Method for producing hydrogen and method for reforming hydrocarbon

Abstract

One embodiment of a method for producing H2 according to the present disclosure comprises: irradiating, with microwaves, a mixture containing a metal and at least one metal oxide under an atmosphere of a gas containing at least one selected from among CO2, H2O, and N2; and exposing a hydrocarbon to the mixture under an atmosphere of a gas containing at least one selected from among CO2, H2O, and N2 while irradiating the mixture with the microwaves. The metal contains at least one metal element that is selected from among Fe, Co, Ni, Mn, Cu, and Ti. The at least one metal oxide is selected from among compounds represented by general formula (1): MaMbO3 (wherein Ma represents one metal element that is selected from among alkaline earth metals and lanthanoids, and Mb represents the same metal element as a metal element contained in the metal).

Description

Method for producing hydrogen and method for reforming hydrocarbons

[0001] This disclosure is H ２ This relates to a method for producing [a certain substance] and a method for modifying hydrocarbons.

[0002] To mitigate global warming, the use of hydrogen as an energy source that does not emit carbon dioxide is necessary. One method of producing hydrogen is the methane reforming reaction, also known as dry reforming, which uses methane, the main component of natural gas and a major greenhouse gas, and carbon dioxide as chemical raw materials (see Non-Patent Literature 1). In the reaction equation, methane reforming uses methane and carbon dioxide as chemical raw materials to produce carbon monoxide and hydrogen. The carbon monoxide produced along with hydrogen can be used as a raw material for various chemical products. Therefore, it is attracting attention from the perspective of the effective utilization of natural gas.

[0003] On the other hand, from the perspective of efficient resource utilization, methods for recycling plastic waste into fuels and chemicals are being considered. However, in the decomposition of plastics, especially polyolefins such as polyethylene and polypropylene, high temperatures are required for decomposition, and the resulting products are complex mixtures, often requiring complicated separation and further conversion processes for recycling as fuels or chemicals.

[0004] Therefore, using the dry reforming reaction, plastic waste is converted to CO2 ２ H by gas ２ A method has been proposed to convert plastic waste and CO into CO (see Non-Patent Document 2). This proposed method involves converting plastic waste and CO on a metal oxide catalyst. ２ By irradiating the gas with microwaves, H ２ And a method of decomposing it into CO.

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

[0006] The present disclosure is excellent in the temperature-rising characteristics by microwaves and their stability, and can efficiently convert hydrocarbons into H ２ to provide a manufacturing method of H ２ .

[0007] As means for solving the above problems, it is as follows. That is, <1> irradiating microwaves to a mixture containing a metal and a metal oxide in an atmosphere of a gas containing at least one selected from CO ２ , H ２ O, and N ２ , and contacting hydrocarbons with the mixture irradiated with the microwaves in an atmosphere of a gas containing at least one selected from CO ２ , H ２ O, and N ２ . The metal is a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti, and the metal oxide is at least one metal oxide selected from compounds represented by the following general formula (1). This is a manufacturing method of H ２ . MaMbO ３ ... General formula (1) However, in the general formula (1), Ma represents one metal element selected from alkaline earth metals and lanthanoids, and Mb represents the same metal element as the metal element contained in the metal. <2> The mixture further contains a compound represented by the following general formula (2). This is the manufacturing method of H ２ described in <1>. 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 representing the composition ratio of Ma to O, and y is y = xz / 2, where z is the oxidation state of Ma. <3> The mixture containing the metal and the metal oxide is obtained by partially hydrogen-reducing a precursor mixture containing at least one metal oxide selected from the compounds represented by general formula (1), or 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), thereby precipitating the metal, as described in <1> or <2> above. ２ This is a method for manufacturing Mb. ｐ O ｑ ...General formula (3) However, in general formula (3), Mb represents the same metallic 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. <4> The metal is Ni, and the metal oxide is LaNiO ３ H as described in any one of the above <1> to <3>. ２ This is a method for producing the following: <5> The mixture containing the metal and the metal oxide is H ２ LaNiO at temperatures above 300°C under an atmosphere of gas containing ３ , or LaNiO ３ The H described in <4> above is obtained by heating a precursor mixture of NiO and partially reducing it with hydrogen to precipitate Ni. ２ This is a method for producing the compound represented by the general formula (2). <6> The compound represented by the general formula (2) is La ２ O ３ H as described in any one of the above items <2> to <5>. ２ This is a method for producing the product. <7> Irradiating with microwaves is a method for heating the hydrocarbon and the mixture to a temperature of 470°C or lower, as described in any one of the above <1> to <6>. ２ This is a method of manufacturing CO. ２ and H ２Irradiating a mixture containing metals and metal oxides with microwaves in an atmosphere of gas containing at least one selected from O, and CO ２ and H ２ A method for modifying hydrocarbons, comprising: bringing a hydrocarbon into contact with the mixture being irradiated with microwaves under an atmosphere of gas containing at least one selected from O; wherein the metal is a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti; and the metal oxide is 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 the same metal element as the metal contained in the aforementioned metal. <9> The mixture further comprises a compound represented by the following general formula (2), and is the hydrocarbon modification method described in <8> above. 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 representing the composition ratio of Ma to O, and y is y = xz / 2, where z is the oxidation state of Ma. <10> The mixture containing the metal and the metal oxide is a method for modifying hydrocarbons according to <8> or <9>, wherein the metal is precipitated by partially hydrogen-reducing a precursor mixture containing at least one metal oxide selected from the compounds represented by general formula (1), or 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).

[0008] Mb ｐ O ｑ ...General formula (3) However, in general formula (3), Mb represents the same metallic 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. <11> The metal is Ni, and the metal oxide is LaNiO ３This is a method for modifying hydrocarbons as described in any one of the above items <8> to <10>. <12> The mixture containing the metal and the metal oxide is H ２ LaNiO at temperatures above 300°C under an atmosphere of gas containing ３ , or LaNiO ３ The hydrocarbon modification method described in <11> involves heating a precursor mixture of and NiO and partially reducing it by hydrogen to precipitate Ni. <13> The compound represented by the general formula (2) is La ２ O ３ This is a method for modifying hydrocarbons according to any one of the above items <9> to <12>. <14> Irradiating with microwaves is a method for modifying hydrocarbons according to any one of the above items <8> to <13>, wherein the temperature of the hydrocarbon and the mixture is heated to 470°C or below.

[0009] According to embodiments of this disclosure, the microwave heating characteristics and stability are excellent, and hydrocarbons can be efficiently converted to H ２ H can be converted to ２ A method for manufacturing this can be provided.

