] or [2], wherein the heat treatment step is carried out at a temperature in the range of 140°C to 180°C. [6] The method for producing a catalyst according to any one of [1] to [5], wherein the heat treatment step is carried out under acidic conditions. [7] The method for producing a catalyst according to any one of [1] to [6], wherein the element (A) is tantalum, and the water-soluble preparation is tantalum oxalate. [8] The method for producing a catalyst according to any one of [1] to [7], wherein the drying and calcining step includes a drying step of drying the mixture after the heat treatment step, and a calcining step of calcining the mixture after the drying step at 110°C to 550°C. [9] The method for producing a catalyst according to any one of [1] to [8], further including a mixture production step of immersing the support in an aqueous solution of the water-soluble preparation to produce the mixture prior to the heat treatment step.

[10] The method for producing a catalyst according to [9], wherein the support has pores, and the aqueous solution of the water-soluble preparation is in an amount that is 0.9 times or more the volume of the pores and 10 times or less the volume of the support.

[11] The method for producing a catalyst according to any one of [1] to

[10] , further comprising, prior to the heat treatment step, a mixture production step of adding water to a dried product containing the water-soluble preparation and the support to produce the mixture.

[12] The method for producing a catalyst according to

[11] , wherein in the mixture production step, the dried product is produced by immersing the support in an aqueous solution of the water-soluble preparation and then drying it.

[0006] According to the present invention, a method for producing a novel catalyst that can provide high 1,3-butadiene selectivity can be provided.

[0007] 1 is a graph showing the 1,3-butadiene selectivity of the catalysts prepared in Examples 1 to 7 and Comparative Example 1.

[0008] Hereinafter, embodiments for carrying out the present invention will be described.

[0009] The catalyst produced in this embodiment is a catalyst for producing 1,3-butadiene from a raw material containing ethanol, and includes an element (A) selected from the group consisting of Groups 4 and 5 of the Periodic Table, and a support.

[0010] Examples of the element (A) include titanium, zirconium, hafnium, vanadium, niobium, tantalum, etc. From the viewpoint of improving the 1,3-butadiene selectivity, the element (A) is preferably at least one selected from zirconium, hafnium, and tantalum.

[0011] Examples of the carrier include silicon dioxide, mesoporous silica, and zeolite. When using zeolite, the element (A) may be added to the zeolite precursor to synthesize the carrier. When zeolite is not used, silicon dioxide alone may be used. Examples of silicon dioxide include amorphous silica, silica sol, silica gel, and colloidal silica. Examples of mesoporous silica include MCM-41, FSM-16, and SBA-15.

[0012] The manufacturing method of this embodiment includes a heat treatment step in which a mixture containing a water-soluble preparation adjusted to the water solubility of element (A), a carrier, and water is heat-treated, and a drying / calcination step in which the mixture after the heat treatment step is dried and calcined. In the heat treatment step, element (A) is immobilized on the carrier. In immobilizing element (A) on the carrier, it is preferable that element (A) is supported on the carrier, and further, it is preferable that element (A) and the carrier are chemically bonded. In the following description, the water-soluble preparation of element (A) may be simply referred to as the water-soluble preparation.

[0013] The water-soluble preparation may be a compound or composition prepared so that the element (A) is water-soluble. For example, the element (A) may be an organic acid salt such as oxalic acid, glycolic acid, lactic acid, malic acid, or citric acid. Examples of the organic acid include dicarboxylic acid and hydroxycarboxylic acid. When the element (A) is tantalum, the water-soluble preparation may be tantalum oxalate. The use of a water-soluble preparation of the element (A) makes the element (A) more easily dispersible in a mixture containing the water-soluble preparation and water (such as an aqueous solution of the water-soluble preparation), and facilitates interaction with the carrier during the heat treatment process.

[0014] (Heat Treatment Step) In the heat treatment step, heat treatment is performed at a heat treatment temperature of 80°C or higher, and at a temperature equal to or lower than the boiling point of water. The heat treatment temperature is preferably higher than 100°C, and may be in the range of 120°C to 200°C, or even in the range of 140°C to 180°C. By performing the heat treatment step, the element (A) may be chemically bonded to the carrier. In this case, for example, a step of desorbing an organic substance such as oxalic acid contained in the water-soluble preparation from the element (A) may be included.

[0015] As shown in Figure 1, the selectivity of 1,3-butadiene can be improved by carrying out the heat treatment step in the range of 120°C to 200°C. In addition, the selectivity of 1,3-butadiene can be further improved by carrying out the heat treatment step in the range of 140°C to 180°C. On the other hand, even when the temperature is relatively low, the selectivity of 1,3-butadiene can be improved by extending the heat treatment time.

