Metal-supported catalyst for the production of alkyl aromatic hydrocarbons, and method for producing alkyl aromatic hydrocarbons using the catalyst.

Abstract

To provide a method of manufacturing an alkyl aromatic hydrocarbon capable of generating an alkyl aromatic hydrocarbon (an aromatic hydrocarbon obtained by substituting a hydrogen of an aromatic rig with a methyl group), at a high yield compared with a ratio for generating methane that is a by-product; to provide a method for manufacturing an alkyl aromatic hydrocarbon capable of generating a polysubstituted alkyl aromatic hydrocarbon (aromatic hydrocarbon in which each of two or more aromatic rings is substituted with a methyl group) at a high yield compared with the ratio at which methane that is a by-product is generated; to provide a catalyst used in the method for manufacturing these alkyl aromatic hydrocarbons.SOLUTION: A metal-supported catalyst for manufacturing an alkyl aromatic hydrocarbon is used for manufacturing an alkyl aromatic hydrocarbon having a methyl group from an aromatic hydrocarbon, carbon dioxide and hydrogen, the metal-supported catalyst for manufacturing the alkyl aromatic hydrocarbon has a support and a metal supported on the support, and the metal has at least two types of metals including Pt as a first metal and at least one type of metal selected from the group consisting of V, W, and Mo as a second metal.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a metal-supported catalyst for producing alkyl aromatic hydrocarbons and a method for producing alkyl aromatic hydrocarbons using the catalyst.

Background Art

[0002] Alkyl aromatic hydrocarbons, particularly alkylbenzenes, have a wide range of uses. For example, toluene is used as aviation gasoline, high-octane blending feedstock oil, paint, and paint. o-Xylene is used, for example, in the synthesis of vitamins and pharmaceuticals, dyes, pesticides, and the production of phthalic anhydride. m-Xylene is used, for example, as a solvent and an intermediate for synthesizing organic compounds such as dyes. p-Xylene is used, for example, in the synthesis of terephthalic acid, and terephthalic acid is used as an intermediate in the production of synthetic resins and fibers such as dacron and mylar. A mixture of xylene isomers is used as aviation gasoline, a protective coating, or a solvent for alkyl resins, lacquers, enamels, and rubber cements.

[0003] Alkyl aromatic hydrocarbons having a methyl group such as toluene and xylene are generally obtained from petroleum refining processes or cracked gases from ethylene crackers. In order to produce a large amount of xylenes, a disproportionation process of toluene or a transalkylation process of toluene and alkylbenzenes having 9 or more carbon atoms is carried out.

[0004] If alkyl aromatic hydrocarbons can be produced using carbon dioxide as an alkylating agent, it is expected to contribute to reducing the load on the global environment.

[0005] When low concentrations of carbon dioxide are used as a raw material for chemical reactions, a large amount of energy is consumed for the concentration and separation of the carbon dioxide. Therefore, methods have been proposed to convert carbon dioxide into methanol or dimethyl ether (DME) for use as a raw material (Patent Document 1). However, in reality, exhaust gases containing low concentrations of carbon dioxide are often released into the atmosphere.

[0006] Therefore, a method has been proposed for obtaining alkyl aromatic hydrocarbons by reacting aromatic hydrocarbons with carbon dioxide, using a heterogeneous catalyst that facilitates the separation of the catalyst and reactants, and yielding alkyl aromatic hydrocarbons in high yield (see Patent Document 2). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5557255 [Patent Document 2] International Publication No. 2021 / 049579 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, while the above-mentioned Patent Document 2 can produce alkyl aromatic hydrocarbons substituted with methyl groups in high yield, it also produces a large amount of methane as a byproduct. In the production of alkyl aromatic hydrocarbons having a methyl group, it is preferable to suppress the generation of methane as a by-product in order to make more effective use of the hydrogen used in the reaction. Furthermore, in the production of alkyl aromatic hydrocarbons having methyl groups, if polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbon, can be obtained in high yield, the range of applications for the obtained alkyl aromatic hydrocarbons will be broadened, which is practically preferable. Therefore, there has been a need for a method that can suppress the formation of methane as a byproduct and produce alkyl aromatic hydrocarbons substituted with methyl groups in high yield, and in particular a method that can produce polysubstituted alkyl aromatic hydrocarbons in which more methyl groups are substituted on the aromatic hydrocarbon in high yield.

