Method for producing chemical substance and method for using catalyst

Abstract

One embodiment of a method for producing a chemical substance according to the present disclosure is a method for producing a chemical substance by converting a starting material in the presence of a catalyst to yield a product, the method including bringing the starting material into contact with the catalyst heated to 400°C or lower by irradiation with microwaves. The starting material and / or the product contains a reducing substance, and the catalyst includes at least one metal oxide selected from among compounds represented by general formula (1). 　General formula (1): MaMbO3 In general formula (1), Ma represents at least one metallic element selected from among the alkaline earth metals and the lanthanoids and Mb represents at least one metallic element selected from among Fe, Co, Ni, Mn, Cu, and Ti.

Description

Method for producing chemical substances and method for using catalysts

[0001] This disclosure relates to a method for producing chemical substances and a method for using catalysts.

[0002] Synthesis gas, which contains hydrogen and carbon monoxide, is widely used as a raw material for various petrochemical products. One known method for producing synthesis gas is the dry reforming reaction, which yields synthesis gas from carbon dioxide and hydrocarbons.

[0003] Generally, dry reforming reactions are carried out at high temperatures, and therefore, heating using microwaves is being considered to efficiently achieve this. However, when perovskite oxides are used in dry reforming reactions, it is known that the power required to maintain the temperature increases over time. This increase in power consumption during dry reforming reactions hinders energy efficiency and the stability of long-term continuous operation of the reaction equipment (see Non-Patent Literature 2).

[0004] On the other hand, catalysts are used in various technological fields such as thermal power plants, steel plants, cement plants, and chemical plants. Perovskite oxides are attracting attention as one type of catalyst (see, for example, Non-Patent Document 1).

[0005] Peng Zhang et al., Applied Catalysis B: Environment and Energy, Volume 345, 15 May 2024, 123718. Hamashima Tatsuya et al., Proceedings of the 130th Symposium on Catalysis, Presentation No. 1D01.

[0006] This disclosure aims to provide a method for producing chemical substances and a method for using a catalyst that can stably convert raw materials and produce products under a reducing atmosphere with low power consumption using microwaves.

[0007] The means for solving the above-mentioned problems are as follows: <1> A method for producing a chemical substance by converting a raw material in the presence of a catalyst, wherein the raw material is in contact with the catalyst which has been heated to 400°C or below by microwave irradiation, at least one of the raw material and the product contains a reducing substance, and the catalyst contains at least one metal oxide selected from compounds represented by the following general formula (1): MaMbO ３ ...General formula (1) However, in the general formula (1), Ma represents one metal element selected from alkaline earth metals and lanthanides, and Mb represents at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti. <2> The method for producing a chemical substance according to <1>, wherein the frequency of the microwave is 915 MHz ± 13 MHz or 2.45 GHz ± 0.9 GHz. <3> The method for producing a chemical substance according to <1> or <2>, wherein the reducing substance is at least one substance selected from the group consisting of hydrogen, hydrocarbons, carbon monoxide, and carbon. <4> The method for producing a chemical substance according to any one of <1> to <3>, wherein the contact is the contact of the raw material with the catalyst heated to 150°C or higher and 400°C or lower by irradiation with the microwave. <5> The at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ The method for producing a chemical substance according to any one of the above items <1> to <4>. <6> The method for producing a chemical substance according to any one of the above items <1> to <5>, wherein the catalyst further comprises a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti. <7> The method for producing a chemical substance according to the above item <6>, wherein the metal is precipitated by partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the above general formula (1). <8> The method for producing a chemical substance according to any one of the above items <1> to <7>, wherein the catalyst further comprises a compound represented by the following general formula (2). Ma ｘ O ｙ...General formula (2) However, in general formula (2), Ma represents the same metal element as Ma in general formula (1), x and y represent positive integers that represent the composition ratio of Ma to O, and y is y = xz / 2, where z is the oxidation state of Ma. <9> The compound represented by general formula (2) is La ２ O ３ The method for producing the chemical substance described in <8> above is as follows: <10> A method for using a catalyst in the production of a chemical substance that converts a raw material to produce a product, wherein the raw material is brought into contact with the catalyst which has been heated to 400°C or below by microwave irradiation, at least one of the raw material and the product contains a reducing substance, and the catalyst contains at least one metal oxide selected from compounds represented by the following general formula (1): MaMbO ３ ...General formula (1) However, in the general formula (1), Ma represents one metal element selected from alkaline earth metals and lanthanides, and Mb represents at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti. <11> The method of using the catalyst described in <10>, wherein the frequency of the microwave is 915 MHz ± 13 MHz or 2.45 GHz ± 0.9 GHz. <12> The method of using the catalyst described in <10> or <11>, wherein the reducing substance is at least one substance selected from the group consisting of hydrogen, hydrocarbons, carbon monoxide, and carbon. <13> The method of using the catalyst described in any one of <10> to <12>, wherein the contact is the contact of the raw material with the catalyst heated to 150°C or higher and 400°C or lower by irradiation with the microwave. <14> The at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３It is the method for using the catalyst according to any one of <10> to <13> above. <15> The method for using the catalyst according to any one of <10> to <14> above, wherein the catalyst further contains a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti. <16> The method for using the catalyst according to <15> above, wherein the metal is deposited by partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1). <17> The method for using the catalyst according to any one of <10> to <16> above, wherein the catalyst further contains a compound represented by the following general formula (2). Ma ｘ O ｙ ... General formula (2) However, in the general formula (2), Ma represents the same metal element as Ma in the general formula (1), x and y represent positive integers representing the composition ratio of Ma and O, y is the oxidation number of Ma as z, and y = xz / 2. <18> The compound represented by the general formula (2) is La ２ O ３ It is the method for using the catalyst according to <17> above.

[0008] According to an embodiment of the present disclosure, it is possible to provide a method for manufacturing a chemical substance and a method for using a catalyst that can stably convert a raw material and generate a product in a reducing atmosphere with low power consumption.

[0009] Figure 1 is a diagram showing an X-ray diffraction spectrum of catalyst A obtained in Production Example 1 by X-ray diffraction method (XRD). The vertical axis represents Intensity (a.u.), and the horizontal axis represents diffraction angle 2θ (degree). Figure 2 is a diagram showing the transition of power consumption and the transition of temperature when catalyst A is heated to 400 °C by microwave in the presence of H ２ in Example 1. The left vertical axis represents power consumption (W), the right vertical axis represents temperature (°C), and the horizontal axis represents time (minutes). Figure 3 is a diagram showing the transition of power consumption and the transition of temperature when H ２Figure 4 shows the changes in power consumption and temperature when catalyst A is heated to 550°C with microwaves in the presence of [a specific element]. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows time (minutes). Figure 4 shows the correlation between power consumption and temperature when catalyst A is heated with microwaves in an atmospheric environment in Comparative Example 2. The vertical axis shows temperature (°C), and the horizontal axis shows power consumption (W). Figure 5 shows the X-ray diffraction spectra obtained by X-ray diffraction (XRD) of catalyst A obtained in Production Example 1 and catalyst B obtained in Production Example 2. The vertical axis shows intensity (a.u.), and the horizontal axis shows 2θ (degree). Figure 6A shows the changes in power consumption (incident wave and reflected wave) and temperature when n-hexane is converted by microwaves in the presence of catalyst B obtained in Production Example 2 in Example 2. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows analysis time (seconds). Figure 6B shows the H2H ２ The signal corresponding to m / z = 2, CO ２ The signals corresponding to m / z = 44, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４ This figure shows the changes in signal intensity at m / z = 16, corresponding to the above. The vertical axis shows the mass spectrometry signal (a.u.), and the horizontal axis shows the analysis time (seconds). Figure 7A shows the changes in power consumption (incident and reflected waves) and temperature when polyethylene is converted by microwave in the presence of catalyst B obtained in Production Example 2 in Example 3. The vertical axis on the left shows power consumption (W), the vertical axis on the right shows temperature (°C), and the horizontal axis shows the analysis time (seconds). Figure 7B shows the changes in H when polyethylene is converted by microwave in the presence of catalyst B obtained in Production Example 2 in Example 3. ２ The signal corresponding to m / z = 2, CO ２ The signals corresponding to m / z = 44, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４This figure shows the change in signal intensity at m / z = 16. The vertical axis shows the mass spectrometry signal (a.u.), and the horizontal axis shows the analysis time (seconds). Figure 8A shows the change in temperature when polyethylene was converted by microwave in the presence of catalyst A obtained in Production Example 1 in Comparative Example 3. The vertical axis shows the temperature (°C), and the horizontal axis shows the analysis time (minutes). Figure 8B shows the change in power consumption (incident wave and reflected wave) when polyethylene was converted by microwave in the presence of catalyst A obtained in Production Example 1 in Comparative Example 3. The vertical axis on the left shows the power consumption (W), and the horizontal axis shows the analysis time (minutes). Figure 8C shows the change in H when polyethylene was converted by microwave in the presence of catalyst A obtained in Production Example 1 in Comparative Example 3. ２ The signal corresponding to m / z = 2, CO ２ The signals corresponding to m / z = 44, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４ This figure shows the change in signal intensity at m / z = 16. The vertical axis represents the mass spectrometry signal (a.u.), and the horizontal axis represents the analysis time (minutes).

