Catalyst, method for producing catalyst, and methods for producing α,β-unsaturated aldehyde, α,β-unsaturated carboxylic acid, and α,β-unsaturated carboxylic acid ester

Abstract

Provided is a catalyst with which it is possible to produce target products such as α,β-unsaturated aldehydes and α,β-unsaturated carboxylic acids with high selectivity. This catalyst for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids contains molybdenum, bismuth, and cesium, and is such that B / A is 1.50 or greater, where A (%) is the ratio of the molar amount of cesium atoms to the total molar amount of all elements in the catalyst, and B (%) is the ratio of the peak area of cesium atoms to the total of the peak areas of the constituent metal elements of the catalyst measured through X-ray photoelectron spectroscopy.

Description

Catalyst, method for producing the catalyst, and method for producing α,β-unsaturated aldehydes, α,β-unsaturated carboxylic acids, and α,β-unsaturated carboxylic acid esters.

[0001] The present invention relates to a catalyst, a method for producing the catalyst, and a method for producing α,β-unsaturated aldehydes, α,β-unsaturated carboxylic acids, and α,β-unsaturated carboxylic acid esters using the catalyst.

[0002] A method is known for producing α,β-unsaturated aldehydes and α,β-unsaturated carboxylic acids by carrying out a gas-phase oxidation reaction in the presence of a metal oxide catalyst, using organic compounds such as propylene, isobutylene, t-butyl alcohol, and methyl-t-butyl ether as raw materials.

[0003] Patent Document 1 describes a method for producing a composite oxide catalyst containing at least molybdenum, bismuth, cobalt and / or nickel, and iron, as a method for producing a catalyst used in producing corresponding unsaturated aldehydes and unsaturated carboxylic acids from olefins. Patent Document 2 describes a catalyst for the synthesis of unsaturated aldehydes and unsaturated carboxylic acids, comprising particles of a composite oxide containing at least molybdenum, iron, and cobalt, wherein the atomic ratios in the bulk composition and surface composition of the particles satisfy specific conditions. Patent Document 3 describes a catalyst for the synthesis of unsaturated aldehydes and unsaturated carboxylic acids, in which the bismuth composition of the catalyst surface relative to the entire catalyst is adjusted to a specific range.

[0004] Japanese Patent Publication No. 2005-169311, Japanese Patent Publication No. 2011-115681, International Publication No. 2022 / 202893

[0005] However, our own investigations have revealed that the performance of the catalysts described in Patent Documents 1 to 3 is not always sufficient, and that many by-products may be generated in reactions using these catalysts. The generation of by-products is a problem that affects the selectivity of target products such as α,β-unsaturated aldehydes and α,β-unsaturated carboxylic acids. Therefore, there is a need for the development of catalysts that can suppress the generation of by-products and have further improved catalytic performance.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a catalyst capable of producing target products such as α,β-unsaturated aldehydes and α,β-unsaturated carboxylic acids with high selectivity, and a method for producing such a catalyst. Another object of the present invention is to provide a method for producing an α,β-unsaturated aldehyde, an α,β-unsaturated carboxylic acid, and an α,β-unsaturated carboxylic acid ester with high selectivity using such a catalyst.

[0007] The present inventors have conducted intensive studies to achieve the above object. As a result, they have found that in a catalyst containing at least molybdenum, bismuth and cesium, by adjusting the cesium composition on the catalyst surface relative to the cesium composition of the entire catalyst, the target product can be produced with high selectivity. That is, the present invention includes the following configurations.

[0008] [1] A catalyst for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid, which contains molybdenum, bismuth and cesium, wherein when A (%) represents the ratio of the molar amount of cesium atoms to the total molar amount of all metal elements in the catalyst, and B (%) represents the ratio of the peak area of cesium atoms to the sum of the peak areas of the constituent metal elements of the catalyst measured by X-ray photoelectron spectroscopy, B / A is 1.50 or more. [2] The catalyst according to [1], wherein the B / A is 2.00 or more. [3] The catalyst according to [1] or [2], wherein the B / A is 2.40 or more. [4] The catalyst according to any one of [1] to [3], wherein the B is 3.00 or more. [5] The catalyst according to any one of [1] to [4], having a composition represented by the following formula (1): Mo ａ Bi ｂ Cs ｃ Fe ｄ M ｅ X ｆ Y ｇ Si ｈ O ｉ(1) In formula (1), Mo, Bi, Cs, Fe, Si, and O represent molybdenum, bismuth, cesium, iron, silicon, and oxygen, respectively; M represents at least one element selected from the group consisting of cobalt and nickel; and X is selected from the group consisting of zinc, chromium, lead, manganese, calcium, magnesium, niobium, silver, barium, tin, tantalum, tungsten, antimony, phosphorus, boron, sulfur, selenium, tellurium, cerium, and titanium. Y represents at least one element, where Y represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and thallium, and a, b, c, d, e, f, g, h, and i represent the atomic ratios of each element, where a = 12, b = 0.01 to 3, c = 0.001 to 2, d = 0 to 8, e = 0 to 12, f = 0 to 8, g = 0 to 2, and h = 0 to 20, and i is the atomic ratio of oxygen necessary to satisfy the valence of each component.

[0009] [6] A method for producing catalysts for the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, comprising the following steps (i) to (iii): (i) A step of preparing a slurry (Solution A) containing molybdenum, bismuth, and cesium and a solvent; (ii) Heating Solution A and adding the solvent at a rate of 0.006 cc / min·cm ２ (iii) A step of drying at the above speed to obtain a residue of liquid A; and (iii) a step of calcining the residue of liquid A. [7] The method for producing a catalyst according to [6], wherein in step (ii), the temperature at which liquid A is heated is at or above the boiling point of the solvent. [8] The method for producing a catalyst according to [6] or [7], wherein in step (ii), the temperature at which liquid A is heated is 130°C or higher. [9] In step (ii), the drying speed of the solvent is 0.010 cc / min·cm ２ The above is a method for producing a catalyst as described in any of [6] to [8].

[0010] A method for producing an α,β-unsaturated aldehyde and / or an α,β-unsaturated carboxylic acid from an alkene, alcohol, or ether using a catalyst described in any of [1] to [5] or a catalyst produced by a manufacturing method described in any of [6] to [9]. A method for producing an α,β-unsaturated carboxylic acid from an α,β-unsaturated aldehyde produced by a manufacturing method described in

[11] . A method for producing an α,β-unsaturated carboxylic acid from an α,β-unsaturated aldehyde produced by a manufacturing method described in

[10] . A method for producing an α,β-unsaturated carboxylic acid ester from an α,β-unsaturated carboxylic acid produced by a manufacturing method described in

[10] . A method for producing an α,β-unsaturated carboxylic acid ester from an α,β-unsaturated carboxylic acid produced by a manufacturing method described in

[10] . A method for producing an α,β-unsaturated carboxylic acid ester from an α,β-unsaturated carboxylic acid produced by a manufacturing method described in

[11] .

[0011] According to the present invention, a catalyst capable of producing a target product with high selectivity and a method for producing such a catalyst can be provided. Furthermore, according to the present invention, by carrying out an oxidation reaction using such a catalyst, the target products, α,β-unsaturated aldehydes and α,β-unsaturated carboxylic acids, as well as α,β-unsaturated carboxylic acid esters, can be produced with high selectivity.