[0009] The present invention aims to provide a method for producing alkyl aromatic hydrocarbons (aromatic hydrocarbons in which hydrogen atoms of the aromatic ring are replaced with methyl groups) in high yield while suppressing the formation of methane as a byproduct. Furthermore, the present invention aims to provide a method for producing alkyl aromatic hydrocarbons (aromatic hydrocarbons in which two or more hydrogen atoms of the aromatic ring are each replaced with methyl groups) in high yield while suppressing the formation of methane as a byproduct. Furthermore, the present invention aims to provide catalysts for use in methods for producing the above-mentioned alkyl aromatic hydrocarbons. [Means for solving the problem]

[0010] The inventors conducted extensive research to solve the above problems and, as a result, discovered that the above problems can be solved by using a metal-supported catalyst, which consists of at least two metals supported on a carrier, namely Pt and a specific metal, as a catalyst for the production of alkyl aromatic hydrocarbons, thereby completing the present invention.

[0011] In other words, the present invention encompasses the following embodiments. [1] A metal-supported catalyst for the production of alkyl aromatic hydrocarbons, used to produce alkyl aromatic hydrocarbons having a methyl group from aromatic hydrocarbons, carbon dioxide, and hydrogen, The metal-supported catalyst for alkyl aromatic hydrocarbon production comprises a carrier and a metal supported on the carrier. The metal-supported catalyst for the production of alkyl aromatic hydrocarbons comprises at least two metals: Pt as the first metal and at least one metal selected from the group consisting of V, W, and Mo as the second metal. [2] The metal-supported catalyst for the production of alkyl aromatic hydrocarbons according to [1], wherein the support is one of titanium oxide, zirconium oxide, or aluminum oxide. [3] The metal-supported catalyst for alkyl aromatic hydrocarbon production according to any one of [1] to [2], wherein the content of Pt, the first metal in the metal-supported catalyst for alkyl aromatic hydrocarbon production, is 0.3% by mass or more and 5.0% by mass or less, based on the mass of the metal-supported catalyst for alkyl aromatic hydrocarbon production. [4] The metal-supported catalyst for alkyl aromatic hydrocarbon production according to any one of [1] to [3], wherein the content of the second metal as an oxide in the metal-supported catalyst for alkyl aromatic hydrocarbon production is 5.0% by mass or more and 50.0% by mass or less, based on the mass of the metal-supported catalyst for alkyl aromatic hydrocarbon production. A method for producing alkyl aromatic hydrocarbons, comprising the step of generating alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen in the presence of a metal-supported catalyst for the production of alkyl aromatic hydrocarbons as described in any of [5][1] to [4], and crystalline aluminosilicate particles. A step of obtaining a plurality of alkyl aromatic hydrocarbons having a methyl group by the method described in [6][5], A step of producing a C8 aromatic hydrocarbon by a transalkylation reaction between the aforementioned multiple types of alkyl aromatic hydrocarbons, A method for producing C8 aromatic hydrocarbons, including [the specified compound]. A method for fixing carbon dioxide, wherein the method according to [7][5] is further characterized by fixing carbon dioxide by using carbon dioxide produced by the combustion of a carbon-containing substance as the carbon dioxide. [Effects of the Invention]

[0012] According to one aspect of the present invention, it is possible to provide a method for producing alkyl aromatic hydrocarbons (aromatic hydrocarbons in which the hydrogen atoms of the aromatic ring are replaced with methyl groups) in a high yield compared to the proportion of methane, which is a by-product. Furthermore, according to one aspect of the present invention, it is possible to provide a method for producing alkyl aromatic hydrocarbons that can produce polysubstituted alkyl aromatic hydrocarbons (aromatic hydrocarbons in which two or more hydrogens of the aromatic ring are each substituted with methyl groups) in high yield, compared to the proportion of methane produced as a by-product. Furthermore, according to one aspect of the present invention, a catalyst for use in a method for producing the above-mentioned alkyl aromatic hydrocarbons can be provided. [Modes for carrying out the invention]

[0013] The present invention will be described in detail below. The following description of the constituent elements is illustrative for illustrating the present invention, and the present invention is not limited to these elements.

[0014] (Metal-supported catalyst for alkyl aromatic hydrocarbon production) Metal-supported catalysts for the production of alkyl aromatic hydrocarbons (hereinafter also referred to as metal-supported catalysts) are used in a method for producing alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen. A metal-supported catalyst comprises a carrier and a metal supported on the carrier. The metal comprises at least two types of metals: a first metal and a second metal. The first metal is Pt, and the second metal is at least one metal selected from the group consisting of V, W, and Mo (hereinafter also referred to as the "specific second metal" or "specific metal").