[0010] The embodiments of this disclosure will be described in detail below. However, the embodiments are not limited to the following description and may be modified as appropriate without departing from the gist of this disclosure. Furthermore, in this specification, the "~" indicating a numerical range means that the numbers described before and after it are included as the lower and upper limits, respectively, unless otherwise specified.

[0011] (Method for producing a chemical substance) A method for producing a chemical substance according to an embodiment of the present disclosure is a method for producing a chemical substance by converting a raw material in the presence of a catalyst, wherein the raw material is in contact with the catalyst which has been heated to 400°C or below by microwave irradiation, at least one of the raw material and the product contains a reducing substance, and the catalyst contains at least one metal oxide selected from compounds represented by the following general formula (1). The method for producing a chemical substance according to an embodiment of the present disclosure may include other treatments other than contact. MaMbO ３...General formula (1) However, in the above general formula (1), Ma represents one metallic element selected from alkaline earth metals and lanthanides, and Mb represents at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

[0012] <Contact> Contact means that the raw material comes into contact with the catalyst, which has been heated to 400°C or below by irradiating it with microwaves.

[0013] The method for producing a chemical substance according to the embodiment of this disclosure involves irradiating a catalyst with microwaves to heat the catalyst to 400°C or below, and then bringing the catalyst into contact with the raw material to convert the raw material. Therefore, the heating of the catalyst to 400°C or below by irradiating it with microwaves and the contact between the raw material and the catalyst heated to 400°C or below may be performed simultaneously. Alternatively, by heating in other processes described later, the catalyst may be irradiated with microwaves first to heat it to a desired temperature, after which the raw material may be added to the catalyst and brought into contact with the raw material.

[0014] <<Catalyst>> In contact with the catalyst, the catalyst is heated to 400°C or below by microwave irradiation. There are no particular restrictions on the lower limit of the catalyst temperature, and it can be appropriately selected depending on the decomposition temperature of the raw materials in the method for producing the chemical substance according to the embodiment of this disclosure, but 150°C or higher is preferred, and 200°C or higher is more preferred. The upper and lower limits of the catalyst temperature can be appropriately combined, for example, 150°C to 400°C, 200°C to 400°C, etc. The catalyst temperature can also be 300°C to 400°C, 350°C to 400°C, etc.

[0015] When contacting the catalyst, it may be heated to a temperature of 400°C or lower, gradually increasing the temperature to the desired temperature, or it may be heated to a constant temperature. The temperature conditions for contact can be appropriately selected depending on the type of raw material.

[0016] During contact, the temperatures of the catalyst and raw materials can be measured using known temperature measuring instruments such as resistance thermometers and thermocouples.

[0017] There are no particular restrictions on the contact time between the catalyst and the raw material, i.e., the heating time of the raw material, and it can be appropriately selected depending on the type of raw material.

[0018] In terms of contact, the ratio of the catalyst mass to the mass of the raw material is not particularly limited, as long as it can be used to apply the desired temperature to the raw material and convert it. It can be appropriately selected depending on the type of raw material, etc.

[0019] The method for producing a chemical substance according to the embodiments of this disclosure involves the conversion of the raw material by contact between the catalyst and the raw material, that is, a reaction between a solid catalyst and a liquid, solid, or gas. Therefore, a batch reaction is possible, but a continuous reaction is desirable when processing large quantities of raw material in order to improve decomposition efficiency. When carrying out a continuous reaction, one method is to set up the catalyst in a reaction tube to form a fixed bed (catalyst layer) and add the raw material thereto. Contact may be carried out while circulating gas as needed.

[0020] The catalyst comprises at least one metal oxide selected from the compounds represented by the general formula (1), and may further contain other components as needed.

[0021] - At least one metal oxide selected from compounds represented by general formula (1) - Specific examples of Ma in general formula (1) include alkaline earth metals such as Be, Mg, Ca, Sr, Ba, and Ra; and lanthanides such as La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among these, lanthanides are preferred for Ma in general formula (1), and La is more preferred.

[0022] In the general formula (1) above, Mb represents at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti. Among these, Co, Ni, and Cu are preferred for Mb in the general formula (1), and Ni is particularly preferred.

[0023] At least one metal oxide selected from the compounds represented by the general formula (1) is ABO ３It is preferable that the compound has a perovskite-type structure represented by the above general formula (1). A is located at the A site of the perovskite-type structure and corresponds to Ma in the above general formula (1). B is located at the B site of the perovskite-type structure and corresponds to Mb in the above general formula (1).

[0024] A specific example of at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ LaFeO ３ LaCoO ３ LaMnO ３ , BaTiO ３ SrTiO ３ CaTiO ３ BaCoO ３ LaCuO ３ These are some examples. Among these, at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ Preferably containing LaNiO ３ It is preferable that it be so.

[0025] There are no particular restrictions on the content of at least one metal oxide selected from the compounds represented by the general formula (1) in the catalyst, and it can be appropriately selected depending on the purpose, but it is preferable that it be the main component of the catalyst. In this disclosure, "main component" means the component that has the largest amount of substance relative to the total mass of the catalyst.

[0026] Furthermore, the catalyst may consist of only at least one metal oxide selected from the compounds represented by the general formula (1).

[0027] [Method for producing at least one metal oxide selected from compounds represented by general formula (1)] As a method for synthesizing at least one metal oxide selected from compounds represented by general formula (1), a method commonly used for producing compounds having a so-called perovskite-type structure can be used. For example, a method in which a basic compound is added to a solution containing a compound having Ma as a constituent element in general formula (1) and a compound having Mb as a constituent element in general formula (1) to obtain a precipitate, and then calcined in air is preferred in terms of good dispersibility.

[0028] The compound containing Ma as a constituent element in the general formula (1) is not particularly limited as long as it can yield at least one metal oxide selected from the compounds represented by the general formula (1), dissolves in the solution, and produces a precipitate of the compound containing Ma as a constituent element upon addition of a basic compound. However, from the viewpoint of solubility and other factors, it is preferable to use a salt containing Ma as a constituent element in the general formula (1). Examples of salts containing Ma as a constituent element in the general formula (1) include nitrates, carbonates, acetates, chlorides, and bromides containing Ma as a constituent element in the general formula (1). These may be used individually or in combination of two or more. Among these, nitrates containing Ma as a constituent element in the general formula (1) are preferred from the viewpoint of solubility and workability such as calcination.

[0029] The compound containing Mb as a constituent element in the general formula (1) is not particularly limited as long as it can yield at least one metal oxide selected from the compounds represented by the general formula (1), dissolves in the solution, and produces a precipitate of the compound containing Mb as a constituent element upon addition of a basic compound. However, from the viewpoint of solubility and other factors, it is preferable to use a salt containing Mb as a constituent element in the general formula (1). Examples of salts containing Mb as a constituent element in the general formula (1) include nitrates, carbonates, acetates, chlorides, or bromides containing Mb as a constituent element in the general formula (1). These may be used individually or in combination of two or more. Among these, nitrates containing Mb as a constituent element in the general formula (1) are preferred from the viewpoint of solubility and workability such as calcination.

