Method and apparatus for producing carbon monoxide

Abstract

A method for producing carbon monoxide, the method comprising a step in which carbon monoxide is produced by a decomposition reaction of at least one of formic acid and a formic acid alkyl ester in the presence of a solid acid catalyst, wherein the total pore volume of pores having a pore diameter of 2 nm or less in the solid acid catalyst is 0.23 cm3 / g or less.

Description

[Technical Field]

[0001] This disclosure relates to a method and apparatus for producing carbon monoxide. [Background technology]

[0002] Conventionally, methods for producing carbon monoxide include steam reforming of natural gas, contact of light hydrocarbons with oxygen in the presence of a partial oxidation catalyst, and decomposition of formic acid. Of these, the method of decomposing formic acid is advantageous because it yields carbon monoxide with high selectivity. Methods for decomposing formic acid to produce carbon monoxide include using mineral acids and using solid acid catalysts. Among these, the method using solid acid catalysts is considered promising as a method that can produce carbon monoxide with a high conversion rate. For example, Patent Document 1 discloses a method for producing carbon monoxide by decomposing formic acid using a solid acid catalyst, and then reducing the hydrogen concentration in the produced carbon monoxide by subjecting it to a purification process using a palladium catalyst or the like. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Korean Published Patent Publication No. 2016-0173781 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the method described in Patent Document 1 above had the following problems. In other words, the method described in Patent Document 1 involves a purification process using a palladium catalyst or the like to reduce the hydrogen concentration of carbon monoxide produced by the decomposition of formic acid. Therefore, the method described in Patent Document 1 had room for improvement in terms of efficiently and inexpensively producing high-purity carbon monoxide. Therefore, there was a need for a method of producing carbon monoxide that could sufficiently reduce the hydrogen concentration in the produced carbon monoxide without performing a purification process to remove hydrogen.

[0005] Accordingly, the present disclosure aims to provide a method and apparatus for producing carbon monoxide that can sufficiently reduce the hydrogen concentration in the produced carbon monoxide without performing a purification step to remove hydrogen. [Means for solving the problem]

[0006] The inventors diligently investigated the above problem. Specifically, they focused on the total pore volume of the solid acid catalyst. Generally, solid acids have pores that adsorb molecules. For example, zeolites are solid acids with micropores, which are pores with a diameter of 2 nm or less, and they adsorb molecules with a smaller diameter than this. Also, because catalysts have a porous structure, many of the active sites are located within the pores, and they react with the raw material molecules through contact between the active sites and the raw material molecules. Therefore, generally, the larger the total pore volume, the greater the amount of raw material molecules adsorbed on the solid acid. The inventors predicted that by increasing the total pore volume, the raw material would be effectively decomposed, resulting in improved selectivity from the raw material to carbon monoxide and a reduction in the concentration of hydrogen, an impurity in the produced carbon monoxide. However, surprisingly, it was found that a smaller total pore volume of the solid acid catalyst resulted in a reduction in the hydrogen concentration in the produced carbon monoxide. Based on this finding, the inventors further diligently conducted research and found that the above problem can be solved by the following disclosure.

[0007] In other words, one aspect of this disclosure includes a step of generating carbon monoxide by a decomposition reaction of at least one of formic acid or alkyl formate as a raw material in the presence of a solid acid catalyst, wherein the solid acid catalyst has a total pore volume of 0.23 cm³ with pores having a pore diameter of 2 nm or less. 3 This is a method for producing carbon monoxide in a quantity of less than / g. According to the present disclosure, in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.23 cm 3 / g or more, 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 disclosure, high-purity carbon monoxide can be efficiently produced at low cost. Alternatively, according to the present disclosure, in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.23 cm 3 / g or more, the conversion rate of the raw material can be improved. Therefore, according to the method for producing carbon monoxide of the present disclosure, carbon monoxide can be efficiently produced.

[0008] In the above method for producing carbon monoxide, in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is preferably 0.20 cm 3 / g or less. In this case, the conversion rate of the raw material can be further improved, and the hydrogen concentration in the produced carbon monoxide can be more sufficiently reduced without performing a purification step for removing hydrogen.