[0015] The metal-supported catalyst of the present invention, which supports at least two kinds of metals, namely Pt and a specific metal, on a carrier, is used as a catalyst for producing alkyl aromatic hydrocarbons. When an alkyl aromatic hydrocarbon having a methyl group is produced from an aromatic hydrocarbon, carbon dioxide, and hydrogen in the presence of the metal-supported catalyst, as shown in the following examples, the production of methane, which is a by-product, can be suppressed while an alkyl aromatic hydrocarbon substituted with a methyl group can be produced in a high yield. Further, when the metal-supported catalyst of the present invention is used as a catalyst for producing alkyl aromatic hydrocarbons, as shown in the following examples, the production of methane, which is a by-product, can be suppressed while a polysubstituted alkyl aromatic hydrocarbon in which more methyl groups are substituted in the aromatic hydrocarbon can be produced in a high yield.

[0016] The carrier is capable of supporting a metal having catalytic activity, and examples thereof include metal oxides. Examples of the metal oxide include metal oxides such as titanium oxide, zirconium oxide, aluminum oxide, or silicon oxide. The primary particle size of the particles as the carrier is, for example, 10 to 1000 nm. Here, the particle size can be determined by X-ray diffraction method.

[0017] The content of Pt, which is the first metal in the metal-supported catalyst, is preferably 0.3% by mass or more and 5.0% by mass or less, or 0.5% by mass or more and 5.0% by mass or less based on the mass of the metal-supported catalyst. When the content of the first metal is within these ranges, alkyl aromatic hydrocarbons tend to be produced particularly at a high yield. When the content of the first metal is low, the hydrogenation activity is low, so the hydrogenation reaction of carbon dioxide hardly proceeds, and it becomes difficult to produce polysubstituted alkyl aromatic hydrocarbons.

[0018] In the metal-supported catalyst, examples of the metal supported on the carrier include a specific second metal selected from the group consisting of V, W, and Mo in addition to Pt, which is the first metal. The second metal may be used as an oxide and may be oxidized after being supported on the carrier as a metal, or may be supported on the carrier as an oxide as it is. The content of the second metal as an oxide in the metal-supported catalyst is 5.0% by mass or more and 50.0% by mass or less, more preferably 5.0% by mass or more and 30.0% by mass or less, based on the mass of the metal-supported catalyst. When the content of the second metal as an oxide is within this range, there is a tendency for the formation of polysubstituted alkyl aromatic hydrocarbons to increase and the formation of methane, a byproduct, to decrease. Furthermore, if the metal-supported catalyst contains two or more types of the second metal, the content of the second metal as an oxide, as described above, is the sum of the two or more types of the second metal.

[0019] Metal-supported catalysts can be prepared by conventional methods. For example, a metal-supported catalyst can be obtained by a method that includes contacting a support with an aqueous solution of a metal compound, removing the solvent from the mixture of the support and the aqueous solution of the metal compound, and calcining the remaining solid material.

[0020] Metal-supported catalysts are usually reduced before being used as reaction catalysts. The method of reduction is not particularly limited. For example, metal-supported catalysts can be reduced by heating the catalyst particles of the metal-supported catalyst in an atmosphere containing hydrogen gas. The temperature for reduction is, for example, 200 to 800°C. The reduction time is 0.1 to 5 hours.

[0021] (Method for producing alkyl aromatic hydrocarbons) The present invention provides a method for producing alkyl aromatic hydrocarbons, which involves using the metal-supported catalyst of the present invention described above to produce alkyl aromatic hydrocarbons having methyl groups. A preferred embodiment of the method for producing alkyl aromatic hydrocarbons includes, for example, a step of generating alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen in the presence of the above-mentioned metal-supported catalyst and crystalline aluminosilicate particles.

[0022] Crystalline aluminosilicate particles used in conjunction with metal-supported catalysts are introduced into the reaction system as separate particles from the metal-supported catalyst. Crystalline aluminosilicate particles are generally particles containing a composite oxide that includes silicon atoms, aluminum atoms, and oxygen atoms. The primary particle size of crystalline aluminosilicate particles is, for example, 0.1 to 500 nm. Here, the particle size can be determined by X-ray diffraction.

[0023] When the composite oxide constituting crystalline aluminosilicate particles is represented by a compositional formula containing SiO2 and Al2O3, the molar ratio of SiO2 to Al2O3 (SiO2 / Al2O3 ratio) is, for example, 5 to 1000 or 20 to 600.

[0024] The crystalline aluminosilicate particles may contain at least one zeolite selected from the group consisting of MOR (mordenite), MFI (ZSM-5), BEA (beta type), FAU (Y type), and CHA (chabasite). These zeolites contain protons (H + ) or ammonium (NH4 + ) may have a cation. For example, the zeolite may be H-MOR, H-MFI, H-BEA or H-FAU having a proton, or NH4-MFI having ammonium.

