Method for producing catalyst, and method for producing α,β-unsaturated aldehyde, α,β-unsaturated carboxylic acid and α,β-unsaturated carboxylic acid ester using the same

Abstract

To provide a catalyst that makes it possible mainly to produce an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid with high selectivity.SOLUTION: The above problem is solved by a catalyst used for producing a corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid by oxidation of a hydrocarbon, the catalyst containing molybdenum, bismuth and cobalt, wherein, in the infrared absorption spectrum of the catalyst, when baseline processing is performed using the minimum absorbance in the wavenumber range of 1000-1300 cm-1 as a background, and A1 is the maximum absorbance in the wavenumber range of 935-950 cm-1, and A2 is the maximum absorbance in the wavenumber range of 830-880 cm-1, the ratio A2 / A1 is less than 0.85.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates mainly to a catalyst used in producing the corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid by the oxidation reaction of a hydrocarbon, and more particularly to a catalyst suitable for use in producing the corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid by the oxidation of propylene, isobutylene, tertiary butanol (hereinafter also referred to as "TBA"), methyl tertiary butyl ether (hereinafter also referred to as "MTBE"), or the like. This application claims priority based on Japanese Patent Application No. 2023-041837, filed on March 16, 2023, the contents of which are incorporated herein by reference. [Background technology]

[0002] As a method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, a method in which a hydrocarbon is oxidized in the presence of a catalyst containing molybdenum and bismuth is known. For example, Patent Document 1 discloses a catalyst containing molybdenum and bismuth, which has R1 = (886 cm) using Raman spectroscopy. -1 ±5cm -1 (maximum value of the peak at 354 cm) ÷ (354 cm -1 ±5cm -1 The document describes a catalyst in which the maximum value of the peak at 1000 kJ / cm2 is 0.45 or more and 5.00 or less. Patent Document 2 also describes a catalyst that contains molybdenum, bismuth, and cobalt as essential components, and in which, when the catalyst is calcined at 550°C, the ratio (J) of the maximum peak intensity within the X-ray diffraction angle range of 2θ=28.4°±0.15° to the maximum peak intensity within the range of 2θ=26.5°±0.3° is 36.0 or more and 57.5 or less in the X-ray diffraction pattern. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 186032 [Patent Document 2] Japanese Patent Publication No. 2020-151612 Summary of the Invention [Problem to be solved by the invention]

[0004] However, from the viewpoint of the selectivity of the target product required industrially, even the catalysts described in Patent Documents 1 and 2 do not necessarily have sufficient performance. Therefore, further improvement in catalytic performance is required.

[0005] An object of the present invention is to provide a catalyst capable of producing primarily α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids with high selectivity, a method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids using the catalyst, and a method for producing α,β-unsaturated carboxylic acid esters using the catalyst. [Means for solving the problem]

[0006] As a result of intensive research in view of the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a catalyst whose absorbance in infrared absorption spectrum (hereinafter also referred to as "IR spectrum") satisfies specific conditions, and have completed the present invention.

[0007] That is, the present invention includes the following. [1]: A catalyst used in producing the corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid by the oxidation reaction of a hydrocarbon, Contains molybdenum, bismuth and cobalt, In the infrared absorption spectrum of the catalyst, the wave number is 1000 to 1300 cm -1 Baseline processing was performed using the minimum absorbance in the range of wavenumber 935-950 cm as the background. -1 The maximum absorbance in the range of A1 and wavenumber 830-880 cm-1 When the maximum absorbance in the range is A2, A2 / A1 is less than 0.85. [2]: The catalyst according to [1], wherein A2 / A1 is 0.10 to 0.70. [3]: The catalyst according to [1] or [2], which has a composition represented by the following formula (I): Mo a Bi b Fe c Co d X e Y f Si g O h (I) (In formula (I), Mo, Bi, Fe, Co, Si, and O represent molybdenum, bismuth, iron, cobalt, silicon, and oxygen, respectively; X represents at least one element selected from the group consisting of nickel, calcium, magnesium, niobium, tungsten, antimony, phosphorus, and titanium; Y represents at least one element selected from the group consisting of cesium, lithium, sodium, potassium, rubidium, and thallium; a, b, c, d, e, f, g, and h represent atomic ratios of each element, where a=12, b=0.01 to 3.00, c=0 to 5.00, d=1.00 to 12.00, e=0 to 8.00, f=0.001 to 2.00, and g=0 to 20.00; and h represents the atomic ratio of oxygen necessary to satisfy the atomic valence of each of the elements.) [4]: The catalyst according to [3], wherein in the formula (I), (c+d) / (b+e)=5.00 or more. [5]: The catalyst according to [3] or [4], wherein in the formula (I), (c+d) / (b+e)=5.40 to 10.00. [6]: The catalyst according to any one of [3] to [5], wherein the element X in the formula (I) is antimony. [7] The catalyst according to any one of [1] to [6], wherein the α,β-unsaturated aldehyde is methacrolein and the α,β-unsaturated carboxylic acid is methacrylic acid. [8]: A method for producing the catalyst according to any one of [1] to [7], comprising the following steps (i) to (iii): (i) A step of mixing a solution or slurry containing molybdenum and bismuth (liquid A) with a solution or slurry containing cobalt (liquid B) to prepare a slurry (liquid C). (ii) A step of dispersing the liquid C to prepare a slurry (liquid D). (iii) A step of drying the solution D to obtain a dried product. [9]: The method for producing a catalyst according to [8], wherein in the step (ii), the liquid C is circulated for 5 minutes to 10 hours during the dispersion treatment of the liquid C.

[10] : The method for producing a catalyst according to [9], wherein in the step (ii), the liquid C is circulated using a circulation pump.

[11] : The method for producing a catalyst according to any one of [8] to

[10] , wherein in the step (ii), after the dispersion treatment, the mixture is kept at 60°C or higher for 20 minutes or more with stirring to prepare Solution D.