[0009] In the above method for producing carbon monoxide, in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is more preferably 0.19 cm 3 / g or less. In this case, the conversion rate of the raw material can be improved, and the hydrogen concentration in the produced carbon monoxide can be more sufficiently reduced without performing a purification step for removing hydrogen.

[0010] In the above method for producing carbon monoxide, the solid acid catalyst is, for example, a proton type zeolite.

[0011] In the above method for producing carbon monoxide, the Si / Al atomic ratio of the proton type zeolite is preferably from 1 to 200. In this case, the catalytic activity of the zeolite is further improved, and the conversion rate of the raw material can be further improved.

[0012] In the method for producing carbon monoxide described above, it is preferable that the decomposition reaction of the raw material is carried out at 100 to 300°C. In this case, there is a tendency that the decomposition reaction can proceed efficiently while more sufficiently reducing the hydrogen concentration in the produced carbon monoxide.

[0013] Another aspect of the present disclosure is a carbon monoxide production apparatus that produces carbon monoxide by a decomposition reaction of at least one of formic acid or an alkyl formate in the presence of a solid acid catalyst, the apparatus including a reactor that contains the solid acid catalyst and produces carbon monoxide by the decomposition reaction of the raw material in the presence of the solid acid catalyst, and in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.23 cm 3 / g or less, which is a carbon monoxide production apparatus. According to this carbon monoxide production apparatus, in the reactor, when carbon monoxide is produced by the decomposition reaction of at least one of formic acid or an alkyl formate in the presence of a solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less in the solid acid catalyst is 0.23 cm 3 / g, the hydrogen concentration in the produced carbon monoxide can be sufficiently reduced without performing a purification step for removing hydrogen as compared with the case where it exceeds / g. Therefore, according to the carbon monoxide production apparatus of the present disclosure, high-purity carbon monoxide can be efficiently produced at low cost. Alternatively, according to the carbon monoxide production apparatus described above, in the reactor, when carbon monoxide is produced by the decomposition reaction of at least one of formic acid or an alkyl formate in the presence of a solid acid catalyst, in the solid acid catalyst, the total pore volume of pores having a pore diameter of less than 2 nm is 0.23 cm 3 / g, the conversion rate of the raw material can be improved as compared with the case where it exceeds / g. Therefore, according to the carbon monoxide production apparatus of the present disclosure, carbon monoxide can be efficiently produced.

[0014] In the carbon monoxide production apparatus described above, in the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.20 cm3 It is preferably below / g. In this case, the conversion rate of the raw material can be further improved, and the hydrogen concentration in the produced carbon monoxide can be more sufficiently reduced without performing a purification step for removing hydrogen.

Advantages of the Invention

[0015] According to the present disclosure, there are provided a method and an apparatus for producing carbon monoxide capable of sufficiently reducing the hydrogen concentration in the produced carbon monoxide without performing a purification step for removing hydrogen.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram showing an embodiment of an apparatus for producing carbon monoxide of the present disclosure. [Figure 2] It is a diagram showing the relationship between the hydrogen concentration in Examples 1 to 3 and Comparative Example 1 and the total pore volume of pores having a pore diameter of 2 nm or less. [Figure 3] It is a diagram showing the relationship between the conversion rate of the raw material in Examples 1 to 3 and Comparative Example 1 and the total pore volume of pores having a pore diameter of 2 nm or less.

Modes for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments.

[0018] The method for producing carbon monoxide according to the present disclosure includes a step of generating carbon monoxide by a decomposition reaction of at least one of formic acid or an alkyl formate ester in the presence of a solid acid catalyst. As the solid acid catalyst, a solid acid catalyst having a total pore volume of pores (hereinafter also referred to as "micropores") having a pore diameter of 2 nm or less of 0.23 cm 3 or less per gram is used. The method for producing carbon monoxide according to the present disclosure can be implemented by, for example, a carbon monoxide production apparatus including a reactor that houses the above solid acid catalyst and generates carbon monoxide by a decomposition reaction of a raw material in the presence of the solid acid catalyst.