[0025] Alkyl aromatic hydrocarbons containing methyl groups are efficiently produced by reacting aromatic hydrocarbons with carbon dioxide and hydrogen in the presence of a metal-supported catalyst and crystalline aluminosilicate particles. The reaction conditions are appropriately adjusted so that the reaction proceeds. The reaction temperature is, for example, 150 to 400°C, preferably 200 to 260°C, and more preferably 220 to 260°C. The reaction temperature should be set appropriately, taking into account the type and content of the metal in the metal-supported catalyst used, the type and content of the support, or differences in reaction conditions (for example, changing the contact time between the catalyst and the various reactants). However, if the reaction temperature is too low, the hydrogenation activity will be low, making alkylation difficult to proceed. The pressure of the reaction atmosphere is, for example, 0.1 to 10 MPa. The ratio (molar ratio, or pressure ratio) of carbon dioxide to hydrogen is, for example, 10:1 to 1:100. Although carbon monoxide may be present in the reaction gas, it is preferable that the ratio (molar ratio, or pressure ratio) of carbon monoxide to carbon dioxide is less than 1, i.e., that there is more carbon dioxide. This is because catalyst poisoning by carbon monoxide is more likely to occur. Furthermore, a higher ratio of carbon dioxide is even more advantageous from the standpoint of effective utilization of carbon dioxide.

[0026] The aromatic hydrocarbons used as raw materials may be, for example, benzene, alkylbenzenes (e.g., toluene, m-xylene), or combinations thereof. When benzene is used, a mixture containing multiple alkyl aromatic hydrocarbons is often produced. Examples of the resulting mixture include a mixture containing toluene and at least one other methylbenzene compound selected from the group consisting of o-xylene, m-xylene, p-xylene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, pentamethylbenzene, and hexamethylbenzene. To incorporate more carbon dioxide into the molecule and use it as a raw material for transalkylation reactions, it is desirable to produce polysubstituted alkyl aromatic hydrocarbons (e.g., pentamethylbenzene, hexamethylbenzene). Using the metal-supported catalyst of the present invention, polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbon, can be produced in high yield.

[0027] C8 aromatic hydrocarbons may be produced by transalkylation reactions between multiple types of alkyl aromatic hydrocarbons. The C8 aromatic hydrocarbons may be o-xylene, m-xylene, p-xylene, or combinations thereof. For example, C8 aromatic hydrocarbons containing xylenes may be produced by transalkylation reactions of a mixture containing toluene and a methylbenzene compound having 9 or more carbon atoms. Transalkylation reactions can be carried out by conventional methods employed by those skilled in the art. Furthermore, in order to effectively utilize hydrogen in the present invention, it is desirable to suppress as much as possible the production of methane and cyclohexane and alkylcyclohexanes, which are by-products of aromatic hydrocarbon nuclear hydrogenation.

[0028] The carbon dioxide used as a raw material may be relatively low-purity carbon dioxide. Mixed gases containing low concentrations of carbon dioxide are generated, for example, in processes where hydrocarbons are burned as fuel or unreacted hydrocarbons are burned in petroleum refining, petrochemicals, power generation, steelmaking, boilers, etc. Generally, exhaust gases emitted from boilers or combustion systems contain carbon dioxide, as well as nitrogen and oxygen from the air, and carbon monoxide from incomplete combustion. In addition, sulfur oxides or nitrogen oxides are often also present. Typically, combustion methods that increase the proportion of air are employed to suppress incomplete combustion, which reduces oxygen as it is consumed in combustion, but increases the concentration of unreacted nitrogen. As a result, small amounts of oxygen and carbon dioxide are contained in a mixed gas that contains an excess of nitrogen. As an example, the composition of the combustion gas in the regeneration tower of a catalytic cracking unit, a typical device in petroleum refining, is generally 80% nitrogen by volume, 15% carbon dioxide by volume, and 2% each of carbon monoxide and oxygen by volume.

[0029] Since some of the carbon monoxide can be used in the alkylation reaction, the raw materials may contain a large amount of carbon monoxide. Nitrogen and oxygen do not inhibit the alkylation reaction, so they may be included in the raw materials.

[0030] The concentration of carbon dioxide in the raw material gas is not particularly limited, but is preferably less than 95% by volume, more preferably less than 50% by volume, and especially preferably less than 20% by volume, based on the volume of the raw material gas. The concentration of carbon dioxide in the raw material gas is preferably 1% or more by volume, more preferably 2% or more by volume, and especially preferably 5% or more by volume, based on the volume of the raw material gas. When the concentration of carbon dioxide in the raw material gas is 1% or more by volume, the reaction can proceed particularly efficiently. Even if the concentration of carbon dioxide in the raw material gas is less than 95% by volume, it can still be used, reducing the energy, equipment, and costs associated with carbon dioxide concentration.