[0010] Figure 1 shows the LaNiO obtained in Preparation Example 1. ３ This figure shows the X-ray diffraction (XRD) spectra of catalyst A obtained in Production Example 1 and catalyst B obtained in Comparative Production Example 1. The horizontal axis represents 2θ (degree), and the vertical axis represents Intensity (a.u.). Figure 2A shows the CO2 diffraction spectrum obtained in Example 1. ２ This figure shows the changes in power consumption (incident and reflected waves) and temperature when catalyst A obtained in Production Example 1 was irradiated with microwaves while n-hexane was added dropwise under flow. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows analysis time (seconds). Figure 2B shows the changes in CO in Example 1. ２ When catalyst A obtained in production example 1 was irradiated with microwaves while n-hexane was added dropwise under flow conditions, H ２ The signal corresponding to m / z = 2, CO ２ A signal corresponding to m / z = 44, CH ４The corresponding signals are m / z = 16, as well as CO and C. ２ H ４ This figure shows the change in signal intensity at m / z = 28, corresponding to CO. The vertical axis shows the mass spectrometry signal (a.u.), and the horizontal axis shows the analysis time (seconds). Figure 3A shows the CO2 in Example 2. ２ This figure shows the changes in power consumption (incident and reflected waves) and temperature when catalyst A obtained in manufacturing example 1 was irradiated with microwaves while polyethylene was being added during the flow process. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows analysis time (seconds). Figure 3B shows the changes in CO in Example 2. ２ When microwaves are irradiated onto catalyst A obtained in manufacturing example 1 while polyethylene is being added during distribution, H ２ The signal corresponding to m / z = 2, CO ２ A signal corresponding to m / z = 44, CH ４ The corresponding signals are m / z = 16, as well as CO and C. ２ H ４ This figure shows the change in signal intensity at m / z = 28, corresponding to CO. The vertical axis shows the mass spectrometry signal (a.u.), and the horizontal axis shows the analysis time (seconds). Figure 4A shows the CO2 in Comparative Example 3. ２ During distribution, while adding polyethylene, the LaNiO obtained in Preparation Example 1 ３ This figure shows the temperature change when microwaves are irradiated onto the material. The vertical axis represents temperature (°C), and the horizontal axis represents analysis time (minutes). Figure 4B shows the CO2 in Comparative Example 3. ２ During distribution, while adding polyethylene, the LaNiO obtained in Preparation Example 1 ３ This figure shows the power consumption (incident and reflected waves) when microwaves are irradiated onto CO. The vertical axis on the left shows power consumption (W), and the horizontal axis shows analysis time (minutes). Figure 4C shows the CO2 in Comparative Example 3. ２ During distribution, while adding polyethylene, the LaNiO obtained in Preparation Example 1 ３ When microwaves are irradiated onto it, H ２ The signal corresponding to m / z = 2, CO ２ A signal corresponding to m / z = 44, CH ４ The corresponding signals are m / z = 16, as well as CO and C.２ H ４ This figure shows the changes in signal intensity at m / z = 28. The vertical axis represents the mass spectrometry signal (a.u.), and the horizontal axis represents the analysis time (minutes). Figure 5A shows the changes in power consumption and temperature when catalyst A obtained in Production Example 1 is irradiated with microwaves in the presence of polyethylene in Example 3. The left vertical axis represents power consumption (W), the right vertical axis represents temperature (°C), and the horizontal axis represents analysis time (minutes). Figure 5B shows the changes in power consumption and temperature when catalyst A obtained in Production Example 1 is irradiated with microwaves in the presence of polyethylene in Example 4. The left vertical axis represents power consumption (W), the right vertical axis represents temperature (°C), and the horizontal axis represents analysis time (minutes). Figure 5C shows the changes in power consumption and temperature when catalyst A obtained in Preparation Example 1 is irradiated with microwaves in the presence of polyethylene in Comparative Example 5. ３ This figure shows the power consumption and temperature changes when microwaves are irradiated onto the catalyst. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows analysis time (minutes). Figure 5D shows the power consumption and temperature changes when microwaves are irradiated onto catalyst B obtained in Comparative Production Example 1 in the presence of polyethylene in Comparative Example 6. The left vertical axis shows power consumption (W), the right vertical axis shows temperature (°C), and the horizontal axis shows analysis time (minutes). Figure 6 shows the H25 power consumption and temperature changes when microwaves are irradiated onto catalyst A obtained in Production Example 1 in the presence of polyethylene in Example 3. ２ This figure shows the change in signal intensity at m / z = 2. The vertical axis shows the mass spectrometry signal (a.u.), and the horizontal axis shows the analysis time (minutes). Figure 7 shows the results in Example 4, Comparative Example 5, and Comparative Example 6, in the presence of polyethylene, for catalyst A obtained in Production Example 1 and LaNiO obtained in Preparation Example 1. ３ , or when the catalyst B obtained in comparative manufacturing example 1 is irradiated with microwaves, H ２ This figure shows the change in signal intensity for m / z = 2. The vertical axis represents the mass spectrometry signal (a.u.), and the horizontal axis represents the analysis time (minutes).

[0011] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the embodiments are not limited by the following description and can be appropriately changed without departing from the gist of the present disclosure. In this specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value, unless otherwise specified.

[0012] (Production method of H ２ ) The production method of H ２ (hereinafter also referred to as "hydrogen") of the present disclosure is to irradiate a mixture containing a metal and a metal oxide with microwaves in an atmosphere of a gas containing at least one selected from CO ２ , H ２ O, and N ２ , and to bring a hydrocarbon into contact with the mixture irradiated with the microwaves in an atmosphere of a gas containing at least one selected from CO ２ , H ２ O, and N ２ . The metal is a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti, and the metal oxide is at least one metal oxide selected from compounds represented by the following general formula (1). The production method of H ２ of the present disclosure may further include other processes other than irradiating with microwaves and contacting, if necessary. MaMbO ３ ・・・General formula (1) However, in the general formula (1), Ma represents one metal element selected from alkaline earth metals and lanthanoids, and Mb represents the same metal element as the metal element contained in the metal).

[0013] The inventors of the present invention have intensively studied a method for producing H ２ for efficiently reforming hydrocarbons. As a catalyst, a mixture containing a metal and a metal oxide is used, and as the metal oxide, at least one metal oxide selected from compounds represented by the general formula (1) is used. Compared with the case where only a metal oxide in the conventional method is used as a catalyst, H ２It has been found that the temperature required for the production of

[0014] As an example of the method for producing H of the present disclosure, the dry reforming reaction represented by the following reaction formula will be described. C ２ H ｎ H ｍ + pCO ２ → qCO + rH ２ Here, C ｎ H ｍ is a general formula representing a hydrocarbon, n represents a positive integer, m represents the unsaturation degree of the hydrocarbon as k (k is a non - negative integer), in the case of a chain hydrocarbon, it is 2n + 2 - 2k, in the case of a monocyclic alicyclic hydrocarbon, it is 2n - 2k, p represents the number of moles of CO ２ reacting with 1 mole of the hydrocarbon, usually n, q represents a number calculated from n + p, and r represents a number calculated from m / 2.