[0019] (solid acid catalyst) While the solid acid catalyst is not particularly limited, proton-type zeolites are preferably used as solid acid catalysts. Examples of proton-type zeolites include mordenite, ZSM-5, beta-type, Y-type, and US-Y-type zeolites. As a proton-type zeolite catalyst, for example, high-silica zeolite catalysts manufactured by Tosoh Corporation can be used.

[0020] In solid acid catalysts, the total pore volume of micropores is 0.23 cm³. 3 The amount is less than or equal to / g. In the solid acid catalyst, the total pore volume of the micropores is 0.23 cm³. 3 If the value is less than / g, the total pore volume of the micropores is 0.23 cm³. 3 Compared to using a solid acid catalyst with a concentration exceeding / g, the hydrogen concentration in the produced carbon monoxide can be sufficiently reduced without a purification process to remove hydrogen. Alternatively, in a solid acid catalyst, if the total pore volume of pores with a pore diameter of 2 nm or less is 0.23 cm³ 3 Compared to cases where the value exceeds / g, the conversion rate of the raw material can be improved. Therefore, carbon monoxide can be produced efficiently according to the carbon monoxide production method of this disclosure. From the viewpoint of improving the conversion rate of the raw material and more sufficiently reducing the hydrogen concentration in the produced carbon monoxide without performing a purification step to remove hydrogen, the total pore volume of the micropores of the solid acid catalyst is preferably 0.20 cm³. 3 It is less than or equal to / g, and more preferably 0.19cm 3 It is less than or equal to / g, and more preferably 0.18cm 3 It is less than or equal to / g, and particularly preferably 0.15cm 3 It is less than or equal to / g. However, in the solid acid catalyst, the total pore volume of the micropores is preferably 0.10 cm³. 3 It is 0.12 cm² or more, and more preferably 0.12 cm². 3 The amount is greater than or equal to / g. In solid acid catalysts, the total pore volume of micropores is 0.10 cm³. 3When the amount is above / g, the decomposition reaction of the raw material proceeds more easily, and as a result, the conversion rate of the raw material tends to improve.

[0021] Pore ​​diameter refers to the value dp obtained by analyzing the measurement results, which are obtained using the BELSORP-MAX analytical instrument (Microtrac-Bel) under the following conditions, using the SF method with the analysis software BELMaster (Microtrac-Bel). (conditions) Measurement temperature: -196℃ Adsorbent: Nitrogen Equilibrium adsorption time: 300 seconds Pretreatment conditions for solid acid catalyst: Under vacuum (Pump specifications: Ultimate pressure 6.7 × 10⁻⁶) -7 Heat treatment (350°C, 5h) at temperatures below Pa.

[0022] The total pore volume of pores having a pore diameter of 2 nm or less is the integrated value ΣVp of pore volume, which can be analyzed and calculated by the SF method in the same way as the pore diameter, and refers to the value when the pore diameter dp calculated as described above is 2 nm or less.

[0023] The Si / Al atomic ratio of the proton-type zeolite used as a solid acid catalyst is not particularly limited, but is preferably 1 or more, and more preferably 5 or more. When the Si / Al atomic ratio is 1 or more, the catalytic activity of the zeolite tends to improve, and the conversion rate of the raw material tends to improve. The Si / Al atomic ratio is preferably 200 or less, more preferably 150 or less, even more preferably 100 or less, and particularly preferably 50 or less. When the Si / Al atomic ratio is 200 or less, the catalytic activity of the zeolite tends to improve, and the conversion rate of the raw material tends to improve. 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 solid acid catalyst, the total pore volume of the micropores is 0.19 cm³. 3If the amount is less than / g, the Si / Al atomic ratio is preferably 5 to 100, more preferably 5 to 50, even more preferably 5 to 30, and particularly preferably 5 to 20. In the solid acid catalyst, the total pore volume of the micropores is 0.19 cm³. 3 When the Si / Al atomic ratio is between 5 and 100 and the amount is less than / g, the conversion rate of the raw material improves significantly. The Si / Al atomic ratio can be determined by solid-state NMR spectroscopy.

[0024] (raw materials) Examples of raw materials include formic acid and alkyl formate esters. These can be used individually or in mixtures. Examples of alkyl formate esters include methyl formate and ethyl formate.

