WO2024135770A1

WO2024135770A1 - Catalyst for producing aromatic compound, method for producing catalyst for producing aromatic compound, and method for producing aromatic compound

Info

Publication number: WO2024135770A1
Application number: PCT/JP2023/045857
Authority: WO
Inventors: 秀之村田; 孝彦大坪; 彰志今村; アシマスルタナ; 功中村
Original assignee: Dic株式会社; 国立研究開発法人産業技術総合研究所
Priority date: 2022-12-23
Filing date: 2023-12-21
Publication date: 2024-06-27

Abstract

Provided is a catalyst which is for producing an aromatic compound, and with which it is possible to efficiently produce an aromatic compound in a single step by using carbon monoxide and hydrogen as raw materials.　The catalyst for producing an aromatic compound comprises: a first catalyst containing at least one among zinc, manganese, cobalt, and iron; a second catalyst containing ZSM-5 zeolite; and a third catalyst containing at least one selected from among SAPO zeolite, FER zeolite, and chabazite-type zeolite (CHA).

Description

CATALYST FOR PRODUCING AROMATIC COMPOUNDS, PROCESS FOR PRODUCING CATALYST FOR PRODUCING AROMATIC COMPOUNDS, AND PROCESS FOR PRODUCING AROMATIC COMPOUNDS

The present invention relates to a catalyst for producing aromatic compounds, a method for producing a catalyst for producing aromatic compounds, and a method for producing aromatic compounds.

In order to build a sustainable society, there is a strong demand in the field of organic synthetic chemistry for the development of clean molecular conversion technologies that reduce the burden on the environment. In particular, the development of catalysts that lead to highly efficient material and energy conversion is important in overcoming the problems of global warming and resource depletion.

Against this background, efforts have been made to develop catalysts that can convert hydrogen obtained by electrolyzing water using renewable energy and carbon dioxide, a cause of global warming, into methane with high efficiency, as well as catalysts that can convert carbon monoxide and hydrogen into methanol with high efficiency. Furthermore, using this methanol as a raw material to convert organic substances currently produced from fossil resources such as petroleum and natural gas would enable the sustainable production of organic substances. For this reason, there has been a demand for the development of catalysts that can convert methanol, which is converted from carbon monoxide and hydrogen, into organic substances produced from fossil resources such as petroleum and natural gas, particularly aromatic compounds that are useful industrially.

　Conventionally, a method for producing methanol by contacting carbon monoxide and hydrogen with a catalyst such as copper or zinc oxide (for example, Non-Patent Document 1) is known. Also, a method for obtaining aromatic compounds by contacting the methanol thus obtained with an acid catalyst such as zeolite (for example, Patent Document 1) is known. Thus, a method for synthesizing aromatic compounds in two stages from carbon monoxide and hydrogen via methanol is known. Also, a method for synthesizing aromatic compounds in one stage using a composite catalyst consisting of an active metal oxide and one or more of ZSM-5 zeolite and metal-modified ZSM-5 is known (for example, Patent Document 2). Furthermore, a method for synthesizing paraxylene in one stage from carbon dioxide and hydrogen instead of carbon monoxide is known (for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 59-136386 Special Publication No. 2019-513541 JP 2019-205969 A

However, in the method of Patent Document 2, the metal catalyst preparation step requires immersing the metal oxide in an etching agent selected from hexamethylenetetramine, ethylenediamine, ammonia, hydrazine hydrate, etc., which places a significant burden on the environment. Furthermore, the zeolite catalyst is limited to one type, ZSM-5 zeolite, so it is not possible to obtain a wide variety of hydrocarbons, including aromatics.

In addition, even in the method of Patent Document 3, the zeolite catalyst is limited to one type, ZSM-5 zeolite, and a process of coating this with silicalite-1 is required, making the catalyst preparation process complicated. In addition, aromatic hydrocarbons synthesized using the catalyst are limited to paraxylene, and various industrially useful aromatics such as benzene and orthoxylene cannot be obtained.

For this reason, methods for efficiently producing industrially useful aromatic compounds such as benzene, toluene, and xylene from carbon monoxide and hydrogen have yet to be fully explored.

The present invention aims to provide a catalyst for producing aromatic compounds that can efficiently produce aromatic compounds in one step using carbon monoxide and hydrogen as raw materials, a method for producing the catalyst for producing aromatic compounds, and a method for producing aromatic compounds using the catalyst for producing aromatic compounds.