[0012] The following describes embodiments of the present invention, but the present invention is not limited to the following embodiments. Furthermore, unless otherwise specified, the notation "XX or more and YY or less" or "XX to YY" indicating a numerical range means a numerical range including the lower and upper limits which are the endpoints. When a numerical range is described in steps, the upper and lower limits of each numerical range, as well as the numerical values ​​described in the examples, can be combined arbitrarily.

[0013] [Catalyst] The catalyst according to the present invention is a catalyst containing at least molybdenum, bismuth, and cesium. For this catalyst, when A (%) is the ratio of the molar amount of cesium atoms to the total molar amount of all metal elements in the catalyst, and B (%) is the ratio of the peak area of ​​cesium atoms to the sum of the peak areas of each of the constituent metal elements of the catalyst, as measured by X-ray photoelectron spectroscopy, then B / A is 1.50 or more. By carrying out a reaction using such a catalyst, the target product can be produced with high selectivity.

[0014] The catalyst according to the present invention is preferably an oxidation catalyst from the viewpoint of selectivity of the target product, and more preferably an oxidation catalyst used in the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids. Specifically, the catalyst is preferably a catalyst for the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids used in the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids by gas-phase oxidation reaction from a raw material organic compound selected from the group consisting of alkenes, alcohols, and ethers. Note that "producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids" means that either α,β-unsaturated aldehydes or α,β-unsaturated carboxylic acids may be produced, or both may be produced.

[0015] (Catalyst Composition) The catalyst according to the present invention, which contains at least molybdenum, bismuth, and cesium, preferably has a composition represented by the following formula (1). The catalyst may also contain small amounts of elements not listed in the following formula (1). Mo ａ Bi ｂ Cs ｃ Fe ｄ M ｅ X ｆ Y ｇ Si ｈ O ｉ(1) In formula (1), Mo, Bi, Cs, Fe, Si, and O represent molybdenum, bismuth, cesium, iron, silicon, and oxygen, respectively. M represents at least one element selected from the group consisting of cobalt and nickel. X represents at least one element selected from the group consisting of zinc, chromium, lead, manganese, calcium, magnesium, niobium, silver, barium, tin, tantalum, tungsten, antimony, phosphorus, boron, sulfur, selenium, tellurium, cerium, and titanium. Y represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and thallium. a, b, c, d, e, f, g, h, and i represent the atomic ratio (molar ratio) of each element. When a = 12, b = 0.01 to 3, c = 0.001 to 2, d = 0 to 8, e = 0 to 12, f = 0 to 8, g = 0 to 2, and h = 0 to 20. i is the atomic ratio of oxygen necessary to satisfy the valence of each component. When M, X, and Y contain two or more elements, e, f, and g represent the sum of the atomic ratios of those two or more elements.

[0016] In formula (1) above, from the viewpoint of improving the selectivity of the target product, when a = 12, b is preferably 0.03 or more, more preferably 0.05 or more. Also, b is preferably 2 or less, more preferably 1 or less. c is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, and particularly preferably 0.3 or more. d is preferably 0.01 or more, more preferably 0.1 or more, even more preferably 1 or more, and particularly preferably 1.5 or more. Also, d is preferably 6 or less, more preferably 4 or less. e is preferably 0.01 or more, more preferably 0.1 or more, even more preferably 1 or more, and particularly preferably 3 or more. Also, e is preferably 10 or less, more preferably 9 or less. f is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.5 or more. Also, f is preferably 6 or less, more preferably 4 or less. g is preferably 1.8 or less, more preferably 1.6 or less, and even more preferably 1.4 or less. h is preferably 18 or less, more preferably 15 or less, and even more preferably 10 or less.

[0017] The catalyst contains molybdenum, bismuth, cesium, and iron and / or silicon as metallic elements, but may also contain one or more metallic elements selected from elements M, X, and Y in formula (1) as other metallic elements. Among the other metallic elements, the catalyst preferably contains element M, and more preferably contains elements M and X.

[0018] The catalyst may have a support for bearing the above elements. The support is not particularly limited and includes silica, alumina, silica-alumina, magnesia, titania, and silicon carbide. Among these, silica is preferred as the support from the viewpoint of preventing the support itself from reacting. In this invention, when a support is used in the catalyst, the support is also considered as part of the catalyst.

[0019] In this invention, the composition of each metal element in the catalyst (catalyst composition) is determined from the amount (moles) of catalyst raw materials of each metal element used in the production of the catalyst. The catalyst composition determined from the amount (moles) of catalyst raw materials of each metal element is equivalent to the catalyst composition obtained by analyzing the bulk composition of the obtained catalyst. The method for analyzing the bulk composition is not particularly limited as long as it is a method capable of analyzing the bulk composition. Examples of main analytical methods include ICP emission spectrometry, atomic absorption spectrometry (AAS), and X-ray fluorescence spectrometry (XRF).

[0020] (Cesium composition B present on the catalyst surface relative to cesium composition A in the entire catalyst) In the catalyst according to the present invention, when A (%) is the ratio of the molar amount of cesium atoms in the catalyst to the total molar amount of all metal elements in the catalyst (i.e., all metal elements other than oxygen that constitute the catalyst) (moles of cesium atoms / total molar amount of metal elements × 100), and B (%) is the ratio of the peak area of ​​cesium atoms to the sum of the peak areas of each of the constituent metal elements of the catalyst (i.e., all metal elements other than oxygen that constitute the catalyst) on the catalyst surface, measured by X-ray photoelectron spectroscopy (peak area of ​​cesium atoms / sum of peak areas of each of the constituent metal elements × 100), then B / A is 1.50 or more. Here, B / A is a value that represents the amount (composition) of cesium atoms present on the catalyst surface relative to the amount (composition) of cesium atoms in the entire catalyst, and a B / A of 1.50 or more indicates that cesium atoms are segregated on the catalyst surface.

[0021] In the present invention, the cesium composition A in the entire catalyst is determined from the amount (moles) of catalyst raw materials of each metal element used in the production of the catalyst. As described above, the cesium composition A in the entire catalyst can also be calculated using ICP emission spectrometry, atomic absorption spectrometry (AAS), and X-ray fluorescence spectrometry (XRF).

[0022] Furthermore, in this invention, the cesium composition B present on the catalyst surface can be determined by performing X-ray photoelectron spectroscopy on the catalyst and calculating the ratio of the peak area of ​​cesium atoms to the sum of the peak areas of each of the constituent metal elements of the catalyst. An example of an analytical instrument used for X-ray photoelectron spectroscopy is the Quantera II (trade name, manufactured by ULVAC-PHIE). The analytical conditions are as follows: X-ray source: HP mode - monochromatic Al line, Suevey (Wide Scan: 1 eV / step, Narrow Scan: 0.1 eV / step (Pass energy 55 eV)), output: 100 W, acquisition angle: 45°. The analysis is performed by linearly scanning a range of 1400 μm with an X-ray beam diameter of 100 μmφ. The sensitivity factor is the one incorporated into the analysis software installed in the instrument. X-ray photoelectron spectroscopy is a technique that measures the composition and chemical state of elements constituting a sample surface by irradiating the sample surface with X-rays and measuring the kinetic energy of photoelectrons emitted from the sample surface. Generally, X-ray photoelectron spectroscopy provides information on elements present within a few nanometers of the sample surface, thus allowing for the acquisition of information related to the composition and chemical state of a catalyst surface.