[0025] (Decomposition reaction) The decomposition reaction of the raw material is carried out by contacting the raw material with a solid acid catalyst and heating it to decompose it. Alternatively, the decomposition reaction of the raw material may be carried out by contacting the raw material with a solid acid catalyst that has been pre-modified with a mineral acid and heating it to decompose it. Contact between the raw material and the solid acid catalyst can be carried out, for example, by contacting a gas or liquid containing the raw material with the solid acid catalyst. When contacting a gas containing the raw material with the solid acid catalyst, a gas containing the vapor of the raw material may be generated from a solution containing the raw material using a vaporizer or the like, and this may be supplied to the solid acid catalyst for contact. It is preferable to carry out the contact between the raw material and the solid acid catalyst by contacting a gas containing the raw material with the solid acid catalyst. In this case, the efficiency of the decomposition reaction tends to improve. When using a liquid containing the raw material, the concentration of the raw material in the liquid is not particularly limited, but from the viewpoint of energy efficiency, it is preferable to have a concentration of 40% by mass or more, based on the mass of the solution (100% by mass). An example of a liquid containing the raw material is an aqueous solution of formic acid.

[0026] Reactors can be a reaction vessel or a reaction tower packed with a catalyst. When using a reaction vessel, carbon monoxide can be generated by placing the catalyst and raw materials in the vessel and heating it. When using a reaction tower packed with a catalyst, carbon monoxide can be generated by passing the vapor of the raw materials through the catalyst packed in the tower and heating it. Considering reaction efficiency, it is preferable to use a reaction tower packed with a catalyst as the reactor. There may be one reaction tower or multiple reaction towers connected together. A reactor composed of multiple reaction towers is advantageous in terms of suppressing uneven distribution of flow velocity within the reactor and securing a heat transfer area for heating. When gas or liquid containing raw materials is continuously supplied to the reactor, the reactor usually has an inlet and outlet for supplying or discharging the gas or liquid, and these are connected to an external flow path.

[0027] The reactor is constructed from a non-metallic material, such as carbon. Reactors made from non-metallic materials are less susceptible to corrosion by the raw materials and carbon monoxide, and are less likely to affect the reaction. When the temperature at which the decomposition reaction of the raw materials takes place (reaction temperature) is relatively low (for example, 100-200°C), it is also possible to use a reactor with a glass-lined surface.

[0028] The space velocity (SV) of the gas containing the raw materials (hereinafter referred to as "raw material gas") is not particularly limited, but is preferably 1000 [1 / h] or less. From the viewpoint of further improving the conversion rate of the raw materials, the SV 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. The space velocity of the raw material gas refers to the value measured on a normal basis. The space velocity of the raw material gas can be calculated, for example, from the supply rate of the raw material gas (g / h) and the volume of the solid acid catalyst, based on the following formula. Space velocity of the raw material gas [1 / h] = Raw material gas supply rate (g / h) × 0.01 ×Concentration (by weight) of at least one of formic acid or alkyl formic ester in the raw material gas ÷ Molecular weight (g / mol) of formic acid or alkyl formate (raw material) × Standard volume: 22.4 (NL / mol) ÷ Volume of solid acid catalyst (L) Furthermore, if the raw material gas is a gas obtained by vaporizing a liquid containing the raw materials (hereinafter referred to as the "raw material liquid"), then "the concentration of at least one of formic acid or alkyl formate in the raw material liquid" shall be defined as "the concentration of at least one of formic acid or alkyl formate in the raw material gas."

[0029] The reaction temperature should be any temperature that allows for the decomposition of the raw materials, but is preferably 100 to 300°C, and more preferably 100 to 200°C. Setting the reaction temperature to 100 to 300°C tends to allow the reaction to proceed efficiently while more sufficiently reducing the hydrogen concentration in the carbon monoxide produced or suppressing the generation of by-products such as hydrogen. If a reaction tower packed with catalyst is used as the reactor, for example, and a heater is installed around the solid acid catalyst, the set temperature of the heater is used as the reaction temperature. The decomposition reaction of the raw materials is usually carried out with the catalyst, raw materials, or both of these heated to the above temperature.