The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved, and have completed the present invention having the following gist.
(1) a first catalyst containing at least one of zinc, manganese, cobalt, and iron;
a second catalyst comprising a ZSM-5 zeolite;
a third catalyst comprising one or more selected from SAPO zeolite, FER zeolite, and chabazite-type zeolite (CHA);
A catalyst for producing aromatic compounds comprising:
(2) The catalyst for producing aromatic compounds according to (1), wherein the SAPO zeolite in the third catalyst is one or more zeolites selected from SAPO-5, SAPO-11, SAPO-17, SAPO-18, SAPO-31, SAPO-34, SAPO-35, SAPO-41, SAPO-42, and SAPO-44.
(3) The catalyst for producing aromatic compounds according to (1) or (2), further comprising a fourth catalyst containing one or more selected from the group consisting of V, Cr, Zr, Cu, Ni, Ce, Pd, Ru, Rh, Mg, Al, Si, Pt, Mo, and Ga.
(4) A method for producing a catalyst for producing aromatic compounds according to any one of (1) to (3), comprising the steps of:
(i) the first catalyst, or, when the aromatic compound production catalyst further comprises a fourth catalyst, a mixture comprising the first catalyst and the fourth catalyst;
(ii) the second catalyst and the third catalyst;
A method for producing a catalyst for aromatic compound production, comprising a step of mixing
(5) A method for producing the catalyst for producing aromatic compounds according to (3), comprising the steps of:
A method for producing a catalyst for aromatic compound production, comprising a step of mixing the first catalyst, the second catalyst, the third catalyst, and the fourth catalyst.
(6) A method for producing an aromatic compound, comprising the steps of:
A method for producing an aromatic compound, comprising contacting a feed gas containing carbon monoxide and hydrogen with the catalyst for producing an aromatic compound according to any one of (1) to (3).

The present invention provides a catalyst for producing aromatic compounds that can efficiently produce aromatic compounds in one step using carbon monoxide and hydrogen as raw materials, a method for producing the catalyst for producing aromatic compounds, and a method for producing aromatic compounds using the catalyst for producing aromatic compounds.

(Catalyst for producing aromatic compounds)
The catalyst for producing aromatic compounds of the present invention catalyzes a synthesis reaction of aromatic compounds using carbon monoxide and hydrogen as raw materials.

The present inventors have found that by combining the first catalyst, the second catalyst, and the third catalyst by mixing or the like, it is possible to produce aromatic compounds from carbon monoxide and hydrogen even at reaction temperatures of 400°C or less, and even 300°C or less, which are lower than those of conventional techniques.
This has led to the development of a catalyst that can suppress coke deposition on the catalyst, maintains catalytic activity for long periods of time, is practical and economical, and also reduces the environmental impact.

In other words, the catalyst for producing aromatic compounds of the present invention includes a first catalyst containing at least one of zinc (Zn), manganese (Mn), cobalt (Co) and iron (Fe), a second catalyst containing ZSM-5 zeolite, and a third catalyst containing at least one selected from SAPO zeolite, FER zeolite and chabazite-type zeolite (CHA).

Furthermore, the catalyst for producing aromatic compounds of the present invention may further include a fourth catalyst containing one or more metals selected from vanadium (V), chromium (Cr), zirconium (Zr), copper (Cu), nickel (Ni), cerium (Ce), palladium (Pd), ruthenium (Ru), rhodium (Rh), magnesium (Mg), aluminum (Al), silicon (Si), platinum (Pt), molybdenum (Mo), and gallium (Ga).

The first catalyst catalyzes the conversion of carbon monoxide and hydrogen into methanol and/or low molecular weight hydrocarbons mainly having 3 or less carbon atoms (hereinafter simply referred to as low molecular weight hydrocarbons). On the other hand, the second catalyst and the third catalyst catalyze the conversion of mainly methanol and/or low molecular weight hydrocarbons into hydrocarbons having 4 or more carbon atoms, including aromatic compounds. In other words, the catalyst for producing aromatic compounds of the present invention is a composite catalyst containing the first, second, and third catalysts, and an optional fourth catalyst as a co-catalyst. This makes it possible to efficiently produce aromatic compounds in one step using carbon monoxide and hydrogen as raw materials.

In this specification, "aromatic compound" refers to aromatic hydrocarbons such as benzene, alkylbenzenes, naphthalene, and alkylnaphthalenes, and more specific examples of aromatic compounds include benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, ethylbenzene, propylbenzene, butylbenzene, phenol, cresol, catechol, styrene, benzaldehyde, benzoic acid, naphthalene, and methylnaphthalene. Among these, from the viewpoint of industrial usefulness, the aromatic compounds produced using the aromatic compound production catalyst of the present invention are preferably monocyclic aromatic compounds such as benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, ethylbenzene, propylbenzene, butylbenzene, phenol, cresol, catechol, styrene, benzaldehyde, and benzoic acid, and more preferably benzene, toluene, and xylene.

<First Catalyst>
The composition of the first catalyst is not particularly limited as long as it contains at least one of zinc, manganese, cobalt, and iron as a catalytic component, and oxides, halides, nitrates, carbonates, acetates, ammonium salts, oxoacids, oxoacid salts, and the like can be used alone or in combination of two or more thereof.

Specifically, when the first catalyst contains zinc, examples of the catalyst include zinc(II), zinc oxide(II), zinc chloride(II), zinc bromide(II), zinc iodide(II), zinc acetate(II), zinc nitrate(II), zinc sulfate(II), zinc carbonate(II), zinc perchlorate(II), zinc stearate(II), zinc tetrafluoroborate(II), zinc borate(II), zinc trifluoromethanesulfonate(II), zinc dimethyldithiocarbamate(II), zinc diethyldithiocarbamate(II), (N,N,N',N'-tetramethylethylenediamine)zinc(II) chloride, zinc(II) acetylacetonate, zinc(II) methoxide, and zinc bis[bis(trimethylsilyl)amide], and any one of these may be used alone or in combination of two or more.

