JP7227564B2 - Catalyst for alcohol synthesis and method for producing alcohol using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a catalyst for synthesizing alcohol and a method for producing alcohol using the same, and more particularly to a catalyst for synthesizing alcohol from CO ₂ and H ₂ and a method for producing alcohol using the catalyst.

Synthetic reaction of alcohol using _CO2 as a raw material is attracting attention from the viewpoint of effective utilization of _CO2 , which is one of the countermeasures against global warming. As catalysts used in the synthesis reaction of alcohols using such CO ₂ as a raw material, for example, JP-A-9-87217 (Patent Document 1) and JP-A-9-221437 (Patent Document 2) disclose CO ₂ Fe, Cu, Zn and K as catalysts used in the ethanol production method using the hydrogenation reaction of Catalysts containing an atomic ratio of K/Fe=0.01 to 0.5 are described. Also, Catal. Lett. , 2013, Vol. 143, pp. 345-355 (Non-Patent Document 1) describes a K/Cu—Zn—Fe catalyst as a catalyst used in a method for synthesizing alcohol using a hydrogenation reaction of CO ₂ . It is also described that the alcohol yield is highest when the composition is CuZnFe _0.5 K _0.15 . However, such catalysts containing Fe, Cu, Zn and K do not necessarily yield sufficiently high alcohol yields.

In addition, Japanese Patent Application Laid-Open No. 2012-217886 (Patent Document 3) describes a catalyst for synthesizing ethanol from CO ₂ and H ₂ , in which an oxide of Cu and Zn is impregnated with an oxide of an alkali metal. is described. Moreover, Patent Document 3 also describes that the yield of ethanol decreases when an oxide of an alkaline earth metal is impregnated instead of an oxide of an alkali metal.

Japanese Patent Laid-Open No. 9-87217 JP-A-9-221437 JP 2012-217886 A

Shanggui Li et al., Catal. Lett. , 2013, Vol. 143, pp. 345-355

The present invention has been made in view of the above-mentioned problems of the prior art, and an alcohol synthesis catalyst capable of synthesizing alcohol from CO ₂ and H ₂ at a high yield, and alcohol production using the same. The object is to provide a manufacturing method.

As a result of intensive research to achieve the above object, the present inventors have found that a catalyst containing Cu, Zn, Fe, and an alkaline earth metal can be used to produce a _high yield from CO2 and _H2 . The inventors have found that alcohol can be synthesized, and have completed the present invention.

That is, the alcohol synthesis catalyst of the present invention contains Cu, Zn, Fe, and an alkaline earth metal , the atomic ratio between Zn and Cu is Zn/Cu = 0.5 to 1.5, and Fe and The atomic ratio of Cu to Fe/Cu is 0.2 to 1.0, the atomic ratio of alkaline earth metal to Cu is alkaline earth metal/Cu=0.02 to 0.5, and CO ₂ and H ₂ as a catalyst for synthesizing ethanol . In such an alcohol synthesis catalyst , the alkaline earth metal is preferably at least one selected from the group consisting of Ca, Sr and Ba.

Further, the catalyst for alcohol synthesis of the present invention preferably further contains Ag, and the atomic ratio between Ag and Cu is Ag/Cu=0.005 to 0.07 .

Furthermore, the method for producing alcohol of the present invention is a method characterized by bringing CO ₂ and H ₂ into contact with the catalyst for alcohol synthesis of the present invention to synthesize ethanol .

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture alcohol with high selectivity and high yield from _CO2 and _H2 .

1 is a graph showing ethanol yields of catalysts obtained in Examples 1-6 and Comparative Examples 1-2. 1 is a graph showing the ethanol selectivity of catalysts obtained in Examples 1-6 and Comparative Examples 1-2. 4 is a graph showing the relationship between Sr/Cu atomic ratio and ethanol yield. 4 is a graph showing ethanol yields of catalysts obtained in Examples 1, 7 to 8 and Comparative Example 2. FIG. 1 is a graph showing the ethanol selectivity of catalysts obtained in Examples 1, 7 to 8 and Comparative Example 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments.

[Catalyst for alcohol synthesis]
First, the catalyst for alcohol synthesis of the present invention will be described. The alcohol synthesis catalyst of the present invention contains Cu, Zn, Fe, and alkaline earth metals. Although the alkaline earth metal is not particularly limited, Ca, Sr, and Ba are preferable, Sr and Ba are more preferable, and Sr is particularly preferable, from the viewpoint that alcohol can be synthesized with high selectivity and high yield.

