Catalyst and method for producing methanol using catalyst

Abstract

The present invention improves the productivity of catalyst production and the yield of a product. This catalyst is for use in a reaction in which a carbon oxide is included in a raw material. The catalyst contains a copper oxide, a zinc oxide, an aluminum oxide, and one or more doping elements. The color of the catalyst in the CIELAB color space is a color in which the range of the L* coordinate is 7.5 to 15.0 inclusive and / or the range of the a* coordinate is -9.0 to 2.0 inclusive. Furthermore, the catalyst has a color in which the range of the L* coordinate is 9.0 to 13.0 inclusive and / or the range of the a* coordinate is -8.0 to -3.0 inclusive.

Description

Catalyst and method for producing methanol using the catalyst

[0001] The present disclosure relates to a catalyst used for a reaction using a carbon oxide as a raw material, and a method for producing methanol using the catalyst.

[0002] Examples of reactions using a carbon oxide as a raw material include a methanol synthesis reaction. Methanol is an industrially important basic raw material. Therefore, for reasons such as energy saving and economic efficiency, there has been a demand for higher efficiency of the production process. A general methanol synthesis process uses, as main raw materials, a carbon oxide (carbon monoxide) derived from synthesis gas, which serves as a carbon source, and hydrogen. It is known that a catalyst composed of copper and zinc oxide (Cu-ZnO catalyst) is used in this synthesis process.

[0003] It is known that in the reaction for synthesizing methanol from carbon oxide and hydrogen, the following elementary reactions and their reverse reactions occur simultaneously, and the reaction proceeds while being affected by chemical equilibrium. CO ２ +3H ２ → CH ３ OH+H ２ O CO+H ２ O → CO ２ +H ２ CO+2H ２ → CH ３ OH As a catalyst for promoting a methanol synthesis reaction, for example, Patent Document 1 discloses a catalyst in which the molar ratio of zinc to copper is 0.5 to 0.7. According to the document, the catalyst may have an alkali metal content of 0 to 0.2 mol%.

[0004] International Publication No. 2013 / 183577 Pamphlet

[0005] For catalysts used in reactions that include carbon oxides as raw materials, improvements in the productivity of catalyst production and in the yield of products are required.

[0006] A catalyst according to one aspect of the present disclosure is a catalyst used for a reaction using a carbon oxide as a raw material, and contains copper oxide, zinc oxide, aluminum oxide, and one or more types of doping elements. In the CIELAB color space defined by the International Commission on Illumination, L ＊The coordinate range is 7.5 or greater and 15.0 or less, and / or a ＊ It has a color whose coordinate range is between -9.0 and -2.0.

[0007] A method for producing methanol according to one aspect of this disclosure includes the step of contacting a raw material gas containing carbon oxides and hydrogen with the catalyst to obtain methanol.

[0008] According to one aspect of this disclosure, it is possible to improve the productivity of catalyst production and increase the yield of the product.

[0009] L of the catalyst relating to the examples and comparative examples of this disclosure ＊ This graph shows the relationship between the value of and the methanol yield. The catalyst a in the examples and comparative examples of this disclosure ＊ This graph shows the relationship between the value of and the methanol yield.

[0010] [Embodiment 1] The catalyst relating to this disclosure will be described in detail below. Hereinafter, the catalyst within the scope of this disclosure will be referred to as the catalyst. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more, B or less".

[0011] This catalyst is used in reactions that involve carbon oxides as raw materials. This catalyst is composed of copper oxide (CuO), zinc oxide (ZnO), and aluminum oxide (Al ２ O ３ ), and one or more doping elements. Furthermore, this catalyst has L in the CIELAB color space as defined by the International Commission on Illumination. ＊ The coordinate range is 7.5 or greater and 15.0 or less, and / or a ＊ It has a color whose coordinate range is between -9.0 and -2.0. This catalyst is L ＊ The coordinate range is 9.0 or greater and 13.0 or less, and / or a ＊ The catalyst may have a color whose coordinate range is between -8.0 and -3.0. The components of this catalyst are not limited to the above components, and may also contain other elements.

[0012] Because this catalyst possesses the above-mentioned characteristics, the number of times the catalyst is washed during the catalyst manufacturing process can be reduced. Furthermore, the yield of the product can be improved.

[0013] Reactions that use carbon oxides as raw materials include, for example, carbon monoxide (CO) and / or carbon dioxide (CO2). ２ The catalytic reaction may include a raw material. More specifically, it may be a methanol synthesis reaction in which a raw material containing a carbon oxide and hydrogen is brought into contact with a catalyst to obtain methanol.