[0030] The solvent for the solution is not particularly limited as long as it can dissolve the compound containing Ma as a constituent element in general formula (1) and the compound containing Mb as a constituent element in general formula (1), but water or alcohol is preferred in terms of ease of handling. Examples of alcohols include methanol, ethanol, and 2-propanol. These may be used individually or in combination of two or more. Furthermore, glycols such as ethylene glycol may be added to the solution for purposes such as adjusting the dispersibility of each substance used in the synthesis.

[0031] The basic compound that can be added to the solution is not particularly limited as long as it can precipitate compounds containing Ma as a constituent element in general formula (1) and compounds containing Mb as a constituent element in general formula (1). However, tetramethylammonium hydroxide (hereinafter also referred to as "TMAH") is preferably used because it dissolves easily in the solution and does not easily remain in the catalyst after calcination. There are no particular restrictions on the method of adding the basic compound to the solution, but it is preferable to add it as a solution in which the basic compound is dissolved in water or alcohol, as this offers good workability and makes it easy to obtain a uniform precipitate. Examples of alcohols that can be used to dissolve the basic compound are the same as those used for the solutions of compounds containing Ma as a constituent element in general formula (1) and compounds containing Mb as a constituent element in general formula (1). There are no particular restrictions on the concentration of the basic compound in the solution, but from the viewpoint of workability and the uniformity of the precipitate obtained, it is preferably 0.5% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 30% by mass or less, relative to the total mass of the solution of the basic compound.

[0032] Another synthesis method for synthesizing at least one metal oxide selected from the compounds represented by the general formula (1) is to physically mix a compound containing Ma as a constituent element in the general formula (1) and a compound containing Mb as a constituent element in the general formula (1), and then calcine them in air. The compound containing Ma as a constituent element in the general formula (1) and the compound containing Mb as a constituent element in the general formula (1) that can be used in the other synthesis method are not particularly limited as long as they can yield at least one metal oxide selected from the compounds represented by the general formula (1) by calcination, but from the viewpoint of stability, it is preferable that they be an oxide containing Ma as a constituent element in the general formula (1) and an oxide containing Mb as a constituent element in the general formula (1), respectively.

[0033] In the synthesis of at least one metal oxide selected from the compounds represented by the general formula (1), there are no particular restrictions on the molar ratio of the compound containing Ma in the general formula (1) as a constituent element to the compound containing Mb in the general formula (1) as a constituent element, and it can be appropriately selected according to the purpose. There are no particular restrictions on the molar ratio of Mb in the compound containing Mb in the general formula (1) to Ma in the compound containing Ma in the general formula (1) as a constituent element, and it can be selected according to the purpose, and it may be in the range of 0.8 to 3. When the molar ratio of Mb in the compound containing Mb in the general formula (1) to Ma in the compound containing Mb in the general formula (1) as a constituent element is 0.8 to 3, it is close to the ratio of Mb to Ma in at least one metal oxide selected from the compounds represented by the general formula (1), and therefore at least one metal oxide selected from the compounds represented by the general formula (1) can be suitably obtained.

[0034] Furthermore, if the molar ratio of Mb in a compound containing Mb in the same general formula (1) to Ma in a compound containing Ma in the same general formula (1) is greater than 1, a compound represented by the following general formula (3) may be formed together with at least one metal oxide selected from the compounds represented by the same general formula (1). If it is desired to form only at least one metal oxide selected from the compounds represented by the same general formula (1) and not the compound represented by the following general formula (3), the molar ratio is preferably 0.80 or more and 1.00 or less. Also, if the compound represented by the following general formula (3) is to be formed together with at least one metal oxide selected from the compounds represented by the same general formula (1), the molar ratio is preferably greater than 1.00 and 3.00 or less, and more preferably 1.01 or more and 3.00 or less.

[0035] Mb ｐ O ｑ...General formula (3) However, in general formula (3), Mb represents the same metal element as Mb in general formula (1), p and q represent positive integers indicating the composition ratio of Mb to O, and q is q = pr / 2, where r is the oxidation state of Mb. For example, at least one of the metal oxides selected from the compounds represented by general formula (1) is LaNiO ３ In that case, the compound represented by the general formula (3) is NiO.

[0036] In the synthesis of at least one metal oxide selected from the compounds represented by the general formula (1), there are no particular restrictions on the calcination temperature of the mixture of a compound containing Ma as a constituent element in the general formula (1) and a compound containing Mb as a constituent element in the general formula (1), and the temperature can be appropriately selected depending on the type of at least one metal oxide selected from the compounds represented by the general formula (1). For example, if the at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ In this case, from the viewpoint of uniformity, stability, and energy efficiency of the resulting metal oxide, the firing temperature of the mixture is preferably 300°C to 1,200°C, and more preferably 550°C to 950°C.

[0037] -Other Components- Other components in the catalyst are not particularly limited as long as they can be heated to 400°C or below by microwave, and can be appropriately selected according to the purpose. Examples include metals, compounds represented by the following general formula (2), and compounds represented by the following general formula (4). These may be used individually or in combination of two or more.

[0038] --Metal-- There are no particular restrictions on the metal contained in the catalyst, and it can be appropriately selected depending on the purpose, but it is preferable that the metal contains at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti. Among these, Ni, Fe, Co, and Cu are preferred, and Ni is more preferred.

[0039] There are no particular restrictions on the state of the metal in the catalyst, but it is preferable that the metal is dispersed or supported on at least one metal oxide selected from the compounds represented by the general formula (1), and it is more preferable that the metal is supported on at least one metal oxide selected from the compounds represented by the general formula (1).

[0040] Preferably, the metal in the catalyst is deposited by partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1).

[0041] The content of the metal in the catalyst is not particularly limited as long as it does not impair the effects of this disclosure, and can be appropriately selected depending on the purpose. For example, if the catalyst is obtained by hydrogen reduction of at least one metal oxide selected from the compounds represented by general formula (1) by the method described later, in terms of heating stability and the efficiency of chemical production, the amount of metal deposited per gram of at least one metal oxide selected from the compounds represented by general formula (1) before reduction is preferably 0.1 mmol to 3.5 mmol, more preferably 0.2 mmol to 3.2 mmol.

[0042] The metal content in the catalyst is, for example, if the catalyst is a compound represented by the general formula (1), LaNiO ３ If it is obtained by hydrogen reduction by the method described later, the H consumed in hydrogen reduction ２ Of these, LaNiO ３ The heating temperature is preferably LaNiO ３ H consumed during the period when the temperature of the reaction tube filled with H was 430°C or higher. ２ It is calculated as being equal to the amount consumed (moles). This is LaNiO ３ In contrast, measurement using the hydrogen-based temperature reduction method ("H ２ When the "TPR measurement" (also called "TPR measurement") is performed, H ２ Two peaks were observed indicating the consumption of LaNiO, one at 300°C–350°C and another at 430°C–570°C. The lower-temperature peak was LaNiO. ３ From La２ Ni ２ O ５ Corresponding to reduction to (see S.P. Singh et al, Scientific reports, 2017, 7:10829, pp. 1-7, DOI: 10.1038 / s41598-017-11091-6), the peak on the high-temperature side is La ２ Ni ２ O ５ Ni precipitates from La ２ O ３ It is thought that this corresponds to a reaction that reduces to La ２ Ni ２ O ５ From La ２ O ３ The reduction to can be expressed by the following reaction equation. Note that H ２ Consumption is measured using a thermal conductivity type (TCD) detector or a mass spectrometer. ２ Ni ２ O ５ +2H ２ →2Ni+La ２ O ３ +2H ２ O

[0043] --Compound represented by general formula (2)-- The catalyst may contain a compound represented by the following general formula (2). Ma ｘ O ｙ ...General formula (2) In general formula (2), Ma represents the same metallic element as Ma in general formula (1), x and y represent positive integers that express the composition ratio of Ma to O, and y is given by y = xz / 2, where z is the oxidation state of Ma.