In the catalyst for alcohol synthesis of the present invention, the form of Cu, Zn, and Fe is not particularly limited, and may be in any form of metal, oxide, salt (e.g., carbonate, nitrate, chloride, sulfate), and the like. may be contained, but it is preferable to contain one in the metal state during the alcohol synthesis reaction. Such Cu, Zn, and Fe are, for example, oxides, salts (e.g., carbonates, nitrates, chlorides, sulfates), etc. during catalyst preparation and before use in alcohol synthesis reactions. Even if it is in the state, it can be converted to the metal state by performing a reduction treatment immediately before it is used in the alcohol synthesis reaction. It can also be converted to a metal state by carrying out the synthesis reaction of alcohol in a reducing atmosphere.

In addition, in the catalyst for alcohol synthesis of the present invention, the form of the alkaline earth metal is not particularly limited, and any form of metal, oxide, salt (e.g., carbonate, nitrate, chloride, sulfate), etc. may contain things.

In the catalyst for alcohol synthesis of the present invention, the atomic ratio of Zn and Cu is preferably Zn/Cu=0.1 to 2.0, more preferably Zn/Cu=0.5 to 1.5. When the Zn/Cu ratio deviates from the above range, alcohol selectivity and yield tend to decrease.

In the alcohol synthesis catalyst of the present invention, the atomic ratio of Fe to Cu is preferably Fe/Cu=0.1 to 2.0, more preferably Fe/Cu=0.2 to 1.0. If the Fe/Cu ratio deviates from the above range, alcohol selectivity and yield tend to decrease.

Further, in the catalyst for alcohol synthesis of the present invention, the atomic ratio between alkaline earth metal and Cu is preferably alkaline earth metal/Cu=0.01 to 1.0, and alkaline earth metal/Cu=0.01 to 1.0. 02 to 0.5 is more preferable, and alkaline earth metal/Cu=0.03 to 0.25 is particularly preferable. When the alkaline earth metal/Cu ratio deviates from the above range, alcohol selectivity and yield tend to decrease.

In addition, the alcohol synthesis catalyst of the present invention may further contain other metals other than Cu, Zn, Fe and alkaline earth metals as long as the effects of the present invention are not impaired. From the viewpoint of further improving the alcohol selectivity and yield in the reaction of synthesizing alcohol from ₂ and _H2 , it is particularly preferred that Ag is further contained.

In the alcohol synthesis catalyst of the present invention, such other metals may be included inside particles containing Cu, Zn, Fe, and alkaline earth metals, or supported on the surface. In addition, the form of such other metal (particularly preferably Ag) is not particularly limited, and any form of metal, oxide, salt (e.g., carbonate, nitrate, chloride, sulfate), etc. may be included.

In the catalyst for alcohol synthesis of the present invention, the atomic ratio of Ag to Cu is preferably Ag/Cu=0.005 to 0.07, more preferably Zn/Cu=0.1 to 2.0. If the Zn/Cu ratio deviates from the above range, the effect of adding Ag may not be sufficiently obtained.

Although the method for preparing the catalyst for alcohol synthesis of the present invention is not particularly limited, the catalyst for alcohol synthesis of the present invention can be obtained, for example, by the following method. That is, first, an aqueous solution containing salts of Cu, Zn, Fe, and alkaline earth metals (e.g., nitrates, acetates, chlorides, sulfates) is added with a basic aqueous solution (e.g., sodium carbonate solution, carbonic acid). sodium hydrogen aqueous solution) is dropped to form a precipitate, and the precipitate is calcined in an oxidizing gas atmosphere (for example, in the air) to obtain the alcohol synthesis catalyst of the present invention.

Also, the method for preparing the alcohol synthesis catalyst of the present invention further containing the other metal (preferably Ag) is not particularly limited, but the following impregnation method can be mentioned, for example. That is, Cu, Zn, Fe, and alkaline earth metal salts (e.g., nitrates, acetates, chlorides, sulfates) are added to an aqueous solution containing a basic aqueous solution (e.g., sodium carbonate solution, sodium bicarbonate solution). aqueous solution) is dropped to generate a precipitate, and the precipitate is immersed in an aqueous solution containing a salt (e.g., nitrate, acetate, chloride, sulfate) of the other metal (particularly preferably Ag). Then, after impregnating the precipitate with a salt of the other metal (especially Ag), the obtained precipitate is calcined in an oxidizing gas atmosphere (for example, in the air) to obtain Cu, Zn , Fe, and an alkaline earth metal, and the other metal (particularly preferably Ag) supported on the catalyst for alcohol synthesis of the present invention can be obtained.