[0015] The dry reforming reaction is endothermic. Therefore, for example, in the conventionally known reaction conditions for the dry reforming reaction of methane, a high temperature exceeding 600°C is required. Existing methods other than the dry reforming reaction for producing hydrogen from hydrocarbons also mostly require high temperatures. Therefore, conventional methods require an extremely high energy input brought about by fuel combustion, and as a result, a large amount of CO ２ emissions are generated.

[0016] In contrast, the method for producing H of the present disclosure uses a mixture containing metals and metal oxides, which has both extremely high H ２ production activity and high stability of heating by microwaves, and can perform a reforming reaction stably at a lower temperature compared to conventional methods. Therefore, it is also advantageous in that it can reduce the emission of CO ２ which is a greenhouse gas. ２

[0017] <Irradiation with microwaves> Irradiation with microwaves is carried out on CO ２ H ２ O, and N ２The method involves irradiating a mixture containing metals and metal oxides with microwaves in an atmosphere of gas containing at least one selected from the following.

[0018] When microwaves are irradiated, the mixture directly absorbs the microwaves and is heated. There are no particular restrictions on the temperature of the heated mixture, and it can be appropriately selected depending on the purpose, but it is preferably 150°C to 470°C, and more preferably 180°C to 440°C. When the temperature of the heated mixture is 150°C to 470°C, high catalytic activity can be obtained. The temperature of the heated mixture is also the reaction temperature at which hydrocarbons undergo catalytic decomposition when microwaves are irradiated. The temperature of the mixture can be measured using known temperature measuring instruments such as resistance thermometers and thermocouples.

[0019] <<Mixture>> The mixture contains metals and metal oxides, and may further contain other components as needed.

[0020] -Metal- The metal in the mixture is a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti. Among these, Co, Ni, and Cu are preferred, and Ni is more preferred.

[0021] There are no particular restrictions on the state of the metal in the mixture, but it is preferable that the metal is dispersed or supported on at least one metal oxide selected from the compounds represented by 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 general formula (1).

[0022] The metal content in the mixture is not particularly limited, as long as it is a mixture with at least one metal oxide selected from the compounds represented by the general formula (1), and can be appropriately selected depending on the purpose. For example, if the mixture is obtained by hydrogen reduction of at least one metal oxide selected from the compounds represented by the general formula (1) by the method described later, the heating stability and H ２In terms of manufacturing efficiency, the amount of metal precipitated per gram of at least one metal oxide selected from the compounds represented by the general formula (1) before reduction is preferably 0.1 mmol to 3.5 mmol, more preferably 0.2 mmol to 3.2 mmol.

[0023] The metal content in the mixture is, for example, if the mixture 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 La ２ 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 O５ +2H ２ →2Ni+La ２ O ３ +2H ２ O

[0024] -Metal Oxides- The metal oxide in the mixture is at least one metal oxide selected from the 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 the same metallic element as the metallic element contained in the above metal.

[0025] Specific examples of Ma in the compound represented by the 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 the general formula (1), and La is more preferred.

[0026] In the compound represented by the general formula (1), Mb represents the same metallic element as the metallic element contained in the metal. Therefore, Mb in the general formula (1) is a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti. For example, when the metal is Ni, the compound represented by the general formula (1) is MaNiO ３ That is the case.

[0027] The compound represented by the general formula (1) above is ABO ３ It 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 compound represented by the above general formula (1). B is located at the B site of the perovskite-type structure and corresponds to Mb in the compound represented by the above general formula (1).

[0028] A specific example of the compound represented by the general formula (1) is LaFeO ３ LaCoO ３ LaMnO ３ , BaTiO ３SrTiO 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 It is preferable that it includes.

[0029] The content of at least one metal oxide selected from the compounds represented by the general formula (1) in the mixture is not particularly limited as long as it is a mixture with a metal, and can be appropriately selected depending on the purpose.

[0030] [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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[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 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.

[0037] 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.

[0038] Mb ｘ O ｙ...General formula (3) However, in general formula (3), Mb represents the same metal element as Mb in general formula (1), x and y represent positive integers indicating the composition ratio of Mb to O, and y is y = xz / 2, where z 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.

[0039] 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.

[0040] -Other components- Other components in the above mixture include H ２ As long as it can be manufactured, there are no particular restrictions, and it can be appropriately selected according to the purpose. The mixture may further contain a compound represented by the following general formula (2) and a compound represented by the following general formula (4). These may be used individually or in combination of two or more.

[0041] -- Compound represented by 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.

[0042] 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 ３ The 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).

[0043] -- Compound represented by 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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).

[0048] The content of other components in the mixture is H ２ As long as it can be manufactured, there are no particular restrictions, and it can be selected as appropriate depending on the purpose.

[0049] Among these, the mixture containing metals and metal oxides is preferably one in which the metal is dispersed or supported on at least one metal oxide selected from the compounds represented by the general formula (1), and LaNiO ３ It is more preferable that the material is Ni-supporting.

[0050] [Method for Producing the Mixture] There are no particular limitations on the method for producing the mixture, 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 producing the mixture. 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.

[0051] Mb ｐ O ｑ...General formula (3) In general formula (3), Mb represents the same metallic 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.

[0052] In this disclosure, "precursor mixture" means a mixture 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), which are in a state in which no metal has been deposited, for use in microwave irradiation, and is a term used to distinguish it from a mixture containing metal and metal oxide used in microwave irradiation.

[0053] 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.

[0054] There are no particular restrictions on the heating temperature when partially hydrogenating at least one metal oxide selected from the compounds represented by the general formula (1), or the precursor mixture, and it can be appropriately selected depending on the purpose. However, when heating is performed by external heating such as an electric furnace, a temperature of 300°C or higher is preferred, 300°C to 570°C is more preferred, 330°C to 570°C is even more preferred, and 360°C to 540°C is particularly preferred. Furthermore, when partially hydrogenating 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 to 570°C is even more preferred, and 430°C to 570°C is most preferred. When the heating temperature when partially hydrogenating 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 suitably partially hydrogenated.

[0055] There are no particular restrictions on the heating time when partially hydrogen-reducing at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, and it can be appropriately selected depending on the purpose. For example, the at least one metal oxide selected from the compounds represented by the general formula (1) is LaNiO ３ Therefore, H is present in an amount of 0.5% to 10% by volume. ２ And, N 90% to 99.5% by volume ２ When heating in an atmosphere containing a gas, the heating time is preferably 3 minutes to 300 minutes, more preferably 5 minutes to 120 minutes, and even more preferably 10 minutes to 90 minutes.