[0044] Since Ma in general formula (2) represents the same metallic element as Ma in general formula (1), Ma in general formula (2) is one metallic element selected from alkaline earth metals and lanthanides. For example, at least one metal oxide selected from the compounds represented by general formula (1) is LaNiO ３ In that case, the compound represented by the general formula (2) is La ２ O ３The compound represented by general formula (2) is preferably produced by hydrogen reduction of at least one metal oxide selected from the compounds represented by general formula (1).

[0045] The content of the compound represented by the general formula (2) in the catalyst is not particularly limited, as long as it does not impair the effects of the present disclosure, and can be appropriately selected depending on the purpose.

[0046] --Compound represented by general formula (4)-- The catalyst may contain the compound represented by the following general formula (4): MaMbO ｚ ...General formula (4) However, in general formula (4), Ma represents the same metallic element as Ma in general formula (1), Mb represents the same metallic element as Mb in general formula (1), and z represents the valence of O less than 3.

[0047] The compound represented by the general formula (4) is a compound that maintains the structure of at least one metal oxide selected from the compounds represented by the general formula (1), but has a defect in which some oxygen atoms are missing.

[0048] Since Ma in general formula (4) is the same metallic element as Ma in general formula (1), Ma in general formula (4) is one metallic element selected from alkaline earth metals and lanthanides.

[0049] Since Mb in general formula (4) is the same metallic element as Mb in general formula (1), Mb in general formula (4) is a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

[0050] For example, if at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ In that case, the compound represented by the general formula (4) is LaNiO ｚ (z < 3). The compound represented by general formula (4) is preferably produced by hydrogen reduction of at least one metal oxide selected from the compounds represented by general formula (1).

[0051] The content of the compound represented by the general formula (4) in the catalyst is not particularly limited, as long as it does not impair the effects of the present disclosure, and can be appropriately selected depending on the purpose.

[0052] Furthermore, it can be confirmed that the catalyst contains at least one metal oxide selected from the compounds represented by the general formula (1), as well as the other components, by analyzing the catalyst using X-ray diffraction.

[0053] The catalyst may be a commercially available product or may be synthesized appropriately by known methods.

[0054] [Method for Manufacturing the Catalyst] There are no particular limitations on the method for manufacturing the catalyst, and it can be appropriately selected according to the purpose. For example, a method of mixing a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti with at least one metal oxide selected from the compounds represented by the general formula (1); a method of partially hydrogen-reducing a precursor mixture (hereinafter sometimes abbreviated as "precursor mixture") containing at least one metal oxide selected from the compounds represented by the general formula (1) or at least one metal oxide selected from the compounds represented by the general formula (1) and a compound represented by the general formula (3) below. Among these, the method of partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is preferred as the method for manufacturing the catalyst. By partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, the metal precipitates. For example, if at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ If this is the case, Ni will precipitate by partially reducing it with hydrogen.

[0055] Mb ｐ O ｑ...General formula (3) However, in general formula (3), Mb represents the same metal element as Mb in general formula (1), p and q represent positive integers indicating the composition ratio of Mb to O, and q is q = pr / 2, where r is the oxidation state of Mb. For example, at least one of the metal oxides selected from the compounds represented by general formula (1) is LaNiO ３ In that case, the compound represented by the general formula (3) is NiO.

[0056] In this disclosure, "precursor mixture" means a catalyst containing at least one metal oxide selected from the compounds represented by general formula (1) and at least one metal oxide represented by the following general formula (3), in a state in which no metal has been deposited, for use in microwave irradiation, and is a term used to distinguish it from catalysts containing metal and metal oxides used in microwave irradiation.

[0057] A method for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is H ２ A suitable method is to partially hydrogenate a mixture of at least one metal oxide selected from the compounds represented by the general formula (1), or the precursor mixture, by heating it in an atmosphere of gas containing the above.

[0058] The heating temperature for at least one metal oxide selected from the compounds represented by the general formula (1) or for partially hydrogen-reducing the precursor mixture is not particularly limited and can be appropriately selected according to the purpose. When heating is carried out by external heating such as an electric furnace, a temperature of 300°C or higher is preferable, a temperature of 300°C or higher and 570°C or lower is more preferable, a temperature of 330°C or higher and 570°C or lower is further preferable, and a temperature of 360°C or higher and 540°C or lower is particularly preferable. When partially hydrogen-reducing only at least one metal oxide selected from the compounds represented by the general formula (1) rather than the precursor mixture, a heating temperature of 430°C or higher and 570°C or lower is even more preferable, and a heating temperature of 430°C or higher and 570°C or lower is most preferable. When the heating temperature for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is 300°C or higher, at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture can be preferably partially hydrogen-reduced.

[0059] The heating time for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is not particularly limited and can be appropriately selected according to the purpose. When at least one metal oxide selected from the compounds represented by the general formula (1) is, for example, LaNiO ３ and is heated in an atmosphere of a gas containing 0.5% by volume or more and 10% by volume or less of H ２ and 90% by volume or more and 99.5% by volume or less of N ２ the heating time is preferably 3 minutes or more and 300 minutes or less, more preferably 5 minutes or more and 120 minutes or less, and further preferably 10 minutes or more and 90 minutes or less.

[0060] The H ２In the treatment in an atmosphere of a gas containing [the relevant substance], the method of heating to the preferred temperature is not particularly limited and can be appropriately selected according to the purpose. However, at least one metal oxide selected from the compounds represented by the general formula (1) or heating of the precursor mixture, preferably heating of LaNiO ３ or a precursor mixture of LaNiO ３ and NiO is preferably carried out by radiant heat because it is easy to perform heat treatment stably at a constant temperature and it is easy to control so that at least one metal oxide selected from the compounds represented by the general formula (1) is not completely reduced.

[0061] As the atmospheric conditions for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, it is preferably an atmosphere of a gas containing H ２ .

[0062] The gas containing H ２ is not particularly limited as long as it contains H ２ . It may be a gas consisting only of H ２ , or may further contain other gases other than H ２ . However, the gas containing H ２ is more preferably an atmosphere of a gas containing H ２ and an inert gas.

[0063] Examples of the inert gas include N ２ , rare gases, etc. Examples of the rare gas include He, Ar, etc. From the viewpoint of production cost, the inert gas is preferably N ２ .

[0064] When partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture in an atmosphere of a gas containing H ２ , the concentration of H ２ is not particularly limited and can be appropriately selected according to the purpose. However, H ２The amount of explosive H is preferably 0.5% to 99.5% by volume relative to the total volume of the gas containing it, more preferably 0.5% to 50% by volume, even more preferably 1% to 50% by volume, and particularly preferably 1% to 20% by volume, from the viewpoint of controlling the reduction rate and appropriately carrying out partial reduction. ２ From the perspective of handling it safely, H ２ H in relation to the total volume of the gas containing ２ The concentration is preferably 0.5% by volume or more and 10% by volume or less.

[0065] H ２ A gas containing N ２ If it contains, N in an atmosphere for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture. ２ There are no particular restrictions on the concentration, and it can be selected appropriately depending on the purpose, but H ２ The amount of explosive H is preferably 0.5% to 99.5% by volume, more preferably 50% to 99.5% by volume, even more preferably 50% to 99% by volume, and particularly preferably 80% to 99% by volume. ２ From the perspective of handling it safely, H ２ N in relation to the total volume of the gas containing ２ The concentration is preferably 90% by volume or more and 99.5% by volume or less.

[0066] A specific example of a method for partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is, for example, H ２ LaNiO at temperatures above 300°C under an atmosphere of gas containing ３ , or LaNiO ３ One method involves heating a precursor mixture of the metal and NiO to partially hydrogenate it. As a result, Ni as a metal precipitates in the catalyst, which includes the metal and the metal oxide, and LaNiO ３ A catalyst is obtained in which Ni is dispersed or supported.

[0067] Also, H ２Before partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture under an atmosphere of gas containing N ２ The pretreatment may be carried out under a gaseous atmosphere. This removes unwanted gases such as oxygen that are generated by heating at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, and prevents unwanted impurities from being included in the catalyst obtained after hydrogen reduction.