[12] : A method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, comprising a step of oxidizing a hydrocarbon in the presence of the catalyst according to any one of [1] to [7].

[13] : A method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, comprising a step of oxidizing a hydrocarbon in the presence of a catalyst produced by the method according to any one of [8] to

[11] .

[14] : A method for producing an α,β-unsaturated carboxylic acid, comprising a step of oxidizing an α,β-unsaturated aldehyde produced by the method according to

[12] .

[15] : A method for producing an α,β-unsaturated carboxylic acid, comprising a step of oxidizing an α,β-unsaturated aldehyde produced by the method according to

[13] .

[16] : A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of esterifying an α,β-unsaturated carboxylic acid produced by the production method according to

[14] .

[17] : A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of esterifying an α,β-unsaturated carboxylic acid produced by the production method according to

[15] .

[18] : A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of oxidizing and esterifying an α,β-unsaturated aldehyde produced by the production method according to

[12] .

[19] : A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of oxidatively esterifying an α,β-unsaturated aldehyde produced by the production method according to

[13] . [Effects of the Invention]

[0008] The present invention can provide a catalyst capable of producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid with high selectivity, and also provides a method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid using the catalyst, and a method for producing an α,β-unsaturated carboxylic acid ester using the catalyst. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an IR spectrum of the catalyst obtained in Example 1. [Figure 2] 1 is an IR spectrum of the catalyst obtained in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following. In this specification, a numerical range expressed using "to" means a range that includes the numerical values written before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0011] [catalyst] A catalyst according to an embodiment of the present invention is a catalyst used in producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid corresponding to a hydrocarbon by an oxidation reaction of the hydrocarbon, and contains molybdenum, bismuth, and cobalt. Furthermore, the catalyst according to the embodiment of the present invention has an IR spectrum with a wave number of 935 to 950 cm -1 The maximum absorbance in the range (absorption band 1) is A1, and the wavenumber is 830-880 cm -1When the maximum absorbance in the range of 1000 to 1300 cm (absorption band 2) is A2, the ratio A2 / A1 is less than 0.85. -1 The minimum absorbance in the range is used as the background for baseline processing.

[0012] By using the above-mentioned catalyst, it is possible to produce an α,β-unsaturated aldehyde and / or an unsaturated carboxylic acid with high selectivity. The catalyst according to the embodiment of the present invention is particularly useful as a catalyst used in producing methacrolein and / or methacrylic acid. In this specification, the expression "α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid" can be rephrased as "at least one selected from the group consisting of α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid."

[0013] <IR spectrum of catalyst> The catalyst according to the embodiment of the present invention has an IR spectrum with a wave number of 935 to 950 cm -1 The maximum absorbance in the range (absorption band 1) is A1, and the wavenumber is 830-880 cm -1 When the maximum absorbance in the range (absorption band 2) is A2, A2 / A1 is less than 0.85. The use of such a catalyst enables the production of α,β-unsaturated aldehydes and / or unsaturated carboxylic acids with high selectivity. The present inventors speculate that the reason for this is as follows.

[0014] In the IR spectrum, wave numbers 935 to 950 cm -1 In the range of 830 to 880 cm, absorption due to the Mo-O stretching vibration of the oxide phase containing cobalt and molybdenum (hereinafter also referred to as the "Co-Mo oxide phase") appears. -1Within this range, absorption due to the Mo-O stretching vibration of an oxide phase containing bismuth and molybdenum (hereinafter referred to as the "Bi-Mo oxide phase") appears. The Bi-Mo oxide phase is thought to function as an active site in the hydrocarbon oxidation reaction. On the other hand, the Co-Mo oxide phase acts as a support for the Bi-Mo oxide phase, facilitating the transfer of oxygen species and promoting the reoxidation of the active sites. When the A2 / A1 ratio is below the specified value, i.e., when the Co-Mo oxide phase exists at a ratio equal to or greater than the specified value relative to the Bi-Mo oxide phase, the oxidation state of the Bi-Mo oxide phase is maintained in a state favorable for the selective oxidation reaction to α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, and the selectivity is thought to be improved.

[0015] The upper limit of A2 / A1 is preferably 0.70 or less, more preferably 0.65 or less, and the lower limit is preferably 0.10 or more, more preferably 0.20 or more. In the present invention, the IR spectrum is measured by a transmission method. For the measurement, for example, a NICOLET 6700 FT-IR (manufactured by Thermo Electron) or the like can be used. The measurement range is a wave number of 800 to 1300 cm. -1 The settings include 64 scans and a data interval of 0.482 cm. -1 Measurement is performed at 1000 KBr. The catalyst to be measured is diluted with KBr powder and pressed into a disk shape using a press. For pressing, an MP-1 mini press or an MT-1 micro tablet molding machine (manufactured by JASCO) can be used. Here, if the absorbance increases, the S / N (ratio of detected signal to noise) decreases, and measurement accuracy deteriorates. Therefore, the amount of catalyst is adjusted so that the maximum absorbance is 1 or less, and diluted with KBr powder. The obtained IR spectrum is measured at wavenumbers of 1000 to 1300 cm. -1 Baseline processing is performed using the minimum absorbance in the range as the background to determine A1 and A2.

[0016] A method for obtaining a catalyst in which A2 / A1 satisfies the above ratio can be, for example, a method for producing a catalyst having a composition represented by formula (I) described below by a method including steps (i) to (iii) described below.