Moreover, the alcohol synthesis catalyst of the present invention further containing the other metal (particularly preferably Ag) can also be prepared by the following coprecipitation method. That is, Cu, Zn, Fe, alkaline earth metals, and other metals (especially preferably Ag) salts of each metal (e.g., nitrate, acetate, chloride, sulfate) Cu, Zn, Fe, It is possible to obtain the alcohol synthesis catalyst of the present invention containing an alkaline earth metal and the other metal (particularly preferably Ag).

In this method for preparing a catalyst for alcohol synthesis, the basic aqueous solution is preferably added dropwise to the aqueous solution containing the metal salt at 50 to 90°C (more preferably 70 to 80°C). Thereby, a catalyst having a high specific surface area can be obtained. The pH of the aqueous solution obtained by dropping the basic aqueous solution into the aqueous solution containing the metal salt is preferably 8-9. As a result, a catalyst having a composition close to that of the raw material solution can be obtained. Furthermore, it is preferable to stir the aqueous solution thus obtained at 50 to 90° C. (more preferably 70 to 80° C.) for 0.5 to 3 hours (more preferably 1 to 2 hours). Thereby, a catalyst having a high specific surface area can be obtained.

The calcination temperature of the precipitate thus obtained is preferably 300 to 500°C, more preferably 300 to 350°C. The firing time is preferably 3 to 10 hours, more preferably 5 to 7 hours. By calcining the precipitate at such a calcining temperature and calcining time, a catalyst with a high specific surface area can be obtained.

The catalyst for alcohol synthesis prepared in this manner usually contains Cu, Zn, Fe, alkaline earth metals, and, if necessary, other metals (particularly preferably Ag), each of which is an oxide or salt ( For example, it exists in the form of carbonates, nitrates, chlorides, sulfates). An alcohol synthesis catalyst containing an oxide or salt of each metal of Cu, Zn, and Fe can be reduced by subjecting it to a reduction treatment prior to the alcohol synthesis reaction, or by conducting the alcohol synthesis reaction in a reducing atmosphere. , into an alcohol synthesis catalyst containing Cu, Zn and Fe in the metal state. The alcohol synthesis catalyst containing Cu, Zn and Fe _{in the} metal state has excellent catalytic activity in the alcohol synthesis reaction. It becomes possible to produce alcohol with high selectivity and high yield. In particular, alcohol synthesis catalysts further containing Ag are excellent _in alcohol selectivity in alcohol synthesis reactions. From ₂ , alcohol can be produced with higher selectivity and higher yield.

The method of the reduction treatment is not particularly limited, but for example, heating a catalyst containing oxides or salts of Cu, Zn and Fe in a pure hydrogen gas atmosphere or a mixed gas atmosphere of hydrogen and an inert gas. There is a method of applying the treatment. The heating temperature (reduction treatment temperature) in such reduction treatment is preferably 250 to 400°C, more preferably 300 to 350°C. The heating time (reduction treatment time temperature) is preferably 0.5 to 3 hours, more preferably 1 to 2 hours. From the viewpoint of preventing reoxidation of the catalyst, such a reduction treatment of the catalyst is preferably carried out immediately before it is used in the alcohol synthesis reaction.

In addition, instead of such reduction treatment before use, the alcohol synthesis reaction using the catalyst for alcohol synthesis of the present invention may be carried out in a reducing atmosphere. As a result, the reduction treatment of the catalyst and the synthesis of alcohol can proceed simultaneously.

The shape of the alcohol synthesis catalyst of the present invention is not particularly limited, and examples thereof include particulate, pellet, and monolithic catalysts supported on honeycomb substrates.

[Method for producing alcohol]
Next, the method for producing alcohol of the present invention will be described. The method for producing alcohol of the present invention is a method of bringing CO ₂ and H ₂ into contact with the catalyst for alcohol synthesis of the present invention to synthesize alcohol. The method of contacting CO ₂ and H ₂ with such an alcohol synthesis catalyst is not particularly limited, and for example, a known solid catalyst bed used for solid catalyst reaction such as a gas phase fixed bed, a gas phase fluid bed, etc. can be used. method.