[0068] There are no particular restrictions on the temperature of the pretreatment, and it can be appropriately selected depending on the purpose, but it is preferable to carry it out at a temperature above the hydrogen reduction temperature and below the decomposition temperature of at least one metal oxide selected from the compounds represented by general formula (1) or at least one metal oxide represented by general formula (3) in the precursor mixture. Specifically, the temperature of the pretreatment is preferably 300°C to 900°C, and more preferably 360°C to 600°C. Furthermore, when hydrogen reduction is performed on only at least one metal oxide selected from the compounds represented by general formula (1) and without including the compound represented by general formula (3), it is particularly preferable that the temperature be 430°C to 900°C, and most preferably 460°C to 900°C.

[0069] There are no particular restrictions on the duration of the pretreatment, and it can be appropriately selected depending on the purpose. However, within the preferred temperature range for pretreatment, it is preferably 1 minute to 120 minutes, more preferably 1 minute to 90 minutes, even more preferably 1 minute to 60 minutes, and particularly preferably 5 minutes to 30 minutes.

[0070] When partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, N ２ The aforementioned pretreatment under a gaseous atmosphere, and H ２The treatment in an atmosphere containing the gas may be carried out continuously or with intervals in between, but from the viewpoint of suppressing the rapid hydrogen reduction of at least one metal oxide selected from the compounds represented by general formula (1) or the precursor mixture and carrying out a uniform partial reduction of at least one metal oxide selected from the compounds represented by general formula (1) or the precursor mixture, it is preferable to perform hydrogen reduction by heating after the pretreatment to a temperature at which at least one metal oxide selected from the compounds represented by general formula (1) or the precursor mixture does not react with hydrogen. For example, if at least one metal oxide selected from the compounds represented by general formula (1) is LaNiO ３ If that is the case, or if at least one metal oxide selected from the compounds represented by the general formula (1) in the precursor mixture is LaNiO ３ Therefore, if at least one metal oxide selected from the compounds represented by the general formula (3) is NiO, it is preferable to perform hydrogen reduction by heating after the pretreatment, returning the temperature to 200°C or below.

[0071] Furthermore, from the viewpoint of sufficiently removing unwanted gases generated by the pretreatment from the atmosphere and preventing unwanted impurities from being included in the catalyst obtained after hydrogen reduction, it is preferable to wait for at least one minute after the pretreatment before performing hydrogen reduction, and more preferably, to wait for at least three minutes before performing hydrogen reduction. Also, from the viewpoint of productivity in catalyst production, the waiting time after the pretreatment before performing hydrogen reduction is preferably two hours or less, and more preferably one hour or less. The lower limit and upper limit of the waiting time after the pretreatment before performing hydrogen reduction can be combined as appropriate, for example, one minute or more and two hours or less, three minutes or more and two hours or less, three minutes or more and two hours or less, three minutes or more and one hour or less.

[0072] Whether the generation of unwanted gases has been sufficiently reduced can be determined by connecting a gas analysis device to the outlet of the heating furnace, reaction vessel, etc., used for the pretreatment and analyzing the resulting values. There are no particular restrictions on the gas analysis device, and it can be appropriately selected depending on the purpose. Examples include mass spectrometers, gas chromatographs, and Fourier transform infrared spectrometers. If the gas analysis device is a mass spectrometer, it can be determined that the generation of unwanted gases generated by the pretreatment has been sufficiently reduced if either the fluctuation of the detected value stabilizes to ±5% or less, or if it is below the lower detection limit.

[0073] When partially hydrogenating at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, H ２ In the treatment under a gas atmosphere containing and the pretreatment, there are no particular limitations on the method of heating to the preferred temperature, and a suitable method can be selected depending on the purpose. However, heating by external heating such as an electric furnace is preferable because it is easier to control the process so that at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture is not completely reduced by hydrogen.

[0074] <<Microwaves>> Microwaves are electromagnetic waves, preferably with a frequency of 300 MHz to 300 GHz. Because microwaves can directly transfer energy to a dielectric material to be heated, the material to be heated can behave like a heat source in conventional heating methods such as electric furnaces. On the other hand, heating by microwaves is internal heating, unlike heating by radiant heat in an electric furnace. In the method for producing a chemical substance according to the embodiment of this disclosure, the material to be heated by microwaves is a catalyst, but the raw material may also be the material to be heated.

[0075] In contact with the catalyst, the microwave frequency is preferably 300 MHz to 300 GHz, but there are no particular restrictions as long as the catalyst can absorb the microwaves and generate heat, and can be appropriately selected according to the purpose, with 915 MHz ± 13 MHz or 2.45 GHz ± 0.9 GHz being more preferable. When the microwave frequency is 300 MHz or higher, the catalyst can be heated to a temperature sufficient for the conversion of the raw material, and when it is 300 GHz or lower, it is preferable from the viewpoint of energy efficiency.

[0076] There are no particular restrictions on the microwave source used for microwave irradiation; it can be appropriately selected according to the output power. Examples include diamond SAW (Surface Acoustic Wave), magnetron, klystron, gyrotron, and semiconductor oscillator. These may be used individually or in combination of two or more.

[0077] Microwave irradiation can be carried out without changing at least one of the electric field strength or magnetic field strength, from the viewpoint of stabilizing the reaction state, such as reaction activity and product selectivity, as well as the catalyst temperature and its temperature distribution. More specifically, for example, irradiation can be carried out continuously without changing the microwave output, frequency, etc. Furthermore, for example, when carrying out two reactions with different conditions consecutively in one pot, the microwave output and frequency can be changed midway as needed.

[0078] There are no particular restrictions on the microwave output; it can be appropriately selected depending on the desired temperature at which contact occurs.

[0079] <<Raw Materials and Products>> At least one of the raw materials and the products contains a reducing substance. There are no particular restrictions on the reducing substance, and it can be appropriately selected depending on the purpose, but hydrogen (in this disclosure, "H") ２ Preferably, the raw material or product contains H ２When the method for producing the chemical substance of this disclosure is applied to a reaction that includes the above-mentioned general formula (1), the effect of stabilizing the heating by irradiating at least one metal oxide selected from the compounds represented by the general formula (1) with microwaves is remarkable and is particularly preferred.

[0080] In this disclosure, hydrocarbons are defined as molecules containing C and H ２ This refers to compounds containing or mixtures thereof. Hydrocarbons may also contain other elements such as oxygen in their molecules.

[0081] There are no particular restrictions on the hydrocarbons used, and they can be appropriately selected depending on the purpose. Examples include chain hydrocarbons such as chain saturated hydrocarbons and chain unsaturated hydrocarbons; and cyclic hydrocarbons such as alicyclic hydrocarbons and aromatic hydrocarbons. These may be used individually or in combination of two or more.

[0082] There are no particular restrictions on the chain-type saturated hydrocarbons, and examples include methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane. The chain-type saturated hydrocarbons may also be branched. Examples of branched chain-type saturated hydrocarbons include isobutane, isopentane, isohexane, and isooctane. These may be used individually or in combination of two or more.

[0083] There are no particular restrictions on the chain-type unsaturated hydrocarbons, and examples include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, dekene, acetylene, and butadiene. The chain-type unsaturated hydrocarbons may also be branched. Examples of branched chain-type unsaturated hydrocarbons include 2-methyl-1-butene, 2-methyl-2-butene, isoprene, and 3-methyl-1-butyne. These may be used individually or in combination of two or more.

[0084] There are no particular restrictions on the alicyclic hydrocarbons, and examples include monocyclic alicyclic compounds such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane, 1,3,5-trimethylcyclohexane, cyclopentadiene, and cyclohexene; bicyclic alicyclic compounds such as bicycloundecane, decahydronaphthalene (decalin), methyldecalin, tetrahydronaphthalene (tetralin), methyltetralin, norbornadiene, norbornadiene; and tricyclic alicyclic compounds such as tetradecahydroanthracene. These may be used individually or in combination of two or more.

[0085] There are no particular restrictions on the aromatic hydrocarbons used, and examples include toluene, o-xylene, p-xylene, m-xylene, ethylbenzene, cumene, styrene, naphthalene, anthracene, and phenanthrene. These may be used individually or in combination of two or more.