[0056] When partially hydrogenating at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, H ２In processing under a gas atmosphere containing the above, 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, but heating of at least one metal oxide selected from the compounds represented by the general formula (1) or the precursor mixture, preferably LaNiO ３ , or LaNiO ３ Heating the precursor mixture of and NiO by radiant heat is preferable because it allows for stable heat treatment at a constant temperature and makes it easier to control the reduction of at least one metal oxide selected from the compounds represented by the general formula (1).

[0057] 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 are as follows: ２ It is preferable that the atmosphere be one containing a gas.

[0058] H ２ Gases containing H ２ As long as it includes H ２ It may be a gas consisting only of H ２ It may contain other gases besides H ２ Gases containing H ２ Furthermore, it is more preferable that the atmosphere be one containing an inert gas.

[0059] Examples of inert gases include N ２ Examples of noble gases include He and Ar. From the viewpoint of manufacturing cost, N is preferred as the inert gas. ２ That is the case.

[0060] H ２ When 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 H ２ There are no particular restrictions on the concentration, and it can be selected appropriately depending on the purpose, but 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.

[0061] 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 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.

[0062] 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 and partially reducing it with hydrogen. As a result, Ni as a metal precipitates in the mixture containing the metal and the metal oxide, and LaNiO ３ A mixture is obtained in which Ni is dispersed or supported.

[0063] 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 mixture obtained after hydrogen reduction.

[0064] 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.

[0065] 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.

[0066] 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, after returning to a temperature of 200°C or lower.

[0067] 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 mixture 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 the production of the mixture, 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.

[0068] 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.

[0069] 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.

[0070] <<CO ２ H ２ O, and N ２ Gas containing at least one selected from >> CO ２ H ２ O, and N ２ CO in a gas containing at least one selected from ２ and H ２ There are no particular restrictions on the concentration of O, and it can be appropriately selected depending on the purpose, but H in this disclosure ２ When the manufacturing method is applied to a dry reforming reaction or steam reforming, 1 volume% or more is preferred, 2 volume% or more is more preferred, and 10 volume% or more is even more preferred. ２ H ２ O, and N ２ CO in a gas containing at least one selected from ２ and H ２There are no particular restrictions on the upper limit of the concentration of O, and it can be appropriately selected according to the purpose. Also, H in this disclosure ２ When the manufacturing method is applied to methods other than dry reforming and steam reforming, CO ２ and H ２ It contains no O at all, N ２ It may also be a gas containing [something].

[0071] CO ２ H ２ O, and N ２ N in a gas containing at least one selected from ２ There are no particular restrictions on the concentration of H in this disclosure, and it can be appropriately selected depending on the purpose, but ２ When the manufacturing method is applied to a dry reforming reaction or steam reforming, a CO2 concentration of 99% by volume or less is preferred, 98% by volume or less is more preferred, and 90% by volume or less is even more preferred. ２ H ２ O, and N ２ N in a gas containing at least one selected from ２ There are no particular restrictions on the lower limit of the concentration, and it can be appropriately selected according to the purpose.

[0072] CO ２ H ２ O, and N ２ CO in a gas containing at least one selected from ２ H ２ O, and N ２ The total concentration of CO is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 30% by volume or more, and more preferably 60% by volume or more. ２ H ２ O, and N ２ CO in a gas containing at least one selected from ２ H ２ O, and N ２ There are no particular restrictions on the upper limit of the total concentration of these substances, and they can be appropriately selected according to the purpose.

[0073] CO ２ H ２ O, and N ２CO in a gas containing at least one selected from ２ H ２ O, and N ２ Other components include, for example, CO and H ２ These are some examples. These may be used individually or in combination of two or more.

[0074] <<Microwaves>> Microwaves are electromagnetic waves, preferably with a frequency of 300 MHz to 300 GHz. Because microwaves can directly transfer energy to the dielectric material being heated, the material being 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 electric furnaces. H of this disclosure ２ In the manufacturing method, the substance heated by microwaves is a mixture containing metals and metal oxides.

[0075] In irradiating with microwaves, the microwave frequency is preferably 300 MHz to 300 GHz, but there are no particular restrictions as long as the mixture absorbs the microwaves and generates heat, and can be appropriately selected according to the purpose, with 0.9 GHz to 6.0 GHz being more preferable, and 2.3 GHz to 6.0 GHz being even more preferable. When the microwave frequency is 300 MHz or higher, H ２ The mixture can be heated to a temperature sufficient for production, and a frequency of 300 GHz or less is preferable from the viewpoint of energy efficiency. When irradiating with microwaves, the microwave frequency can be, for example, 915 MHz ± 13 MHz, 2.45 GHz ± 0.9 GHz, etc.

[0076] There are no particular restrictions on the microwave sources that can be used for microwave irradiation; they 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 performed continuously without changing the microwave output and frequency, from the viewpoint of stabilizing the reaction state, such as reaction activity and product selectivity, as well as the temperature and temperature distribution of the mixture. 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 power; it can be appropriately selected depending on the target temperature to be reached by the microwave irradiation.

[0079] <Contact> Contact is CO ２ H ２ O, and N ２ The hydrocarbon is brought into contact with the mixture being irradiated with microwaves in an atmosphere of gas containing at least one selected from the following.

[0080] H of this disclosure ２ The manufacturing method is CO ２ H ２ O, and N ２ In an atmosphere of gas containing at least one selected from, the mixture is irradiated with microwaves, and when hydrocarbons come into contact with the mixture, H ２ This method can produce [the product]. Therefore, it is preferable that the microwave irradiation and contact occur simultaneously, but the microwave heating catalyst and the substrate to be reacted may be brought into contact beforehand, and then microwaves may be irradiated to bring the microwave heating catalyst to the desired temperature, or after the mixture reaches the desired temperature by microwave irradiation, hydrocarbons may be added to the mixture and the mixture and hydrocarbons may be brought into contact.

[0081] H of this disclosure ２ The manufacturing method is CO ２ H ２ O, and N ２ In an atmosphere of gas containing at least one selected from, the mixture and hydrocarbons come into contact, causing the hydrocarbons to decompose. That is, since it is a reaction between a solid catalyst and a liquid, solid, or gas, it may be a batch reaction, but H２ To improve the efficiency of CO2 production, a continuous reaction is desirable when processing large quantities of hydrocarbons. When a continuous reaction is carried out, the mixture is placed in a reaction tube and used as a fixed bed or fluidized bed. ２ H ２ O, and N ２ One method involves adding hydrocarbons to a mixture layer while a gas containing at least one selected from the above is flowing through it.