[0031] The partial pressure ratio of hydrogen to carbon dioxide is preferably 2 or more and less than 70, more preferably 5 or more and less than 70. When the partial pressure ratio of hydrogen to carbon dioxide is high within the above range, the conversion of carbon dioxide tends to proceed efficiently. Conversely, when the partial pressure ratio of hydrogen to carbon dioxide is low within the above range, the progress of the nuclear hydrogenation reaction of aromatic hydrocarbon compounds tends to be suppressed.

[0032] The total pressure of the raw materials is preferably 1 MPa or more and less than 7.6 MPa, more preferably 1.5 MPa or more and less than 7.6 MPa. If the total pressure of the raw materials is higher within the above range, the alkylation reaction tends to proceed more easily. Conversely, if the total pressure of the raw materials is lower within the above range, the progress of the nuclear hydrogenation reaction of aromatic hydrocarbon compounds tends to be suppressed.

[0033] The ratio of aromatic hydrocarbon compounds to catalyst is preferably 0.1 or more and less than 20, and more preferably 0.5 or more and less than 10, when benzene is used as a raw material. When the ratio of aromatic hydrocarbon compounds to catalyst is low within the above range, the alkylation reaction tends to proceed sufficiently. Furthermore, when the ratio of aromatic hydrocarbon compounds to catalyst is high within the above range, it is economically advantageous.

[0034] In the methods illustrated above, carbon dioxide contained in exhaust gas can be fixed by using a raw material gas containing carbon dioxide produced by the combustion of a carbon-containing substance. By using the method for producing alkyl aromatic hydrocarbons of the present invention, carbon dioxide can be fixed efficiently. The carbon-containing substance may be a hydrocarbon. [Examples]

[0035] The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to these examples.

[0036] (Test Example 1) 1-1. Metal-supported catalysts <Example 1-1> Metal-supported catalyst particles, in which Pt and Mo were supported on titanium oxide particles, were prepared by the following method. A mixture of 1.1039 g of ammonium heptamolybdate tetrahydrate (Wako Pure Chemical Industries), 2.01 g of titanium dioxide particles (P-25, Nippon Aerosil), and 100 mL of deionized water was stirred at room temperature for 30 minutes. The solvent was removed from the mixture under reduced pressure while heating to 50°C, and the residue was dried overnight at 110°C. The dried solid was ground using an agate mortar and pestle. The resulting powder was calcined at 500°C for 3 hours under an air atmosphere to obtain titanium dioxide particles supported with MoO3. A mixture of the obtained particles with 1.9565 g of dinitrodiammineplatinum(II) nitric acid solution (Furuya Metal) and 100 mL of deionized water was stirred at room temperature for 30 minutes. The solvent was removed from the mixture under reduced pressure while heating to 50°C, and the residue was dried overnight at 110°C. The dried solid was ground using an agate mortar and pestle. The obtained powder was calcined at 500°C for 3 hours in an atmospheric environment to obtain metal-supported catalyst particles in which MoO3 and Pt metal were supported on titanium oxide. The Pt metal content, calculated from the amount of material used, was 3% by mass, based on the amount of metal-supported catalyst particles, and the MoO3 content was 30% by mass, based on the amount of metal-supported catalyst particles.

[0037] <Comparative Example 1-1> A mixture of 1.9565 g of diamminedinitroplatinum(II) nitric acid solution (Furuya Metal), 2.91 g of titanium dioxide particles (P-25, Nippon Aerosil), and 400 mL of deionized water was stirred at room temperature for 30 minutes. The solvent was then removed by distillation under reduced pressure while heating to 50°C, and the residue was dried overnight at 110°C. The dried solid was ground using an agate mortar and pestle, and then calcined at 500°C for 3 hours under an air atmosphere to obtain metal-supported catalyst particles in which Pt metal was supported on titanium dioxide. The Pt metal content calculated from the amount charged was 3% by mass, based on the amount of metal-supported catalyst particles.

[0038] <Comparative Example 1-2> Except for using 0.1297 g of ammonium perrhenate (SIGMA-ALDRICH) instead of diamminedinitroplatinum(II) nitric acid solution, metal-supported catalyst particles in which Re was supported on titanium oxide particles were obtained in the same manner as in Comparative Example 1-1. The Re metal content calculated from the amount charged was 3% by mass, based on the amount of metal-supported catalyst particles.

