Method for producing carbon monoxide and production apparatus

Abstract

The present invention provides a method for producing carbon monoxide, which includes a step of generating carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst. The solid acid catalyst has a BET specific surface area of 590 m 2 / g or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for producing carbon monoxide and a production apparatus. BACKGROUND

[0002] In the past, as a method for producing carbon monoxide, a method for producing carbon monoxide by steam reforming of natural gas, a method for producing carbon monoxide by contacting oxygen with a light hydrocarbon in the presence of a partial oxidation catalyst (see Patent Literature 1 described below), or a method for producing carbon monoxide by decomposing formic acid, and the like are known. Among these, the method for producing carbon monoxide by decomposing formic acid is advantageous because carbon monoxide is obtained at a high selectivity. As the method for producing carbon monoxide by decomposing formic acid, a method using a mineral acid, a method using a solid acid catalyst are known. Among these, the method using a solid acid catalyst is promising as a method capable of producing carbon monoxide at a high conversion rate.

[0003] Prior Art Documents

[0004] Patent Literature

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2019-181375 SUMMARY

[0006] Technical Problem to be Solved by the Invention

[0007] However, in terms of the conversion rate of the raw material, the method for producing carbon monoxide using a solid acid catalyst still has room for improvement.

[0008] Therefore, an object of the present application is to provide a method for producing carbon monoxide and a production apparatus capable of improving the conversion rate of the raw material.

[0009] Means for Solving the Technical Problem

[0010] The present inventors and others have made intensive studies in order to solve the above problem. Specifically, the present inventors and others have made studies focusing on the BET specific surface area of the solid acid catalyst. Generally, the larger the BET specific surface area becomes, the more the contact area of the raw material with the solid acid catalyst increases, and therefore the present inventors and others predicted that by increasing the BET specific surface area of the solid acid catalyst, the raw material would be effectively decomposed, as a result of which the conversion rate of the raw material would be improved. However, unexpectedly, it was clarified that the smaller the BET specific surface area of the solid acid catalyst, the larger the conversion rate of the raw material becomes. Therefore, as a result of further repeated intensive studies based on such insight by the present inventors and others, it was found that the above problem can be solved by the following invention.

[0011] That is, one aspect of the present application is a method for producing carbon monoxide, which includes a step of generating carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst having a BET specific surface area of 590 m 2 / g or less.

[0012] According to the present application, compared to a case where the BET specific surface area of the solid acid catalyst exceeds 590 m 2 / g, the conversion rate of the raw material can be improved. Therefore, according to the method for producing carbon monoxide of the present application, carbon monoxide can be efficiently produced.

[0013] Further, according to the present application, compared to a case where the BET specific surface area of the solid acid catalyst exceeds 590 m 2 / g, the hydrogen concentration in the produced carbon monoxide can be sufficiently reduced without performing a purification step for removing hydrogen. Therefore, according to the method for producing carbon monoxide of the present application, high-purity carbon monoxide can also be efficiently and at low cost produced.

[0014] Another aspect of the present application is a device for producing carbon monoxide, which generates carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst having a BET specific surface area of 590 m 2 / g or less.

[0015] According to the device for producing carbon monoxide, if carbon monoxide is generated by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst in a reactor, compared to a case where the BET specific surface area of the solid acid catalyst exceeds 590 m 2 / g, the conversion rate of the raw material can be improved. Therefore, according to the device for producing carbon monoxide of the present application, carbon monoxide can be efficiently produced.

[0016] Further, according to the above-mentioned device for producing carbon monoxide, if carbon monoxide is generated by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst in a reactor, compared to a case where the BET specific surface area of the solid acid catalyst exceeds 590 m 2 / g, the hydrogen concentration in the produced carbon monoxide can be sufficiently reduced without performing a purification step for removing hydrogen. Therefore, according to the device for producing carbon monoxide of the present application, high-purity carbon monoxide can also be efficiently and at low cost produced.

[0017] In the above-mentioned method for producing carbon monoxide or device for producing carbon monoxide, the solid acid catalyst is, for example, a proton-type zeolite.

[0018] In the above carbon monoxide production method or production apparatus, the Si / Al atomic ratio of the proton-type zeolite is preferably 1 to 200.