When the first catalyst contains manganese, examples of the manganese include manganese oxide (II), manganese oxide (IV), manganese chloride (II), manganese fluoride (II), manganese bromide (II), manganese iodide (II), manganese acetate (II), manganese nitrate (II), manganese sulfate (II), manganese carbonate (II), manganese phosphate (II), manganese perchlorate (II), manganese borate (II), potassium permanganate, manganese (II) acetylacetonate, manganese (II) acetate, manganese (III) acetylacetonate, manganese (III) acetate, etc., and one of these can be used alone or two or more can be used in combination.

When the first catalyst contains cobalt, examples of the catalyst include cobalt(II) oxide, cobalt(III) oxide, cobalt(II,III) oxide, cobalt(II) acetate, cobalt(II) chloride, cobalt(II) bromide, cobalt(II) iodide, cobalt(II) fluoride, cobalt(III) fluoride, cobalt(II) sulfate, cobalt(II) nitrate, cobalt(II) hydroxide, cobalt(II) phosphate, cobalt(II) carbonate, cobalt(II) cyanide, sodium tris(carbonate)cobalt(III)ate, cobalt(II) acetylacetonate hydrate, cobalt(III) acetylacetonate, etc., and one of these may be used alone or two or more may be used in combination.

When the first catalyst contains iron, for example, iron (II), iron oxide (II), iron oxide (III), iron oxide (II, III), iron chloride (II), iron chloride (III), iron fluoride (III), iron bromide (II), iron bromide (III), iron iodide (II), iron acetate (II), iron nitrate (III), iron sulfate (II), iron sulfate (III), iron carbonate (II), iron phosphate (III), iron perchlorate (II), iron perchlorate (III), iron stearate (II), iron tetrafluoroboron (IV), iron tetrafluoroboron (III), iron tetrafluoroboron (II ... Examples of iron(II) acid, iron(II) borate, iron(II) trifluoromethanesulfonate, iron(II) dimethyldithiocarbamate, iron(II) diethyldithiocarbamate, (N,N,N',N'-tetramethylethylenediamine)iron(II) chloride, iron(II) acetylacetonate, iron(II) methoxide, and bis[bis(trimethylsilyl)amide]iron, among which one can be used alone or two or more can be used in combination.

The first catalyst is mainly composed of the compounds listed above, which contain at least one of zinc, manganese, cobalt, and iron, but the first catalyst may also contain other compounds resulting from the production of the first catalyst.

The form of the first catalyst is not particularly limited, and may be, for example, granular or film-like. When the first catalyst is granular, it is preferable that the particle size is small. The small particle size increases the surface area of the catalyst, and allows efficient conversion of carbon monoxide and hydrogen to methanol and/or low molecular weight hydrocarbons.

When the first catalyst is granular, the average particle size of the first catalyst is not particularly limited, and is, for example, 1 nm to 100 μm, preferably 2 nm to 10 μm, and more preferably 5 nm to 1 μm. If the average particle size is within the above range, the mass transfer between the first to fourth catalysts is accelerated and the flow resistance of the raw material gas can be maintained low. The average particle size can be determined, for example, by X-ray diffraction.

The specific surface area of the first catalyst is not particularly limited, and is, for example, 0.01 m ² /g or more and 2000 m ² /g or less, preferably 0.1 m ² /g or more and 1000 m ² /g or less, and more preferably 0.5 m ² /g or more and 500 m ² /g or less. If the specific surface area is within the above range, active sites for the reaction of hydrogen and carbon monoxide can be sufficiently supplied, and the occurrence of a partial pressure difference between carbon monoxide and hydrogen in the first catalyst can be suppressed. This allows efficient conversion of carbon monoxide and hydrogen to methanol and/or low molecular weight hydrocarbons. The specific surface area of the catalyst can be calculated, for example, by the Brunauer-Emmett-Teller (BET) method.

The content of the first catalyst is not particularly limited, and is, for example, 1.0% by mass or more and 95% by mass or less, preferably 2.0% by mass or more and 80% by mass or less, based on the total amount of the catalyst for producing aromatic compounds. It is more preferably 10.0% by mass or more and 70% by mass or less.

When two or more types of first catalysts are used as the catalyst of the present invention, it is preferable to compound the metal salts by means of coprecipitation or other methods to compound the metal salts at the molecular or nano level. By compounding the first catalyst at the molecular or nano level, it is possible to efficiently convert carbon monoxide and hydrogen into methanol and/or low molecular weight hydrocarbons.

The average particle size of the catalyst in which two or more types of first catalysts are composited by means of coprecipitation or the like is not particularly limited, but is, for example, 1 nm or more and 1000 μm or less, and preferably 10 nm or more and 500 μm or less.

<Second Catalyst>
The second catalyst contains ZSM-5 (Zeolite Socony Mobil-5) zeolite. ZSM-5 zeolite is an aluminosilicate zeolite having three-dimensional pores composed of 10-membered rings, and has a framework structure code of MFI type as compiled in the database of the International Zeolite Association.

The molar ratio of silica atoms to aluminum atoms (Si/Al ratio) of the second catalyst is not particularly limited, and is, for example, 10 to 1000, and preferably 20 to 900. If the Si/Al ratio is within the above range, the catalyst has excellent heat resistance and reaction selectivity, and can efficiently convert methanol and/or low molecular weight hydrocarbons to aromatic compounds.