[0017] <Catalyst composition> As described above, the catalyst according to the embodiment of the present invention contains molybdenum, bismuth, and cobalt. From the viewpoint of improving the selectivity of the target product, the ratio of the number of bismuth atoms to the number of molybdenum atoms, which is taken as 12, is preferably 0.01 to 3.00. The lower limit of the ratio of the number of bismuth atoms is more preferably 0.03 or more, and even more preferably 0.05 or more. The upper limit is more preferably 2.00 or less, and particularly preferably 1.00 or less. From the same viewpoint, the ratio of the number of cobalt atoms to the number of molybdenum atoms, which is taken as 12, is preferably 1.00 to 12.00. The lower limit of the ratio of the number of cobalt atoms is preferably 2.00 or more, more preferably 3.00 or more. The upper limit is preferably 11.00 or less, more preferably 10.00 or less.

[0018] Other elements may also be contained, such as iron, silicon, oxygen, nickel, calcium, magnesium, niobium, tungsten, antimony, phosphorus, titanium, cesium, lithium, sodium, potassium, rubidium, or thallium. From the viewpoint of improving the selectivity of the target product, it is preferable that iron and antimony are contained, and it is also preferable that at least one element selected from the group consisting of cesium, lithium, sodium, potassium, rubidium, and thallium is contained.

[0019] The catalyst according to the embodiment of the present invention may also have a carrier for supporting the above-mentioned elements. The carrier is not particularly limited, and examples thereof include silica, alumina, silica-alumina, magnesia, titania, and silicon carbide. Among these, silica is preferred in order to prevent the carrier itself from reacting. In this specification, when a carrier is used in the catalyst, the carrier is also considered to be part of the catalyst.

[0020] From the viewpoint of improving the selectivity of the target product, the catalyst according to the embodiment of the present invention preferably has a composition represented by the following formula (I): The catalyst may contain small amounts of elements not represented by the following formula (I). Mo a Bi b Fe c Co d X e Y f Si g O h (I) In formula (I), Mo, Bi, Fe, Co, Si, and O represent molybdenum, bismuth, iron, cobalt, silicon, and oxygen, respectively. X represents at least one element selected from the group consisting of nickel, calcium, magnesium, niobium, tungsten, antimony, phosphorus, and titanium, and is preferably antimony. Y represents at least one element selected from the group consisting of cesium, lithium, sodium, potassium, rubidium, and thallium. a, b, c, d, e, f, g, and h represent the atomic ratios of each element, where a = 12, b = 0.01-3.00, c = 0-5.00, d = 1.00-12.00, e = 0-8.00, f = 0.001-2.00, and g = 0-20.00, and h represents the oxygen atomic ratio required to satisfy the valence of each of the components.

[0021] In the formula (I), from the viewpoint of improving the selectivity of the target product, it is preferable that b, c, d, e, f, and g satisfy the following conditions. The lower limit of b is preferably 0.03 or more, more preferably 0.05 or more, and the upper limit of b is preferably 2.00 or less, more preferably 1.00 or less. The lower limit of c is preferably 0.01 or more, more preferably 0.10 or more, and even more preferably 0.50 or more, and the upper limit of c is preferably 4.50 or less, more preferably 4.00 or less, and even more preferably 3.50 or less. The lower limit of d is preferably 2.00 or more, more preferably 3.00 or more, and the upper limit of d is preferably 11.00 or less, more preferably 10.00 or less. The lower limit of e is preferably 0.10 or more, more preferably 0.20 or more, and even more preferably 0.50 or more, and the upper limit of e is more preferably 6.00 or less, and even more preferably 4.00 or less.

[0022] In the formula (I), the lower limit of (c + d) / (b + e) is preferably 5.00 or more, more preferably 5.40 or more, even more preferably 5.50 or more, and particularly preferably 5.60 or more. The upper limit of (c + d) / (b + e) is preferably 10 or less, more preferably 9.00 or less, even more preferably 8.00 or less, and particularly preferably 7.50 or less. Here, (c + d), i.e., the composition ratio of iron and cobalt, is thought to contribute to the formation of the Co-Mo oxide phase. Furthermore, (b + e), i.e., the composition ratio of bismuth and X element, is thought to contribute to the formation of the Bi-Mo oxide phase. By controlling (c + d) / (b + e) within the above range, these oxide phases are formed in a suitable ratio, and a catalyst that satisfies specific conditions in the IR spectrum can be easily obtained.

[0023] The lower limit of f is preferably 0.05 or more, more preferably 0.10 or more, and even more preferably 0.20 or more, and the upper limit of f is preferably 1.80 or less, more preferably 1.60 or less, and even more preferably 1.40 or less. The upper limit of g is preferably 15.00 or less, and more preferably 10.00 or less. The atomic ratio of each element in this specification is a value determined by dissolving the catalyst in hydrochloric acid and analyzing the components by ICP emission spectrometry.

[0024] [Catalyst manufacturing method] The catalyst according to the above embodiment contains molybdenum, bismuth, and cobalt, and can be produced according to a known catalyst production method as long as the A2 / A1 ratio in the IR spectrum is less than 0.85. However, the catalyst is preferably produced by a method according to another embodiment of the present invention, which includes the following steps (i) to (iii): (i) A step of mixing a solution or slurry containing molybdenum and bismuth (liquid A) with a solution or slurry containing cobalt (liquid B) to prepare a slurry (liquid C). (ii) A step of dispersing the slurry (liquid C) to prepare a slurry (liquid D). (iii) A step of drying the solution D to obtain a dried product. The method for producing a catalyst according to the present invention may further include a calcination step and a molding step, which will be described later. Each step will be described in detail below.

[0025] <Process (i)> In step (i), a solution or slurry containing molybdenum and bismuth (liquid A) is mixed with a solution or slurry containing cobalt (liquid B) to prepare a slurry (liquid C). Solution A is prepared by mixing raw material compounds of molybdenum and bismuth with a solvent, and preferably further mixing raw material compounds of the X and Y elements in formula (I).

[0026] The amounts of the raw material compounds used in Solution A may be adjusted appropriately to obtain a desired catalyst composition. The amount of solvent used in Solution A is not particularly limited, but is preferably 70 to 400 parts by mass per 100 parts by mass of the total of the raw material compounds.