[0039] <Comparative Example 1-3> A mixture of 1.1039 g of ammonium heptamolybdate tetrahydrate (Wako Pure Chemical Industries), 2.01 g of titanium dioxide particles (P-25, Nippon Aerosil), and 100 mL of deionized water was stirred at room temperature for 30 minutes. The solvent was removed by distillation under reduced pressure while heating the mixture to 50°C, and the residue was dried overnight at 110°C. The dried solid was ground using an agate mortar and pestle. The resulting powder was calcined at 500°C for 3 hours in an air atmosphere to obtain titanium dioxide particles supported with MoO3.

[0040] 1-2. Methylation reaction of benzene 100 mg of crystalline aluminosilicate particles and each metal-supported catalyst particle were packed into a fixed-bed reactor to a metal content of 0.0081 mmol, and the reactor was reduced at 500°C for 0.5 hours under a hydrogen gas flow of 20 mL / min. Zeolite particles (mordenite (H-MOR), SiO2 / Al2O3 = 90 / 1 (molar ratio), manufactured by Tosoh Corporation) were used as crystalline aluminosilicate particles. The metal-supported catalyst particles treated with reduction and the zeolite particles were mixed in an autoclave with 1 mmol of benzene, ensuring they were not exposed to air. Subsequently, hydrogen at 5 MPa and carbon dioxide at 1 MPa were introduced into the autoclave. The reaction was carried out in an autoclave at 240°C for 12 hours. The products were analyzed by gas chromatography, and the yield of each component was determined relative to the amount of benzene or CO2 charged. The results are shown in Table 1. The abbreviations in the table refer to the following compounds.

[0041] 123-Tri-MB:1,2,3-trimethylbenzene 124-Tri-MB:1,2,4-trimethylbenzene 135-Tri-MB:1,3,5-trimethylbenzene 1234-Tetra-MB:1,2,3,4-Tetramethylbenzene 1235-Tetra-MB:1,2,3,5-Tetramethylbenzene 1245-Tetra-MB:1,2,4,5-Tetramethylbenzene PMB: Pentamethylbenzene HMB: Hexamethylbenzene EB: Ethylbenzene CH:Cyclohexane MCH: Methylcyclohexane C2-C4: Hydrocarbons with 2 to 4 carbon atoms

[0042] The yield results for each component obtained were evaluated as follows. This allowed us to evaluate the yield of alkyl aromatic hydrocarbons containing methyl groups relative to the proportion of methane, a by-product. In this evaluation, weighting was applied according to the number of methyl groups substituted on the aromatic hydrocarbon, so that polysubstituted alkyl aromatic hydrocarbons, where more methyl groups are substituted on the aromatic hydrocarbon, received a higher evaluation. Details of the evaluation are as follows.

[0043] [Evaluation Method] To calculate the yield of alkyl aromatic hydrocarbons converted to the number of methyl groups, determine the value in 1) according to the following method. 1) Calculation method: For toluene, multiply the yield by 1; for xylene, multiply the yield by 2; for trimethylbenzene, multiply the yield by 3; for tetramethylbenzene, multiply by 4; for pentamethylbenzene, multiply the yield by 5; and for hexamethylbenzene, multiply the yield by 6. Then sum all of these up. Next, the yield of the by-product methane is taken as the value in 2). Then, determine the value of 3) according to the method below. 3) Calculation method: Calculate 1) / 2). For example, using Example 2a as an example, the value of 3) can be calculated as follows. Value of 1): 14.2 × 1 + (2.8 + 2.5 + 2.8) × 2 + (0.8 + 2.6 + 0.2) × 3 + (0.2 + 0.0 + 2.2) × 4 + 7.0 × 5 + 3.0 × 6 = 103.6 Value 2): 10.0 3) Value: 103.6 / 10.0 = 10.4

[0044] For the value in 3), the yield of polysubstituted alkyl aromatic hydrocarbons relative to the amount of methane produced as a by-product is evaluated according to the following criteria. -Evaluation Criteria- A:3) Value is 10 or greater The value of B:3) is between 7.5 and 10. The value of C:3) is between 3.5 and 7.5. The value of D:3) is less than 3.5

[0045] [Table 1]

[0046] As shown in Table 1, when a combination of metal-supported catalyst particles having a first metal, Pt, and a second metal, Mo, and crystalline aluminosilicate particles (zeolite particles in this case) was used to produce alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons (benzene in this case), carbon dioxide, and hydrogen, it was confirmed that alkyl aromatic hydrocarbons having methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct.