[0023] According to the present invention, by carrying out a reaction (preferably an oxidation reaction) using a catalyst in which the B / A ratio satisfies the above range, the target product can be produced with high selectivity. The reason for this is not clear, but the inventors speculate as follows: Cesium, by being present on the surface of the catalyst, has the effect of promoting the dissociative adsorption of oxygen molecules and blocking acid sites on the catalyst surface. Therefore, when the B / A ratio is 1.50 or higher, that is, when there are a sufficient number of cesium atoms on the catalyst surface, oxygen uptake is promoted, and the reduced state of the catalyst surface can be maintained in a state suitable for oxidation reactions. In addition, by the cesium atoms moderately blocking the acid sites on the catalyst surface, side reactions are suppressed, and as a result, the selectivity of the target product is improved.

[0024] The B / A ratio is preferably 1.60 or higher, more preferably 2.00 or higher, even more preferably 2.10 or higher, even more preferably 2.40 or higher, and particularly preferably 2.50 or higher. Furthermore, the B / A ratio is preferably 10.00 or lower, more preferably 7.00 or lower, and even more preferably 5.00 or lower. If the B / A ratio is 10.00 or lower, there will be no excess cesium atoms on the catalyst surface, and the decrease in catalytic activity due to excessive covering of acid sites with cesium atoms can be suppressed. From the viewpoint of controlling the B / A ratio to the above preferred range, B is preferably 3.00 or higher, more preferably 4.00 or higher, even more preferably 4.50 or higher, and particularly preferably 5.00 or higher.

[0025] As shown in the examples described later, the present invention has found that by setting the B / A ratio of the catalyst to 1.50 or higher, the selectivity of the target product in a reaction using the catalyst can be greatly improved compared to a catalyst with a B / A ratio of less than 1.50. Methods for controlling the B / A ratio of the catalyst include adjusting the type and amount of catalyst raw materials containing cesium, the heating temperature and heating time of the slurry containing the catalyst raw materials, etc., during the catalyst preparation process. However, in the present invention, it is presumed that the B / A ratio of the catalyst depends more on the catalyst preparation process than on the type and amount of catalyst raw materials containing metal elements. That is, as a method for producing a catalyst having a B / A ratio within the above range, for example, a method for producing a catalyst by following the steps below can be cited: (i) a step of preparing a slurry (solution A) containing at least molybdenum, bismuth, and cesium, and a solvent; and (ii) heating solution A and adding 0.006 cc / min·cm of solvent. ２ A step of drying at the above speed to obtain the residue of liquid A. The effects of the present invention are more pronounced when the catalyst according to the present invention is manufactured through such a process. Needless to say, even if the catalyst is not manufactured through the above process, any catalyst according to the present invention with a B / A ratio of 1.50 or higher can be used to achieve the effects of the present invention. For each of the above steps, refer to the corresponding steps in the catalyst manufacturing method described later.

[0026] In the present invention, the density of the catalyst is not particularly limited, but from the viewpoint of improving the durability of the catalyst, 0.2 g / cm³ is preferred. ３ Preferably, it is 0.5 g / cm³ or more. ３ It is more preferable that the concentration be greater than or equal to 1 g / cm³. ３ It is even more preferable that the above conditions are met. On the other hand, from the viewpoint of improving the selectivity of the target product, the density of the catalyst should be 50 g / cm³. ３ Preferably, it is 30 g / cm³. ３ It is more preferable that the following conditions apply: 20 g / cm³ ３ The following is even more preferable:

[0027] [Method for Producing a Catalyst] The method for producing a catalyst according to the present invention is a method for producing a catalyst containing at least molybdenum, bismuth, and cesium, and comprises the following steps (i) to (iii): (i) a step of preparing a slurry (solution A) containing at least molybdenum, bismuth, and cesium and a solvent; (ii) heating solution A and adding 0.006 cc / min·cm of solvent. ２ (iii) A step of drying at the above speed to obtain the residue of liquid A; and a step of calcining the residue of liquid A. The catalyst manufacturing method according to the present invention may further include a molding step described later. The catalyst obtained by the catalyst manufacturing method according to the present invention preferably has a B / A ratio of 1.50 or more, and is preferably the catalyst according to the present invention. Each step will be described in detail below.

[0028] (Step (i)) In step (i), a slurry (Solution A) containing at least molybdenum, bismuth, and cesium, and a solvent is prepared by mixing at least molybdenum raw material, bismuth raw material, and cesium raw material with a solvent. In step (i), raw materials of metal elements other than molybdenum, bismuth, and cesium that are included in formula (1) may be further mixed. That is, Solution A may contain other metal elements included in formula (1) in addition to molybdenum, bismuth, and cesium. The amount of raw materials of each metal element included in formula (1) (hereinafter also referred to as "catalyst raw materials") used may be adjusted as appropriate to obtain the desired catalyst composition.

[0029] The catalyst raw materials are not particularly limited, and one or more selected from nitrates, carbonates, bicarbonates, acetates, ammonium salts, sulfates, oxides, chlorides, hydroxides, halides, oxoacids, and oxoate salts of each metal element can be used alone or in combination of two or more. Specifically, examples of molybdenum raw materials include ammonium paramolybdate, molybdenum trioxide, molybdic acid, 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 cesium raw materials include cesium nitrate, cesium sulfate, cesium chloride, cesium carbonate, and cesium acetate, with cesium nitrate being preferred. Examples of iron raw materials include iron nitrate, iron hydroxide, and iron trioxide, with iron nitrate being preferred. Examples of cobalt raw materials include cobalt nitrate, cobalt sulfate, cobalt chloride, cobalt carbonate, and cobalt acetate, with cobalt nitrate being preferred. Examples of antimony raw materials include antimony oxides such as antimony trioxide and antimony pentoxide, as well as trivalent antimony compounds and pentavalent antimony compounds such as antimony acetate.

[0030] The solvent is not particularly limited as long as it can dissolve or disperse the catalyst raw materials, and one or more selected from water and organic solvents can be used. The solvent preferably contains water, more preferably 50% by mass or more of the total solvent is water, and even more preferably 80% by mass or more of the total solvent is water, and water alone can also be used. The organic solvent is not particularly limited, and examples include alcohol and acetone. The amount of solvent used is not particularly limited, but it is preferably 30 to 400 parts by mass per 100 parts by mass of the total catalyst raw materials.

[0031] When preparing solution A, all catalyst materials may be mixed with the solvent at once. Alternatively, for example, solution A1, which is a mixture of some catalyst materials and the solvent, and solution A2, which is a mixture of other catalyst materials and the solvent, may be prepared separately, and then solution A1 and solution A2 may be mixed together to prepare solution A. Furthermore, solution A may be prepared by mixing solution A1, solution A2, and the remaining catalyst materials.