[0030] The carbon monoxide produced may contain trace amounts of hydrogen, carbon dioxide, and methane as by-products, in addition to water. Therefore, the method for producing carbon monoxide may further include steps to remove unreacted raw materials and by-products from the carbon monoxide removed from the reactor, and steps to remove water from the carbon monoxide. The raw materials and by-products can be removed by conventional washing methods, thereby obtaining high-purity carbon monoxide. The raw materials and carbon dioxide can be easily removed, for example, with caustic soda. Water can be removed, for example, by cooling or adsorption with a dehydrating agent. It is possible to achieve a purity of 99.99% or higher for the carbon monoxide after these steps have removed water, raw materials, and by-products. Such high-purity carbon monoxide can be used in a variety of applications, including in the semiconductor manufacturing field.

[0031] Figure 1 is a schematic diagram showing one embodiment of a carbon monoxide production apparatus of the present disclosure. As shown in Figure 1, the carbon monoxide production apparatus 10 of the present disclosure comprises a reactor 1 and a solid acid catalyst 2 housed in the reactor 1. The reactor 1 is the reactor described above, and the solid acid catalyst 2 is the solid acid catalyst described above. The reactor 1 has an inlet 1a and an outlet 1b for supplying or discharging gas or liquid. Outside the reactor 1, a channel 3 for supplying at least one of formic acid or alkyl formic acid as a raw material is connected to the inlet 1a, and a channel 4 for discharging gas or liquid is connected to the outlet 1b. The carbon monoxide production apparatus 10 may further optionally include a heating device (not shown) for heating the solid acid catalyst 2, the raw materials or both, a device (not shown) for removing unreacted raw materials and by-products from the carbon monoxide-containing product, and a device (not shown) for removing water from the product.

[0032] In the carbon monoxide production apparatus 10, the raw materials are supplied to the reactor 1 through the inlet 1a via the flow path 3 and pass through the solid acid catalyst 2. At this time, carbon monoxide is produced by the decomposition reaction of the raw materials in the presence of the solid acid catalyst. The product containing carbon monoxide is discharged from the outlet 1b of the reactor 1 through the flow path 4. In this way, carbon monoxide is produced.

[0033] The summary of this disclosure is as follows: [1] The process includes generating carbon monoxide by a decomposition reaction of at least one of the raw materials, formic acid or alkyl formate, in the presence of a solid acid catalyst, wherein the solid acid catalyst has pores with a pore diameter of 2 nm or less and the total pore volume of pores is 0.23 cm³. 3 A method for producing carbon monoxide that is less than or equal to / g. [2] In the solid acid catalyst, the total pore volume of the pores is 0.20 cm³. 3 A method for producing carbon monoxide as described in [1], wherein the amount is less than or equal to / g. [3] In the solid acid catalyst, the total pore volume of the pores is 0.19 cm³. 3 A method for producing carbon monoxide as described in [2], wherein the amount is less than or equal to / g. [4] A method for producing carbon monoxide according to any one of [1] to [3], wherein the solid acid catalyst is a proton-type zeolite. [5] The method for producing carbon monoxide according to [4], wherein the Si / Al atomic ratio of the proton-type zeolite is 1 to 200. [6] A method for producing carbon monoxide according to any one of [1] to [5], wherein the decomposition reaction of the raw materials is carried out at 100 to 300°C. [7] A carbon monoxide production apparatus for producing carbon monoxide by the decomposition reaction of at least one of formic acid or alkyl formate as a raw material in the presence of a solid acid catalyst, comprising a reactor containing the solid acid catalyst and for producing carbon monoxide by the decomposition reaction of the raw material in the presence of the solid acid catalyst, wherein the solid acid catalyst has a total pore volume of 0.23 cm³ of pores with a pore diameter of 2 nm or less. 3 A carbon monoxide production apparatus that produces carbon monoxide at a concentration of less than / g. [8] In the solid acid catalyst, the total pore volume of the pores is 0.20 cm³. 3 A carbon monoxide production apparatus as described in [7], wherein the amount is less than or equal to / g. [Examples]

[0034] The present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited to the following examples.