[0014] In this catalyst, the copper oxide content may be 50 to 80% by mass, preferably 55 to 80% by mass, and more preferably 60 to 79% by mass. By setting the copper oxide content to 50 to 80% by mass, the methanol yield can be improved.

[0015] Furthermore, in this catalyst, the mass content ratio of zinc oxide to copper oxide may be 0.10 to 0.52, preferably 0.15 to 0.50, and more preferably 0.18 to 0.45. The mass content ratio of zinc oxide to copper oxide can be determined by dividing the mass of zinc oxide contained in this catalyst by the mass of copper oxide. If the content ratio is too low, aggregation of Cu crystals is likely to occur, and the activity may decrease rapidly. If the content ratio is too high, the amount of Cu, which is the active component, will decrease, and the activity may decrease. By setting the mass content ratio of zinc oxide to copper oxide to 0.10 to 0.52, a catalyst with high catalytic activity can be realized.

[0016] The doping elements contained in this catalyst may be rare earth elements, alkali metals, alkaline earth metals, transition metals, or metal oxides. The elements used as doping elements may be samarium, gallium, tantalum, palladium, zirconium, magnesium, silicon, boron, cerium, lanthanum, neodymium, europium, or erbium. For example, the doping elements contained in this catalyst may be rare earth elements. The content of rare earth elements in this catalyst may be 100 wt ppm or more, preferably 1000 wt ppm or more, and more preferably 5000 wt ppm or more. In addition, the rare earth element contained in this catalyst may be samarium.

[0017] Furthermore, in the present catalyst, the element ratio (molar ratio) of the doping element to copper may be less than 0.01, preferably 0.005 or less, more preferably 0.003 to 0.005. Furthermore, in the present catalyst, the element ratio (molar ratio) of the doping element to zinc may be less than 0.022. Furthermore, in the present catalyst, the element ratio (molar ratio) of the doping element to aluminum may be less than 0.25, preferably less than 0.1, more preferably 0.015 to 0.090.

[0018] <Method for Producing Catalyst> Next, a method for producing the present catalyst will be described. The method for producing a catalyst according to the present disclosure is not particularly limited, and may be a known method. For example, the catalyst may be produced by precipitating an aqueous acidic salt solution of each metal element constituting the catalyst with a precipitant, followed by drying and calcination (see Japanese Patent Application Laid-Open No. 2010-194421).

[0019] More specifically, the method for producing a catalyst may include the following steps (1) to (5):

[0020] (1) Coprecipitation step: a step of adding a precipitant to a solution or suspension of an acidic salt or metal compound of each metal element constituting the catalyst to precipitate a composite salt (mainly carbonate). In the coprecipitation step, aging may be performed for a predetermined period of time to obtain a highly active catalyst precursor. (2) Washing step: a step of filtering and washing the composite salt. (3) Drying step: a step of drying the cake obtained by filtration. (4) Calcination step: a step of calcining the composite salt to convert it into an oxide. (5) Molding step: a step of tableting and molding the powdered oxide obtained through the calcination step.

[0021] In the above coprecipitation step (1), an acidic solution and a precipitant may be simultaneously added to a solution or suspension of one or more acidic salts or metal compounds to precipitate the composite salt. The solution or suspension of the acidic salt or metal compound and the acidic solution may contain copper, zinc, aluminum and the doping element. The acidic salt of each metal element may be one or more selected from the group consisting of nitrates, sulfates, acetates, formates, oxalates, phosphates, aluminic acid and halides, and is preferably a nitrate or a sulfate.

[0022] The metal compound of each metal element may be one or more selected from the group consisting of oxides and carbonates, preferably an oxide, and more preferably an alumina sol. The precipitating agent may be one or more selected from the group consisting of sodium carbonate, sodium bicarbonate, and sodium hydroxide, and is preferably sodium carbonate. In the above (1) coprecipitation step, the solvent may be one or more selected from the group consisting of water, methanol, ethanol, isopropanol, ethyl acetate, tetrahydrofuran, and dichloromethane, preferably water and ethanol, and more preferably water.