[0019] In this case, there is a tendency to further improve the catalytic activity of the zeolite and improve the conversion rate of the raw material.

[0020] In the above carbon monoxide production method, the decomposition reaction of the raw material is preferably performed at 100 to 300°C.

[0021] In this case, there is a tendency to inhibit the generation of by-products such as hydrogen, further sufficiently reduce the hydrogen concentration in the produced carbon monoxide, and effectively perform the decomposition reaction.

[0022] In the above carbon monoxide production method or production apparatus, the solid acid catalyst preferably has a BET specific surface area of 480 m 2 / g or less.

[0023] In this case, the hydrogen removal purification process is not performed, and the hydrogen concentration in the produced carbon monoxide can be further sufficiently reduced.

[0024] Effects of the Invention

[0025] According to the present application, a carbon monoxide production method and production apparatus capable of improving the conversion rate of a raw material can be provided.

[0026] Further, according to the present application, a carbon monoxide production method and production apparatus in which the hydrogen removal purification process is not performed and the hydrogen concentration in the produced carbon monoxide can be sufficiently reduced can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic view showing an embodiment of a carbon monoxide production apparatus of the present application. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present application will be described in detail. However, the present application is not limited to the following embodiments.

[0029] The carbon monoxide production method of the present application includes a step of producing carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst. As the solid acid catalyst, a solid acid catalyst having a BET specific surface area of 590 m 2 / g or less can be used. The carbon monoxide production method of the present application can be implemented, for example, by a carbon monoxide production apparatus provided with a reactor that houses the above solid acid catalyst and produces carbon monoxide by a decomposition reaction of a raw material in the presence of the solid acid catalyst.

[0030] (solid acid catalyst)

[0031] The solid acid catalyst is not particularly limited, and as the solid acid catalyst, for example, a proton type zeolite is preferably used. As the proton type zeolite, zeolites such as mordenite, ZSM-5, beta type, Y type, and US-Y type can be given. As the proton type zeolite catalyst, for example, a high-silica zeolite catalyst manufactured by TOSOH CORPORATION or the like can be used.

[0032] The BET specific surface area of the solid acid catalyst is 590 m 2 / g or less. If the BET specific surface area of the solid acid catalyst is 590 m 2 / g or less, the conversion rate of the raw material can be improved compared to the case where a solid acid catalyst having a BET specific surface area exceeding 590 m 2 / g is used. Furthermore, if the BET specific surface area of the solid acid catalyst is 590 m 2 / g or less, the hydrogen concentration in the carbon monoxide manufactured can be sufficiently reduced without performing a purification process for removing hydrogen compared to the case where a solid acid catalyst having a BET specific surface area exceeding 590 m 2 / g is used.

[0033] The BET specific surface area of the solid acid catalyst is preferably 580 m 2 / g or less, more preferably 550 m 2 / g or less, and further preferably 500 m 2 / g or less. From the viewpoint of more sufficiently reducing the hydrogen concentration in the carbon monoxide manufactured without performing a purification process for removing hydrogen, the BET specific surface area of the solid acid catalyst is preferably 480 m 2 / g or less, more preferably 450 m 2 / g or less, and further preferably 400 m 2 / g or less.

[0034] However, the BET specific surface area of the solid acid catalyst is preferably 100 m 2 / g or more, more preferably 200 m 2 / g or more, and particularly preferably 300 m 2 / g or more. If the BET specific surface area of the solid acid catalyst is 100 m 2 / g or more, the decomposition reaction of the raw material is more easily performed, and as a result, there is a tendency to more improve the conversion rate of the raw material.

[0035] The BET specific surface area refers to a value measured under the following conditions using a BELSORP-MAX (manufactured by Microtrac BEL Corp.) as an analysis device.