The average particle size of the second catalyst is not particularly limited, and is, for example, 0.01 μm to 1000 μm, preferably 0.02 μm to 200 μm, and more preferably 0.05 μm to 100 μm. If the average particle size is within the above range, the mass transfer between the first to fourth catalysts is accelerated, and the flow resistance of the raw material gas can be maintained low.

The specific surface area of the second catalyst is not particularly limited and is, for example, ¹ m2/g to 1000 ^m2 /g, preferably ¹⁰ m2/g to 800 ^m2 /g, and more preferably 100 ^m2 /g to 700 ^m2 /g. If the specific surface area is within the above range, a sufficient number of active sites can be supplied for the reaction of methanol and/or low molecular weight hydrocarbons and the synthesis of organic compounds.

The content of the second catalyst is not particularly limited, and is, for example, 5% by mass or more and 99% by mass or less, preferably 20% by mass or more and 98% by mass or less, and more preferably 30% by mass or more and 90% by mass or less, based on the total amount of catalyst for producing aromatic compounds.

<Third Catalyst>
The third catalyst is a zeolite catalyst containing one or more selected from SAPO zeolite, FER zeolite, and chabazite-type zeolite (CHA).

SAPO zeolite is a silicoaluminophosphate type zeolite. There are no particular limitations on the SAPO zeolite, and examples include zeolites such as SAPO-5, SAPO-11, SAPO-17, SAPO-18, SAPO-31, SAPO-34, SAPO-35, SAPO-41, SAPO-42, and SAPO-44. One of these can be used alone, or two or more can be used in combination.

FER zeolite is an aluminosilicate zeolite whose skeleton structure code is FER type, as listed in the database of the International Zeolite Association.

Chabazite-type zeolite (CHA) is an aluminosilicate zeolite whose skeletal structure code is CHA type, as listed in the International Zeolite Association database.

The Si/Al ratio, average particle size, and specific surface area of the third catalyst are not particularly limited, and can be, for example, within the preferred ranges described for the second catalyst.

The content of the third catalyst is not particularly limited, and is, for example, from 0.01% by mass to 99% by mass, preferably from 0.1% by mass to 80% by mass, and more preferably from 1% by mass to 50% by mass, based on the total weight of the second catalyst and the third catalyst.

Optional Catalyst Components
In order to further enhance catalytic activity, the catalyst for producing aromatic compounds of the present invention may further contain, in addition to the first, second, and third catalysts described above, a fourth catalyst that catalyzes the conversion of mainly methanol and/or low molecular weight hydrocarbons into aromatic compounds having 4 or more carbon atoms, including aromatic compounds.

<The Fourth Catalyst>
The fourth catalyst includes, as a catalytic component, one or more of vanadium (V), chromium (Cr), zirconium (Zr), copper (Cu), nickel (Ni), cerium (Ce), palladium (Pd), ruthenium (Ru), rhodium (Rh), magnesium (Mg), aluminum (Al), silicon (Si), platinum (Pt), molybdenum (Mo), and gallium (Ga).

The V, Cr, Zr, Cu, Ni, Ce, Pd, Ru, Rh, Mg, Al, Si, Pt, Mo, and Ga contained in the fourth catalyst are not particularly limited, and may be metals, metal-containing oxides, halides, nitrates, carbonates, acetates, ammonium salts, oxoacids, oxoacid salts, etc., used alone or in combination of two or more kinds.

Specific examples of the catalytic components of the fourth catalyst include chromium (III) oxide, zirconium (IV) oxide, copper (II) oxide, nickel (II) oxide, cerium (IV) oxide, palladium (II) oxide, ruthenium (V) oxide, rhodium (III) oxide, magnesium (II) oxide, aluminum (III) oxide, silicon dioxide, platinum (IV) oxide, molybdenum (VI) oxide, gallium (III) oxide, platinum, etc., and one of these can be used alone or two or more can be used in combination.

The fourth catalyst is mainly composed of the above-mentioned metal compounds containing one or more of V, Cr, Zr, Cu, Ni, Ce, Pd, Ru, Rh, Mg, Al, Si, Pt, Mo, and Ga, but other compounds resulting from the production of the fourth catalyst may also be contained in the fourth catalyst.

The form of the fourth catalyst is not particularly limited, and may be, for example, granular or film-like. When the fourth catalyst is granular, it is preferable that the particle size is small. The small particle size allows a sufficient supply of active sites, and allows efficient conversion of carbon monoxide and hydrogen to methanol and/or low molecular weight hydrocarbons.

The average particle size and specific surface area of the fourth catalyst are not particularly limited, and can be, for example, within the preferred ranges described for the first catalyst.

When a fourth catalyst is included, the content of the fourth catalyst is not particularly limited and is, for example, 0.01 mass% or more and 99 mass% or less, preferably 0.1 mass% or more and 80 mass% or less, and more preferably 1 mass% or more and 50 mass% or less, relative to the total weight of the first catalyst and the fourth catalyst.
Furthermore, the fourth catalyst is preferably composited with the first catalyst by means of coprecipitation or the like, thereby forming a composite at a molecular or nano level. By forming a composite of the first and fourth catalysts at a molecular or nano level, carbon monoxide and hydrogen can be efficiently converted into methanol and/or low molecular weight hydrocarbons.