[0086] Furthermore, in the method for producing chemical substances according to the embodiments of this disclosure, hydrocarbons such as natural gas, natural liquefied gas (LNG), shale gas, city gas, LPG (liquefied petroleum gas), gasoline, naphtha, kerosene, diesel fuel, plastic pyrolysis oil, plastics, biomass, and off-gases discharged from petroleum refining facilities or petrochemical facilities may also be used. These may be used individually or in combination of two or more.

[0087] As for plastics used as hydrocarbon raw materials, there are no particular restrictions as long as they contain hydrocarbons, and they can be appropriately selected according to the purpose. Examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC), polyvinyl chloride (PVC), polyvinylidene chloride, chlorinated polyethylene, polyamide, polyurethane, acrylonitrile-butadiene-styrene copolymer, and polymethyl methacrylate. Among these, plastics used as hydrocarbon raw materials are those that yield H per unit mass of plastic. ２ Due to the large amount of [unclear], it is preferable that at least one selected from polyethylene and polypropylene be used. These may be used individually or in combination of two or more. From the viewpoint of reducing environmental impact, it is preferable that the plastic used as a hydrocarbon raw material contains waste plastic (e.g., containers and packaging).

[0088] As long as the biomass used as a hydrocarbon raw material contains hydrocarbons, there are no particular restrictions, and it can be appropriately selected according to the purpose. Examples include woody waste such as forest residues, thinned wood, unused trees, sawmill residues, construction waste, and rice straw; secondary products such as wood chips and pellets made from woody waste; papermaking waste such as waste paper that can no longer be recycled; food waste such as agricultural residues and kitchen waste; and activated sludge. These may be used individually or in combination of two or more.

[0089] These hydrocarbons may be gases, liquids, or solids at room temperature (25°C), but liquids or solids are preferred because they offer good handling and the reaction proceeds easily at low temperatures. Examples of hydrocarbons that are liquid or solid at around room temperature include saturated hydrocarbons such as n-pentane, isopentane, and chain-type saturated hydrocarbons having 6 or more carbon atoms; unsaturated hydrocarbons such as 2-butyne, 1-pentene, cis-2-pentene, trans-2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 1,3-pentadiene, isoprene, 1-pentine, 2-pentine, 3-methyl-1-butine, and chain-type unsaturated hydrocarbons having 6 or more carbon atoms; and alicyclic hydrocarbons having 5 or more carbon atoms such as cyclopentane, cyclohexane, methylcyclohexane, cyclohexene, and cyclopentadiene.

[0090] There are no particular restrictions on the amount of catalyst used relative to the amount of hydrocarbon added, and it can be appropriately selected depending on the purpose. However, in the case of a continuous reaction, the total amount of circulating hydrocarbon per gram of catalyst is preferably 0.001 g / min to 10 g / min, and more preferably 0.01 g / min to 1 g / min. In the case of a batch reaction, the mass ratio (hydrocarbon:catalyst) is preferably 1:1,000 to 1:1, and more preferably 1:500 to 1:10.

[0091] An example of a method for producing a chemical substance according to the embodiments of this disclosure is a dry reforming reaction shown in the following reaction formula, but is not limited to this. [Reaction Formula 1] C ｎ H ｍ +pCO ２ →qCO+rH ２ Here, C ｎ H ｍ is a general formula for hydrocarbons, where n is a positive integer, m is the degree of unsaturation of the hydrocarbon (where k is 0 or a positive integer), and is 2n + 2 - 2k for chain hydrocarbons and 2n - 2k for monocyclic alicyclic hydrocarbons, and p is the reaction of CO with 1 mole of hydrocarbon. ２ This indicates the number of moles, which is usually n, where q is the number calculated from n + p, and r is the number calculated from m / 2.

[0092] Dry reforming reactions are endothermic, and in the same reaction field, C ｎ H ｍ H ２ O, CO, CO ２ H ２ All of these factors are present. Therefore, generally, high temperatures are required for the reaction to proceed under equilibrium conditions. Consequently, conventional methods require extremely high energy input from the combustion of fuel, or even when attempts are made to reduce energy consumption by using microwave heating, the heating may not be stable.

[0093] In contrast, the method for producing a chemical substance according to the embodiment of this disclosure, by using the catalyst, can efficiently convert the substance at a low temperature using microwaves. Therefore, greenhouse gases such as CO2 can be produced. ２ It is also advantageous in that it can reduce the release of [unclear / unclear].

[0094] <<Gas>> Contact may be carried out in an atmospheric environment, but as mentioned above, it may also be carried out while circulating a gas as needed. There are no particular restrictions on the type of gas, and it can be appropriately selected according to the purpose, and it may be an active gas or an inert gas.

[0095] There are no particular restrictions on the active gas; for example, H ２ , O ２ These are some examples. These may be used individually or in combination of two or more.

[0096] There are no particular restrictions on the inert gas; for example, N ２ CO ２ Examples include Ar. These may be used individually or in combination of two or more.

[0097] <Other Processing> Other processing is not particularly limited and can be appropriately selected depending on the purpose. Examples include heating the catalyst to 400°C or below by irradiating it with microwaves, and recovering the product produced by the chemical substance production method according to the embodiment of this disclosure.

[0098] <<Heating>> Heating involves irradiating the catalyst with microwaves to a temperature of 400°C or lower. Heating is preferably performed before contact. The method for producing a chemical substance according to the embodiment of this disclosure, which includes heating, is preferable in that, when the raw material and the catalyst are brought into contact during contact, the catalyst has reached the desired heating temperature, resulting in good reaction efficiency.

[0099] <<Recovery>> Recovery refers to the recovery of products formed when raw materials are converted through contact. There are no particular restrictions on the recovery method, and a suitable method can be selected from known methods depending on the type of product.

[0100] <Applications> The method for producing chemical substances according to the embodiments of this disclosure can be applied to various technical fields such as chemical reactions in electrodes, piezoelectric elements, thermoelectric elements, dielectrics, etc.; exhaust gas treatment in thermal power plants, steel plants, cement plants, chemical plants, etc.; hydrocarbon decomposition treatment; and the manufacture of various chemical products.

[0101] The method for producing chemical substances according to the embodiments of this disclosure can be suitably applied not only to reaction systems that are typically heated by microwave irradiation, but also to reaction systems that are typically heated by radiant heat from an electric furnace or the like.

[0102] (Method of using the catalyst) A method of using the catalyst according to the embodiments of this disclosure is a method of using the catalyst in the production of a chemical substance that converts a raw material to produce a product, wherein the raw material is in contact with the catalyst which has been heated to 400°C or below by microwave irradiation, at least one of the raw material and the product contains a reducing substance, and the catalyst contains at least one metal oxide selected from compounds represented by the following general formula (1). The method of using the catalyst according to the embodiments of this disclosure may include other treatments other than contact. MaMbO ３ ...General formula (1) However, in the above general formula (1), Ma represents one metallic element selected from alkaline earth metals and lanthanides, and Mb represents at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

[0103] Since contact and other treatments in the method of using the catalyst according to the embodiments of this disclosure can be carried out in the same manner as in the method of producing the chemical substance according to the embodiments of this disclosure, a detailed description is omitted.

[0104] The method of using the catalyst according to the embodiments of this disclosure allows for the stable conversion of raw materials and production of products under a reducing atmosphere with low power consumption using microwaves.

[0105] The embodiments of this disclosure will be described in more detail below with reference to manufacturing examples, examples, comparative examples, and test examples, but the embodiments are not limited to these manufacturing examples, examples, comparative examples, and test examples.

[0106] (Manufacturing Example 1: Manufacturing of Catalyst A) Nickel(II) nitrate hexahydrate (Ni(NO) ３ ) ２ 6H ２ 5.82 g (20.0 mmol) of lanthanum (O, formula weight 290.79, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and lanthanum (III) nitrate hexahydrate (La(NO) ３ ) ３ 6H ２ 8.66 g (20.0 mmol) of nickel(II) nitrate hexahydrate (formula weight 433.01, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in a 200 mL beaker, and purified water was added up to the 50 mL mark. A stirrer tip was placed in the beaker, the opening of the beaker was covered with plastic wrap, and the mixture was stirred with a magnetic stirrer. Stirring was stopped when nickel(II) nitrate hexahydrate and lanthanum(III) nitrate hexahydrate had dissolved in the water, and the aqueous solution containing nickel(II) nitrate hexahydrate and lanthanum(III) nitrate hexahydrate was transferred to a titration burette.