[0036] (Conditions)

[0037] Measurement temperature: -196°C

[0038] Adsorbent: nitrogen

[0039] Equilibrium adsorption time: 300 seconds

[0040] Pre-treatment conditions of the solid acid catalyst: heat treatment under vacuum (pump specification: limit pressure 6.7 x 10 -7 Pa) (350°C, 5h)

[0041] The Si / Al atomic ratio of the proton-type zeolite used as the solid acid catalyst is not particularly limited, and is preferably 1 or more, more preferably 5 or more. If the Si / Al atomic ratio is 1 or more, there is a tendency to further improve the catalytic activity of the zeolite and improve the conversion rate of the raw material. The Si / Al atomic ratio is preferably 200 or less, more preferably 150 or less, still more preferably 100 or less, and particularly preferably 50 or less. If the Si / Al atomic ratio is 200 or less, there is a tendency to further improve the catalytic activity of the zeolite and improve the conversion rate of the raw material. Therefore, from the viewpoint of improving the conversion rate of the raw material, the Si / Al atomic ratio of the proton-type zeolite is preferably 1 to 200. In particular, in the case where the BET specific surface area of the solid acid catalyst is 300 to 500 m 2 / g, the Si / Al atomic ratio is preferably 5 to 150, more preferably 5 to 50, still more preferably 5 to 30, and particularly preferably 5 to 20. In the case where the BET specific surface area of the solid acid catalyst is 300 to 500 m 2 / g, if the Si / Al atomic ratio is 5 to 50, the conversion rate of the raw material is significantly improved.

[0042] In addition, the Si / Al atomic ratio can be found by measurement based on the solid NMR method.

[0043] (Raw material)

[0044] As the raw material, formic acid and formic acid alkyl esters can be given. These can be used individually or also as a mixture. As the formic acid alkyl ester, for example, formic acid methyl ester and formic acid ethyl ester can be given.

[0045] (Decomposition reaction)

[0046] The decomposition reaction of the raw material is performed by bringing the raw material into contact with the solid acid catalyst and heating it to decompose. Alternatively, the decomposition reaction of the raw material can also be performed by bringing the raw material into contact with the solid acid catalyst which is preliminarily modified with a mineral acid and heating it to decompose. The contact of the raw material with the solid acid catalyst can be performed, for example, by bringing a gas or a liquid containing the raw material into contact with the solid acid catalyst. In the case where a gas containing the raw material is brought into contact with the solid acid catalyst, a gas generator or the like can be used to generate a gas containing a vapor of the raw material from a solution containing the raw material, which is supplied to the solid acid catalyst to be contacted. The contact of the raw material with the solid acid catalyst is preferably performed by bringing a gas containing the raw material into contact with the solid acid catalyst. In this case, there is a tendency to improve the efficiency of the decomposition reaction. In the case where a liquid containing the raw material is used, the concentration of the raw material in the liquid is not particularly limited, and from the viewpoint of energy efficiency, it is preferably 40% by mass or more, based on the mass of the solution (100% by mass). As the liquid containing the raw material, for example, a water solution of formic acid can be given.

[0047] The decomposition reaction of the raw material can be performed using a reactor. As the reactor, a reaction vessel or a reaction column packed with a catalyst can be used. In the case where a reaction vessel is used as the reactor, the catalyst and the raw material are charged into the reaction vessel and heated, whereby carbon monoxide is generated. In the case where a reaction column packed with a catalyst is used as the reactor, for example, a vapor of the raw material is passed through the catalyst packed in the reaction column and heated, whereby carbon monoxide is generated. If the reaction efficiency is considered, it is preferable to use a reaction column packed with a catalyst as the reactor. The reaction column can be one, or a plurality of reaction columns can be connected. The reactor composed of a plurality of reaction columns is advantageous in terms of suppression of the deviation of the flow rate distribution in the reactor and securing of the heat transfer area for heating. In the case where a gas or a liquid containing the raw material is continuously supplied to the reactor, the reactor generally has an inlet and an outlet for supplying or discharging the gas or the liquid, which are connected to the flow path outside.

[0048] The reactor is composed of, for example, a non-metallic material such as carbon. The reactor formed of a non-metallic material is less likely to be corroded by the raw material and carbon monoxide, and is less likely to be affected on the reaction. In the case where the temperature at which the decomposition reaction of the raw material is performed (reaction temperature) is a relatively low temperature (for example, 100 to 200°C), as the reactor, a reactor having a surface treated by glass lining can also be used.

[0049] The space velocity (SV) of the gas containing the raw material (hereinafter, referred to as "raw material gas") is not particularly limited, and is preferably 1000 [1 / h] or less. From the viewpoint of further improving the conversion rate of the raw material, the space velocity of the raw material gas is more preferably 280 [1 / h] or less, and particularly preferably 240 [1 / h] or less. However, the SV is preferably 0.1 [1 / h] or more, more preferably 100 [1 / h] or more, and particularly preferably 200 [1 / h] or more.