[0027] Solution B is prepared by mixing a raw material compound of cobalt with a solvent, and preferably also mixing in a raw material compound of iron. The amounts of the raw material compounds used in Solution B may be adjusted appropriately to obtain a desired catalyst composition. The amount of solvent used in the solution B is not particularly limited, but is preferably 30 to 230 parts by mass per 100 parts by mass of the total of the raw material compounds.

[0028] There are no particular limitations on the raw material compounds, but oxides, chlorides, hydroxides, sulfates, nitrates, carbonates, ammonium salts, acetates, or mixtures thereof of the respective elements can be used. Examples of molybdenum raw materials include ammonium paramolybdate, molybdenum trioxide, and molybdenum chloride, with ammonium paramolybdate being preferred. Examples of bismuth raw materials include bismuth nitrate, bismuth oxide, and bismuth subcarbonate, with bismuth oxide being preferred. Examples of cobalt raw materials include cobalt nitrate, cobalt hydroxide, cobalt oxide, and cobalt chloride, with cobalt nitrate being preferred. One raw material compound may be used alone, or two or more may be used in combination.

[0029] The solvent preferably contains water, and more preferably contains 50 mass % or more of water, and may also contain an organic solvent such as alcohol or acetone. The above-mentioned liquids A and B are mixed together to prepare a slurry (liquid C).

[0030] <Process (ii)> In step (ii), the slurry (liquid C) obtained in step (i) is subjected to a dispersion treatment to prepare a slurry (liquid D). By dispersing liquid C to uniformly disperse the solids in liquid C, the cobalt and bismuth contained in the raw material compounds efficiently form Co-Mo oxide phases and Bi-Mo oxide phases, making it easy to obtain a catalyst that satisfies specific conditions in the IR spectrum.

[0031] Examples of a method for dispersing Liquid C include a method in which Liquid C in a container is treated using a high-pressure, ultrasonic, or stirring homogenizer, and it is preferable to use a stirring homogenizer.

[0032] During the dispersion treatment of Liquid C, it is preferable to circulate Liquid C for 5 minutes to 10 hours. This allows the solid content in Liquid C to be dispersed more uniformly. Note that "circulation" refers to the operation of discharging Liquid C out of the container and then returning it to the container.

[0033] The lower limit of the dispersion treatment time is preferably 10 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more, and the upper limit of the time is preferably 9 hours or less, more preferably 8 hours or less, and even more preferably 7 hours or less.

[0034] The dispersion treatment is preferably carried out at a temperature of 20 to 90°C for Liquid C. From the viewpoint of efficiently and uniformly dispersing the solid content in Liquid C, it is preferable to use a circulation pump for circulating Liquid C. As the circulation pump, a centrifugal pump, a mixed flow pump, an axial flow pump, a positive displacement pump, or the like can be used.

[0035] After dispersing Solution C, it is preferable to hold the resulting slurry at 60°C or higher for 20 minutes or longer while stirring to prepare Solution D. This further promotes the formation of particles containing the Co-Mo oxide phase and Bi-Mo oxide phase. The lower limit of the holding temperature is preferably 70° C. or higher, more preferably 80° C. or higher. The upper limit of the holding temperature is the boiling point of the solvent or lower, preferably 150° C. or lower, more preferably 130° C. or lower. The lower limit of the holding time is preferably 30 minutes or more, more preferably 40 minutes or more, and the upper limit of the holding time is preferably 4 hours or less, more preferably 2 hours or less. The method of stirring the slurry is preferably a method using a rotary blade stirrer or a magnetic stirrer.

[0036] <Step (iii)> In step (iii), the solution D obtained in step (ii) is dried to obtain a dried product. There are no particular limitations on the method for drying Solution D, and examples thereof include drying using a tray dryer, drying using a spray dryer, drying using a slurry dryer, drying using a drum dryer, and pulverizing the massive solid obtained by evaporation to dryness. There are no particular limitations on the drying conditions, and when using a tray dryer, for example, drying is preferably carried out at a temperature of 30 to 150°C. When using a spray dryer, it is preferable to set the inlet temperature to 100 to 500°C and the outlet temperature to 100 to 300°C.

[0037] The dried product obtained in step (iii) exhibits catalytic properties and can be used as a catalyst, but it is preferable to further perform calcination or molding, as described below, to improve catalytic performance. In an embodiment of the present invention, the term "catalyst" refers to both the calcined and molded products.

[0038] <Firing process> The dried product obtained in the step (iii) may contain salts such as nitric acid derived from the raw material compounds, etc. Therefore, it is preferable to calcinate the dried product to remove such salts and obtain a calcined product.

[0039] The calcination can be carried out after the molding step described below is carried out to obtain a molded product, but from the viewpoint of catalyst strength, it is preferable to carry out the calcination before the molding step. The calcination may be carried out only once, or may be carried out multiple times in combination with the molding step described below. It is preferable to first carry out a primary calcination of the dried product in order to remove salts, and then carry out the molding step described below, followed by a secondary calcination to form the final catalytic active site structure. Alternatively, the primary and secondary calcinations may be carried out, followed by the molding step.

[0040] The calcination is preferably carried out under a flow of an oxygen-containing gas such as air, or under a flow of an inert gas such as nitrogen, carbon dioxide, helium, or argon. From the viewpoint of the selectivity of the resulting catalyst, the calcination temperature is preferably 200 to 700°C, and more preferably the lower limit is 250°C or higher and the upper limit is 600°C or lower. The calcination time is appropriately selected depending on the target catalyst, but from the viewpoint of the selectivity of the obtained catalyst, it is preferably 10 minutes to 10 hours, with the lower limit more preferably 1 hour or more and the upper limit more preferably 7 hours or less, and even more preferably 6 hours or less. Note that the calcination time means the time for which calcination is continued after a predetermined calcination temperature is reached.