[0107] Separately, 125 mL of a 10% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) was added to a 500 mL beaker, and a stirrer tip was placed inside. While stirring the TMAH aqueous solution with a magnetic stirrer, an aqueous solution containing nickel(II) nitrate hexahydrate and lanthanum(III) nitrate hexahydrate, which had been transferred to a titration burette, was added dropwise at a rate of 2 times every 3 seconds. After the addition was complete, the mixture was stirred with a magnetic stirrer for another hour, and then allowed to stand for 1 hour. The mixture after standing was filtered by suction, and purified water was added to the filtrate and filtered by suction repeatedly until the pH of the filtrate was 8-9, and the mixture was washed. After thorough washing, the filtrate was transferred to a firing dish and baked overnight in a 90°C oven to dry it. The dried filtrate was pulverized for 20 minutes using a mortar and pestle. After pulverization, the powder of the filtrate was transferred to a crucible and baked at 850°C for 5 hours to obtain catalyst A.

[0108] (Test Example 1: XRD Analysis) Catalyst A, a product obtained in Manufacturing Example 1, was analyzed by X-ray diffraction (XRD) under the following analytical conditions. The analyzed X-ray diffraction spectrum (XRD spectrum) is shown in Figure 1. [Analytical Conditions] ・Apparatus: Ultima IV (manufactured by Rigaku Corporation) ・X-ray source: Cu-Kα rays ・Scanning range: 20°≦2θ / degree≦80° ・Scanning axis: 2θ / θ

[0109] The peaks were identified by comparing the obtained X-ray diffraction patterns with literature values. From the results in Figure 1, the X-ray diffraction spectrum of the powder (catalyst A) obtained in production example 1 is LaNiO ３ It had only peaks that belonged to LaNiO. This indicates that the powder obtained in Production Example 1 was LaNiO. ３ This indicates that...

[0110] (Example 1) Catalyst A (LaNiO) obtained in Production Example 1 ３ 0.2 g of the powder was weighed out and filled into a quartz reaction tube with an inner diameter of 8 mm, and the reaction tube was set in the microwave generator described below. [Microwave Generator] ・Device: MR-2G-100 (manufactured by Ryowa Electronics Co., Ltd.) ・Frequency: 2.45 GHz ± 0.05 GHz ・Irradiation mode: Single mode (maximum magnetic field strength on the central axis) ・Cavity size: 10 mm diameter, 100 mm length ・Maximum input power: 100 W

[0111] H in the reaction tube ２ and N ２ mixed gas (5% by volume H ２ / 95% N by volume ２ While the solution was flowing through the reaction tube at a rate of 30 mL / min, microwaves were irradiated, and the reaction tube was heated to 400°C at a rate of 10°C / min. The power consumption and temperature of the reaction tube during this period were measured and the results are shown in Figure 2. Figure 2 shows that in Example 1, H ２ This figure shows the changes in power consumption and temperature when catalyst A is heated to 400°C with microwaves in the presence of [the substance].

[0112] In Example 1, a slight increase in power consumption was observed from around 250°C, but the increase was sufficiently small.

[0113] (Comparative Example 1) The reaction tube was heated in the same manner as in Example 1, except that the temperature of the reaction tube was changed from being heated to 400°C at 10°C / min to being heated to 550°C at 10°C / min. The power consumption and temperature of the reaction tube during this period were measured and the results are shown in Figure 3. Figure 3 shows that in Comparative Example 1, H ２ This figure shows the power consumption and temperature changes when catalyst A is heated to 550°C with microwaves in the presence of [the substance].

[0114] In Comparative Example 1, the power consumption, which was less than 20W at 400°C, began to rise sharply above 400°C, exceeding 75W at 550°C.

[0115] (Comparative Example 2) Catalyst A (LaNiO) obtained in Production Example 1 ３ 0.5 g of the powder was weighed out and packed into a quartz reaction tube with an inner diameter of 8 mm, and set in the microwave generator used in Example 1. ２ and N ２ Without circulating the mixed gas, the power consumption of microwave irradiation was varied from 10W to 40W in 10W increments under atmospheric conditions. For each power consumption, the temperature was measured when the temperature change over 5 minutes was less than 10°C and the system stabilized. The results are shown in Figure 4. Figure 4 shows the correlation between power consumption and temperature when catalyst A was heated with microwaves under atmospheric conditions in Comparative Example 2.

[0116] From a comparison between Example 1 and Comparative Example 1, the reducing substance H ２ In the presence of catalyst A (LaNiO ３ When heating the powder (H) with microwaves, it was found that the heating characteristics by microwaves deteriorate rapidly above 400°C, so it is preferable to use it at temperatures below 400°C. On the other hand, when heating the reducing substance H ２ In Comparative Example 2, where catalyst A was heated with microwaves in the absence of reducing substances, the microwave heating characteristics of catalyst A did not deteriorate even when the temperature exceeded 400°C. Therefore, from a comparison between Comparative Example 1 and Comparative Example 2, it was found that the deterioration of the microwave heating characteristics of catalyst A above 400°C is a phenomenon limited to the presence of reducing substances.

[0117] (Manufacturing Example 2: Manufacturing of Catalyst B) Catalyst A (LaNiO) obtained in Manufacturing Example 1 ３ 0.25 g of the powder was weighed out and packed into a quartz reaction tube with an inner diameter of 8 mm. This reaction tube was then placed in an electric furnace (ceramic electric tubular furnace, manufactured by Asahi Rika Seisakusho Co., Ltd.) equipped with a thermometer. A mass spectrometer was connected to the outlet of the reaction tube. ２ The electric furnace was heated to a set temperature of 500°C while the gas was flowing at a flow rate of 100 mL / min. After the electric furnace reached 500°C, it was held at 500°C for 10 minutes, and then the heating by the electric furnace was stopped. After confirming that the electric furnace temperature had dropped to 25°C, N was flowed into the reaction tube. ２ Gas, H ２ and N ２ mixed gas (5% by volume H ２ / 95% N by volume ２The system was switched to a different setting and flowed at a rate of 30 mL / min. After confirming that the mass spectrometer connected to the outlet of the reaction tube was stable, the electric furnace was set to a heating rate of 10 °C / min and a temperature of 500 °C, and heating was started. After the electric furnace reached 500 °C, it was held at 500 °C for 30 minutes, and after stopping the heating by the electric furnace, the reaction tube was cooled to 25 °C. The catalyst obtained in Production Example 2 was designated as "Catalyst B". The analysis conditions using the mass spectrometer were as follows: [Analysis Conditions] ・Apparatus: BELMASS (Microtrac-Bel Co., Ltd.) ・Emission current: 1.0 mA ・SEM: 1000 V

[0118] (Test Example 2: XRD Analysis) Catalyst A from Production Example 1 and Catalyst B from Production Example 2 were analyzed using Cu-Kα X-ray diffraction (XRD) under the same analytical conditions as in Test Example 1. The analyzed X-ray diffraction spectra are shown in Figure 5.

[0119] The peaks were identified by comparing the obtained X-ray diffraction patterns with literature values. From the results in Figure 5, the X-ray diffraction spectrum of catalyst B in production example 2 is LaNiO ３ Peaks attributed to Ni, peaks attributed to La ２ O ３ It has a peak that is attributed to LaNiO ３ Ni, and La ２ O ３ It was found to be a mixture of [something].