In the alcohol production method of the present invention, the molar ratio of CO ₂ and H ₂ is preferably CO ₂ /H ₂ =1/20 to 1/3, more preferably 1/10 to 1/3. If the CO _{2 /} H ₂ ratio is less than the lower limit, the CO ₂ raw material ratio tends to decrease, and the amount of alcohol produced per hour tends to decrease. rate tends to decline. Further, even when the reduction treatment of the catalyst and the synthesis of the alcohol are carried out simultaneously, the molar ratio of CO ₂ and H ₂ is preferably CO ₂ /H ₂ =1/20 to 1/3, and 1/10 to 1/1. /3 is more preferred. If the CO ₂ /H ₂ ratio is less than the lower limit, the CO ₂ raw material ratio tends to decrease, and the amount of alcohol produced per hour tends to decrease. High catalytic activity cannot be obtained in the synthesis reaction, and alcohol selectivity and yield tend to decrease.

The temperature (reaction temperature) at which CO ₂ and H ₂ are brought into contact with the alcohol synthesis catalyst is preferably 250 to 350°C, more preferably 280 to 320°C. Also, the reaction pressure is preferably 0.1 to 10 MPa, more preferably 0.5 to 5 MPa.

The alcohol thus obtained is mainly ethanol, but the alcohol obtained by the alcohol production method of the present invention may contain alcohols other than ethanol, such as methanol, propanol, and butanol.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

(Example 1)
First, copper nitrate, zinc nitrate, iron nitrate and strontium nitrate were dissolved in ion-exchanged water so that the atomic ratio of each metal was Cu:Zn:Fe:Sr=1:1:0.5:0.15. A raw material solution A was prepared. Also, raw material solution B was prepared by dissolving sodium carbonate in ion-exchanged water. The concentration of sodium carbonate in the raw material solution B was adjusted so that the pH of the obtained solution was within the range of 8 to 9 when the same amount of the raw material solution A and the raw material solution B were mixed.

Next, the raw material solution A and the raw material solution B were each heated to 70° C., and the same amount of the raw material solution A was added dropwise to the raw material solution B using a liquid feed pump. After the dropwise addition was completed, the mixture was stirred at 80°C for 1 hour, and the resulting precipitate was recovered by centrifugation, purified by repeating washing with ion-exchanged water and centrifugation, and then dried at 110°C overnight to obtain a solid. got This solid was calcined in air at 350° C. for 6 hours to obtain a catalyst powder. This catalyst powder was formed into pellets having a particle size of 0.5 to 1.0 mm by a cold isostatic pressing method (CIP method) to prepare catalyst pellets containing Cu, Zn, Fe and Sr.

(Example 2)
Cu, Zn and Fe were mixed in the same manner as in Example 1 except that the raw material solution A was prepared so that the atomic ratio of each metal was Cu: Zn: Fe: Sr = 1: 1: 0.5: 0.05. Catalyst pellets containing Sr (particle size: 0.5-1.0 mm) were prepared.

(Example 3)
Cu, Zn and Fe were mixed in the same manner as in Example 1 except that the raw material solution A was prepared so that the atomic ratio of each metal was Cu: Zn: Fe: Sr = 1: 1: 0.5: 0.10. Catalyst pellets containing Sr (particle size: 0.5-1.0 mm) were prepared.

(Example 4)
Cu, Zn and Fe were mixed in the same manner as in Example 1 except that the raw material solution A was prepared so that the atomic ratio of each metal was Cu: Zn: Fe: Sr = 1: 1: 0.5: 0.30. Catalyst pellets containing Sr (particle size: 0.5-1.0 mm) were prepared.

(Example 5)
Example 1 except that barium nitrate was used instead of strontium nitrate, and raw material solution A was prepared so that the atomic ratio of each metal was Cu:Zn:Fe:Ba=1:1:0.5:0.15. Catalyst pellets (particle diameter: 0.5 to 1.0 mm) containing Cu, Zn, Fe and Ba were prepared in the same manner as in .