[0041] When the dried product is subjected to primary firing and then to a molding step described below, followed by secondary firing, the firing temperature for the primary firing is preferably 200 to 600° C. More preferably, the lower limit of the firing temperature for the primary firing is 250° C. or higher, and the upper limit is 450° C. or lower. The firing time for the primary firing is preferably 0.5 to 5 hours.

[0042] The primary firing may be performed using, for example, a box-type firing furnace, a tunnel-type firing furnace, or the like, in which the dried material is fired in a fixed state, or using a rotary kiln, or the dried material may be fired while being fluidized.

[0043] The firing temperature for the secondary firing is preferably 300 to 700° C. More preferably, the lower limit of the firing temperature for the secondary firing is 400° C. or higher, and the upper limit is 600° C. or lower. The firing time for the secondary firing is preferably 10 minutes to 10 hours, with the lower limit being more preferably 1 hour or more, and the upper limit being more preferably 7 hours or less, and even more preferably 6 hours or less.

[0044] The secondary firing may be carried out in a firing furnace such as a box-type firing furnace or a tunnel-type firing furnace, in which the molded product or the primary fired product is fired in a fixed state, or may be carried out in a rotary kiln or the like, in which the molded product is fired while being fluidized.

[0045] <Forming process> In the molding step, the dried product before or after firing is molded to obtain a molded product. There are no particular limitations on the molding method, and a general powder molding machine such as a tablet molding machine, an extrusion molding machine, or a tumbling granulator can be used.

[0046] During molding, conventionally known additives may be added to the dried product before or after firing, such as organic compounds such as polyvinyl alcohol and carboxymethyl cellulose, inorganic compounds such as graphite and diatomaceous earth, and inorganic fibers such as glass fiber, ceramic fiber, and carbon fiber.

[0047] The shape of the molded product may be any shape, such as a sphere, a cylinder, a ring, a star, or granules that have been crushed and classified after molding. The outer diameter of the molded product after firing is preferably 0.01 to 2 cm. By having the outer diameter be 0.01 cm or more, α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid can be produced stably over a long period of time. Furthermore, by having the outer diameter be 2 cm or less, the strength of the molded product can be maintained. The lower limit of the outer diameter is more preferably 0.05 cm or more, and even more preferably 0.1 cm or more. Furthermore, the upper limit of the outer diameter is more preferably 1.5 cm or less, and even more preferably 1 cm or less.

[0048] The outer surface area of the molded product after firing is 0.01 to 4 cm 2 It is preferable that the outer surface area is 0.01 cm 2 By satisfying the above conditions, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be stably produced over a long period of time. 2 The selectivity of α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid is improved by the external surface area being 0.05 cm or less. 2 More preferably, it is 0.1 cm or more. 2 It is more preferable that the outer surface area is 3 cm or more. 2 It is more preferable that it is less than 2 cm 2 It is even more preferable that:

[0049] The volume of the molded product after firing is 0.0002 to 5 cm 3 Preferably, the volume is 0.0002 cm 3By satisfying the above conditions, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be stably produced over a long period of time. 3 The selectivity of the α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid is improved by the volume being equal to or less than 0.002 cm 3 . 3 More preferably, it is 0.02 cm or more. 3 It is more preferable that the upper limit of the volume is 1 cm. 3 It is more preferable that it is less than 0.5 cm 3 It is even more preferable that:

[0050] The mass of the molded product after calcination is preferably 0.002 to 0.5 g / piece. By having a mass of 0.002 g / piece or more, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be produced stably over a long period of time. Furthermore, by having a mass of 0.5 g / piece or less, the selectivity for α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids is improved. The lower limit of the mass is more preferably 0.01 g / piece or more, and even more preferably 0.05 g / piece or more. Furthermore, the upper limit of the mass is more preferably 0.3 g / piece or less, and even more preferably 0.2 g / piece or less.

[0051] The packed bulk density of the molded product after firing is 0.2 to 1 g / cm 3 It is preferable that the packed bulk density is 0.2 g / cm 3 By satisfying the above conditions, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be stably produced over a long period of time. 3 The selectivity for α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid is improved by the bulk density being 0.3 g / cm or less. 3 More preferably, it is 0.4 g / cm or more. 3 The upper limit of the packed bulk density is 0.9 g / cm. 3 More preferably, it is 0.8 g / cm or less. 3It is even more preferable that: The packed bulk density of the molded product means the value calculated from the total mass of the molded product when the molded product is packed into a 100 mL measuring cylinder using a method in accordance with JIS-K 7365.

[0052] The resulting molded product may be supported on a carrier. Examples of the carrier used for supporting the catalyst include inert materials such as silica, alumina, silica-alumina, magnesia, titania, and silicon carbide. The molded product may also be diluted with these inert materials before use.

[0053] [Method for producing α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid] According to another embodiment of the present invention, there is provided a method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, which comprises a step of oxidizing a hydrocarbon in the presence of the catalyst described above, thereby producing the corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid. According to yet another embodiment, there is provided a method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, which comprises a step of oxidizing a hydrocarbon in the presence of the catalyst produced by the method described above, thereby producing the corresponding α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid. According to this method, the α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acid can be obtained with high selectivity.

[0054] Specifically, the hydrocarbon may be a raw organic compound such as propylene, isobutylene, TBA, or MTBE. The α,β-unsaturated aldehyde corresponding to propylene is acrolein, and the α,β-unsaturated carboxylic acid corresponding to propylene is acrylic acid. The α,β-unsaturated aldehyde corresponding to isobutylene is methacrolein, and the α,β-unsaturated carboxylic acid corresponding to isobutylene is methacrylic acid. The α,β-unsaturated aldehyde corresponding to TBA is methacrolein, and the α,β-unsaturated carboxylic acid corresponding to TBA is methacrylic acid. The α,β-unsaturated aldehyde corresponding to MTBE is methacrolein, and the α,β-unsaturated carboxylic acid corresponding to MTBE is methacrylic acid. From the viewpoint of improving the selectivity of the product, the α,β-unsaturated aldehyde and the α,β-unsaturated carboxylic acid are preferably methacrolein and methacrylic acid, respectively.