[0120] (Example 2) The reaction tube containing catalyst B manufactured in Manufacturing Example 2 was used as is, and the reaction tube was set in the microwave generator used in Example 1. 100% CO2 was released from the top of the reaction tube. ２Gas was flowed at 50 mL / min. After confirming that the mass spectrometer connected to the outlet of the reaction tube was stable, the microwave generator was set to 300°C and heating was started. After the temperature of the reaction tube reached 300°C, after confirming that the mass spectrometer connected to the outlet of the reaction tube was stable again, n-hexane, a reducing hydrocarbon, was added at 20 μL / min through the raw material inlet connected to the inlet side of the reaction tube. After that, heating continued for 2,000 seconds with the reaction tube set to 300°C, then the microwave generator was set to 350°C, and heating was continued for 1,000 seconds after the temperature stabilized. Furthermore, the microwave generator was set to 400°C, and heating was continued for 900 seconds after the temperature stabilized, before heating was stopped. The total time from the start to the stop of microwave irradiation was 4,900 seconds. During the period from the start to the stop of microwave heating, the signal was checked with the mass spectrometer and the atmospheric gas CO was detected. ２ In addition to the signal corresponding to m / z = 44, H ２ The signals corresponding to m / z = 2, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４ A signal corresponding to m / z = 16 was detected. Mass spectrometry was performed under the same analytical conditions as in Manufacturing Example 2.

[0121] With the start of microwave heating set as 0 minutes, Figure 6A shows the power consumption (incident and reflected waves) and temperature changes, and Figure 6B shows the CO2 levels measured by a mass spectrometer. ２ H ２ , and CH ４ The changes in signal intensity corresponding to m / z are shown. From these results, it can be seen that H ２ It was found that a substance was generated, and that catalyst B was stably heated between 300°C and 400°C.

[0122] (Example 3) The reaction tube containing catalyst B manufactured in Manufacturing Example 2 was used as is, and the reaction tube was set in the microwave generator used in Example 1. 100% CO2 was released from the top of the reaction tube. ２The gas was flowed at 50 mL / min. After confirming that the mass spectrometer connected to the outlet of the reaction tube was stable, the microwave generator was set to 350°C and heating was started. After the temperature of the reaction tube reached 250°C, after confirming that the mass spectrometer connected to the outlet of the reaction tube was stable again, polyethylene (PE) (catalog No. 427772, manufactured by Sigma-Aldrich), a reducing hydrocarbon, was added at a rate of 20 mg / min through the raw material inlet connected to the inlet side of the reaction tube. After that, heating was continued for 2,000 seconds with the reaction tube set to 350°C, and then the heating was stopped. From the start of polyethylene addition until the stopping of heating, the signal was checked with the mass spectrometer and the atmospheric gas CO was detected. ２ In addition to the signal corresponding to m / z = 44, H ２ The signals corresponding to m / z = 2, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４ A signal corresponding to m / z = 16 was detected. Mass spectrometry was performed under the same analytical conditions as in Manufacturing Example 2.

[0123] With the start of polyethylene input set as 0 minutes, Figure 7A shows the power consumption (incident and reflected waves) and temperature changes, and Figure 7B shows the CO2 levels measured by a mass spectrometer. ２ H ２ CO and C ２ H ４ , and CH ４ The changes in signal intensity corresponding to m / z are shown. From these results, it was found that catalyst B was heated stably and the reaction proceeded below 350°C. 900 seconds after the start of polyethylene input, H in the outlet gas ２ The concentration was 13.3% by volume.

[0124] (Comparative Example 3) Catalyst A (LaNiO) produced in Manufacturing Example 1 ３ 0.50 g of the powder was weighed out and packed into a quartz reaction tube with an inner diameter of 8 mm, and then set in the microwave generator used in Example 1. CO was released from the top of the reaction tube. ２ and N ２ mixed gas (10% CO2 by volume) ２ / 90% N by volume２ The solution was passed through at a rate of 20 mL / min. After confirming that the mass spectrometer connected to the outlet of the reaction tube was stable, the input power of the microwave generator was set to 20 W, and heating was started. From then until the end of the test, the power consumption values ​​of the microwave generator (incident and reflected waves) were recorded. 380 seconds after the start of heating, it was confirmed that the temperature of the reaction tube had stabilized at 497°C, and polyethylene, a reducing hydrocarbon, was added at a rate of 10 mg / min through the raw material inlet connected to the inlet side of the reaction tube.

[0125] Immediately after the start of microwave irradiation, the temperature of the reaction tube rose rapidly to around 530°C, then dropped sharply to around 350°C, and then rose again, reaching equilibrium at around 395°C. Therefore, 725 seconds after the start of microwave irradiation, the power input to the microwave generator was changed to 40W. The temperature of the reaction tube rose again, reaching 545°C before dropping again. Furthermore, around 805 seconds after the start of microwave irradiation, the reflected wave increased sharply, fluctuating wildly between 10W and 25W. For this reason, the microwave generator was stopped 950 seconds after the start of microwave irradiation.

[0126] The microwave generator's power input was set to 20W, and the timing of the start of heating was set to 0 seconds. When the signal was checked with a mass spectrometer, the ambient gas CO was detected. ２ In addition to the signal corresponding to m / z = 44, H ２ The signals corresponding to m / z = 2, CO and C ２ H ４ This corresponds to m / z = 28, and CH ４ A signal corresponding to m / z = 16 was detected. Mass spectrometry was performed under the same analytical conditions as in Manufacturing Example 2.

[0127] Figure 8A shows the temperature progression, Figure 8B shows the power consumption (incident and reflected waves) progression, and Figure 8C shows the CO2 measured by a mass spectrometer. ２ H ２ CO and C ２ H ４ , and CH ４The graph shows the changes in signal intensity corresponding to m / z. In Figures 8A to 8C, 0 seconds indicates the timing when the input power of the microwave generator was set to 20W and heating began in Comparative Example 3. Also, in Figures 8A to 8C, the time during which polyethylene (PE) was input is indicated by arrows.

[0128] As described above, this disclosure has been explained based on specific embodiments and examples, but these embodiments and examples are merely presented as examples, and this disclosure is not limited to the above embodiments and examples. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, additions, modifications, etc., are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0129] This international application claims priority under Japanese Patent Application No. 2024-157061, filed on 10 September 2024, and Japanese Patent Application No. 2024-162636, filed on 19 September 2024, which are incorporated herein by reference to the entire contents of Japanese Patent Application No. 2024-157061 and Japanese Patent Application No. 2024-162636.

Claims

1. A method for producing a chemical substance by converting a raw material in the presence of a catalyst, comprising: contacting the raw material with a catalyst heated to 400°C or below by microwave irradiation; at least one of the raw material and the product containing a reducing substance; and the catalyst containing at least one metal oxide selected from compounds represented by the following general formula (1): MaMbO ３ ...General formula (1) However, in the above general formula (1), Ma represents one metallic element selected from alkaline earth metals and lanthanides, and Mb represents at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

2. The method for producing a chemical substance according to claim 1, wherein the frequency of the microwave is 915 MHz ± 13 MHz or 2.45 GHz ± 0.9 GHz.

3. The method for producing a chemical substance according to claim 1 or claim 2, wherein the reducing substance is at least one substance selected from the group consisting of hydrogen, hydrocarbons, carbon monoxide, and carbon.

4. The method for producing a chemical substance according to any one of claims 1 to 3, wherein the contact is the raw material coming into contact with the catalyst which has been heated to 150°C or more and 400°C or less by irradiation with microwaves.

5. At least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ A method for producing a chemical substance according to any one of claims 1 to 4.

6. The method for producing a chemical substance according to any one of claims 1 to 5, wherein the catalyst further comprises a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

7. The method for producing a chemical substance according to claim 6, wherein the metal is precipitated by partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1).

8. A method for producing a chemical substance according to any one of claims 1 to 7, wherein the catalyst further comprises a compound represented by the following general formula (2). ｘ O ｙ ...General formula (2) In general formula (2), Ma represents the same metallic element as Ma in general formula (1), x and y represent positive integers that express the composition ratio of Ma to O, and y is given by y = xz / 2, where z is the oxidation state of Ma.

9. The compound represented by general formula (2) is La ２ O ３ The method for producing a chemical substance according to claim 8.

10. A method for using a catalyst in the production of a chemical substance that converts a raw material to produce a product, comprising: contacting the raw material with the catalyst heated to 400°C or below by microwave irradiation; at least one of the raw material and the product containing a reducing substance; and the catalyst containing at least one metal oxide selected from compounds represented by the following general formula (1). MaM NitO ３ ...General formula (1) However, in the above general formula (1), Ma represents one metallic element selected from alkaline earth metals and lanthanides, and Mb represents at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti.

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