[0016] When element (A) is released from the water-soluble preparation, the water solubility at room temperature and normal pressure may decrease, but the above-mentioned heat treatment conditions can maintain or increase the solubility of element (A). The element (A) forms a chemical bond with the support, thereby obtaining a catalyst whose activity is stably maintained. The heat treatment step may be a process in which a substance in which element (A) and the support are chemically bonded is synthesized according to a hydrothermal treatment method.

[0017] The heat treatment step may be performed under conditions in which liquid water is present. The conditions under which liquid water is present at high temperatures as described above may be selected to be higher pressure than atmospheric pressure (approximately 0.1 MPa). When performing the heat treatment step under high pressure, an autoclave can be used. For example, the vapor pressure in the container during treatment at 140 to 180°C is 0.37 to 1.02 MPa, and the vapor pressure during treatment at 120 to 200°C is 0.2 to 1.2 MPa.

[0018] The heat treatment step is preferably carried out under acidic conditions. If necessary, a pH adjuster may be added to the mixture. By carrying out the heat treatment step under acidic conditions, the burden on the support can be reduced. If the heat treatment step is carried out at a pH of 7.0 or higher, the element (A) precipitates in the mixture containing the water-soluble preparation and water (such as an aqueous solution of the water-soluble preparation), resulting in a decrease in catalytic performance. Furthermore, the support is likely to become brittle. Therefore, the heat treatment step is preferably carried out under acidic conditions.

[0019] (Mixture Production Step 1) The production method of this embodiment may include a mixture production step of immersing a carrier in an aqueous solution of a water-soluble preparation to produce a mixture containing the water-soluble preparation, the carrier, and water prior to the heat treatment step. In this case, the production method of this embodiment includes the mixture production step, the heat treatment step, and the drying / calcination step.

[0020] In the mixture production step, if the carrier has pores, the aqueous solution of the water-soluble preparation may be present in an amount that is 0.9 times or more the volume of the pores and 10 times or less the volume of the carrier. The volume of the carrier may be the total volume of the carrier to be immersed. At least a part or all of the pores may be filled with the aqueous solution. The aqueous solution of the water-soluble preparation may be absorbed into the pores of the carrier, or the aqueous solution of the water-soluble preparation may be present in a liquid phase outside the carrier.

[0021] (Mixture Production Step 2) The production method of this embodiment may include a mixture production step in which, prior to the heat treatment step, water is added to a dried product containing the water-soluble preparation and the carrier to produce a mixture containing the water-soluble preparation, the carrier, and water. In this mixture production step, the dried product may be produced by immersing the carrier in an aqueous solution of the water-soluble preparation and then drying. In this case, the production method of this embodiment includes a dried product production step, a mixture production step, a heat treatment step, and a drying / calcination step.

[0022] When a dried product production step is performed, the element (A) may be supported on a carrier during drying. In this case, in the dried product, the element (A) may be supported on a carrier in the form of a water-soluble preparation, or the element (A) may not be chemically bonded to the carrier.

[0023] At the stage of adding water to the dried product, at least a portion of the water-soluble preparation contained in the dried product may be dissolved or wet. At least a portion of the water-soluble preparation may remain in a dry state while the carrier is wet. When the carrier has pores, the aqueous solution of the water-soluble preparation may be in an amount of 0.9 times or more the volume of the pores and 10 times or less the volume of the carrier. At the stage of immersing the carrier in the aqueous solution of the water-soluble preparation, at least a portion or all of the pores may be filled with the aqueous solution. The aqueous solution of the water-soluble preparation may be absorbed into the pores of the carrier, or the aqueous solution of the water-soluble preparation may exist in a liquid phase outside the carrier. In the dried product, the water may volatilize, and the solid of the water-soluble preparation may remain on the outer surface or in the pores of the carrier.

[0024] (Drying / calcining step) The drying / calcining step may include a drying step in which the mixture after the heat treatment step is dried, and a calcining step in which the mixture after the drying step is calcined at 110°C to 550°C. Drying and calcining of the mixture may proceed in one step. The catalyst of this embodiment is produced by calcining the mixture. That is, after the calcining step, the catalyst production process is completed without performing additional steps such as modification with Si. Therefore, the catalyst after the calcining step is ready to be used as a product. Even if the number of steps is reduced by omitting Si modification, a high 1,3-butadiene selectivity can be obtained.