[0082] When performing a batch reaction, the mixture is placed in a reaction vessel such as a reaction tube, and a solid hydrocarbon is placed on top of it as a fixed bed, and the inside of the reaction vessel is treated with CO2. ２ H ２ O, and N ２ A method of heating as a gas atmosphere containing at least one selected from, or placing the mixture in a sealable reaction vessel such as an autoclave, and CO ２ H ２ O and N ２ One example is a method of sealing a liquid or gaseous hydrocarbon as a gas atmosphere containing at least one selected from the following.

[0083] The reaction vessel is made of a material that is inert to microwaves but transmits microwaves. Quartz is one example of such a material.

[0084] <<Hydrocarbons>> H in this disclosure ２ In the manufacturing method, 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] Furthermore, H of this disclosure ２In the manufacturing method, 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 or petrochemical facilities may also be used. These may be used individually or in combination of two or more.

[0091] 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).

[0092] 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.

[0093] These hydrocarbons may be gases, liquids, or solids at around room temperature (25°C), but liquids or solids are preferred because they are easier to handle and the reactions proceed more 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.

[0094] There are no particular restrictions on the amount of mixture 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 mixture 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:mixture) is preferably 1:1,000 to 1:1, and more preferably 1:500 to 1:10.

[0095] <Other Processing> There are no particular restrictions on other processing, and it can be selected as appropriate depending on the purpose. For example, H ２ H produced in the manufacturing method ２ Other examples include recovering products such as CO.

[0096] <<Recovery>> Recovery involves the modification of hydrocarbons by microwave irradiation and contact, resulting in the production of H ２ The goal is to recover the products, such as CO. There are no particular restrictions on the recovery method, and any known method can be appropriately selected. For example, separation by pressurized distillation is one possible method.

[0097] H ２ When useful components such as CO are generated along with H ２The other useful components may be recovered together or separately, and after being recovered together, H is used by a known method. ２ Other useful components may be separated from this.

[0098] (Method for modifying hydrocarbons) The method for modifying hydrocarbons according to this disclosure is CO ２ and H ２ Irradiating a mixture containing metals and metal oxides with microwaves in an atmosphere of gas containing at least one selected from O, and CO ２ and H ２ The hydrocarbon is brought into contact with the mixture being irradiated with microwaves in an atmosphere of a gas containing at least one selected from O, wherein the metal is a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti, and the metal oxide is at least one metal oxide selected from compounds represented by the following general formula (1). The hydrocarbon modification method of this disclosure may further include, if necessary, other treatments other than microwave irradiation and 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 the same metallic element as the metallic element contained in the above metal.

[0099] In the hydrocarbon modification methods of this disclosure, irradiating with microwaves, contacting with microwaves, and other treatments are CO ２ and H ２ Except that the process is carried out in an atmosphere of gas containing at least one selected from O, the H of this disclosure ２ Since this can be done in the same manner as the manufacturing method described above, a detailed explanation will be omitted.

[0100] <<CO ２ and H ２ Gas containing at least one selected from O >> CO ２ and H ２ CO in a gas containing at least one selected from O ２ of and H ２There are no particular restrictions on the concentration of O, and it can be appropriately selected depending on the purpose, but it is preferably 1% by volume or more, more preferably 2% by volume or more, and even more preferably 3% by volume or more. ２ and H ２ CO in a gas containing at least one selected from O ２ and H ２ There are no particular restrictions on the upper limit of the O concentration, and it can be appropriately selected according to the purpose. Also, CO ２ and H ２ Gases containing at least one selected from O include CO generated from various processes. ２ From the perspective of effectively utilizing CO2 to mitigate global warming, ２ It is preferable to use a gas containing [the specified substance].

[0101] The hydrocarbon reforming method of this disclosure, when using a mixture containing a metal and a metal oxide as a catalyst, and when using at least one metal oxide selected from the compounds represented by the general formula (1) as the metal oxide, yields H compared to the conventional method in which only a metal oxide is used as a catalyst. ２ The temperature required for its production is lowered, and especially when the reaction is carried out continuously at a constant temperature, the heating characteristics and stability of microwave heating are significantly improved.

[0102] CO in the hydrocarbon reforming method of this disclosure ２ and H ２ CO is a gas containing at least one selected from O. ２ When using a gas containing CO, i.e., when performing a dry reforming reaction as a hydrocarbon reforming, ２ The conversion rate is preferable as it is higher, but preferably 40% or more, and more preferably 45% or more. ２ The conversion rate is the value obtained by the method described in the examples.

[0103] The embodiments of this disclosure will be described in more detail below with reference to preparation examples, manufacturing examples, test examples, examples, and comparative examples, but the embodiments are not limited to these preparation examples, manufacturing examples, test examples, examples, and comparative examples.

[0104] (Preparation example 1: LaNiO３ Preparation of (Ni(NO)) 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.

[0105] Separately, 125 mL of 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution 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 ground using a mortar and pestle for 20 minutes. After grinding, the powder of the filtrate was transferred to a crucible and baked at 850°C for 5 hours to obtain LaNiO ３ I obtained it.

[0106] (Manufacturing Example 1: Manufacturing of Catalyst A) LaNiO obtained in Preparation Example 1 ３0.2 g of the powder was weighed out and filled into a quartz reaction tube with an outer diameter of 10 mm and 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. N 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 ２ The flow rate was switched to 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 Example 1 was designated as "Catalyst A". The analysis conditions using the mass spectrometer were as follows: 5 vol% H ２ / 95% N by volume ２ During the period when the reaction tube temperature was 430°C or higher, the H2C was measured using a mass spectrometer. ２ Consumption is LaNiO ３ The amount was 3.1 mmol per gram of powder. ２ Consumption is as described above, LaNiO ３ The amount of Ni precipitated in the reaction was assumed to be equal to the amount of Ni precipitated in the reaction. Based on the results of preliminary experiments, the temperature of the reaction tube was assumed to be equal to the temperature of the electric furnace, and the analysis conditions using the mass spectrometer were as follows: [Analysis conditions] ・Apparatus: BELMASS (Microtrac-Bel Corporation) ・Emission current: 1.0 mA ・SEM: 1000 V

[0107] (Comparative manufacturing example 1: Manufacturing of catalyst B) LaNiO obtained in preparation example 1 ３0.2 g of the powder was weighed out and filled into a quartz reaction tube with an outer diameter of 10 mm and 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. N ２ While flowing gas at a flow rate of 100 mL / min, the electric furnace was set to a temperature of 600°C and the heating was started. After the electric furnace reached 600°C, it was held at 600°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 ２ The 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 600 °C, and heating was started. After the electric furnace reached 600 °C, it was held at 600 °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 Comparative Production Example 1 was designated as "Catalyst B". 5 vol% H ２ / 95% N by volume ２ During the period when the reaction tube temperature was 430°C or higher, the H2C was measured using a mass spectrometer. ２ Consumption is LaNiO ３ The concentration was 4.1 mmol per gram of powder. ２ Consumption is as described above, LaNiO ３ The amount of Ni precipitated in the reaction tube was assumed to be equal to that in the reaction tube. Based on the results of preliminary experiments, the temperature of the reaction tube was assumed to be equal to that of the electric furnace, and mass spectrometry was performed under the same analytical conditions as in Production Example 1.