[0050] The space velocity of the raw material gas refers to a value measured by a standard conversion reference. The space velocity of the raw material gas can be calculated, for example, from the supply rate (g / h) of the raw material gas and the volume of the solid acid catalyst, according to the following formula.

[0051] Space velocity of raw material gas [1 / h] = supply rate of raw material gas (g / h) x 0.01 x concentration of at least one of formic acid or formic acid alkyl ester in raw material gas (wt%) ÷ molecular weight of formic acid or formic acid alkyl ester (g / mol) x standard state volume 22.4 (NL / mol) ÷ volume of solid acid catalyst (L)

[0052] In addition, in the case where the raw material gas is a gas obtained by gasifying a liquid containing the raw material (hereinafter, referred to as "raw material liquid"), the "concentration of at least one of formic acid or formic acid alkyl ester in the raw material liquid" is written as the "concentration of at least one of formic acid or formic acid alkyl ester in the raw material gas".

[0053] The reaction temperature is a temperature at which the decomposition of the raw material can be performed, and is preferably 100 to 300°C, and more preferably 100 to 200°C. By setting the reaction temperature to 100 to 300°C, there is a tendency to suppress the generation of by-products such as hydrogen, further sufficiently reduce the hydrogen concentration in the manufactured carbon monoxide, and effectively perform the reaction. As the reactor, for example, a reaction column filled with a catalyst is used, and in the case where a heater is provided around the solid acid catalyst, the set temperature of the heater is set to the reaction temperature. The decomposition reaction of the raw material is generally performed in a state where the catalyst, the raw material, or both are heated to the above-mentioned temperature.

[0054] The generated product, carbon monoxide-containing gas or liquid, sometimes contains water and extremely small amounts of hydrogen, carbon dioxide, and methane as by-products. Therefore, the carbon monoxide production method can further include a process of removing unreacted raw material and by-products from the carbon monoxide-containing product (gas or liquid) extracted from the reactor and a process of removing water from the product. The raw material and by-products can be removed by a general cleaning method, and thus carbon monoxide of high purity can be obtained. The raw material and carbon dioxide can be easily removed by, for example, caustic soda. Water can be removed by, for example, cooling and adsorption to a dehydration material. By these processes, the purity of carbon monoxide in the product after removal of water, raw material, and by-products can be 99.99% or more. Such carbon monoxide of high purity can be used for various purposes including the field of semiconductor production.

[0055] Figure 1 is a schematic diagram showing an embodiment of a carbon monoxide production apparatus of the present application. As shown in Figure 1 the carbon monoxide production apparatus 10 of the present application is provided with a reactor 1 and a solid acid catalyst 2 housed in the reactor 1. As the reactor 1, the above-described reactor can be used, and as the solid acid catalyst 2, the above-described solid acid catalyst can be used. The reactor 1 has an inlet la and an outlet lb for supplying or discharging gas or liquid. On the outside of the reactor 1, a flow path 3 for supplying a raw material of at least one of formic acid or formic acid alkyl ester is connected to the inlet la, and a flow path 4 for discharging gas or liquid is connected to the outlet lb. The carbon monoxide production apparatus 10 can further include, as needed, a heating device (not shown) for heating the solid acid catalyst 2, the raw material, or both, a device (not shown) for removing unreacted raw material and by-products from the carbon monoxide-containing product, and a device (not shown) for removing water from the product.

[0056] In the carbon monoxide production apparatus 10, the raw material is supplied to the reactor 1 through the inlet la via the flow path 3 and passes through the solid acid catalyst 2. At this time, carbon monoxide is generated by a decomposition reaction of the raw material in the presence of the solid acid catalyst. The carbon monoxide-containing product is discharged from the outlet lb of the reactor 1 via the flow path 4. In this way, carbon monoxide is produced.

[0057] In addition, the present application is outlined as follows.

[0058] [1] A carbon monoxide production method including a process of generating carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or formic acid alkyl ester in the presence of a solid acid catalyst having a BET specific surface area of 590 m 2 / g or less.

[0059] [2] The carbon monoxide production method according to [1], wherein

[0060] The solid acid catalyst is a proton-type zeolite.