[0032] (Step (ii)) In step (ii), the solution A obtained in step (i) is heated, and the solvent in solution A is diluted to 0.006 cc / min·cm. ２ By drying at the above rate, the residue of solution A is obtained. Note that "Heat solution A and remove the solvent in solution A to 0.006 cc / min·cm ２ "Drying at the above speed" quantitatively defines the state of the solvent when heating solution A and drying the solvent in solution A. The drying speed of the solvent in solution A (drying rate) is determined by the amount of solvent in solution A (cc), the time taken for the solvent to completely evaporate (min), and the opening area of ​​the heating container used for drying (cm²). ２) and can be calculated from the above. The time taken for the solvent to completely evaporate is measured visually, so the numerical values ​​of the drying rate in this specification may include a range of measurement error that is normally acceptable to those skilled in the art. The temperature at which liquid A is heated in this step is preferably above a temperature that can boil at least a portion of the solvent in liquid A. The temperature at which liquid A is heated varies depending on the solvent used when preparing liquid A, but for example, it is preferably above the boiling point of the solvent contained in liquid A, more preferably above 100°C, and can also be 130°C or higher. The temperature at which liquid A is heated is the temperature of the heating container in which liquid A is placed and heated, and is the temperature of the surface of the heating container measured using a thermometer such as a radiation thermometer. For example, if water is used alone as the solvent in step (i), the boiling point of water is 100°C, so by heating liquid A in a heating container of 130°C or higher, the water boils and bubbles are generated. These bubbles stir liquid A, and the metal oxide particles contained in liquid A are dried while maintaining a high dispersion state in liquid A. Furthermore, this drying process makes it easier for cesium to be arranged on the surface of the dried metal oxide particles. On the other hand, when drying solution A is carried out by known methods such as drum drying or spray drying, the evaporation of the solvent proceeds instantaneously, making it difficult for the metal oxide particles to disperse in solution A. Also, when drying solution A by a general evaporation-to-drying method in which the solvent is not boiling, it is difficult for the metal oxide particles to achieve a high degree of dispersion. As described above, the temperature at which solution A is heated (the temperature of the heating container) is preferably above a temperature that can boil at least a portion of the solvent in solution A, more preferably at least 30°C higher than the boiling point of the solvent, and particularly preferably at least 130°C when the solvent is only water.

[0033] In this process, the drying rate of the solvent in solution A is 0.007 cc / min·cm. ２ Preferably, it is 0.008 cc / min·cm. ２ It is more preferable that the amount be greater than or equal to 0.010 cc / min·cm ２ It is even more preferable that the concentration be greater than or equal to 0.020 cc / min·cm ２It is even more preferable that the above conditions are met. In investigating a method for producing a catalyst having a B / A ratio of 1.50 or more, the present inventors found that by bringing at least a portion of the solvent in the drying step of the solvent in liquid A to a boiling state, the desired catalyst is more easily obtained. That is, in the method for producing a catalyst according to the present invention, the drying rate of the solvent in liquid A is at least 0.006 cc / min·cm ２ However, from the viewpoint of bringing at least a portion of the solvent to a boiling state, the drying rate of the solvent should be 0.010 cc / min·cm. ２ The above is preferable. The drying rate of the solvent in solution A is 0.010 cc / min·cm. ２ In the above case, the solvent is expected to boil, and the metal oxide particles in solution A will be dispersed more efficiently. Also, as mentioned above, if the evaporation of the solvent proceeds instantaneously, that is, if the drying rate is too high, the metal oxide particles in solution A may not disperse easily. Therefore, the drying rate should be 10.00 cc / min·cm. ２ Preferably, it is 5.00 cc / min·cm ２ It is more preferable that the following is the case: 3.00 cc / min·cm ２ The following is even more preferable. Thus, the inventors have found that controlling the drying rate of the solvent in solution A to a specific range is one means of controlling the B / A ratio of the resulting catalyst to 1.50 or higher.

[0034] (Step (iii)) In step (iii), a catalyst is obtained by calcining the residue of liquid A obtained in step (ii) (hereinafter also referred to as "residue" or "dried material"). Calcination can be performed after obtaining a molded product by carrying out the molding process described later, but from the viewpoint of catalyst strength, it is preferable to perform calcination before the molding process. Calcination may be performed only once, or it may be performed in multiple steps in combination with the molding process described later. For example, first a primary calcination may be performed, the molding process described later may be carried out on the obtained primary calcined product, and then a secondary calcination may be carried out on the obtained molded product. Alternatively, after the primary and secondary calcinations, the molding process may be carried out on the obtained catalyst. In this invention, the term catalyst is used collectively to refer to a calcined product obtained by calcining a dried material, a molded product obtained by molding a dried material, and a product obtained by calcining and molding a dried material.

[0035] The firing is preferably carried out under the flow of an oxygen-containing gas such as air or an inert gas. "Inert gas" means a gas that does not reduce catalytic activity, and examples include nitrogen, carbon dioxide, helium, and argon. The firing temperature is preferably 200°C to 700°C. The lower limit of the firing temperature is more preferably 300°C, the upper limit is more preferably 500°C, and even more preferably 450°C. The firing time is preferably 0.5 hours to 40 hours, with a lower limit of 1 hour being more preferably. The firing time refers to the time from when the predetermined firing temperature is reached until that temperature is maintained.

[0036] In the present invention, it is preferable to perform primary firing on the residue (dried material) of liquid A obtained in step (ii), followed by molding, and then perform secondary firing on the resulting molded product. In this case, the firing temperature for primary firing is preferably 200°C to 600°C, with a lower limit of 250°C being more preferable and an upper limit of 450°C being more preferable. The firing time for primary firing is preferably 0.5 hours to 5 hours from the viewpoint of improving the selectivity of the target product. The type of firing furnace and firing method during primary firing are not particularly limited, and for example, a box-type firing furnace or a tunnel-type firing furnace may be used to fire the dried material or molded product in a fixed state. Alternatively, a rotary kiln or the like may be used to fire the dried material or molded product while it is flowing.

[0037] The firing temperature for the secondary firing is preferably 300°C to 700°C, with a lower limit of 400°C being more preferable and an upper limit of 600°C being more preferable. The firing time for the secondary firing is preferably 10 minutes to 10 hours, with a lower limit of 1 hour being more preferable, from the viewpoint of improving the selectivity of the target product. The type of firing apparatus and firing method for the secondary firing are not particularly limited, and for example, a box-type firing furnace or a tunnel-type firing furnace may be used to fire the molded product or the primary fired product in a fixed state. Alternatively, a rotary kiln or the like may be used to fire the molded product or the primary fired product while it is flowing.

[0038] (Molding Process) The catalyst manufacturing method according to the present invention may include a molding process in which the residue (dried product) of liquid A obtained in step (ii) or the calcined product obtained in step (iii) is molded to obtain a molded product. The molding method is not particularly limited, and known dry or wet molding methods can be applied. Examples of molding methods include tableting, extrusion molding, pressure molding, and rolling granulation. When molding, conventionally known additives may be added. Examples of additives include organic compounds such as polyvinyl alcohol and carboxymethylcellulose, inorganic compounds such as graphite and diatomaceous earth, and inorganic fibers such as glass fibers, ceramic fibers, and carbon fibers. These additives can be used individually or in combination of two or more.

[0039] The shape of the molded product is not particularly limited, and any shape can be spherical, cylindrical, ring-shaped, star-shaped, or granular after crushing and classification. Among these, spherical, cylindrical, and ring-shaped are preferred from the viewpoint of mechanical strength. The size of the molded product is not particularly limited, but for example, in the case of a spherical shape, the diameter of the sphere is preferably 0.1 mm to 10 mm. The diameter of the sphere is more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. Also, the diameter of the sphere is more preferably 8 mm or less, and even more preferably 6 mm or less. In the case of a ring-shaped or cylindrical shape, the diameter and height of the circle at the base of the ring or cylinder are both preferably 0.1 mm to 10 mm. The diameter and height are more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. Also, the diameter and height are more preferably 8 mm or less, and even more preferably 6 mm or less. In the case of other shapes, the distance between the two furthest points in the three-dimensional structure of the catalyst is preferably 0.1 mm to 10 mm. The distance between the two points is more preferably 0.5 mm or more, even more preferably 1 mm or more, and particularly preferably 3 mm or more. Furthermore, the distance between the two points is more preferably 8 mm or less, and even more preferably 6 mm or less. When the shape of the molded product is within the above range, the selectivity of the target product and the catalyst lifetime tend to improve.