[0108] (Test Example 1: XRD Analysis) Catalyst A obtained in Production Example 1, Catalyst B obtained in Comparative Production Example 1, and LaNiO obtained in Preparation Example 1 ３ The following analysis was performed using X-ray diffraction (XRD) under the specified conditions. The analyzed X-ray diffraction spectrum is shown in Figure 1. [Analysis 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 powder obtained in Preparation Example 1 is LaNiO ３ Since it only showed peaks that belonged to LaNiO ３ It was confirmed that the catalyst A, which was obtained in Production Example 1, is LaNiO ３ La ２ O ３ Peaks attributed to , and Ni were observed. This is LaNiO ３ It is partially reduced by hydrogen, LaNiO ３ This means that it is a mixture containing and Ni. In contrast, catalyst B, which is the product obtained in comparative production example 1, is La ２ O ３ And peaks attributed to Ni were observed, but LaNiO ３ No peaks attributable to LaNiO were observed. ３ It was found that all of it was reduced by hydrogen.

[0110] (Example 1) The reaction tube containing catalyst A manufactured in Manufacturing Example 1 was used as is, and the reaction tube was set in the following microwave generator. [Microwave Generator] ・Device: MR-2G-100 (manufactured by Ryowa Electronics Co., Ltd.) ・Frequency: 2.45 GHz ± 0.05 GHz ・Irradiation mode: Single mode (maximum electric field strength on the central axis) ・Cavity size: 10 mm diameter, 100 mm length ・Maximum input power: 100 W

[0111] 100% CO2 by volume from the top of the reaction tube ２ The 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 a temperature of 300°C and heating was started. After the temperature of the reaction tube reached 300°C, it was confirmed again that the mass spectrometer connected to the outlet of the reaction tube was stable, and n-hexane (density at 20°C 0.66 g / cm³) was identified as a hydrocarbon. ３ CO2 is introduced at a rate of 20 μL / min through the raw material inlet connected to the inlet side of the reaction tube. ２Hydrogen was generated by reacting n-hexane with the reaction tube. After that, heating was continued for 2,000 seconds with the reaction tube set to 300°C. Then, the microwave generator was set to 350°C, and after the temperature stabilized, heating was continued for 1,000 seconds. Finally, the microwave generator was set to 400°C, and after the temperature stabilized, heating was continued for 900 seconds before stopping the heating. The total time from the start to the stop of microwave irradiation was 4,900 seconds. Mass spectrometry was performed under the same analytical conditions as in Manufacturing Example 1.

[0112] <Microwave heating behavior after hydrocarbon input> With the start of microwave heating set as 0 minutes, Figure 2A shows the changes in power consumption (incident wave and reflected wave) and temperature. As shown in Figure 2A, while maintaining a constant temperature, almost no increase was observed in either the incident wave or the reflected wave of the microwave generator, and stable heating could be continued.

[0113] <Confirmation of Mass Spectrometry Results> In addition, from the start of microwave heating until the cessation of heating, the mass spectrometer connected to the reaction tube was used to analyze CO under the same analytical conditions as in Production Example 1. ２ H ２ ,CH ４ , as well as CO and C ２ H ４ The results of the mass spectrometry analysis are shown in Figure 2B. Upon examining the signal, it was determined that the ambient gas was CO. ２ In addition to the signal corresponding to m / z = 44, H ２ A signal corresponding to m / z = 2, CH ４ The corresponding signals are m / z = 16, as well as CO and C. ２ H ４ A signal corresponding to m / z = 28 was detected.

[0114] Mass spectrometry results showed that H was present in all temperature ranges of 300°C, 350°C, and 400°C. ２ The occurrence of [unclear] was confirmed.

[0115] (Example 2) The reaction tube containing catalyst A manufactured in Manufacturing Example 1 was used as is, and the reaction tube was set in the same microwave generator as 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, polyethylene (catalog No. 427772, manufactured by Sigma-Aldrich) was added as hydrocarbons at a rate of 20 mg / min through the raw material inlet connected to the inlet side of the reaction tube, and CO2 was introduced. ２ Hydrogen was generated by reacting polyethylene with the substance. The start of the dropwise addition of polyethylene was set to 0 seconds, and then heating was continued for 2,000 seconds at the set temperature of 350°C in the reaction tube, after which heating was stopped.

[0116] <Heating behavior by microwave after hydrocarbon input> With the timing of polyethylene input set as 0 seconds, Figure 3A shows the changes in power consumption (incident wave and reflected wave) and temperature. As shown in Figure 3A, except during the heating process up to 350°C, while maintaining a constant temperature, almost no increase was observed in either the incident wave or the reflected wave of the microwave generator, and stable heating could be continued.

[0117] <Confirmation of Mass Spectrometry Results> In addition, from the start of microwave heating until the stop of heating, CO2 was analyzed under the same analytical conditions as in Manufacturing Example 1 using a mass spectrometer connected to the reaction tube. ２ H ２ ,CH ４ , as well as CO and C ２ H ４ The results of the mass spectrometry analysis are shown in Figure 3B. Upon examining the signal, it was determined that the ambient gas was CO. ２ In addition to the signal corresponding to m / z = 44, H ２ A signal corresponding to m / z = 2, CH ４ The corresponding signals are m / z = 16, as well as CO and C. ２ H ４ A signal corresponding to m / z = 28 was detected.

[0118] Mass spectrometry results showed H ２ CO was observed to be generated. Also, CO was observed at 900 seconds from the start of microwave heating. ２ The conversion rate was 48.4%, H ２ The content of was 13.3%, and the content of CO was 28.1%.２ The content of H ２ For the signal corresponding to m / z = 2, H of known concentration ２ Using standard gases, a calibration curve was prepared in advance using the absolute calibration curve method and determined. Furthermore, the CO content was determined by combining CO and C. ２ H ４ For the signal corresponding to m / z = 28, a calibration curve was prepared in advance using the absolute calibration curve method with a CO standard gas of known concentration. All signals at m / z = 28 observed upon introduction of polyethylene under catalytic heating were attributed to CO and determined accordingly.