[0061] [3] The carbon monoxide production method according to [2], wherein

[0062] The Si / Al atomic ratio of the proton-type zeolite is 1 to 200.

[0063] [4] The carbon monoxide production method according to any one of [1] to [3], wherein

[0064] The decomposition reaction of the raw material is performed at 100 to 300°C.

[0065] [5] The carbon monoxide production method according to any one of [1] to [4], wherein

[0066] The solid acid catalyst has a BET specific surface area of 480 m 2 / g or less.

[0067] [6] A carbon monoxide production device that produces carbon monoxide through a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst, the carbon monoxide production device comprising a reactor that houses the solid acid catalyst and produces carbon monoxide through a decomposition reaction of the raw material in the presence of the solid acid catalyst, the solid acid catalyst having a BET specific surface area of 590 m 2 / g or less.

[0068] [7] The carbon monoxide production device according to [6], wherein

[0069] The solid acid catalyst is a proton-type zeolite.

[0070] [8] The carbon monoxide production device according to [7], wherein

[0071] The Si / Al atomic ratio of the proton-type zeolite is 1 to 200.

[0072] [9] The carbon monoxide production device according to [6], wherein

[0073] The solid acid catalyst has a BET specific surface area of 480 m 2 / g or less.

[0074] Example

[0075] Hereinafter, the present application will be further concretely described by citing examples. However, the present application is not limited to these examples.

[0076] (Example 1)

[0077] A column having an inner diameter of 2.5 cm and a length of 25 cm as a reactor was packed with a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 20, BET specific surface area: 397 m 2 / g) in a length of 10 cm as a solid acid catalyst. The amount of the zeolite catalyst used was set to 35 g (49 mL). The column packed with the catalyst was heated from the outside with a heater set to 175°C, and a vapor of formic acid at 120°C generated by passing a formic acid aqueous solution having a concentration of 76% by weight through a vaporizer was fed at a feeding rate of 31 g / h from one end of the column. In this way, the vapor of formic acid was brought into contact with the solid acid catalyst, and a decomposition reaction was performed, whereby a gas containing carbon monoxide was generated. At this time, the space velocity of the vapor of formic acid (raw material gas) was 234 [1 / h] on a standard conversion basis.

[0078] Furthermore, the gas discharged from the other end of the column was passed through an aqueous solution of caustic soda having a concentration of 20% by weight and water in this order. With the aqueous solution of caustic soda, a trace amount of carbon dioxide contained in the gas was removed. After the gas passed through the aqueous solution of caustic soda and water was cooled and dried, the amount of hydrogen in the gas was quantified by gas chromatography as a detector equipped with a PDD (Pulsed Discharge Detector), and the conversion rate of formic acid and the selectivity to carbon monoxide were calculated from the amount of hydrogen found and the flow rate of the gas. Furthermore, the rate of improvement in the conversion rate based on Comparative Example 1 was calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 75%, and the rate of improvement in the conversion rate based on Comparative Example 1 was 134%. Furthermore, the selectivity to carbon monoxide was 99.99% or more, and the hydrogen concentration was 2.2 ppm.

[0079] In addition, the BET specific surface area of the solid acid catalyst was measured using a BELSORP-MAX (manufactured by Microtrac BEL Corp.) as an analysis device under the following conditions.

[0080] (Conditions)

[0081] Measurement temperature: -196°C

[0082] Adsorbent: nitrogen

[0083] Equilibrium adsorption time: 300 seconds

[0084] Pretreatment conditions of the solid acid catalyst: heat treatment under vacuum (pump specifications: limit pressure 6.7 x 10 -7 Pa or less) (350°C, 5 h)

[0085] (Example 2)

[0086] As the solid acid catalyst filled in the column, 39 g (49 mL) of a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 110, BET specific surface area: 477 m 2 / g), and otherwise, the reaction was carried out in the same manner as in Example 1 to generate a gas containing carbon monoxide. Also, the conversion rate of formic acid and the selectivity to carbon monoxide were calculated in the same manner as in Example 1, and the improvement rate of the conversion rate based on Comparative Example 1 was calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 60%, and the improvement rate of the conversion rate based on Comparative Example 1 was 88%. Also, the selectivity to carbon monoxide was 99.99% or more. Further, the gas passing through the aqueous caustic soda solution and water was cooled and dried, and then the amount of hydrogen in the gas was quantified by gas chromatography using PDD as a detector, and the hydrogen concentration was calculated from the amount of hydrogen and the flow rate of the gas. The results are shown in Table 1. As shown in Table 1, the hydrogen concentration was 4.9 ppm.