[0040] The external surface area of ​​the molded product is not particularly limited, but from the viewpoint of stably producing the target product over a long period of time, it is 0.01 cm². ２ The above is preferable, and 0.05 cm ２ The above is more preferable, 0.1 cm ２ The above is even more preferable. On the other hand, from the viewpoint of improving the selectivity of the target product, the outer surface area of ​​the molded product should be 4 cm². ２ The following is preferable: 3 cm ２ The following is more preferable: 2 cm ２ The following are even more preferable.

[0041] The volume of the molded product is not particularly limited, but from the viewpoint of stably producing the target product over a long period of time, it is 0.0002 cm³. ３ The above is preferable, and 0.002 cm ３ The above is more preferable, 0.02 cm ３The above is even more preferable. On the other hand, from the viewpoint of improving the selectivity of the target product, the volume of the molded product should be 5 cm³. ３ The following is preferable: 1 cm ３ The following is more preferable: 0.5 cm ３ The following are even more preferable.

[0042] The mass of the molded product is not particularly limited, but from the viewpoint of stably producing the target product over a long period of time, it is preferably 0.002 g / piece or more, more preferably 0.01 g / piece or more, and even more preferably 0.05 g / piece or more. On the other hand, from the viewpoint of improving the selectivity of the target product, the mass of the molded product is preferably 0.5 g / piece or less, more preferably 0.3 g / piece or less, and even more preferably 0.2 g / piece or less.

[0043] The bulk density of the molded product is not particularly limited, but from the viewpoint of stably producing the target product over a long period of time, 0.2 g / cm³ is recommended. ３ The above is preferable, 0.3 g / cm³ ３ The above is more preferable, 0.4 g / cm³ ３ The above is even more preferable. On the other hand, from the viewpoint of improving the selectivity of the target product, the packing bulk density of the molded product should be 1 g / cm³. ３ The following is preferable: 0.9 g / cm³ ３ The following is more preferable: 0.8 g / cm³ ３ The following is even more preferable. The bulk density of the molded product refers to the value calculated from the total mass of the molded product when it is filled into a 100 mL graduated cylinder, in accordance with the method of JIS-K 7365:1999.

[0044] The resulting molded product may be supported on a carrier. Examples of carriers include silica, alumina, silica-alumina, magnesia, titania, and silicon carbide. The molded product can also be used after being diluted with the above-mentioned carrier.

[0045] As described above, a catalyst can be manufactured. It is preferable that the catalyst obtained by the catalyst manufacturing method according to the present invention is the catalyst described above. For preferred embodiments of the catalyst obtained by the catalyst manufacturing method according to the present invention, please refer to the description in the catalyst section above.

[0046] [Method for Producing α,β-Unsaturated Aldehydes and / or α,β-Unsaturated Carboxylic Acids] In the method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids according to the present invention, the catalyst according to the present invention or a catalyst produced by the method for producing the catalyst according to the present invention is used to produce the corresponding α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids from alkenes, alcohols, or ethers. Examples of alkenes include propylene and isobutylene. Examples of alcohols include t-butyl alcohol and isobutyl alcohol. Examples of ethers include methyl-t-butyl ether. By oxidizing these raw material organic compounds using a catalyst, the corresponding α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be produced. For example, if the raw material organic compound is propylene, the corresponding α,β-unsaturated aldehyde is acrolein, and the corresponding α,β-unsaturated carboxylic acid is acrylic acid. Furthermore, when the raw material organic compound is isobutylene, t-butyl alcohol, isobutyl alcohol, or methyl-t-butyl ether, the corresponding α,β-unsaturated aldehyde is methacrolein, and the corresponding α,β-unsaturated carboxylic acid is methacrylic acid. From the viewpoint of selectivity for the target product, the α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid are preferably (meth)acrolein and (meth)acrylic acid, respectively, and more preferably methacrolein and methacrylic acid. Note that "(meth)acrolein" refers to acrolein and methacrolein, and "(meth)acrylic acid" refers to acrylic acid and methacrylic acid.

[0047] The method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids according to the present invention can be carried out by contacting a catalyst according to the present invention or a catalyst produced by the method for producing the catalyst according to the present invention with a raw material gas containing the raw material organic compound and oxygen in a reactor. The reactor is not particularly limited, but it is preferable to use a tubular reactor equipped with reaction tubes filled with catalyst. Industrially, it is more preferable to use a multi-tube reactor equipped with multiple such reaction tubes. The catalyst layer in the reactor may be a single layer, or multiple catalysts with different activities may be packed into multiple layers. Furthermore, the catalyst may be diluted with an inert carrier to control its activity before packing.

[0048] The concentration of the raw material organic compound in the raw material gas is preferably 1% to 20% by volume, more preferably 3% by volume at the lower limit and 10% by volume at the upper limit. The raw material organic compound may contain small amounts of impurities that do not substantially affect this reaction, such as lower saturated alkanes. The concentration of oxygen in the raw material gas is preferably 0.1 to 5 moles per mole of the raw material organic compound, more preferably 0.5 moles at the lower limit and 3 moles at the upper limit. From an economic standpoint, air is preferred as the oxygen source. If necessary, an oxygen-enriched gas may be used by mixing pure oxygen with air or the like.

[0049] From an economic standpoint, the raw material gas may be diluted with an inert gas such as nitrogen and carbon dioxide. Furthermore, water vapor may be added to the raw material gas. By carrying out the reaction in the presence of water vapor, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids can be obtained with higher selectivity. The concentration of water vapor in the raw material gas is preferably 0.1% to 50% by volume, more preferably 1% by volume at the lower limit and more preferably 40% by volume at the upper limit.

[0050] The reaction pressure is preferably 0 MPa(G) to 1 MPa(G). Here, "(G)" means gauge pressure, and 0 MPa(G) means the reaction pressure is atmospheric pressure. The reaction temperature is preferably 200°C to 450°C, with a lower limit of 250°C being more preferable and an upper limit of 400°C being more preferable. The contact time between the raw material gas and the catalyst is preferably 0.5 seconds to 15 seconds. The lower limit of the contact time is more preferably 1 second, with an upper limit of 10 seconds being more preferable and an even more preferable 5 seconds.

[0051] As described above, according to the present invention, α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids corresponding to the used raw material organic compounds can be obtained with high selectivity.

[0052] [Method for Producing α,β-Unsaturated Carboxylic Acids] In the method for producing α,β-unsaturated carboxylic acids according to the present invention, a corresponding α,β-unsaturated carboxylic acid is produced from an α,β-unsaturated aldehyde produced by the above-described method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids according to the present invention. Examples of α,β-unsaturated aldehydes include (meth)acrolein, crotonaldehyde (β-methylacrolein), and cinnamaldehyde (β-phenylacrolein). The resulting α,β-unsaturated carboxylic acid is an α,β-unsaturated carboxylic acid in which the aldehyde group of the α,β-unsaturated aldehyde is converted to a carboxyl group. Specifically, when the α,β-unsaturated aldehyde is (meth)acrolein, (meth)acrylic acid is obtained. From the viewpoint of selectivity for the target product, the α,β-unsaturated aldehyde and α,β-unsaturated carboxylic acid are preferably (meth)acrolein and (meth)acrylic acid, respectively, and more preferably metacrolein and methacrylic acid.