[0119] CO ２ When calculating the conversion rate, CO ２ For the signal corresponding to m / z = 44, a calibration curve was prepared in advance using the absolute calibration curve method with a standard gas of known concentration. ２ The concentration of "CO ２ (in) The CO2 was determined according to the calibration curve from the signal value at m / z = 44 shown by the mass spectrometer connected to the outlet of the reaction tube. ２ The concentration of "CO ２ (out) and according to the following formula, CO ２ The conversion rate was calculated. CO ２ Conversion rate (%) = {CO ２ (in)-CO ２ (out) / CO ２ (in) × 100

[0120] (Comparative Example 1) CO2 was heated to 350°C in the same manner as in Example 2, except that the heating method was changed from irradiating with a microwave electric field of 2.45 GHz ± 0.05 GHz to heating in an electric furnace (ceramic electric tubular furnace, manufactured by Asahi Rika Seisakusho Co., Ltd.) to heating in an electric furnace (ceramic electric tubular furnace). ２ It was reacted with polyethylene.

[0121] <Confirmation of Mass Spectrometry Results> From the start of microwave heating until the heating is stopped, CO2 was analyzed using a mass spectrometer connected to the reaction tube under the same analytical conditions as in Production Example 1. ２ H ２ ,CH ４ , as well as CO and C ２ H ４Mass spectrometry was performed. The results of the mass spectrometry showed that in Comparative Example 1, H ２ No generation was observed.

[0122] (Comparative Example 2) In Example 2, catalyst A produced in Production Example 1 was used with LaNiO obtained in Preparation Example 1. ３ Except for the change, the CO was manufactured in the same manner as in Example 2. ２ It was reacted with polyethylene.

[0123] <Confirmation of Mass Spectrometry Results> From the start of microwave heating until the heating is stopped, CO2 was analyzed using a mass spectrometer connected to the reaction tube under the same analytical conditions as in Production Example 1. ２ H ２ ,CH ４ , as well as CO and C ２ H ４ Mass spectrometry was performed. The results of the mass spectrometry showed that in Comparative Example 2, H ２ No generation was observed.

[0124] (Comparative Example 3) LaNiO ３ 0.2 g of the powder was weighed out and filled into a quartz reaction tube with an inner diameter of 8 mm. This reaction tube was then set in the same microwave generator as in Example 1. CO was released from the top of the reaction tube. ２ and N ２ A mixed gas (10% CO2 by volume) ２ / 90% N by volume ２ CO2 was introduced at a rate of 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 a constant input of 20 W and heating was started. After the temperature of the reaction tube reached 500°C, polyethylene (catalog No. 427772, manufactured by Sigma-Aldrich) was introduced as hydrocarbons at a rate of 10 mg / min through the raw material inlet connected to the inlet side of the reaction tube, and CO2 was introduced. ２ It was reacted with polyethylene.

[0125] <Confirmation of microwave heating behavior and mass spectrometry results after hydrocarbon input> With the timing of polyethylene input set as 0 minutes, Figure 4A shows the temperature changes of the reaction tube, and Figure 4B shows the changes in power consumption (incident wave and reflected wave). Figure 4C shows the changes in the intensity of the mass spectrometry signal. Mass spectrometry was performed using a mass spectrometer connected to the reaction tube from the start of microwave heating until the heating was stopped, and the signal at m / z = 28 was analyzed for the N in the flowing gas. ２ To eliminate the influence of CO2, a correction was made to set the detected value at the start of distribution to zero. Otherwise, the same analytical conditions as in Manufacturing Example 1 were used. ２ H ２ ,CH ４ , as well as CO and C ２ H ２ Mass spectrometry was performed.

[0126] The temperature of the reaction tube rose to around 500°C, H ２ Although the formation of H was observed, the temperature of the reaction tube immediately dropped to below 400°C, ２ The amount produced decreased sharply. Therefore, when the input of the microwave generator was increased to 40W, the temperature of the reaction tube and H ２ Although the amount of microwaves generated recovered, the reflected waves from the microwave generator suddenly increased, so the microwave generator was shut down.

[0127] Examples 1 and 2 and Comparative Examples 1 to 3 are summarized in Table 1 below.

[0128]

[0129] From the results in Table 1, the metal oxide LaNiO ３ Compared to Comparative Examples 2 and 3, in which microwaves were irradiated to LaNiO ３ By reducing it with hydrogen, LaNiO ３ Ni is partially precipitated from it, and Ni and LaNiO ３ In Examples 1 and 2, when catalyst A, which was in a mixture state with H, was irradiated with microwaves, the reaction proceeded efficiently at low temperatures. ２ The generation efficiency is improved, as well as the generation of microwaves and H ２It was found that the stability of the production of was improved. In addition, in Comparative Example 1, which was heated to the same temperature as in Example 2 using an electric furnace, H ２ It could not be generated.

[0130] (Example 3) Using the same reaction tube containing catalyst A manufactured in Manufacturing Example 1, 2 mg of polyethylene (catalog No. 427772, manufactured by Sigma-Aldrich) was placed on catalyst A inside the reaction tube and set in the same microwave generator as in Example 1. 100 vol% N ２ The gas was flowed at 30 mL / min. After confirming that the mass spectrometer connected to the outlet of the reaction tube was stable, the microwave generator was set to 70°C and heating was started. After the temperature of the reaction tube reached 70°C, it was heated at a rate of 10°C / min, and while the reaction tube was being heated, the mass spectrometer was used to measure H ２ We observed the time course of the signal intensity.

[0131] Figure 5A shows the relationship between time, power consumption, and temperature, with the start of heating defined as 0 minutes. Also, with the start of heating defined as 0 minutes, the relationship between temperature and H in mass spectrometry is shown. ２ Figure 6 shows the relationship with the signal intensity at m / z = 2, which corresponds to H. As shown in these figures, heating up to 400°C can be done without problems by microwave irradiation, ２ The detection start temperature for a signal corresponding to m / z = 2 was 225°C.

[0132] (Example 4) In Example 3, polyethylene was heated in the same manner as in Example 3, except that the microwave generator used in Example 1 was replaced with 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

[0133] Figure 5B shows the relationship between time, power consumption, and temperature, with the start of heating defined as 0 minutes. Also, with the start of heating defined as 0 minutes, the relationship between temperature and H in mass spectrometry is shown. ２Figure 7 shows the relationship with the signal intensity at m / z = 2, which corresponds to H. As shown in these figures, heating up to 400°C can be done without problems by microwave irradiation, ２ The detection start temperature for a signal corresponding to m / z = 2 was 214°C.