[0025] The drying and firing process may be carried out at a temperature at which the water contained in the mixture after the heat treatment process can be evaporated and at a temperature equal to or higher than the decomposition temperature of the water-soluble preparation. For example, the firing process may be carried out in the range of 110°C to 400°C or 150°C to 250°C. In this embodiment, for example, when tantalum oxalate is used as the water-soluble preparation, the firing process may be carried out at a temperature equal to or higher than the decomposition temperature of tantalum oxalate. Alternatively, when tantalum oxalate is decomposed into tantalum oxide and oxalic acid after the heat treatment process, the firing process may be carried out at a temperature equal to or higher than the decomposition temperature of oxalic acid.

[0026] When Si modification is omitted, the catalyst of this embodiment can be produced, for example, without including a reaction product with a silicon compound having a hydrolyzable group. Here, a silicon compound having a hydrolyzable group is a compound in which 1 to 4 hydrolyzable groups are bonded to a silicon atom. Examples of the hydrolyzable group include hydrogen, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. A silicon compound having a hydrolyzable group is represented, for example, by the following formula (1): SiY ｎ R （４－ｎ） ...(1)

[0027] In formula (1), each Y is independently a hydrolyzable group. R is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. n is an integer of 1 to 4. The substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms is not particularly limited, and examples include alkyl groups having 1 to 20 carbon atoms (methyl, ethyl, propyl, etc.), aryl groups having 6 to 20 carbon atoms (phenyl, tolyl, etc.), and aralkyl groups having 7 to 20 carbon atoms (benzyl, phenethyl, etc.). When two or more Y or R are bonded, they may be the same or different. Furthermore, the silicon compound having a hydrolyzable group may be a partial polycondensate in which at least a portion has been polycondensed.

[0028] In the catalyst production method of this embodiment, when the Si modification is omitted, the mixture containing the water-soluble preparation, the carrier, and water prior to the heat treatment step may be a mixture that does not contain the silicon compound having a hydrolyzable group. 29 When the signal intensity of the maximum value in the Si-NMR chemical shift value near −111 ppm is taken as 1, the signal intensity at the chemical shift value −105 ppm may be less than 0.55.

[0029] The catalyst of this embodiment may contain, in addition to the element (A) and the carrier, metals such as zinc, silver, copper, and gold, alkali metals, alkaline earth metals, lanthanoids, etc. The shape of the catalyst is not particularly limited, and known shapes such as granular, columnar, cylindrical, and honeycomb shapes can be used.

[0030] [Method for Producing 1,3-Butadiene] The method for producing 1,3-butadiene using the catalyst of this embodiment is characterized by bringing a raw material containing at least ethanol into contact with the catalyst under heating. The origin of the ethanol is not particularly limited, and examples thereof include ethanol derived from biomass such as sugarcane or corn, or from petroleum, coal, or natural gas. The use of biomass-derived ethanol can contribute to reducing greenhouse gas emissions.

[0031] The raw material may be ethanol alone, or may contain acetaldehyde together with ethanol. When acetaldehyde is contained, the molar ratio of ethanol to acetaldehyde (EtOH:AcH) is in the range of 95:5 to 40:60, preferably 90:10 to 50:50, and more preferably 85:15 to 50:50.

[0032] The reaction conditions are not particularly limited, and well-known systems such as a batch system, a semi-batch system, a continuous system, etc. A continuous system allows for large-scale synthesis, reduces the operational workload, and reuses unreacted raw materials in the reaction system to improve the utilization rate of raw material ethanol, thereby enabling simple and efficient separation and recovery of 1,3-butadiene.

[0033] Examples of methods for contacting the raw material with the catalyst include a suspension bed method, a fluidized bed method, and a fixed bed method. The raw material may be supplied by either a gas phase method or a liquid phase method, with the gas phase method being preferred. When the reaction is carried out in the gas phase, the raw material gas may be supplied to the reactor without dilution, or may be supplied to the reactor after being appropriately diluted with an inert gas such as nitrogen, helium, argon, or water vapor. During the reaction, acetaldehyde may be added to the raw material containing ethanol to adjust the molar ratio (EtOH:AcH) to the above-mentioned ratio.

[0034] After completion of the reaction, the reaction product can be separated and purified into light gases, C4 fractions, heavy components, water, ethanol, acetaldehyde, etc., by separation means such as distillation or extraction, or a combination thereof. The above-mentioned catalyst can be used for the efficient production of 1,3-butadiene, and therefore has high industrial applicability.