[0055] The method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid according to an embodiment of the present invention can be carried out by contacting the above-described catalyst with a raw material gas containing a hydrocarbon and oxygen in a reactor. The reactor may be one generally used for gas-phase oxidation, and it is preferable to use a tubular reactor equipped with a reaction tube filled with a catalyst. From an industrial perspective, it is also preferable to use a multi-tubular reactor equipped with a plurality of the reaction tubes.

[0056] The hydrocarbon concentration in the raw material gas is not particularly limited, but is preferably 1 to 20% by volume, with the lower limit being more preferably 3% by volume or more and the upper limit being 10% by volume or less. The oxygen source for the raw material gas is not particularly limited, but it is industrially advantageous to use air. If necessary, a gas obtained by mixing pure oxygen with air or the like can also be used. The oxygen content in the raw material gas is not particularly limited, but is preferably 10 to 500% by volume relative to the hydrocarbon, with a lower limit of 50% by volume or more and an upper limit of 300% by volume or less. From an economical viewpoint, it is preferable to use the raw material gas diluted with nitrogen gas, an inert gas such as carbon dioxide gas, or water vapor.

[0057] The contact time between the raw material gas and the catalyst is not particularly limited, but is preferably 0.5 to 10 seconds, with the lower limit being more preferably 1 second or more and the upper limit being more than 5 seconds. The pressure during the oxidation reaction is usually from atmospheric pressure to several atmospheres. The temperature during the oxidation reaction is preferably 200 to 450°C, with the lower limit being more preferably 250°C or higher and the upper limit being more preferably 400°C or lower.

[0058] [Method of producing α,β-unsaturated carboxylic acid] A method for producing an α,β-unsaturated carboxylic acid according to another embodiment of the present invention includes a step of oxidizing the α,β-unsaturated aldehyde produced by the above-described method, and the corresponding α,β-unsaturated carboxylic acid is produced by this oxidation. From the viewpoint of improving the selectivity of the product, the α,β-unsaturated aldehyde and the α,β-unsaturated carboxylic acid are preferably methacrolein and methacrylic acid, respectively.

[0059] The method for producing an α,β-unsaturated carboxylic acid according to an embodiment of the present invention can be carried out by contacting a catalyst for producing an α,β-unsaturated carboxylic acid with a raw material gas containing an α,β-unsaturated aldehyde in a reactor. A heteropolyacid catalyst is preferably used as the catalyst. The reactor may be the same as that used in the above-described method for producing an α,β-unsaturated aldehyde.

[0060] The concentration of the α,β-unsaturated aldehyde in the raw material gas is not particularly limited, but is preferably 1 to 20% by volume, with the lower limit being more preferably 3% by volume or more and the upper limit being 10% by volume or less. The oxygen source for the raw material gas is not particularly limited, but it is industrially advantageous to use air. If necessary, a gas obtained by mixing pure oxygen with air or the like can also be used. The oxygen content in the raw material gas is not particularly limited, but is preferably 40 to 400% by volume relative to the α,β-unsaturated aldehyde, with the lower limit being more preferably 50% by volume or more and the upper limit being 300% by volume or less. From an economical viewpoint, it is preferable to use the raw material gas diluted with nitrogen gas, an inert gas such as carbon dioxide gas, or water vapor.

[0061] There is no particular limitation on the contact time between the raw material gas and the catalyst for producing an α,β-unsaturated carboxylic acid, but it is preferably 1.5 to 15 seconds. The pressure during the oxidation reaction is usually from atmospheric pressure to several atmospheres. The temperature during the oxidation reaction is preferably 200 to 400°C, and the lower limit is more preferably 250°C or higher.

[0062] [Method of producing α,β-unsaturated carboxylic acid ester] A method for producing an α,β-unsaturated carboxylic acid ester according to another embodiment of the present invention includes a step of esterifying the α,β-unsaturated carboxylic acid produced by the above-described method, and is a method for producing an α,β-unsaturated carboxylic acid ester by this esterification.

[0063] The alcohol to be reacted with the α,β-unsaturated carboxylic acid is not particularly limited, and examples thereof include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, etc. Examples of the resulting α,β-unsaturated carboxylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, etc.

[0064] The esterification reaction can be carried out in the presence of an acid catalyst such as a sulfonic acid type cation exchange resin. The temperature during the esterification reaction is preferably 50 to 200°C.

[0065] A method for producing an α,β-unsaturated carboxylic acid ester according to yet another embodiment of the present invention includes a step of oxidatively esterifying the α,β-unsaturated aldehyde produced by the above-described method, and is a method for producing an α,β-unsaturated carboxylic acid ester by this oxidative esterification, where "oxidative esterification" means oxidation followed by further esterification. As for the oxidative esterification of an α,β-unsaturated aldehyde, i.e., a method of oxidizing an α,β-unsaturated aldehyde and then esterifying the α,β-unsaturated carboxylic acid produced by the oxidation, the methods described above in [Method for producing an α,β-unsaturated carboxylic acid] and [Method for producing an α,β-unsaturated carboxylic acid ester] can be used. [Example]

[0066] Hereinafter, examples of producing a catalyst according to an embodiment of the present invention and examples of reactions using the catalyst will be described together with comparative examples.

[0067] (Catalyst composition ratio) The composition of each element was determined by dissolving the catalyst in hydrochloric acid and analyzing the components by ICP emission spectrometry.