[0023] The washing step described in (2) above is performed to remove precipitating agents such as alkali metal salts. It is known that if the removal of precipitating agents is insufficient, the catalytic activity will decrease significantly. Therefore, this washing is usually carried out until the alkali metals are removed to a level that does not affect the methanol synthesis reaction. A common washing method involves removing water from the precipitate obtained in the coprecipitation step by filtration, and then adding clean water to the filtrate to redisperse the precipitate. After that, the dispersion is filtered again. By repeating this series of operations, the precipitating agent in the precipitate can be reduced to a concentration below the target level. As an indicator to confirm that the precipitating agent in the precipitate is below the target level, the condition of electrical conductivity of the filtrate ≤ 30 μS / cm may be adopted.

[0024] Because this catalyst has the characteristics described above, the number of times the catalyst is washed in the washing process can be reduced, thereby improving the productivity of the catalyst.

[0025] <Method for Producing Methanol> The following describes a method for producing methanol using this catalyst. A methanol production method according to one embodiment of this disclosure includes the step of contacting a raw material gas containing carbon oxides and hydrogen with the catalyst according to this disclosure to obtain methanol. As described above, this catalyst has the characteristics described above and can improve methanol yield.

[0026] The reaction conditions in this process may be, for example, a reaction temperature of 150 to 300°C and a reaction pressure (gauge pressure) of 0.5 to 10 MPaG.

[0027] An example of a reactor used in this process is a fixed-bed reactor. Alternatively, an internal condensation reactor may be used, which has a condensation surface and allows the methanol synthesis reaction to proceed by condensing the high-boiling components, including methanol and water, within the reactor.

[0028] <Raw Material Gas> The raw material gas contains carbon oxides and hydrogen. In the methanol production method according to this embodiment, the raw material gas may contain carbon dioxide and hydrogen. Alternatively, carbon monoxide and carbon dioxide may be included as carbon oxides. When both carbon monoxide and carbon dioxide are used as carbon oxides, they may be included in any ratio.

[0029] The molar ratio of hydrogen to carbon oxides in the raw material gas is not particularly limited. The raw material gas may contain components other than carbon oxides and hydrogen, as long as they do not affect methanol production. Examples of such components include third components such as nitrogen and impurities such as by-products associated with carbon oxide production. The raw material gas may also contain water.

[0030] Carbon oxides, hydrogen, and water vapor may be introduced into the reactor separately, or as a mixed gas in any combination.

[0031] [Use of Catalyst] When this catalyst is used in reactions that include carbon oxides as raw materials, such as methanol production methods, the catalyst may be used after being reduced with a reducing gas (hydrogen, a mixture of hydrogen and nitrogen, a gas containing carbon monoxide, etc.). By contacting this catalyst containing copper oxide with a reducing gas, CuO can be reduced to Cu, which has catalytic activity.

[0032] Furthermore, after the reaction using this catalyst is complete, the catalyst may be subjected to an inert treatment by oxidation with an oxidizing gas such as oxygen. By contacting the used catalyst with an oxidizing gas, the Cu can be oxidized back to CuO, which has low reaction activity.

[0033] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, the examples are catalysts within the scope of the present disclosure (the present catalyst), and the comparative examples are catalysts outside the scope of the present disclosure.

[0034] <Measurement of Catalyst Color> The colors of the catalysts in the examples and comparative examples can be expressed by coordinates in the CIELAB color space (L*a*b* color space). The coordinates in the CIELAB color space (L*a*b* color space) are shown below. ＊ a ＊ , and b ＊ This section describes a measurement method for identifying the ).

[0035] A 2 mm thick spacer was placed on a colorless, transparent glass plate with a thickness of 1.1 mm, and the catalyst to be measured was gently filled and leveled. A colorless, transparent glass plate with a thickness of 1.1 mm was placed on top of the spacer filled with catalyst to prepare the measurement sample. From above the measurement sample, the lightness L*, chromaticity a*, and chromaticity b* were measured using a white-calibrated portable colorimeter TES-3250 manufactured by TES ELECTRICAL ELECTRONIC. If the catalyst was in pellet or granular form exceeding 300 μm, it was crushed using a mortar and pestle, and the resulting material, classified into the 150 to 300 μm range using metal sieves with mesh sizes of 150 μm and 300 μm, was used as the packing sample.

[0036] <Measurement of electrical conductivity (μS / cm) of filtrate> The electrical conductivity of the filtrate in the washing process was measured at room temperature using an ECTestr11+ manufactured by Toyotane Co., Ltd.