[0035] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0036] (Example 1) As a water-soluble preparation of the element (A), an aqueous solution of tantalum oxalate (TANiOBIS, Ta ２ O ５192 g / L) was used. The pH of the tantalum oxalate aqueous solution was approximately 1.5. 0.82 g of the tantalum oxalate aqueous solution was further diluted by adding 14.10 g of distilled water. The pH of the diluted tantalum oxalate aqueous solution was approximately 2.0. Spherical silica having a particle size of 1.18 to 2.36 mm was used as the carrier. 10.00 g of spherical silica was added to the diluted tantalum oxalate aqueous solution to obtain a mixture containing a water-soluble preparation of element (A), a carrier, and water. The moisture content of a sample of the mixture containing the water-soluble preparation, a carrier, and water was measured using a moisture meter manufactured by KETT Corporation and was found to be 50 to 60%.

[0037] A mixture containing a water-soluble preparation, a carrier, and water: about 4.00 cm ３ The mixture was placed in a container in a wet state, placed in an autoclave, and subjected to hydrothermal treatment at 160°C for 10 hours. The container had an outer cylinder made of SUS and an inner cylinder made of polytetrafluoroethylene (PTFE), and had a capacity of approximately 50 cm ３ The following items were used.

[0038] (Example 2) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 80°C. (Example 3) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 100°C. (Example 4) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 120°C. (Example 5) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 140°C. (Example 6) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 180°C. (Example 7) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 200°C. (Example 8) Hydrothermal treatment was carried out in the same manner as in Example 4, except that the hydrothermal treatment time was 36 hours. (Comparative Example 1) Hydrothermal treatment was carried out in the same manner as in Example 1, except that the hydrothermal treatment temperature was changed to 60°C.

[0039] (Example 9) As a water-soluble preparation of the element (A), an aqueous solution of tantalum oxalate (TANiOBIS, Ta ２ O ５192 g / L) was used. The pH of the tantalum oxalate aqueous solution was approximately 1.5. 1.14 g of the tantalum oxalate aqueous solution was further diluted by adding 30.57 g of distilled water. The pH of the diluted tantalum oxalate aqueous solution was approximately 1.8. Spherical silica having a particle size of 1.18 to 2.36 mm was used as the carrier. 10.00 g of spherical silica was added to the diluted tantalum oxalate aqueous solution to obtain a mixture containing a water-soluble preparation of element (A), the carrier, and excess water.

[0040] The entire mixture containing the water-soluble preparation, the carrier, and excess water was placed in a container, which was then placed in an autoclave and subjected to hydrothermal treatment at 160°C for 10 hours. The container had an outer cylinder made of SUS and an inner cylinder made of polytetrafluoroethylene (PTFE), and had a capacity of approximately 50 cm3. ３ The following items were used.

[0041] Comparative Example 2 As a water-soluble preparation of the element (A), an aqueous solution of tantalum oxalate (TANiOBIS, Ta ２ O ５ A tantalum oxalate aqueous solution (178 g / L) was used. The pH of the tantalum oxalate aqueous solution was approximately 1.5. 1.16 g of the tantalum oxalate aqueous solution was further diluted by adding 30.56 g of distilled water. The pH of the diluted tantalum oxalate aqueous solution was approximately 1.8. Spherical silica with a particle size of 1.18 to 2.36 mm was used as the carrier. 10.00 g of spherical silica was added to the diluted tantalum oxalate aqueous solution to obtain a mixture containing a water-soluble preparation of element (A), the carrier, and excess water. A tetraethylammonium hydroxide aqueous solution (Sigma-Aldrich, 35 wt%) was then added to adjust the pH to 10.

[0042] The entire mixture containing the water-soluble preparation, the carrier, and excess water, and further adjusted to pH 10 with a tetraethylammonium hydroxide aqueous solution, was placed in a container, charged into an autoclave, and subjected to hydrothermal treatment at 160 ° C. for 10 hours. The container had an outer cylinder made of SUS and an inner cylinder made of polytetrafluoroethylene (PTFE), and had a capacity of approximately 50 cm ３ The following items were used.

[0043] (Example 10) As a water-soluble preparation of the element (A), an aqueous solution of tantalum oxalate (TANiOBIS, Ta ２ O５ 178 g / L) was used. The pH of the tantalum oxalate aqueous solution was approximately 1.5. 3.74 g of the tantalum oxalate aqueous solution was further diluted by adding 41.23 g of distilled water. The pH of the diluted tantalum oxalate aqueous solution was approximately 1.8. Spherical silica with a particle size of 1.18 to 2.36 mm was used as the carrier. 30.00 g of spherical silica was added to the diluted tantalum oxalate aqueous solution to obtain a mixture containing a water-soluble preparation of element (A), the carrier, and water. This was dried at 60°C for 10 hours to obtain a dried product containing the water-soluble preparation and the carrier.