(Example 6)
A raw material solution C was prepared by dissolving silver nitrate in ion-exchanged water. A solid material (Cu:Zn:Fe:Sr=1:1:0.5:0.15) prepared in the same manner as in Example 1 was immersed in this raw material solution C, and the atomic ratio of each metal was Cu. The solid was impregnated with silver nitrate so that :Zn:Fe:Sr:Ag=1:1:0.5:0.15:0.01. After that, the solid was dried and calcined in air at 350° C. for 6 hours to obtain a catalyst powder. This catalyst powder was molded into pellets having a particle size of 0.5 to 1.0 mm by a cold isostatic pressing method (CIP method) to prepare catalyst pellets containing Cu, Zn, Fe, Sr and Ag. .

(Example 7)
Example 6 except that the solid was impregnated with silver nitrate so that the atomic ratio of each metal was Cu: Zn: Fe: Sr: Ag = 1: 1: 0.5: 0.15: 0.02. Catalyst pellets (particle size: 0.5 to 1.0 mm) containing Cu, Zn, Fe, Sr and Ag were prepared in the same manner.

(Example 8)
Example 6 except that the solid was impregnated with silver nitrate so that the atomic ratio of each metal was Cu: Zn: Fe: Sr: Ag = 1: 1: 0.5: 0.15: 0.05. Catalyst pellets (particle size: 0.5 to 1.0 mm) containing Cu, Zn, Fe, Sr and Ag were prepared in the same manner.

(Comparative example 1)
In the same manner as in Example 1, Cu and Catalyst pellets containing Zn and Fe (particle size: 0.5-1.0 mm) were prepared.

(Comparative example 2)
First, a raw material solution A was prepared by dissolving copper nitrate, zinc nitrate and iron nitrate in ion-exchanged water so that the atomic ratio of each metal was Cu:Zn:Fe=1:1:0.5. Also, raw material solution B was prepared by dissolving sodium carbonate in ion-exchanged water. The concentration of sodium carbonate in the raw material solution B was adjusted so that the pH of the obtained solution was within the range of 8 to 9 when equal amounts of the raw material solution A and the raw material solution B were mixed.

Next, the raw material solution A and the raw material solution B were each heated to 70° C., and the same amount of the raw material solution A was added dropwise to the raw material solution B using a liquid feed pump. After the dropwise addition was completed, the mixture was stirred at 80°C for 1 hour, and the resulting precipitate was recovered by centrifugation, purified by repeating washing with ion-exchanged water and centrifugation, and then dried at 110°C overnight to obtain a solid. got

Next, K ₂ CO ₃ was dissolved in ion-exchanged water, and the resulting aqueous solution was added to the solid matter so that the atomic ratio of each metal was Cu: Zn: Fe: K = 1: 1: 0.5: 0.15. After being impregnated so as to obtain a catalyst powder, the solid was dried and calcined in the air at 350° C. for 6 hours. This catalyst powder was formed into pellets having a particle size of 0.5 to 1.0 mm by a cold isostatic pressing method (CIP method) to prepare catalyst pellets containing Cu, Zn, Fe and K.

<X-ray fluorescence analysis (XRF)>
Elemental analysis of the obtained catalyst powder was performed using a scanning fluorescent X-ray analyzer ("ZSX Primus II" manufactured by Rigaku Corporation) to determine the atomic ratio of each metal contained. Table 1 shows the atomic ratio of each metal contained in the catalyst powders obtained in Examples 1 and 5.

As shown in Table 1, it was confirmed that the atomic ratio of each metal contained in the obtained catalyst pellets substantially coincided with the charged atomic ratio.

<Synthesis of ethanol (1)>
First, the obtained catalyst pellets (particle size: 0.5 to 1.0 mm) were packed in a reaction vessel (inner diameter: 20 mm) so that the volume of the catalyst layer was 5 ml, and H ₂ (30% ) and N ₂ (70%) at a flow rate of 500 ml/min, the temperature in the reaction vessel: 300 ° C., the total pressure in the reaction vessel: 2 MPa (gauge pressure) for 1 hour. was reduced.

Next, while supplying a raw material gas consisting of CO ₂ (20%), H ₂ (60%) and N ₂ (20%) to the catalyst layer after the reduction treatment at a flow rate of 500 ml / min, the temperature in the reaction vessel A synthesis reaction of ethanol was carried out under the conditions of 300° C. and a total pressure in the reaction vessel of 2 MPa (gauge pressure).