[0037] <Preparation of Catalyst> (Example 1) Solution A was prepared by dissolving 96.0 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 16.1 g of zinc nitrate hexahydrate, and 0.9 g of samarium nitrate hexahydrate in 152 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 49.4 g of dense soda ash in 280 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 43.8 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0038] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 8.85 g / min, while solution B was added dropwise to maintain the pH in the flask at 6.8. The supply of solution B was stopped when the entire volume of solution A had been added. The mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0039] Next, the precipitate obtained from the mixture was filtered and washed with pure water until the electrical conductivity of the filtrate was 30 μS / cm or less. The reslurrying and filtration process using 1 L of pure water was repeated four times until the electrical conductivity of the filtrate was 30 μS / cm or less.

[0040] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst E1. L of catalyst E1 ＊ is 10.15, a ＊ is -6.18, b ＊ The value was -0.36.

[0041] (Example 2) Solution A was prepared by dissolving 118.7 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 13.8 g of zinc nitrate hexahydrate, and 0.9 g of samarium nitrate hexahydrate in 100 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 42.7 g of dense soda ash in 242 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 12.5 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0042] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 7.77 g / min, while solution B was added dropwise to maintain the pH in the flask at 5.8. Once all of solution A had been added, the supply of solution B was stopped, and the mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0043] Next, the precipitate obtained from the mixture was filtered and washed with pure water until the electrical conductivity of the filtrate was 30 μS / cm or less. The reslurrying and filtration process using 1 L of pure water was repeated three times until the electrical conductivity of the filtrate was 30 μS / cm or less.

[0044] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst E2. ＊ is 9.59, a ＊ is -4.41, b ＊ The value was 0.66.

[0045] (Example 3) Solution A was prepared by dissolving 96.0 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 22.9 g of zinc nitrate hexahydrate, and 0.9 g of samarium nitrate hexahydrate in 131 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 45.4 g of dense soda ash in 257 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 25.3 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0046] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 8.34 g / min, while solution B was added dropwise to maintain the pH of solution C at 6.3. The supply of solution B was stopped when the entire volume of solution A had been added. The mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0047] Next, the precipitate obtained from the mixture was filtered and washed with pure water until the electrical conductivity of the filtrate was 30 μS / cm or less. The reslurrying and filtration process using 1 L of pure water was repeated four times until the electrical conductivity of the filtrate was 30 μS / cm or less.

[0048] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst E3. L of catalyst E3 ＊ is 12.16, a ＊ is -3.49, b ＊ The result was 3.99.

[0049] (Example 4) Solution A was prepared by dissolving 96.0 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 22.9 g of zinc nitrate hexahydrate, and 0.9 g of samarium nitrate hexahydrate in 131 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 45.4 g of dense soda ash in 257 g of pure water. Separately from Solutions A and B, Solution C was prepared by suspending 25.3 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0050] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 8.34 g / min, while solution B was added dropwise to maintain the pH in the flask at 6.3. The supply of solution B was stopped when the entire volume of solution A had been added. The mixture was stirred at 70°C for 2.5 hours to allow it to mature.

[0051] Next, the precipitate obtained from the mixture was filtered and washed with pure water until the electrical conductivity of the filtrate was 30 μS / cm or less. The reslurrying and filtration process using 1 L of pure water was repeated four times until the electrical conductivity of the filtrate was 30 μS / cm or less.

[0052] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst E4. ＊ is 12.14, a ＊ is -3.40, b ＊ The value was 4.13.

[0053] (Comparative Example 1) Solution A was prepared by dissolving 73.4 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 32.7 g of zinc nitrate hexahydrate, and 0.9 g of samarium nitrate hexahydrate in 159 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 47.5 g of dense soda ash in 269 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 35.8 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0054] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 8.85 g / min, while solution B was added dropwise to maintain the pH in the flask at 6.3. Once the entire volume of solution A had been added, the supply of solution B was stopped, and the mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0055] Next, the precipitate obtained from the mixture was filtered. The filtered precipitate was subjected to reslurrying with 1 L of pure water and filtration four times, but the electrical conductivity of the filtrate did not fall below 30 μS / cm, remaining at 48 μS / cm.

[0056] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst C1. L of catalyst C1 ＊ is 15.90, a ＊ is 0.81, b ＊ The result was 6.76.

[0057] (Comparative Example 2) Solution A was prepared by dissolving 73.4 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 33.7 g of zinc nitrate hexahydrate, and 1.4 g of samarium nitrate hexahydrate in 151 g of pure water. Separately from Solution A, Solution B was prepared by dissolving 46.4 g of dense soda ash in 263 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 30.8 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 350 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0058] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 8.66 g / min, while solution B was added dropwise to maintain the pH in the flask at 6.8. Once the entire volume of solution A had been added, the supply of solution B was stopped, and the mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0059] Next, the precipitate obtained from the mixture was filtered. The filtered precipitate was subjected to reslurrying with 1 L of pure water and filtration four times, but the electrical conductivity of the filtrate did not fall below 30 μS / cm, remaining at 61 μS / cm.