[0053] The method for producing α,β-unsaturated carboxylic acids according to the present invention can be carried out by contacting a catalyst according to the present invention or a catalyst produced by the method for producing the catalyst according to the present invention with a raw material gas containing α,β-unsaturated aldehyde and oxygen in a reactor. The reactor can be the same type of reactor used in the above-described method for producing α,β-unsaturated aldehyde and / or α,β-unsaturated carboxylic acids. The catalyst layer in the reactor may be a single layer, or multiple catalysts with different activities may be packed into multiple layers. Furthermore, the catalyst may be diluted with an inert support to control its activity before packing.

[0054] The concentration of α,β-unsaturated aldehyde in the raw material gas is preferably 1% to 20% by volume, more preferably 3% by volume at the lower limit and 10% by volume at the upper limit. The α,β-unsaturated aldehyde may contain small amounts of impurities that do not substantially affect this reaction, such as lower saturated aldehydes. The concentration of oxygen in the raw material gas is preferably 0.4 to 4 moles per mole of α,β-unsaturated aldehyde, more preferably 0.5 moles at the lower limit and 3 moles at the upper limit. From an economic standpoint, air is preferred as the oxygen source for the raw material gas. If necessary, an oxygen-enriched gas may be used by mixing pure oxygen with air or the like.

[0055] From an economic standpoint, the raw material gas may be diluted with an inert gas such as nitrogen and carbon dioxide. Furthermore, water vapor may be added to the raw material gas. By carrying out the reaction in the presence of water vapor, α,β-unsaturated carboxylic acids can be obtained with higher selectivity. The concentration of water vapor in the raw material gas is preferably 0.1% to 50% by volume, more preferably 1% by volume at the lower limit and more preferably 40% by volume at the upper limit.

[0056] The reaction pressure is preferably 0 MPa(G) to 1 MPa(G). The reaction temperature is preferably 200°C to 450°C, with a lower limit of 250°C being more preferable and an upper limit of 400°C being more preferable. The contact time between the raw material gas and the catalyst is preferably 0.5 seconds to 15 seconds. The lower limit of the contact time is more preferably 1 second, with an upper limit of 10 seconds being more preferable and an even more preferable 5 seconds.

[0057] [Method for Producing α,β-Unsaturated Carboxylic Acid Esters] In the method for producing α,β-unsaturated carboxylic acid esters according to the present invention, an α,β-unsaturated carboxylic acid produced by the above-mentioned method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids according to the present invention, or an α,β-unsaturated carboxylic acid produced by the above-mentioned method for producing α,β-unsaturated carboxylic acids according to the present invention, is esterified. The alcohol used for esterification is not particularly limited and includes methanol, ethanol, propanol, isopropanol, butanol, and isobutanol. Examples of the resulting α,β-unsaturated carboxylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate. The esterification reaction can be carried out in the presence of an acidic catalyst such as a sulfonic acid type cation exchange resin. The reaction temperature is preferably 50°C to 200°C.

[0058] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" means parts by mass. In the following examples and comparative examples, the catalyst composition was calculated from the amount of raw materials charged.

[0059] (X-ray photoelectron spectroscopy analysis) X-ray photoelectron spectroscopy analysis was performed on the catalyst, and B (%) was determined by calculating the ratio of the peak area of ​​cesium atoms to the sum of the peak areas of each constituent metal element of the catalyst (peak area of ​​cesium atoms / sum of peak areas of each constituent metal element × 100). The analytical instrument used was Quantera II (trade name, manufactured by ULVAC-PHI). The analytical conditions were as follows: X-ray source: HP mode - monochromatic Al line, Suevey (Wide Scan: 1 eV / step, Narrow Scan: 0.1 eV / step (Pass energy 55 eV)), output: 100 W, acquisition angle: 45°. The analysis was performed by linearly scanning a range of 1400 μm with an X-ray beam diameter of 100 μmφ.

[0060] (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. The analysis of the raw material gas and products in the reaction evaluation was performed using gas chromatography under the following conditions. <Analysis of raw material gas> Gas chromatograph: GC-8A (trade name, manufactured by Shimadzu Corporation); Column: Stainless steel column (length 2.0 m x inner diameter 3.0 mm); Packing material: Benzyl Ether 20% Shimalite (trade name, manufactured by Shimadzu Corporation). <Analysis of methacrolein> Gas chromatograph: GC-2014 (trade name, manufactured by Shimadzu Corporation); Column: 007-CW (trade name, length 60 m x inner diameter 0.32 mm, film thickness: 3.0 μm, manufactured by QUADREX). <Analysis of methacrylic acid> Gas chromatograph: GC-2014 (product name, manufactured by Shimadzu Corporation); Column: DB-FFAP (product name, length 30 m x inner diameter 0.32 mm, film thickness 1.00 μm, manufactured by Agilent Technologies, Inc.).

[0061] From the gas chromatography results, the total selectivity (%) of the generated methacrolein (MAL) and methacrylic acid (MAA) was determined using the following formula: Total selectivity (%) of methacrolein and methacrylic acid = (P1 + P2) / M1 × 100 In the above formula, M1 represents the number of moles of isobutylene reacted per unit time, P1 represents the number of moles of methacrolein generated per unit time, and P2 represents the number of moles of methacrylic acid generated per unit time.

[0062] [Example 1] Solution A1 was obtained by mixing 100.0 parts of ammonium paramolybdate tetrahydrate and 4.6 parts of cesium nitrate with 200.0 parts of pure water at 60°C as a solvent. Separately from Solution A1, Solution A2 was obtained by mixing 45.8 parts of iron(III) nitrate nonahydrate and 109.9 parts of cobalt(II) nitrate hexahydrate with 200.0 parts of pure water at 20°C (room temperature). Next, Solution A1 and Solution A2 were mixed. After heating the resulting mixture to 95°C, 6.6 parts of bismuth(III) oxide and 6.9 parts of antimony trioxide were mixed in. Solution A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained solution A was transferred to a stainless steel heating container (opening diameter: 21 cm), and the solvent was dried by vigorously boiling it at 130°C (drying time: 20 min) to obtain the residue (dried material) of solution A (drying rate: 0.067 cc / min·cm). ２ ). The temperature is the surface temperature of the heating container measured using a radiation thermometer (product name: FT3700, manufactured by HIOKI E.E. CORPORATION). The drying rate is calculated using the amount of solvent in liquid A (cc), the time taken for the solvent to completely evaporate (drying time: min), and the opening area of ​​the heating container used for drying (cm²). ２ ) and were calculated from. The obtained dried material was first calcined at 300°C for 1 hour under air circulation, and then pulverized. Next, the pulverized calcined dried material was pressure-molded and then crushed to obtain crushed particles. Next, the crushed particles were classified, and crushed particles that passed through a sieve with a mesh size of 2.36 mm and did not pass through a sieve with a mesh size of 0.71 mm were collected. Next, the collected crushed particles were secondarily calcined at 500°C for 3 hours under air circulation to obtain a catalyst. The oxygen-free composition of the obtained catalyst was Mo １２ Bi ０．６ Fe ２．４ Co ８ Sb １ Cs ０．５ Furthermore, X-ray photoelectron spectroscopy analysis was performed on the catalyst.

[0063] Next, the obtained catalyst was packed into a stainless steel reaction tube to form a catalyst layer, and the oxidation reaction of isobutylene was carried out under the following conditions: Raw material gas composition: 5% isobutylene by volume, 12% oxygen by volume, 10% water vapor by volume, and 73% nitrogen by volume; Reaction pressure: 0 MPa (atmospheric pressure); Reaction temperature: 340°C; Contact time: The contact time between the raw material gas and the catalyst was adjusted so that the conversion rate of isobutylene was 95%.