[0134] (Comparative Example 4) In this comparative example, polyethylene was heated in the same manner as in Example 3, except that the reaction tube was set in the same microwave generator as in Example 1 and heated by irradiating it with microwaves, and instead the reaction tube was set in an electric furnace (ceramic electric tubular furnace, manufactured by Asahi Rika Seisakusho Co., Ltd.) and heated at a rate of 10°C / min.

[0135] With the start of heating as 0 minutes, temperature and H in mass spectrometry ２ Figure 7 shows the relationship with the signal intensity corresponding to m / z = 2. ２ The detection start temperature for a signal corresponding to m / z = 2 was 368°C.

[0136] (Comparative Example 5) In Example 4, catalyst A produced in Production Example 1 was used with LaNiO obtained in Preparation Example 1. ３ Except for the change, the method is the same as in Example 4 for H ２ It generated.

[0137] Figure 5C shows the relationship between time, power consumption, and temperature, with the start of heating defined as 0 minutes. Also, with the start of heating defined as 0 minutes, the relationship between temperature and H in mass spectrometry is shown. ２ Figure 7 shows the relationship with the signal intensity at m / z = 2, which corresponds to H. As shown in these figures, heating up to 400°C was possible without any problems by microwave irradiation, but H ２ No signal corresponding to m / z = 2 was detected. That is, H ２ No generation was observed.

[0138] (Comparative Example 6) In Example 4, the polyethylene was heated in the same manner as in Example 4, except that catalyst A produced in Production Example 1 was replaced with catalyst B produced in Comparative Production Example 1.

[0139] Figure 5D shows the relationship between time, power consumption, and temperature, with the start of heating defined as 0 minutes. Also, with the start of heating defined as 0 minutes, the relationship between temperature and H in mass spectrometry is shown.２ Figure 7 shows the relationship with the signal intensity at m / z = 2. As shown in these figures, the temperature stopped rising even when applying 90W or more, close to the maximum power specified in the device specifications, around 200°C, so the experiment was terminated. During this time, H ２ No signal corresponding to m / z = 2 was detected.

[0140] Examples 3-4 and Comparative Examples 4-6 are summarized in Table 2 below.

[0141]

[0142] From the results in Table 2, the metal oxide LaNiO ３ Compared to Comparative Example 5, in which microwaves were irradiated to LaNiO ３ By reducing it with hydrogen, LaNiO ３ Ni is partially precipitated from it, and Ni and LaNiO ３ In Examples 3 and 4, when catalyst A, which was in a mixture state with H, was irradiated with microwaves, the reaction proceeded efficiently at low temperatures. ２ The generation efficiency is improved, as well as the generation of microwaves and H ２ It was found that the stability of the production of was improved. In addition, in Comparative Example 4, which was heated to the same temperature as in Example 3 using an electric furnace, H ２ It could not be generated. Also, LaNiO ３ In catalyst B, which does not contain microwave heating and H ２ The stability of its generation was poor.

[0143] 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.

[0144] This international application claims priority under Japanese Patent Application No. 2024-157058, filed on 10 September 2024, and Japanese Patent Application No. 2024-162634, filed on 19 September 2024, which are incorporated herein by reference to the entire contents of Japanese Patent Application No. 2024-157058 and Japanese Patent Application No. 2024-162634.

Claims

1. CO ２ H ２ O, and N ２ Irradiating a mixture containing metals and metal oxides with microwaves in an atmosphere of gas containing at least one selected from CO ２ H ２ O, and N ２ The process involves a hydrocarbon being brought into contact with the mixture being irradiated with microwaves under an atmosphere of gas containing at least one selected from, and wherein the metal is a metal containing at least one metallic element selected from Fe, Co, Ni, Mn, Cu, and Ti, and the metal oxide is at least one metal oxide selected from compounds represented by the following general formula (1), H ２ Manufacturing method. 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 the same metallic element as the metallic element contained in the above metal.

2. The method for producing H according to claim 1, wherein the mixture further contains a compound represented by the following general formula (2). 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, and y is the oxidation number of Ma as z, and y = xz / 2.

3. The mixture containing the metal and the metal oxide is obtained by partially hydrogen-reducing a 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 at least one metal oxide represented by the following general formula (3), thereby precipitating the metal, as described in claim 1 or claim 2. ２ A method for manufacturing Mb. ｐ O ｑ ...General formula (3) In general formula (3), Mb represents the same metallic 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.

4. The metal is Ni, and the metal oxide is LaNiO ３ H according to any one of claims 1 to 3. ２ A method for manufacturing this product.

5. The mixture containing the metal and the metal oxide is H ２ LaNiO at temperatures above 300°C under an atmosphere of gas containing ３ , or LaNiO ３ The H according to claim 4, obtained by heating a precursor mixture of and NiO and partially reducing it by hydrogen to precipitate Ni. ２ A method for manufacturing this product.

6. The compound represented by the general formula (2) above is La ２ O ３ H according to any one of claims 2 to 5. ２ A method for manufacturing this product.

7. The H according to any one of claims 1 to 6, wherein the irradiation of microwaves heats the temperature of the hydrocarbon and the mixture to 470°C or below. ２ A method for manufacturing this product.

8. CO ２ and H ２ Irradiating a mixture containing metals and metal oxides with microwaves in an atmosphere of gas containing at least one selected from O, and CO ２ and H ２ A method for modifying hydrocarbons, comprising: bringing a hydrocarbon into contact with the mixture being irradiated with microwaves in an atmosphere of a gas containing at least one selected from O; wherein the metal is a metal containing at least one metal element selected from Fe, Co, Ni, Mn, Cu, and Ti; and the metal oxide is 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 the same metallic element as the metallic element contained in the above metal.

9. The hydrocarbon modification method according to claim 8, wherein the mixture 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.

10. The hydrocarbon modification method according to claim 8 or 9, wherein the mixture containing the metal and the metal oxide is obtained by partially hydrogen-reducing a precursor mixture containing at least one metal oxide selected from the compounds represented by general formula (1), or 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), thereby precipitating the metal. ｐ O ｑ ...General formula (3) In general formula (3), Mb represents the same metallic 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.

11. The metal is Ni, and the metal oxide is LaNiO ３ The method for modifying hydrocarbons according to any one of claims 8 to 10.

12. The mixture containing the metal and the metal oxide is H ２ LaNiO at temperatures above 300°C under an atmosphere of gas containing ３ , or LaNiO ３ A method for modifying hydrocarbons according to claim 11, wherein Ni is precipitated by heating a precursor mixture of Ni and NiO and partially reducing it with hydrogen.

13. The compound represented by the general formula (2) above is La ２ O ３ The method for modifying hydrocarbons according to any one of claims 9 to 12.

14. The method for modifying a hydrocarbon according to any one of claims 8 to 13, wherein the irradiation of microwaves heats the hydrocarbon and the mixture to a temperature of 470°C or lower.

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