The average particle size of the catalyst obtained by combining the first catalyst and the fourth catalyst by means of coprecipitation or the like is not particularly limited, but is, for example, from 1 nm to 1000 μm, and preferably from 10 nm to 500 μm.

(Other optional ingredients)
From the viewpoint of improving moldability, the catalyst for producing aromatic compounds may contain other optional components such as a molding aid, as long as the effects of the present invention are not impaired. The molding aid may be, for example, at least one selected from the group consisting of a thickener, a surfactant, a water retention agent, a plasticizer, a binder raw material, etc. In addition, the catalyst for producing aromatic compounds may contain other useful components as long as the effects of the present invention are not impaired.

As described above, the catalyst for producing aromatic compounds of the present invention includes the first, second and third catalysts. Alternatively, the catalyst for producing aromatic compounds of the present invention includes the first to fourth catalysts.
In the catalyst for producing aromatic compounds, the composite state of the catalysts is not particularly limited, and for example, when the first to fourth catalysts are granular, they may be physically mixed. Alternatively, when the first to fourth catalysts are film-like, the first to fourth catalysts may be laminated. Furthermore, for example, a core-shell type configuration may be used, in which the second and third catalysts are the core and the first catalyst is the shell. Note that even when the catalyst for producing aromatic compounds of the present invention contains an optional fourth catalyst, it can be in the composite state described above.

The ratio of the zeolite catalyst content (total amount of the second catalyst and the third catalyst) to the metal catalyst content (total amount of the first catalyst and any fourth catalyst) during production can be optimized by adjusting the masses of the first to fourth catalysts when mixed. In the catalyst after mixing, the ratio can be determined, for example, using a scanning inductively coupled plasma method (ICP).

The catalyst for producing aromatic compounds of the present invention described above can efficiently produce aromatic compounds in one step using carbon monoxide and hydrogen as raw materials. In hydrocarbons containing aromatic compounds and having 4 or more carbon atoms, the methanol and/or low molecular weight hydrocarbons produced are immediately converted, improving the yield compared to the conventional two-step synthesis method.

The methanol and/or low molecular weight hydrocarbons produced by the aromatic compound production catalyst of the present invention can be isolated as products. Furthermore, the produced methanol and/or low molecular weight hydrocarbons such as methanol, ethylene, and ethane can be recycled and reintroduced into the reactor as intermediate products of aromatic compounds, and ultimately converted into the desired aromatic compounds.

In addition, since the methanol synthesis reaction using carbon monoxide and hydrogen as raw materials is an exothermic reaction, by utilizing this heat generation to convert methanol and/or low molecular weight hydrocarbons into aromatic compounds, heat can be used more efficiently than in the conventional two-stage synthesis method, providing a method for producing aromatic compounds that contributes to reducing the environmental burden.

Furthermore, compared to conventional techniques, the catalyst of the present invention can produce aromatic compounds containing at least one aromatic compound at low temperatures of 400°C or less, and even 300°C or less.

Furthermore, the catalyst of the present invention can produce aromatic compounds even at low pressures of 5 MPa or less, or even 1 MPa or less.

Aromatic compounds produced using the catalyst of the present invention can be easily separated into their individual components using known and commonly used liquid separation techniques such as distillation.

(Method for producing a catalyst for producing aromatic compounds)
The method for producing a catalyst for producing aromatic compounds of the present invention is not particularly limited, and may, for example, include a step of mixing one or more types of first catalysts with a second and a third catalyst. Alternatively, it may include a step of mixing one or more types of first catalysts with a second, a third, and a fourth catalyst. Alternatively, it may include a step of mixing a mixture containing two or more types of first catalysts with a second and a third catalyst. Alternatively, it may include a step of mixing a mixture containing two or more types of first catalysts with a second, a third, and a fourth catalyst. Alternatively, it may include a step of mixing a mixture containing one or more types of first catalysts and one or more types of fourth catalysts with a second and a third catalyst. Alternatively, it may include a step of mixing a mixture containing two or more types of first catalysts and one or more types of fourth catalysts with a second and a third catalyst.

Specifically, for example, a solution containing two or more types of a first catalyst, a solution containing a second catalyst, and a solution containing a third catalyst are mixed together, and after removing the solvent, the catalyst for producing aromatic compounds can be obtained by a method including a step of calcining the remaining solid material containing the first, second, and third catalysts.
Alternatively, a poor solvent, or an acid or an alkali may be added to a solution containing two or more types of first catalysts to co-precipitate the two or more types of first catalysts to form a composite, which is then mixed with the second and third catalysts and further calcined to obtain the catalyst for producing aromatic compounds of the present invention.
Alternatively, a poor solvent, or an acid or an alkali may be added to a solution containing two or more types of first catalysts to co-precipitate the two or more types of first catalysts to form a composite, which is then mixed with the second, third, and fourth catalysts and further calcined to obtain the catalyst for producing aromatic compounds of the present invention.