[0087] (Example 3)

[0088] As the solid acid catalyst filled in the column, 36 g (49 mL) of a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 9, BET specific surface area: 485 m 2 / g), and otherwise, the reaction was carried out in the same manner as in Example 1 to generate a gas containing carbon monoxide. Also, the conversion rate of formic acid and the selectivity to carbon monoxide were calculated in the same manner as in Example 1, and the improvement rate of the conversion rate based on Comparative Example 1 was calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 73%, and the improvement rate of the conversion rate based on Comparative Example 1 was 128%. Also, the selectivity to carbon monoxide was 99.99% or more, and the hydrogen concentration was 6.9 ppm.

[0089] (Example 4)

[0090] As the solid acid catalyst filled in the column, 35 g (49 mL) of a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 20, BET specific surface area: 571 m 2 / g), and otherwise, the reaction was carried out in the same manner as in Example 1 to generate a gas containing carbon monoxide. Also, the conversion rate of formic acid and the selectivity to carbon monoxide were calculated in the same manner as in Example 1, and the improvement rate of the conversion rate based on Comparative Example 1 was calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 62%, and the improvement rate of the conversion rate based on Comparative Example 1 was 94%. Also, the selectivity to carbon monoxide was 99.99% or more, and the hydrogen concentration was 6.9 ppm.

[0091] (Example 5)

[0092] A column having an inner diameter of 2.5 cm and a length of 25 cm as a reactor was packed with a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 12, BET specific surface area: 381 m 2 / g) as a solid acid catalyst in a length of 10 cm. The amount of the zeolite catalyst used was set to 40 g (49 mL). The column packed with the catalyst was heated from the outside with a heater set to 175°C, and a vapor of formic acid at 120°C generated by passing a formic acid aqueous solution having a concentration of 76% by weight through a vaporizer was fed from one end of the column at a feed rate of 31 g / h. In this way, the vapor of formic acid was brought into contact with the solid acid catalyst, and a decomposition reaction was performed, thereby generating a gas containing carbon monoxide. At this time, the space velocity of the vapor of formic acid (raw material gas) was 234 [1 / h] on a standard conversion basis.

[0093] Furthermore, the carbon monoxide discharged from the other end of the column was passed through an aqueous caustic soda solution having a concentration of 20% by weight and water in this order. With the aqueous caustic soda solution, a trace amount of carbon dioxide contained in the carbon monoxide was removed. After the gas passed through the aqueous caustic soda solution and water was cooled and dried, the amount of hydrogen in the carbon monoxide was quantified by gas chromatography as a detector equipped with a PDD, and from the amount of hydrogen found and the flow rate of the gas, the conversion rate of formic acid, the selectivity to carbon monoxide, and the hydrogen concentration were found. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 89%, and the rate of increase in the conversion rate based on Comparative Example 1 was 178%. Also, the selectivity to carbon monoxide was 99.99% or more, and the hydrogen concentration was 1.8 ppm.

[0094] In addition, with respect to the BET specific surface area of the solid acid catalyst, the same analysis device as in Example 1 was used, and the measurement was performed under the same conditions as in Example 1.

[0095] (Comparative Example 1)

[0096] As the solid acid catalyst packed in the column, 34 g (49 mL) of a zeolite catalyst (manufactured by TOSOH CORPORATION, Si / Al atomic ratio: 15, BET specific surface area: 599 m 2 / g), except that the reaction was carried out in the same manner as in Example 1 to generate a gas containing carbon monoxide. Furthermore, the conversion rate of formic acid and the selectivity for carbon monoxide were determined in the same manner as in Example 1. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 32%, and the selectivity for carbon monoxide was 99.99% or higher. Additionally, Comparative Example 1 was used as the benchmark for the improvement rate of conversion; therefore, in Table 1, the improvement rate of conversion rate for Comparative Example 1 is shown as "-". Furthermore, the hydrogen concentration was determined in the same manner as in Example 5. The results are shown in Table 1. As shown in Table 1, the hydrogen concentration was 11 ppm.