[0068] (IR spectrum measurement of catalyst) The IR spectrum of the catalyst was measured by the transmission method using a NICOLET 6700 (manufactured by Thermo Electron). A DTGS detector was used, and the measurement range was 400 to 4000 cm. -1 ,The number of scans is 64, and the data interval is 0.482 cm. -1 The measurement sample was prepared by mixing 0.5 mg of catalyst with 100 mg of KBr powder, diluting the mixture, and then compressing 15 mg of the diluted mixture in a press to form a disk with a diameter of 5 mm.

[0069] (Reaction evaluation) The reaction evaluation of the catalysts in the examples and comparative examples was carried out using the production of methacrolein and methacrylic acid by oxidation of isobutylene as an example. Analysis in the reaction evaluation was carried out by gas chromatography (apparatus: GC-2014 manufactured by Shimadzu Corporation, column: DB-FFAP manufactured by J&W, 30 m x 0.32 mm, film thickness 0.25 μm). From the results of gas chromatography, the selectivity of the produced methacrolein and methacrylic acid was calculated using the following formula. Total selectivity of methacrolein and methacrylic acid (%) = ((number of moles of methacrolein produced + number of moles of methacrylic acid produced) / number of moles of isobutylene reacted) × 100

[0070] Example 1 50.4 parts by mass of ammonium paramolybdate tetrahydrate, 3.3 parts by mass of bismuth oxide, and 3.5 parts by mass of antimony trioxide were mixed with 200 parts by mass of room temperature pure water, heated to 60°C, and then a solution of 2.3 parts by mass of cesium nitrate mixed with 20.7 parts by mass of pure water was added to obtain Solution A. Furthermore, 23.1 parts by mass of iron(III) nitrate nonahydrate and 55.4 parts by mass of cobalt(II) nitrate hexahydrate were mixed with 100 parts by mass of room temperature pure water to prepare Solution B. Next, Solutions A and B were mixed to prepare Solution C. The resulting solution C was dispersed for 90 minutes using a stirring homogenizer while circulating using a circulation pump. The dispersed slurry was then heated to 95°C and held for 1 hour while stirring using a rotary blade stirrer to prepare solution D. The obtained solution D was evaporated to dryness at 130°C to obtain a dried product. The dried product was subjected to primary calcination in an air atmosphere at 300°C for 1 hour. Then, the dried product after the primary calcination was subjected to secondary calcination in an air atmosphere at 500°C for 6 hours to obtain a catalyst. The composition of the catalyst excluding oxygen was Mo 12 Bi 0.60 Fe 2.40 Co 8.00 Sb 1.00 Cs 0.50 The IR spectrum of the catalyst was also measured. The obtained A2 / A1 value is shown in Table 1, and the IR spectrum is shown in Figure 1. The catalyst was packed into a stainless steel reactor tube, and a feed gas consisting of 5% by volume of isobutylene, 12% by volume of oxygen, 10% by volume of steam, and 73% by volume of nitrogen was passed through the catalyst in the reactor tube for a contact time of 0.18 seconds, and the reaction was evaluated at a temperature of 330°C. The results are shown in Table 1.

[0071] <Example 2> A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass, antimony trioxide was 2.4 parts by mass, and cobalt (II) nitrate hexahydrate was 62.3 parts by mass. The composition of the elements of the catalyst excluding oxygen was Mo. 12 Bi 0.90 Fe 2.40 Co 9.00 Sb 0.70 Cs 0.50 The IR spectrum of the catalyst was also measured. The A2 / A1 ratio obtained is shown in Table 1, and the IR spectrum is shown in Figure 2. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0072] Example 3 A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass, antimony trioxide was 2.4 parts by mass, and iron (III) nitrate nonahydrate was 17.3 parts by mass. The composition of the elements of the catalyst excluding oxygen was Mo. 12 Bi 0.90 Fe 1.80 Co 8.00 Sb 0.70 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0073] Example 4 A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 1.7 parts by mass, iron (III) nitrate nonahydrate was 17.3 parts by mass, and cobalt (II) nitrate hexahydrate was 48.5 parts by mass. The composition of the catalyst, excluding oxygen, was Mo.12 Bi 0.30 Fe 1.80 Co 7.00 Sb 1.00 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0074] <Example 5> A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 1.7 parts by mass, antimony trioxide was 4.5 parts by mass, and iron (III) nitrate nonahydrate was 28.8 parts by mass. The composition of the catalyst, excluding oxygen, was Mo. 12 Bi 0.30 Fe 3.00 Co 8.00 Sb 1.30 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0075] Example 6 A catalyst was prepared in the same manner as in Example 1, except that the amount of antimony trioxide was 4.5 parts by mass and the amount of iron (III) nitrate nonahydrate was 28.8 parts by mass. The composition of the elements of the catalyst excluding oxygen was Mo. 12 Bi 0.60 Fe 3.00 Co 8.00 Sb 1.30 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0076] Example 7 A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass, iron (III) nitrate nonahydrate was 17.3 parts by mass, and cobalt (II) nitrate hexahydrate was 62.3 parts by mass. The composition of the catalyst, excluding oxygen, was Mo. 12 Bi 0.90 Fe 1.80 Co 9.00 Sb 1.00 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, reaction evaluation was carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0077] Example 8 A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass, antimony trioxide was 2.4 parts by mass, and iron (III) nitrate nonahydrate was 17.3 parts by mass. The composition of the elements of the catalyst excluding oxygen was Mo. 12 Bi 0.90 Fe 1.80 Co 8.00 Sb 0.70 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, IR spectrum was measured in the same manner as in Example 1. The results are shown in Table 1.

[0078] <Comparative Example 1> A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass, antimony trioxide was 4.5 parts by mass, and iron (III) nitrate nonahydrate was 28.8 parts by mass. The composition of the elements of the catalyst excluding oxygen was Mo. 12 Bi 0.90 Fe 3.00 Co 8.00 Sb 1.30 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, IR spectrum was measured in the same manner as in Example 1. The results are shown in Table 1.