[0060] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst C2.＊ is 20.50, a ＊ is -1.96, b ＊ The value was 3.95.

[0061] (Comparative Example 3) Solution A was prepared by mixing and dissolving 73.4 g of a 50% by mass aqueous solution of copper nitrate trihydrate, 23.3 g of zinc nitrate hexahydrate, and 0.3 g of samarium nitrate hexahydrate. Separately from Solution A, Solution B was prepared by dissolving 53.8 g of dense soda ash in 305 g of pure water. Further separately from Solutions A and B, Solution C was prepared by suspending 63.8 g of alumina sol 200 (manufactured by Nissan Chemical Corporation) in 543 g of pure water. Solution C was prepared in a glass separable flask equipped with a stirrer.

[0062] After raising the temperature of solution C to 70°C while stirring, solution A was added dropwise to solution C at a rate of 3.23 g / min, while solution B was added dropwise to maintain the pH of solution C at 5.8. Once all of solution A had been added, the supply of solution B was stopped, and the mixture was stirred at 70°C for 1.5 hours to allow it to mature.

[0063] Next, the precipitate obtained from the mixture was filtered. The filtered precipitate was subjected to reslurrying with 1 L of pure water and filtration eight times, but the electrical conductivity of the filtrate did not fall below 30 μS / cm, remaining at 73 μS / cm.

[0064] The recovered wet cake was dried at 120°C. Next, it was baked in air at 300°C for 6 hours to obtain catalyst C3. L of catalyst C3 ＊ is 7.42, a ＊ is -9.26, b ＊ The value was -1.26.

[0065] <Activity Evaluation> Methanol was produced using catalysts E1 to E4 as examples and catalysts C1 to C3 as comparative examples, and the methanol yield was measured.

[0066] Approximately 0.05 g of the catalyst prepared as described above was packed into the reactor. A mixed gas of 24 vol% carbon dioxide, 72 vol% hydrogen, and 4 vol% argon was flowed through the catalyst layer of the reactor at atmospheric pressure. During flow, the amount of catalyst per hour of the total molar amount of carbon dioxide and hydrogen was set to 0.7 g. The reactor was heated to 280°C, and the reduction reaction was carried out for 2 hours.

[0067] Subsequently, the pressure was changed to 4 MPaG and the temperature to 240°C, and the reaction was carried out. After 15 to 30 hours, the gas was analyzed by gas chromatography, and the methanol yield was determined by subtracting the carbon monoxide yield (production rate) from the carbon dioxide consumption rate.

[0068] Table 1 below shows the catalyst composition, data during catalyst preparation, and measured catalyst color for Examples E1-E4 and Comparative Examples C1-C3. Table 2 below shows the number of washes required during the washing process in catalyst production for Examples E1-E4 and Comparative Examples C1-C3, due to the electrical conductivity of the washing solution being below 30 μS, and the methanol yield results when methanol synthesis experiments were conducted using each catalyst.

[0069] Figure 1 also shows the L of each catalyst. ＊ This graph shows the relationship between the value of and methanol yield. Figure 2 shows the a of each catalyst. ＊ This graph shows the relationship between the value of and the methanol yield.

[0070]

[0071]

[0072] As shown in Table 2, the methanol yield using catalysts E1 to E4, which are examples, was 6.9% or higher. On the other hand, the methanol yield using catalysts C1 to C3, which are comparative examples, was 6.7% or lower. Therefore, it has been demonstrated that catalysts within the scope of this disclosure can improve methanol yield compared to catalysts outside the scope of this disclosure.

[0073] Furthermore, for catalysts E1 to E4, which are examples, the number of washes required in the washing process during catalyst manufacturing to achieve an electrical conductivity of 30 μS / cm in the filtrate was four or less. On the other hand, for catalysts C1 to C3, which are comparative examples, the number of washes required in the washing process during catalyst manufacturing to achieve an electrical conductivity of 30 μS / cm in the filtrate was five or more. Therefore, it has been demonstrated that catalysts within the scope of this disclosure can reduce the number of washes required in the washing process and improve catalyst productivity compared to catalysts outside the scope of this disclosure.