[0097] (Comparative Example 2)

[0098] As a solid acid catalyst packed in the column, 32 g (49 mL) of a zeolite catalyst (manufactured by TOSOHCORPORATION, Si / Al atomic ratio: 3, BET specific surface area: 614 m²) was used. 2 / g), except that the reaction was carried out in the same manner as in Example 1 to generate a gas containing carbon monoxide. Furthermore, the conversion rate of formic acid and the selectivity for carbon monoxide were determined in the same manner as in Example 1, and the improvement rate of conversion rate compared to Comparative Example 1 was calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 22%, and the improvement rate of conversion rate compared to Comparative Example 1 was -31%. Furthermore, the selectivity for carbon monoxide was 99.99% or higher. In addition, the hydrogen concentration was determined in the same manner as in Example 5. The results are shown in Table 1. As shown in Table 1, the hydrogen concentration was 90 ppm.

[0099] (Comparative Example 3)

[0100] As the solid acid catalyst packed in the column, 35 g (49 mL) of zeolite catalyst (manufactured by TOSOHCORPORATION, Si / Al atomic ratio: 3, BET specific surface area: 662 m²) was used. 2 The reaction was carried out in the same manner as in Example 5, except that the reaction produced a gas containing carbon monoxide. Furthermore, the conversion rate of formic acid, the selectivity for carbon monoxide, and the hydrogen concentration were determined in the same manner as in Example 5. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid was 21%, representing an improvement of -34% compared to Comparative Example 1. Furthermore, the selectivity for carbon monoxide was 99.93% or higher, and the hydrogen concentration was 644 ppm.

[0101] [Table 1]

[0102]

[0103] As shown in Table 1, the conversion rate of raw materials in Examples 1-5 was significantly higher than that in Comparative Examples 1-3.

[0104] It was thus confirmed that if the BET specific surface area of the solid acid catalyst was set to 590 m 2 / g or less, the conversion rate of the raw material could be improved compared to the case where the BET specific surface area of the solid acid catalyst exceeded 590 m 2 / g.

[0105] It was also confirmed from the results shown in Table 1 that the hydrogen concentration in the carbon monoxide was significantly reduced in Examples 1 to 5 compared to Comparative Examples 1 to 3.

[0106] It was thus confirmed that if the BET specific surface area of the solid acid catalyst was set to 590 m 2 / g or less, the hydrogen concentration in the carbon monoxide produced could be sufficiently reduced without performing a purification process for removing hydrogen compared to the case where the BET specific surface area of the solid acid catalyst exceeded 590 m 2 / g.

[0107] Explanation of symbols

[0108] 1 - reactor, la - inlet, lb - outlet, 2 - solid acid catalyst, 3, 4 - flow path, 10 - carbon monoxide production device.

Claims

1. A method for producing carbon monoxide, comprising a step of generating carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst, The solid acid catalyst has a BET specific surface area of 590 m 2 / g or less, the solid acid catalyst is a proton type zeolite.

2. The method for producing carbon monoxide according to claim 1, wherein the Si / Al atomic ratio of the proton type zeolite is 1 to 200.

3. The method for producing carbon monoxide according to claim 1 or 2, wherein the decomposition reaction of the raw material is performed at 100 to 300°C.

4. The method for producing carbon monoxide according to claim 1, wherein The solid acid catalyst has a BET specific surface area of 480 m 2 / g or less.

5. An apparatus for producing carbon monoxide, which generates carbon monoxide by a decomposition reaction of a raw material of at least one of formic acid or a formic acid alkyl ester in the presence of a solid acid catalyst, the apparatus for producing carbon monoxide comprises a reactor which houses the solid acid catalyst and generates carbon monoxide by a decomposition reaction of a raw material in the presence of the solid acid catalyst, The solid acid catalyst has a BET specific surface area of 590 m 2 / g or less, the solid acid catalyst is a proton type zeolite.

6. The apparatus for producing carbon monoxide according to claim 5, wherein the Si / Al atomic ratio of the proton type zeolite is 1 to 200.

7. The apparatus for producing carbon monoxide according to claim 5, wherein The solid acid catalyst has a BET specific surface area of 480 m 2 / g or less.

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