Also, for example, a solution containing one or more types of a first catalyst can be mixed with a solution containing one or more types of a fourth catalyst, and then a poor solvent, or an acid or an alkali can be added to co-precipitate the first and fourth catalysts to form a composite, which can then be mixed with the second and third catalysts and further calcined to obtain the catalyst for producing aromatic compounds of the present invention.

For example, a solution containing one or more types of a first catalyst, a solution containing one or more types of a second catalyst, and a solution containing one or more types of a third catalyst can be mixed together, and then a poor solvent, or an acid or an alkali can be added to co-precipitate the first, second, and third catalysts to form a composite, which can then be mixed with a fourth catalyst and further calcined to obtain the catalyst for producing aromatic compounds of the present invention.

Alternatively, the catalyst for producing aromatic compounds of the present invention can be obtained by preparing a metal catalyst containing the first catalyst, a zeolite catalyst containing the second catalyst, and a zeolite catalyst containing the third catalyst, and mixing these metal catalysts and zeolite catalysts. In this case, the metal catalyst can be obtained, for example, by adding a poor solvent, an acid, or an alkali to a solution containing two or more types of the first catalyst, or the first catalyst and the fourth catalyst, co-precipitating the first catalyst to form a composite, and then calcining the resulting mixture. On the other hand, the zeolite catalyst can be obtained by using a commonly known preparation method, for example, by subjecting a mixed solution containing various desired components to a drying and calcination process, or by adding an acid to the resulting solid matter and filtering, drying, and calcining the resulting mixture. The zeolite catalyst has a second catalyst and a third catalyst. The obtained metal catalyst and zeolite catalyst are mixed, for example, in a mortar, to prepare the catalyst for producing aromatic compounds of the present invention.

The solution containing the catalyst of the present invention is preferably an aqueous solution. The aqueous solution may contain an organic solvent compatible with water. Examples of the organic solvent compatible with water include alcohols having 1 to 4 carbon atoms.
The solution may contain, in addition to the solvent, for example, a ligand and the like.
The mixing (composite processing) can be carried out, for example, using a mortar, a ball mill, an automatic kneader, or the like.

The calcination temperature when calcining the solid is not particularly limited, and may be 300°C or higher and 600°C or lower. If the calcination temperature is 300°C or higher, it is easy to obtain a catalyst with thermal stability that can withstand long-term use and high catalytic activity. Furthermore, if the calcination temperature is 600°C or lower, the catalyst tends to easily form porous structures. The calcination time is not particularly limited, and may be 0.1 hours or higher and 24 hours or lower.

After the firing step is completed, the resulting fired product may be subjected to an appropriate post-treatment.
As a post-treatment, for example, the obtained fired product may be washed and filtered.
The washing can be carried out, for example, with water or a mixture of water and alcohol.

After filtration, the mixture can be dried as appropriate. The drying can be performed under normal pressure or under reduced pressure, but it is preferable to perform the drying under reduced pressure in terms of improving efficiency. The temperature during drying can be, for example, 20°C or higher and 100°C or lower. The drying time during drying can be, for example, 0.1 hours or higher and 24 hours or lower.

More specifically, the method for producing the catalyst for producing aromatic compounds can be the following method.
For example, aqueous solutions containing zinc and manganese as the first catalyst are prepared separately, and then mixed together to form a mixed solution.
After obtaining the mixed solution, an alkali such as sodium carbonate (Na ₂ CO ₃ ) is added to co-precipitate the first catalyst to obtain a precipitate.
Next, the precipitate is filtered and recovered, then dried and calcined to obtain a metal catalyst consisting of a zinc-manganese composite powder.
Here, the drying of the precipitate may be performed under normal pressure or under reduced pressure, but it is preferable to perform the drying under reduced pressure from the viewpoint of improving efficiency. The temperature during drying may be, for example, 20° C. or higher and 120° C. or lower. The drying time during drying may be, for example, 0.1 hours or higher and 24 hours or lower.
The calcination temperature performed after drying the precipitate is not particularly limited, and may be 300° C. or higher and 600° C. or lower. If the calcination temperature is 300° C. or higher, it is easy to obtain a catalyst with thermal stability that can withstand long-term use and high catalytic activity. If the calcination temperature is 600° C. or lower, the catalyst tends to form porosity. The calcination time is not particularly limited, and may be 0.1 hours or higher and 24 hours or lower.
On the other hand, the zeolite catalyst containing the second catalyst and the zeolite catalyst containing the third catalyst are prepared by synthesizing the zeolite catalyst using a commonly known method or by purchasing the zeolite catalyst.
The metal catalyst and the zeolite catalyst are then mixed and composited to obtain a catalyst for producing aromatic compounds.
Here, the mixing (composite processing) can be carried out using, for example, a mortar, a ball mill, an automatic kneader, or the like.

(Method for producing aromatic compounds)
The production of aromatic compounds can be carried out by contacting a feed gas containing carbon monoxide and hydrogen with the catalyst for producing aromatic compounds of the present invention.

The carbon monoxide as the raw material gas is not particularly limited, but is preferably carbon monoxide obtained by electrolytic reduction of carbon dioxide using electricity derived from renewable energy. The hydrogen as the raw material gas is not particularly limited, but is preferably hydrogen obtained by electrolysis of water using electricity derived from renewable energy. This makes it possible to further reduce greenhouse gas emissions overall.
In addition, carbon monoxide and hydrogen in the exhaust gas generated by incomplete combustion of combustible waste such as waste plastics or biomass, or carbon monoxide and hydrogen obtained by steam reforming or dry reforming low molecular weight hydrocarbons such as methane contained in natural gas can also be used as raw material gas.