[0047] (Test Example 2) <Example 1-1> Example 1-1 is as described above.

[0048] <Example 2-1> Except for using 1.0134 g of ammonium tungstate-para-pentahydrate (Wako Pure Chemical Industries) instead of ammonium heptamolybdate tetrahydrate, metal-supported catalyst particles in which WO3 was supported on titanium dioxide were obtained in the same manner as in Example 1-1. The WO3 content, calculated from the amount used, was 30% by mass, based on the amount of metal-supported catalyst particles.

[0049] <Example 2-2> Metal-supported catalyst particles were prepared in the same manner as in Example 1-1, except that zirconium oxide particles (JRC-ZRO-5 (trade name), manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd.) were used instead of titanium oxide particles as the support.

[0050] The methylation reaction of benzene was tested under the same conditions as in Test Example 1, except that each of the obtained metal-supported catalyst particles was used. Table 2 shows the results of gas chromatography analysis of the product.

[0051] [Table 2]

[0052] As shown in Table 2, when metal-supported catalyst particles, in which the primary metal Pt and the secondary metal are supported on various carriers, were used in combination with crystalline aluminosilicate particles to produce alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen, it was confirmed that alkyl aromatic hydrocarbons having methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct.

[0053] (Test Example 3) <Example 1-1> Example 1-1 is as described above.

[0054] <Examples 3-1 to 3-4> Except for changing the amount of Pt metal to 0.3% by mass, 0.5% by mass, 1.0% by mass, or 5.0% by mass, based on the mass of the metal-supported catalyst particles, the metal-supported catalyst particles of Examples 3-1 to 3-4 were prepared in the same manner as in Example 1-1.

[0055] The methylation reaction of benzene was tested under the same conditions as in Test Example 1, except that each of the obtained metal-supported catalyst particles was used. Table 3 shows the results of gas chromatography analysis of the product.

[0056] [Table 3]

[0057] As shown in Table 3, when various metal-supported catalyst particles with different amounts of Pt were used in combination with crystalline aluminosilicate particles to produce alkyl aromatic hydrocarbons containing methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen, it was confirmed that alkyl aromatic hydrocarbons containing methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted onto the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct. Examples 3-1 to 3-3 received a C rating, the same level as Comparative Example 1-1. This is because the Pt content was considerably lower, ranging from 0.3% to 1% by mass, compared to Comparative Example 1-1. However, the fact that the same evaluation results as Comparative Example 1-1 were obtained even with such a low Pt content demonstrates how excellent the metal-supported catalyst of the present invention is in generating alkyl aromatic hydrocarbons having methyl groups.

[0058] (Test Example 4) <Example 1-1> Example 1-1 is as described above.

[0059] <Examples 4-1 to 4-5> Except for changing the amount of MoO3 to 5.0% by mass, 10.0% by mass, 15.0% by mass, 20.0% by mass, or 50.0% by mass, based on the mass of the metal-supported catalyst particles, the metal-supported catalyst particles of Examples 4-1 to 4-5 were prepared in the same manner as in Example 1-1.

[0060] The methylation reaction of benzene was tested under the same conditions as in Test Example 1, except that each of the obtained metal-supported catalyst particles was used. Table 4 shows the results of gas chromatography analysis of the product.

[0061] [Table 4]

[0062] As shown in Table 4, when various metal-supported catalyst particles with different amounts of MoO3 were used in combination with crystalline aluminosilicate particles to produce alkyl aromatic hydrocarbons containing methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen, it was confirmed that alkyl aromatic hydrocarbons containing methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct.

[0063] (Test Example 5) <Example 4-3> Example 4-3 is as described above.

[0064] <Examples 5-1 to 5-5> The methylation reaction of benzene using the metal-supported catalyst particles and crystalline aluminosilicate of Example 4-3 was tested under the same conditions as in Test Example 1, except that the reaction temperature for generating alkyl aromatic hydrocarbons having methyl groups was changed to 220°C, 230°C, 250°C, 260°C, or 280°C. Table 5 shows the results of gas chromatography analysis of the product.

[0065] [Table 5]

[0066] As shown in Table 5, when metal-supported catalyst particles and crystalline aluminosilicate particles were used in combination to produce alkyl aromatic hydrocarbons containing methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen at various reaction temperatures, it was confirmed that alkyl aromatic hydrocarbons containing methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted onto the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct. Examples 5-1 and 5-2 received a C rating, the same level as Comparative Example 1-1. This is because the reaction temperature was lower than that of Comparative Example 1-1 (240°C). However, the fact that the same evaluation results as Comparative Example 1-1 were obtained even at such a low reaction temperature demonstrates how excellent the metal-supported catalyst of the present invention is in producing alkyl aromatic hydrocarbons having methyl groups.