[0064] [Example 2] Solution A1 was obtained by mixing 100.0 parts of ammonium paramolybdate tetrahydrate and 4.6 parts of cesium nitrate with 200.0 parts of pure water at 60°C as a solvent, and then adding 300 ml of 28% by mass aqueous ammonia solution (194.4 parts of water) to adjust the pH to 10. Separately from Solution A1, Solution A2 was obtained by mixing 45.8 parts of iron(III) nitrate nonahydrate and 109.9 parts of cobalt(II) nitrate hexahydrate with 200.0 parts of pure water at 20°C (room temperature). Next, Solution A1 and Solution A2 were mixed. After heating the resulting mixture to 95°C, 6.6 parts of bismuth(III) oxide and 6.9 parts of antimony trioxide were added. Solution A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained solution A was transferred to a stainless steel heating container (opening diameter: 21 cm), and the solvent was dried by vigorously boiling it at 130°C to obtain the residue (dried material) of solution A. The dried material was fired and molded in the same manner as in Example 1 to obtain a catalyst. The oxygen-free composition of the obtained catalyst was Mo １２ Bi ０．６ Fe ２．４ Co ８ Sb １ Cs ０．５ The catalyst was then subjected to X-ray photoelectron spectroscopy analysis. Next, the reaction was evaluated using the obtained catalyst in the same manner as in Example 1.

[0065] [Example 3] Solution A1 was obtained by mixing 100.0 parts of ammonium paramolybdate tetrahydrate, 4.6 parts of cesium nitrate, 6.6 parts of bismuth(III) oxide, and 6.9 parts of antimony trioxide with 200.0 parts of pure water at 60°C as a solvent. Separately from Solution A1, Solution A2 was obtained by mixing 45.8 parts of iron(III) nitrate nonahydrate and 109.9 parts of cobalt(II) nitrate hexahydrate with 200.0 parts of pure water at 20°C (room temperature). Next, Solution A1 and Solution A2 were mixed. The resulting mixture was heated to 95°C and then stirred for 1 hour while maintaining the temperature at 95°C to obtain Solution A. The obtained Solution A was transferred to an evaporating dish (opening diameter: 15 cm) and left to stand in a drying oven (product name: hot air circulation type drying oven, manufactured by Fuji Kiden) set to 100°C to obtain the residue (dried product) of Solution A. During this drying process, the solvent (water) in solution A did not boil. The resulting dried material was calcined and molded in the same manner as in Example 1 to obtain a catalyst. The oxygen-free composition of the obtained catalyst was Mo １２ Bi ０．６ Fe ２．４ Co ８ Sb １ Cs ０．５ The catalyst was then subjected to X-ray photoelectron spectroscopy analysis. Next, the reaction was evaluated using the obtained catalyst in the same manner as in Example 1.

[0066] [Example 4 (Reference Example 4)] Solution A1 was obtained by mixing 3.0 parts of ammonium paramolybdate tetrahydrate, 0.14 parts of cesium nitrate, 0.3 parts of bismuth(III) oxide, and 0.15 parts of antimony trioxide with 13.0 parts of pure water at 60°C as the solvent. Separately from Solution A1, Solution A2 was obtained by mixing 1.39 parts of iron(III) nitrate nonahydrate and 3.33 parts of cobalt(II) nitrate hexahydrate with 6.0 parts of pure water at 20°C (room temperature). Next, Solution A1 and Solution A2 were mixed and the resulting mixture was heated to 95°C. Solution A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained Solution A was transferred to an evaporating dish (opening diameter: 7 cm) and left to stand in a drying oven set to 100°C to obtain the residue (dried product) of Solution A. Note that the solvent (water) in Solution A did not boil during this drying process. The obtained dried material was subjected to primary calcination at 300°C for 1 hour under air circulation, and then pulverized. Next, the pulverized particles were classified, and the particles that passed through a sieve with a mesh size of 2.36 mm but did not pass through a sieve with a mesh size of 0.71 mm were collected. Then, the collected pulverized particles were subjected to secondary calcination at 500°C for 3 hours under air circulation to obtain a catalyst. The oxygen-free composition of the obtained catalyst was Mo １２ Bi ０．９ Fe ２．４ Co ８ Sb ０．７ Cs ０．５ The catalyst was then subjected to X-ray photoelectron spectroscopy analysis. Next, the reaction was evaluated using the obtained catalyst in the same manner as in Example 1.

[0067] [Example 5 (Reference Example 5)] Using 13.0 parts of pure water at 60°C as a solvent, 3.0 parts of ammonium paramolybdate tetrahydrate, 0.14 parts of cesium nitrate, 0.2 parts of bismuth (III) oxide, and 0.15 parts of antimony trioxide were mixed to obtain liquid A1. Separately from liquid A1, 1.04 parts of iron (III) nitrate nonahydrate and 3.33 parts of cobalt (II) nitrate hexahydrate were mixed into 6.0 parts of pure water at 20°C (room temperature) to obtain liquid A2. Next, liquid A1 and liquid A2 were mixed, and the resulting mixture was heated to 95°C. Liquid A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained liquid A was transferred to an evaporation dish (opening diameter: 7 cm) and left standing still in a dryer set to 100°C to obtain a residue (dried product) of liquid A. In this drying step, the solvent (water) in liquid A did not boil. A catalyst was obtained by calcining the obtained dried product in the same manner as in Example 4. The composition of the obtained catalyst excluding oxygen is Mo １２ Bi ０．６ Fe １．８ Co ８ Sb ０．７ Cs ０．５ . Further, X-ray photoelectron spectroscopy analysis was performed on the catalyst. Next, reaction evaluation was carried out using the obtained catalyst by the same method as in Example 1.

[0068] [Example 6] Liquid A1 was obtained by mixing 100.0 parts of ammonium paramolybdate tetrahydrate and 4.6 parts of cesium nitrate using 200.0 parts of pure water at 60°C as a solvent. Separately from Liquid A1, 57.2 parts of iron(III) nitrate nonahydrate and 109.9 parts of cobalt(II) nitrate hexahydrate were mixed into 200.0 parts of pure water at 20°C (room temperature) to obtain Liquid A2. Next, Liquid A1 and Liquid A2 were mixed. After heating the obtained mixed liquid to 95°C, the mixture was stirred for 1 hour while maintaining the liquid temperature at 95°C. 6.6 parts of bismuth(III) oxide and 6.9 parts of antimony trioxide were mixed thereinto, and the mixture was stirred for 1 hour while maintaining the liquid temperature at 95°C, thereby obtaining Liquid A. The obtained Liquid A was transferred to a stainless steel heating container (opening diameter: 21 cm), and the solvent was dried while boiling vigorously at 130°C, whereby a residue (dried product) of Liquid A was obtained. The catalyst was obtained by calcining and molding the dried product in the same manner as in Example 1. The composition of the obtained catalyst excluding oxygen is Mo １２ Bi ０．６ Fe ３．０ Co ８ Sb １ Cs ０．５ . Further, X-ray photoelectron spectroscopy analysis was performed on the catalyst. Next, reaction evaluation was carried out using the obtained catalyst by the same method as in Example 1.