The raw material gases carbon monoxide and hydrogen may be supplied separately, but are usually supplied as a mixed gas. The raw material gas may contain compounds other than carbon monoxide and hydrogen. For example, it may further contain inert gases such as nitrogen and argon, and carbon dioxide. From the viewpoint of productivity, it is preferable for the raw material gas of carbon monoxide and hydrogen to be a gas in which the total of carbon monoxide and hydrogen is 50 volume % or more of the total.

The volume ratio of hydrogen to carbon monoxide (hydrogen/carbon monoxide) in the raw material gas, under standard conditions of room temperature and normal pressure, is preferably from 0.2 to 5, and more preferably from 1 to 4. When the volume ratio of hydrogen/carbon monoxide is within the above range, the hydrogenation reaction of carbon monoxide tends to proceed sufficiently.
When carbon dioxide is contained in the raw material gas, the volume ratio of hydrogen to carbon dioxide in the raw material gas (hydrogen/carbon dioxide) is preferably 0.1 or more and 10 or less.

The reactor used for contacting the raw material gas with the catalyst for producing aromatic compounds is not particularly limited, and examples include general reactors for gas phase synthesis processes such as fixed beds, entrained beds, and fluidized beds, reactors for liquid phase synthesis processes such as slurry beds, and microchannel reactors.

When carrying out a reaction to produce aromatic compounds, a reducing gas such as hydrogen gas can be circulated to reduce the catalyst before the raw material gas is supplied to produce the aromatic compounds. This type of reduction can be carried out, for example, at a temperature of 150 to 600°C for 1 to 48 hours, although there are no particular limitations.

The conditions for producing the aromatic compound are not particularly limited, and the conditions can be set depending on the type of reactor.
In addition, when carrying out a reaction to produce aromatic compounds, the product gas obtained by contacting the raw material gas with the catalyst for producing aromatic compounds may be contacted again with the catalyst for producing aromatic compounds. This can increase the yield of conversion of the raw material gas to aromatic compounds. In addition, ethylene, propylene, and methanol contained in the product gas are further converted into aromatic compounds by repeatedly reacting with the catalyst, so that the yield and selectivity of aromatic compounds can be increased. When the product gas is contacted with the catalyst multiple times, the product gas alone may be used, or the product gas may be mixed with the raw material gas.

For example, the reaction temperature during the reaction to produce aromatic compounds is not particularly limited, and can be 150 to 700°C, preferably 200 to 600°C, and more preferably 200°C to 500°C. The pressure in the system during the reaction is not particularly limited, and can be, for example, 0.1 to 10.0 MPa, preferably 0.5 to 8.0 MPa, and more preferably 0.8 MPa to 6.0 MPa. Furthermore, the reaction time during the reaction to produce aromatic compounds using the catalyst of the present invention is not particularly limited, as long as it is at least 1 second, and preferably 5 seconds or more.

For example, the gas hourly space velocity (GHSV) during the reaction for producing aromatic compounds is not particularly limited, and is preferably 10 h ⁻¹ or more, more preferably 100 h ⁻¹ or more. If the GHSV is 10 h ⁻¹ or more, the reactor size can be made smaller. In addition, the GHSV is preferably 100,000 h ⁻¹ or less, and more preferably 50,000 h ⁻¹ or less. If the GHSV is 100,000 h ⁻¹ or less, the selectivity of aromatic compounds tends to be higher. Here, the GHSV is the ratio (F/V) of the feed rate (feed amount/time) F of the raw material gas to the volume V of the catalyst for producing aromatic compounds in the reactor. The amounts of gas and catalyst used may be appropriately selected from more preferable ranges depending on the reaction conditions, the activity of the catalyst, etc., and the GHSV is not limited to the above range.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. In the examples, the terms "parts", "%", etc. are based on mass unless otherwise specified.

(Preparation of catalyst for producing aromatic compounds)
<Preparation Example 1: Preparation of zinc-manganese composite catalyst and catalyst for producing aromatic compounds>
Zinc nitrate hexahydrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and manganese (II) nitrate hexahydrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were each dissolved in 200 g of water to prepare aqueous solutions containing zinc and manganese. Next, the two types of aqueous solutions were separated and mixed so that the mass ratio of zinc and manganese was the mass ratio shown in Table 1 to prepare 200 g of a zinc and manganese mixed solution. Then, 0.5 M aqueous sodium carbonate solution was dropped into the aqueous solution to co-precipitate zinc and manganese, and the precipitate was filtered and collected. The precipitate was dried in air at 110° C. for 12 hours and then calcined at 400° C. to obtain a zinc-manganese composite powder. Next, the zinc-manganese composite powder, ZSM-5 zeolite (manufactured by ZEOLYST, model number: CBV 5524G), and CHA zeolite (manufactured by Clariant, product name: CZC) were weighed out in the mass ratios shown in Table 1, and a composite treatment was carried out using an agate mortar to prepare a catalyst for producing aromatic compounds as shown in Preparation Example 1 in Table 1.