[0079] <Comparative Example 2> A catalyst was prepared in the same manner as in Example 1, except that antimony trioxide was 4.5 parts by mass, iron (III) nitrate nonahydrate was 28.8 parts by mass, and cobalt (II) nitrate hexahydrate was 48.5 parts by mass. The composition of the catalyst, excluding oxygen, was Mo. 12 Bi 0.60 Fe 3.00 Co 7.00 Sb 1.30 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, IR spectrum measurement and reaction evaluation were carried out in the same manner as in Example 1. The obtained results are shown in Table 1.

[0080] <Comparative Example 3> A catalyst was prepared in the same manner as in Example 1, except that bismuth oxide was 5.0 parts by mass and cobalt (II) nitrate hexahydrate was 48.5 parts by mass. The composition of the catalyst, excluding oxygen, was Mo. 12 Bi 0.90 Fe 2.40 Co 7.00 Sb 1.00 Cs 0.50 The IR spectrum of the catalyst was also measured, and the A2 / A1 ratio obtained is shown in Table 1. Using the obtained catalyst, IR spectrum was measured in the same manner as in Example 1. The results are shown in Table 1.

[0081] [Table 1]

[0082] As shown in Table 1, Examples 1 to 8, which used catalysts whose IR spectrum absorbance satisfied the specified conditions, had better total selectivity for methacrolein and methacrylic acid than Comparative Examples 1 to 3, which did not satisfy the conditions. It should be noted that methacrylic acid can be obtained by oxidizing the methacrolein obtained in this example, and methacrylic acid esters can be obtained by esterifying the methacrylic acid. [Industrial Applicability]

[0083] According to the present invention, it is possible to provide a catalyst that can produce an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid with high selectivity.

Claims

1. A catalyst used in producing a corresponding α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid by an oxidation reaction of a hydrocarbon, comprising: Contains molybdenum, bismuth and cobalt, In the infrared absorption spectrum of the catalyst, the wave number is 1000 to 1300 cm －１ Baseline processing was performed using the minimum absorbance in the range of wavenumber 935 to 950 cm as the background. －１ The maximum absorbance in the range of A1 and wavenumber 830 to 880 cm －１ When the maximum absorbance in the range is A2, A2 / A1 is less than 0.

85.

2. 2. The catalyst according to claim 1, wherein A2 / A1 is 0.10 to 0.

70.

3. The catalyst according to claim 1, having a composition represented by the following formula (I): Mo ａ Bi ｂ Fe ｃ Co ｄ X ｅ Y ｆ Si ｇ O ｈ ・・・(I) (In formula (I), Mo, Bi, Fe, Co, Si, and O represent molybdenum, bismuth, iron, cobalt, silicon, and oxygen, respectively; X represents at least one element selected from the group consisting of nickel, calcium, magnesium, niobium, tungsten, antimony, phosphorus, and titanium; Y represents at least one element selected from the group consisting of cesium, lithium, sodium, potassium, rubidium, and thallium; a, b, c, d, e, f, g, and h represent the atomic ratios of each element, where a=12, b=0.01 to 3.00, c=0 to 5.00, d=1.00 to 12.00, e=0 to 8.00, f=0.001 to 2.00, and g=0 to 20.00; and h represents the atomic ratio of oxygen necessary to satisfy the atomic valence of each element.)

4. The catalyst according to claim 3, wherein in formula (I), (c+d) / (b+e)=5.00 or more.

5. The catalyst according to claim 4, wherein in formula (I), (c+d) / (b+e)=5.40 to 10.

00.

6. 4. The catalyst according to claim 3, wherein the X element in formula (I) is antimony.

7. 2. The catalyst according to claim 1, wherein the α,β-unsaturated aldehyde is methacrolein and the α,β-unsaturated carboxylic acid is methacrylic acid.

8. A method for producing the catalyst according to claim 1, comprising the following steps (i) to (iii): (i) A step of mixing a solution or slurry containing molybdenum and bismuth (liquid A) with a solution or slurry containing cobalt (liquid B) to prepare a slurry (liquid C). (ii) A step of dispersing the liquid C to prepare a slurry (liquid D). (iii) A step of drying the solution D to obtain a dried product.

9. 9. The method for producing a catalyst according to claim 8, wherein in the step (ii), the solution C is circulated for 5 minutes to 10 hours during the dispersion treatment of the solution C.

10. The method for producing a catalyst according to claim 9, wherein in the step (ii), the solution C is circulated using a circulation pump.

11. 9. The method for producing a catalyst according to claim 8, wherein in the step (ii), after the dispersion treatment, the solution D is prepared by maintaining the mixture at 60°C or higher for 20 minutes or longer with stirring.

12. A method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, comprising a step of oxidizing a hydrocarbon in the presence of the catalyst according to any one of claims 1 to 7.

13. A method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, comprising a step of oxidizing a hydrocarbon in the presence of a catalyst produced by the production method according to any one of claims 8 to 11.

14. A method for producing an α,β-unsaturated carboxylic acid, comprising a step of oxidizing the α,β-unsaturated aldehyde produced by the method according to claim 12.

15. A method for producing an α,β-unsaturated carboxylic acid, comprising a step of oxidizing the α,β-unsaturated aldehyde produced by the method according to claim 13.

16. A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of esterifying the α,β-unsaturated carboxylic acid produced by the production method according to claim 14.

17. A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of esterifying the α,β-unsaturated carboxylic acid produced by the production method according to claim 15.

18. A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of oxidatively esterifying the α,β-unsaturated aldehyde produced by the method according to claim 12.

19. A method for producing an α,β-unsaturated carboxylic acid ester, comprising a step of oxidatively esterifying the α,β-unsaturated aldehyde produced by the method according to claim 13.

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