[0044] 6 g of the dried product containing the water-soluble preparation and the carrier and 18.92 g of distilled water were placed in a container, charged into an autoclave, and subjected to hydrothermal treatment at 160 ° C. for 10 hours. The container had an outer cylinder made of SUS and an inner cylinder made of polytetrafluoroethylene (PTFE), and had a capacity of approximately 50 cm ３ The following items were used.

[0045] (Production of catalyst) The mixture after the hydrothermal treatment was dried at 120°C for 10 hours and then calcined at 200°C for 6 hours.

[0046] (Production of 1,3-butadiene using the catalyst) Using the obtained catalyst, a process for producing 1,3-butadiene from a raw material containing ethanol was carried out. 0.95 g of the catalyst crushed to 300 to 710 μm was packed into an SUS reaction tube with an inner diameter of 8 mm. A mixed raw material of ethanol and acetaldehyde adjusted to a molar ratio of 80:20 was added at a WHSV of 1.0 h. －１ The feedstock was supplied at a rate of 1,3-1,4-tetrafluoroethylene (TFE) and reacted at a reaction temperature of 330°C and a feedstock partial pressure of 0.26 MPaA. The results of measuring the feedstock conversion and 1,3-butadiene (BD) selectivity are shown in Table 1. As shown in Table 1, in Examples 1 to 10, a high 1,3-butadiene selectivity was obtained by using a water-soluble preparation in which the element (A) was adjusted to be water-soluble, and by performing heat treatment under conditions where the heat treatment temperature was 80°C or higher and the heat treatment temperature was equal to or lower than the boiling point of water. In Comparative Example 1, the treatment temperature was low, and the performance of BD selectivity decreased. In Comparative Example 2, the pH during heat treatment was high, making the support brittle, and the performance of feedstock conversion decreased.

[0047]

[0048] In Table 1, the value corresponding to the ratio of the amount of aqueous solution to the volume of the pores is indicated as "H ２ The pore volume was expressed as "0 volume / spherical silica pore volume".

[0049] The catalyst of the present invention can be used for producing 1,3-butadiene from a raw material containing ethanol.

Claims

1. A method for producing a catalyst for producing 1,3-butadiene from a raw material containing ethanol, comprising: a heat treatment step of heat-treating a mixture containing a water-soluble preparation of element (A) selected from the group consisting of Groups 4 and 5 of the periodic table, adjusted to be water-soluble, a carrier, and water, at a heat treatment temperature of 80°C or higher under conditions that are equal to or lower than the boiling point of water, thereby immobilizing element (A) on the carrier; and a drying and calcination step of drying and calcining the mixture after the heat treatment step.

2. The method for producing a catalyst according to claim 1, wherein the heat treatment is carried out in the presence of liquid water in the heat treatment step.

3. The method for producing a catalyst according to claim 1 or 2, wherein the heat treatment temperature is higher than 100°C.

4. The method for producing a catalyst according to claim 1 or 2, wherein the heat treatment step is carried out at a temperature in the range of 120°C to 200°C.

5. The method for producing a catalyst according to claim 1 or 2, wherein the heat treatment step is carried out at a temperature in the range of 140°C to 180°C.

6. The method for producing a catalyst according to claim 1 or 2, wherein the heat treatment step is carried out under acidic conditions.

7. The method for producing a catalyst according to claim 1 or 2, wherein the element (A) is tantalum and the water-soluble preparation is tantalum oxalate.

8. The method for producing a catalyst according to claim 1 or 2, wherein the drying and calcining step comprises a drying step of drying the mixture after the heat treatment step, and a calcining step of calcining the mixture after the drying step at 110°C to 550°C.

9. The method for producing a catalyst according to claim 1 or 2, further comprising, prior to the heat treatment step, a mixture production step of immersing the support in an aqueous solution of the water-soluble preparation to produce the mixture.

10. The method for producing a catalyst according to claim 9, wherein the support has pores and the aqueous solution of the water-soluble preparation has a volume that is at least 0.9 times the volume of the pores and not more than 10 times the volume of the support.

11. The method for producing the catalyst according to claim 1 or 2, further comprising, prior to the heat treatment step, a mixture production step of adding water to a dried product containing the water-soluble preparation and the carrier to produce the mixture.

12. The method for producing a catalyst according to claim 11, wherein in the mixture production step, the dried product is produced by immersing the support in an aqueous solution of the water-soluble preparation and then drying it.

Images