Comparative Preparation Example 1: Preparation of zinc-manganese composite catalyst and catalyst for producing aromatic compounds
Zinc nitrate hexahydrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and manganese (II) nitrate hexahydrate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were each dissolved in 200 g of water to prepare aqueous solutions containing zinc and manganese. Next, the two types of aqueous solutions were separated and mixed so that the mass ratio of zinc and manganese was the mass ratio shown in Table 1 to prepare 200 g of a zinc and manganese mixed solution. Then, 0.5 M aqueous sodium carbonate solution was dropped into the aqueous solution to co-precipitate zinc and manganese, and the precipitate was filtered and collected. The precipitate was dried in air at 110° C. for 12 hours, and then calcined at 400° C. to prepare a catalyst for producing aromatic compounds described in Comparative Preparation Example 1 in Table 1.

(Production of aromatic compounds)
(Examples 1 to 4, Comparative Examples 1 to 4)
Aromatic compounds were continuously synthesized from carbon monoxide and hydrogen using the aromatic compound production catalysts shown in Table 1, and the catalytic performance of the aromatic compound production catalysts was evaluated by measuring the CO conversion and the selectivity of each aromatic compound.

500 mg of the catalyst for producing aromatic compounds shown in Tables 1 and 2 was placed in the center of a quartz reaction tube (fixed-bed reactor) with an inner diameter of 12 mm, and the position of the catalyst was fixed with coal wool. After replacing the atmosphere in the reaction tube with nitrogen, the temperature was raised to 300°C while hydrogen gas was flowed at 40 mL/min. Next, hydrogen gas and carbon monoxide gas were supplied at the feed gas ratio and space velocity (GHSV) shown in the reaction conditions in Tables 3 and 4, respectively, and the temperature and pressure of the gas supplied to the reaction tube were controlled to the values shown in the reaction conditions in Tables 3 and 4.

The product was injected into a gas chromatograph (Shimadzu, product number GC-2014) and then analyzed with a detector (Shimadzu, hydrogen flame ionization detector, SH-Alumina BOND/Na ₂ SO ₄ 30 m×0.32 mm capillary column).

From the concentration of each component by analysis, the CO conversion rate (%) and aromatic compound selectivity (%) were calculated using the following formula to evaluate the catalytic function of the catalyst for aromatic compound production. The organic compounds to be measured were methane (CH ₄ ), ethylene (C ₂ H ₄ ), ethane (C ₂ H ₆ ), propylene (C ₃ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), methanol (CH ₃ OH), benzene, toluene, p-xylene, m-xylene, and o-xylene, and the selectivity (%) of each aromatic compound was calculated from the total volume of these aromatic compounds to be measured. The results are shown in Tables 3 and 4.

As shown in Table 2, the catalysts of Examples 1 to 4 were capable of producing aromatic compounds in one stage using carbon monoxide and hydrogen as raw materials. Furthermore, the catalysts of Examples 1 to 4 showed excellent CO conversion rates and selectivities for each aromatic compound, and were particularly excellent in selectivity for aromatic compounds among aromatic compounds. On the other hand, the catalysts of Comparative Examples 1 to 4 were inferior in CO conversion rate and selectivity for each aromatic compound.

In addition, the catalysts of Examples 1 to 4 have high selectivity for ethylene, propylene, and methanol, and it is expected that the yield of aromatic compounds will be as high as 50% or more by repeatedly contacting the reaction gas from which these ethylene, propylene, and methanol are recovered with the catalyst.

Claims

A first catalyst containing at least one of zinc, manganese, cobalt, and iron;
a second catalyst comprising a ZSM-5 zeolite;
a third catalyst comprising one or more selected from SAPO zeolite, FER zeolite, and chabazite-type zeolite (CHA);
A catalyst for producing aromatic compounds comprising:
The catalyst for producing aromatic compounds according to claim 1, wherein the SAPO zeolite in the third catalyst is one or more zeolites selected from SAPO-5, SAPO-11, SAPO-17, SAPO-18, SAPO-31, SAPO-34, SAPO-35, SAPO-41, SAPO-42, and SAPO-44.
The catalyst for producing aromatic compounds according to claim 1, further comprising a fourth catalyst containing one or more selected from V, Cr, Zr, Cu, Ni, Ce, Pd, Ru, Rh, Mg, Al, Si, Pt, Mo, and Ga.
A method for producing the catalyst for producing aromatic compounds according to any one of claims 1 to 3, comprising the steps of:
(i) the first catalyst, or, when the aromatic compound production catalyst further comprises a fourth catalyst, a mixture comprising the first catalyst and the fourth catalyst;
(ii) the second catalyst and the third catalyst;
A method for producing a catalyst for aromatic compound production, comprising a step of mixing
A method for producing the catalyst for producing aromatic compounds according to claim 3, comprising the steps of:
A method for producing a catalyst for aromatic compound production, comprising a step of mixing the first catalyst, the second catalyst, the third catalyst, and the fourth catalyst.
1. A method for producing aromatic compounds, comprising:
A method for producing an aromatic compound, comprising contacting a feed gas containing carbon monoxide and hydrogen with the catalyst for producing an aromatic compound according to any one of claims 1 to 3.