[0069] [Comparative Example 1] Liquid A1 was obtained by mixing 3.0 parts of ammonium paramolybdate tetrahydrate, 0.14 parts of cesium nitrate, 0.1 parts of bismuth(III) oxide, and 0.15 parts of antimony trioxide using 13.0 parts of pure water at 60°C as a solvent. Separately from Liquid A1, 1.73 parts of iron(III) nitrate nonahydrate and 2.91 parts of cobalt(II) nitrate hexahydrate were mixed into 6.0 parts of pure water at 20°C (room temperature) to obtain Liquid A2. Next, Liquid A1 and Liquid A2 were mixed, and the obtained mixed liquid was heated to 95°C. Liquid A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained Liquid A was transferred to an evaporation dish (opening diameter: 7 cm) and left to stand in a dryer set to 100°C, whereby a dried product was obtained. In this drying step, the solvent (water) in Liquid A did not boil. The catalyst was obtained by calcining the obtained dried product in the same manner as in Example 4. The composition of the obtained catalyst excluding oxygen is Mo１２ Bi ０．３ Fe ３ Co ７ Sb ０．７ Cs ０．５ The catalyst was then subjected to X-ray photoelectron spectroscopy analysis. Next, the reaction was evaluated using the obtained catalyst in the same manner as in Example 1.

[0070] [Comparative Example 2] Solution A1 was obtained by mixing 3.0 parts of ammonium paramolybdate tetrahydrate, 0.14 parts of cesium nitrate, 0.1 part of bismuth(III) oxide, and 0.27 parts of antimony trioxide with 13.0 parts of pure water at 60°C as a solvent. Separately from Solution A1, Solution A2 was obtained by mixing 1.73 parts of iron(III) nitrate nonahydrate and 3.74 parts of cobalt(II) nitrate hexahydrate with 6.0 parts of pure water at 20°C (room temperature). Next, Solution A1 and Solution A2 were mixed and the resulting mixture was heated to 95°C. Solution A was obtained by stirring for 1 hour while maintaining the liquid temperature at 95°C. The obtained Solution A was transferred to an evaporating dish (opening diameter: 7 cm) and left to stand in a drying oven set to 100°C to obtain a dried product. Note that the solvent (water) in Solution A did not boil during this drying process. The obtained dried product was calcined in the same manner as in Example 4 to obtain a catalyst. The oxygen-free composition of the resulting catalyst is Mo １２ Bi ０．３ Fe ３ Co ９ Sb １．３ Cs ０．５ The catalyst was then subjected to X-ray photoelectron spectroscopy analysis. Next, the reaction was evaluated using the obtained catalyst in the same manner as in Example 1.

[0071] Table 1 shows the calculated A (%), B (%), and B / A values ​​for the catalysts obtained in the examples and comparative examples, as well as the results of the reaction evaluation using each catalyst. Table 2 shows the heating and drying conditions of solution A in the examples (reference examples) and comparative examples, as well as the results of the reaction evaluation using each catalyst. In calculating the value of A, the following molecular weights were used for each catalyst raw material: ammonium paramolybdate tetrahydrate: 1235.93; cesium nitrate: 194.91; iron(III) nitrate nonahydrate: 404.00; cobalt(II) nitrate hexahydrate: 291.03; bismuth(III) oxide: 465.96; antimony trioxide: 291.52. Furthermore, in determining the drying rate, the amount of solvent in solution A included the amount of water derived from the catalyst raw materials, i.e., the amount of crystal water contained in the hydrate (molecular weight of water: 18.02).

[0072]

[0073]

[0074] As shown in Table 1, in Examples 1 to 6, which used catalysts with a B / A ratio of 1.50 or higher, methacrolein and methacrylic acid were obtained with higher selectivity compared to Comparative Examples 1 and 2, which used catalysts with a B / A ratio of less than 1.50. Furthermore, focusing on the catalyst manufacturing method, as shown in Table 2, the drying rate in the step of drying the solvent in solution A was 0.006 cc / min·cm. ２ The catalysts according to Examples 1 to 3 and 6 described above have a drying rate of 0.006 cc / min·cm. ２ Compared to the catalysts in the comparative examples or reference examples, which were less than the specified values, the selectivity for methacrolein and methacrylic acid was improved. 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.

[0075] Although several preferred embodiments of the present invention have been described in detail above, it should be understood that the present invention is not limited to the above embodiments, and various modifications and variations are possible without departing from the spirit or scope of the appended claims.

[0076] This application claims priority based on Japanese Patent Application No. 2025-029882, filed on 27 February 2025, and all of its contents are incorporated herein by reference.

[0077] The catalyst and the catalyst obtained by the manufacturing method according to the present invention are catalysts that can produce the target product with high selectivity and are industrially useful.

Claims

1. A catalyst for the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, wherein the ratio of the molar amount of cesium atoms to the total molar amount of all metal elements in the catalyst is A (%), and the ratio of the peak area of ​​cesium atoms to the sum of the peak areas of each of the constituent metal elements of the catalyst, as measured by X-ray photoelectron spectroscopy, is B (%), and B / A is 1.50 or more.

2. The catalyst according to claim 1, wherein the B / A ratio is 2.00 or greater.

3. The catalyst according to claim 1, wherein the B / A ratio is 2.40 or higher.

4. The catalyst according to claim 1, wherein B is 3.00 or greater.

5. The catalyst according to claim 1, which has a composition represented by the following formula (1): Mo ａ Bi ｂ Cs ｃ Fe ｄ M ｅ X ｆ Y ｇ Si ｈ O ｉ    (1) In formula (1), Mo, Bi, Cs, Fe, Si, and O each represent molybdenum, bismuth, cesium, iron, silicon, and oxygen, respectively; M represents at least one element selected from the group consisting of cobalt and nickel; X represents at least one element selected from the group consisting of zinc, chromium, lead, manganese, calcium, magnesium, niobium, silver, barium, tin, tantalum, tungsten, antimony, phosphorus, boron, sulfur, selenium, tellurium, cerium, and titanium; Y represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and thallium; a, b, c, d, e, f, g, h, and i each represent the atomic ratio of the corresponding element; when a=12, b=0.01 to 3, c=0.001 to 2, d=0 to 8, e=0 to 12, f=0 to 8, g=0 to 2, and h=0 to 20; and i is the atomic ratio of oxygen required to satisfy the valence of each of the aforementioned components.

6. A method for producing catalysts for the production of α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids, comprising the following steps (i) to (iii): (i) A step of preparing a slurry (Solution A) containing molybdenum, bismuth, and cesium, and a solvent; (ii) Heating Solution A and adding the solvent at a rate of 0.006 cc / min·cm ２ (iii) A step of drying at the above speed to obtain the residue of liquid A; and (iii) a step of calcining the residue of liquid A.

7. The method for producing a catalyst according to claim 6, wherein in step (ii), the temperature at which the liquid A is heated is equal to or greater than the boiling point of the solvent.

8. The method for producing a catalyst according to claim 6, wherein in step (ii), the temperature at which the liquid A is heated is 130°C or higher.

9. In step (ii), the rate at which the solvent is dried is 0.010 cc / min·cm. ２ The method for producing a catalyst according to claim 6.

10. A method for producing α,β-unsaturated aldehydes and / or α,β-unsaturated carboxylic acids from alkenes, alcohols, or ethers, using a catalyst described in any one of claims 1 to 5 or a catalyst produced by a manufacturing method described in any one of claims 6 to 9.

11. A method for producing an α,β-unsaturated carboxylic acid, comprising producing an α,β-unsaturated carboxylic acid from an α,β-unsaturated aldehyde produced by the manufacturing method described in claim 10.

12. A method for producing an α,β-unsaturated carboxylic acid ester from an α,β-unsaturated carboxylic acid produced by the manufacturing method described in claim 10.

13. A method for producing an α,β-unsaturated carboxylic acid ester from an α,β-unsaturated carboxylic acid produced by the manufacturing method described in claim 11.

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