[0074] Also, as shown in Figure 1, L ＊ The methanol yield for catalysts E1 to E4, whose coordinate range was 7.5 to 15.0, was 6.9% or higher. On the other hand, the methanol yield for comparative examples catalysts C1 to C3 was 6.7% or lower. Therefore, L ＊ It has been demonstrated that catalysts with a coordinate range of 7.5 to 15.0 can improve methanol yield compared to catalysts outside this range.

[0075] Also, as shown in Figure 2, a ＊ The methanol yield for catalysts E1 to E4, whose coordinate range was between -9.0 and -2.0, was 6.9% or higher. On the other hand, the methanol yield for comparative examples catalysts C1 to C3 was 6.7% or lower. Therefore, a ＊ It has been demonstrated that catalysts with a coordinate range of -9.0 to -2.0 can improve methanol yield compared to catalysts outside this range.

[0076] [Additional Notes] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0077] [Summary] (1) The catalyst according to Embodiment 1 of this disclosure is a catalyst used in a reaction that includes carbon oxide as a raw material, and comprises copper oxide, zinc oxide, aluminum oxide, and one or more doping elements, and in the CIELAB color space as defined by the International Commission on Illumination, L ＊The coordinate range is 7.5 or greater and 15.0 or less, and / or a ＊ It has a color whose coordinate range is between -9.0 and -2.0.

[0078] (2) The catalyst according to Embodiment 2 of the present disclosure is, in Embodiment 1 above, the L ＊ The coordinate range is 9.0 or more and 13.0 or less, and / or the a ＊ It has a color whose coordinate range is between -8.0 and -3.0.

[0079] (3) The catalyst according to embodiment 3 of the present disclosure has a copper oxide content of 50% by mass or more and 80% by mass or less in embodiment 1 or 2 above.

[0080] (4) In any of the embodiments 1 to 3 described above, the catalyst according to embodiment 4 of the present disclosure has an elemental ratio of the doped element to the copper element of less than 0.01.

[0081] (5) In any of the embodiments 1 to 4 above, the catalyst according to embodiment 5 of the present disclosure has a mass content ratio of zinc oxide to copper oxide of 0.1 to 0.5.

[0082] (6) The catalyst according to embodiment 6 of the present disclosure is characterized in that the doped element is a rare earth element in any of embodiments 1 to 5 above.

[0083] (7) The catalyst according to embodiment 7 of the present disclosure has a content of 100 wt ppm or more of the rare earth element in embodiment 6 above.

[0084] (8) The catalyst according to embodiment 8 of the present disclosure is characterized in that the rare earth element in embodiment 6 or 7 is samarium.

[0085] (9) A method for producing methanol according to aspect 9 of the present disclosure includes the step of contacting a raw material gas containing a carbon oxide and hydrogen with a catalyst according to any one of claims 1 to 8 to obtain methanol.

[0086] (10) The method for producing methanol according to aspect 10 of the present disclosure is, in aspect 9 above, wherein the carbon oxide is carbon dioxide.

Claims

1. A catalyst used in reactions involving carbon oxides as raw materials, comprising copper oxide, zinc oxide, aluminum oxide, and one or more doping elements, and having an L-value in the CIELAB color space as defined by the International Commission on Illumination. ＊ The coordinate range is 7.5 or greater and 15.0 or less, and / or a ＊ A catalyst having a color whose coordinate range is between -9.0 and -2.

0.

2. Said L ＊ The coordinate range is 9.0 or more and 13.0 or less, and / or the a ＊ The catalyst according to claim 1, wherein the color has a coordinate range of -8.0 or more and -3.0 or less.

3. The catalyst according to claim 1, wherein the copper oxide content is 50% by mass or more and 80% by mass or less.

4. The catalyst according to claim 1, wherein the elemental ratio of the doped element to the copper element is less than 0.

01.

5. The catalyst according to claim 1, wherein the mass content ratio of zinc oxide to copper oxide is 0.1 to 0.

5.

6. The catalyst according to claim 1, wherein the doping element is a rare earth element.

7. The catalyst according to claim 6, wherein the content of the rare earth element is 100 wt ppm or more.

8. The catalyst according to claim 6, wherein the rare earth element is samarium.

9. A method for producing methanol, comprising the step of contacting a raw material gas containing carbon oxide and hydrogen with a catalyst according to any one of claims 1 to 8 to obtain methanol.

10. The method for producing methanol according to claim 9, wherein the carbon oxide is carbon dioxide.

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