Using a Fourier transform infrared spectrophotometer (FT-IR), the concentration of ethanol in the gas discharged from the reaction vessel (catalyst layer) is measured, and the selectivity and yield of ethanol when the ethanol concentration becomes constant. It was calculated by the following formula. The results are shown in Table 2 and FIGS. 1-3.
Ethanol selectivity [%] = Ethanol production amount [ppmC]/ _CO2 reaction amount [ppmC]
×100
Ethanol yield [%] = _CO2 conversion [%] x ethanol selectivity [%]/100

As shown in Table 2 and FIG. 1, when catalysts containing Cu, Zn, Fe and alkaline earth metals were used (Examples 1 to 5), catalysts containing no alkaline earth metals were used. It was found that the yield of ethanol was improved compared to the case (Comparative Example 1) and the case of using a catalyst containing K instead of an alkaline earth metal (Comparative Example 2). This is because the catalysts obtained in Examples 1-5 and Comparative Examples 1-2 had similar conversion rates of CO ₂ , so as shown in Table 2 and FIG. It was found that the ethanol selectivity of the catalyst obtained in Example 5 was improved compared to the catalysts obtained in Comparative Examples 1 and 2.

Further, as shown in Table 2 and FIGS. 1 to 2, when using a catalyst containing Cu, Zn, Fe, alkaline earth metal and Ag (Example 6), Cu, Zn, Fe Compared with the case of using a catalyst containing an alkaline earth metal (Example 1), the yield of ethanol was about the same, but it was found that the selectivity of ethanol was greatly increased. From this, by adding Ag to a catalyst containing Cu, Zn, Fe and an alkaline earth metal, the amount of by-products in the ethanol synthesis reaction is reduced, and ethanol and by-products are separated after synthesis. It has been found that the energy required for the synthesis can be reduced, and the effects of by-products can be reduced when the catalyst exhaust gas is repeatedly used for the synthesis of ethanol.

Furthermore, as shown in FIG. 3, it was found that ethanol can be synthesized from CO ₂ and H ₂ with a particularly high yield when the atomic ratio of Sr and Cu is Sr/Cu=0.03 to 0.24. rice field.

<Synthesis of ethanol (2)>
Ethanol synthesis reaction was carried out in the same manner as <Synthesis of ethanol (1)> except that a raw material gas consisting of CO ₂ (25%) and H ₂ (75%) was used as the raw material gas, and ethanol was selected. Percentage and yield were calculated. The results are shown in Table 3 and FIGS. 4-5.

As shown in Table 3 and FIG. 4, when Ag was added to the catalyst containing Cu, Zn, Fe and alkaline earth metals, the yield of ethanol increased as the amount added increased. This is because when a gas consisting only of CO ₂ (25%) and H ₂ (75%) is used as the raw material gas, the catalysts obtained in Examples 1 and 7-8 have the same conversion rate of CO ₂ . As shown in Table 3 and FIG. 5, it was found that the ethanol selectivity improved as the amount of Ag added increased.

As described above, according to the present invention, it is possible to obtain a catalyst capable of synthesizing alcohol with high selectivity and high yield. Therefore, the catalyst for alcohol synthesis of the present invention is useful as a catalyst capable of synthesizing alcohol from CO ₂ and H ₂ with high selectivity and high yield. The alcohol production method of the present invention used is useful as a method capable of efficiently producing alcohol from CO ₂ and H ₂ .

Claims (4)

containing Cu, Zn, Fe, and alkaline earth metals;
The atomic ratio of Zn and Cu is Zn/Cu=0.5 to 1.5,
The atomic ratio of Fe and Cu is Fe/Cu=0.2 to 1.0,
The atomic ratio between alkaline earth metal and Cu is alkaline earth metal/Cu = 0.02 to 0.5,
Is _a catalyst for the synthesis of ethanol from CO2 _and H2
A catalyst for alcohol synthesis characterized by: 2. The catalyst for alcohol synthesis according to claim 1 , wherein said alkaline earth metal is at least one selected from the group consisting of Ca, Sr and Ba. further containing Ag,
Atomic ratio of Ag and Cu is Ag/Cu=0.005 to 0.07
3. The catalyst for alcohol synthesis according to claim 1 or 2, characterized by: A method for producing alcohol, comprising contacting CO ₂ and H ₂ with the catalyst for alcohol synthesis according to any one of claims 1 to 3 to synthesize ethanol .

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