[0067] (Test Example 6) <Examples 6-1 to 6-2> Except for using aluminum oxide particles (Catapal B (trade name) Sasol, calcined at 900°C for 3 hours) as the support instead of titanium oxide particles, metal-supported catalyst particles of Examples 6-1 to 6-2 were prepared in the same manner as in Example 1-1, in which Pt and Mo were supported on aluminum oxide particles. The amounts of Pt and MoO3 were as shown in Table 6 below, and metal-supported catalyst particles for Examples 6-1 to 6-2 were prepared.

[0068] Using the metal-supported catalyst particles obtained, the methylation reaction of benzene was tested under the same conditions as in Test Example 1. The reaction temperatures for generating alkyl aromatic hydrocarbons containing methyl groups in each example are shown in Table 6 below. Table 6 shows the results of gas chromatography analysis of the product.

[0069] [Table 6]

[0070] As shown in Table 6, when metal-supported catalyst particles, in which a first and second metal are supported on an aluminum oxide support, and crystalline aluminosilicate particles were used in combination to produce alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen, it was confirmed that alkyl aromatic hydrocarbons having methyl groups could be produced in high yield while suppressing the formation of methane as a byproduct. In particular, it was confirmed that polysubstituted alkyl aromatic hydrocarbons, in which more methyl groups are substituted on the aromatic hydrocarbons, could be produced in high yield while suppressing the formation of methane as a byproduct.

[0071] According to the present invention, alkyl aromatic hydrocarbons having methyl groups can be obtained in high yield from aromatic hydrocarbons, carbon dioxide, and hydrogen using a heterogeneous catalyst. Furthermore, low concentrations of carbon dioxide, which were previously generated by the combustion of carbon-containing substances and released into the atmosphere, can also be used as a raw material. Therefore, exhaust gases containing low concentrations of carbon dioxide that were previously released into the atmosphere (for example, mixed gases produced by the combustion of hydrocarbons at oil refineries, power plants, etc.) can be efficiently utilized. As a result, it is expected that this will lead to a further reduction in the burden on the global environment.

Claims

1. A metal-supported catalyst for the production of alkyl aromatic hydrocarbons, used in combination with crystalline aluminosilicate particles to produce alkyl aromatic hydrocarbons having a methyl group from aromatic hydrocarbons, carbon dioxide, and hydrogen, The crystalline aluminosilicate particles are mordenite, and the molar ratio of SiO₂ to Al₂O₃ in the mordenite is 20 to 600. The metal-supported catalyst for alkyl aromatic hydrocarbon production comprises a carrier and a metal supported on the carrier. The carrier is one of titanium oxide, zirconium oxide, or aluminum oxide. The metal comprises at least two types of metals, with Pt as a first metal and at least one metal selected from the group consisting of V, W, and Mo as a second metal, wherein the second metal is included as an oxide.

2. The metal-supported catalyst for alkyl aromatic hydrocarbon production according to claim 1, wherein the content of Pt, which is the first metal, in the metal-supported catalyst for alkyl aromatic hydrocarbon production is 0.3% by mass or more and 5.0% by mass or less, based on the mass of the metal-supported catalyst for alkyl aromatic hydrocarbon production.

3. The metal-supported catalyst for alkyl aromatic hydrocarbon production according to claim 1 or 2, wherein the content of the second metal as an oxide in the metal-supported catalyst for alkyl aromatic hydrocarbon production is 5.0% by mass or more and 50.0% by mass or less, based on the mass of the metal-supported catalyst for alkyl aromatic hydrocarbon production.

4. A method for producing alkyl aromatic hydrocarbons having methyl groups, characterized by generating alkyl aromatic hydrocarbons having methyl groups from aromatic hydrocarbons, carbon dioxide, and hydrogen in the presence of a metal-supported catalyst for producing alkyl aromatic hydrocarbons according to any one of claims 1 to 3, and crystalline aluminosilicate particles.

5. The method according to claim 4 provides a step of obtaining a plurality of alkyl aromatic hydrocarbons having a methyl group, A step of producing a C8 aromatic hydrocarbon by a transalkylation reaction between the aforementioned multiple types of alkyl aromatic hydrocarbons, A method for producing C8 aromatic hydrocarbons, including [the specified compound].

6. A method for fixing carbon dioxide, wherein the method according to claim 4 comprises fixing carbon dioxide by using carbon dioxide produced by the combustion of a carbon-containing substance as the carbon dioxide.

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