[0035] (Example 1) A zeolite catalyst (manufactured by Tosoh Corporation, Si / Al atomic ratio: 12, total pore volume of micropores: 0.15 cm) was used as a solid acid catalyst in a column with an inner diameter of 2.5 cm and a length of 25 cm. 3 A column was packed with zeolite catalyst (1 / g) to a length of 10 cm. The amount of zeolite catalyst used was 40 g (49 mL). The column packed with catalyst was heated externally with a heater set to 175°C, and 120°C formic acid vapor, generated by passing a 76 wt% formic acid aqueous solution through a vaporizer, was fed from one end of the column at a supply rate of 31 g / h. In this way, the formic acid vapor was brought into contact with the solid acid catalyst and decomposed to produce carbon monoxide. At this time, the space velocity of the formic acid vapor (raw material gas) was 234 [1 / h] on a normal basis. Then, the carbon monoxide discharged from the other end of the column was passed through a 20% by weight aqueous solution of caustic soda, followed by water. The caustic soda solution removed trace amounts of carbon dioxide contained in the carbon monoxide. After cooling and drying the carbon monoxide that had passed through the caustic soda solution and water, the amount of hydrogen in the carbon monoxide was quantified using gas chromatography equipped with a PDD (Pulsed Discharge Detector) as the detector. From the determined amount of hydrogen and the flow rate of carbon monoxide, the conversion rate of formic acid (raw material), the selectivity to carbon monoxide, and the hydrogen concentration were determined. The improvement rate of the conversion rate relative to Example 3 was also calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid (raw material) was 89%, and the improvement rate of the conversion rate relative to Example 3 was 178%. Furthermore, the selectivity to carbon monoxide was 99.99% or higher, and the hydrogen concentration was 1.8 ppm. Furthermore, the total pore volume of the micropores in the solid acid catalyst was measured using a BELSORP-MAX analyzer (Microtrac-Bel) under the following conditions. (conditions) Measurement temperature: -196℃ Adsorbent: Nitrogen Equilibrium adsorption time: 300 seconds Pretreatment conditions for solid acid catalyst: Under vacuum (Pump specifications: Ultimate pressure 6.7 × 10⁻⁶) -7Heat treatment (350°C, 5h) at temperatures below Pa.

[0036] (Example 2) As the solid acid catalyst to be packed into the column, 39 g (49 mL) of zeolite catalyst (manufactured by Tosoh Corporation, Si / Al atomic ratio: 110, total pore volume of micropores: 0.19 cm³) was used. 3 The reaction was carried out in the same manner as in Example 1, except that ( / g) was used, to produce carbon monoxide. The conversion rate of formic acid (raw material), the selectivity for carbon monoxide, and the hydrogen concentration were then determined in the same manner as in Example 1. The improvement rate of the conversion rate relative to Example 3 was also calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid (raw material) was 60%, and the improvement rate of the conversion rate relative to Example 3 was 88%. Furthermore, the selectivity for carbon monoxide was 99.99% or higher, and the hydrogen concentration was 4.9 ppm.

[0037] (Example 3) As the solid acid catalyst to be packed into the column, 34 g (49 mL) of zeolite catalyst (manufactured by Tosoh Corporation, Si / Al atomic ratio: 15, total pore volume of micropores: 0.23 cm³) was used. 3 The reaction was carried out in the same manner as in Example 1, except that ( / g) was used, to produce carbon monoxide. The conversion rate of formic acid (raw material), the selectivity for carbon monoxide, and the hydrogen concentration were then determined in the same manner as in Example 1. The improvement rate of the conversion rate relative to Example 3 was also calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid (raw material) was 32%, and the improvement rate of the conversion rate relative to Example 3 was 0%. The selectivity for carbon monoxide was 99.99% or higher, and the hydrogen concentration was 11 ppm.

[0038] (Comparative Example 1) As the solid acid catalyst to be packed into the column, 35 g (49 mL) of zeolite catalyst (manufactured by Tosoh Corporation, Si / Al atomic ratio: 3, total pore volume of micropores: 0.25 cm³) was used. 3The reaction was carried out in the same manner as in Example 1, except that ( / g) was used, to produce carbon monoxide. The conversion rate of formic acid (raw material), the selectivity for carbon monoxide, and the hydrogen concentration were then determined in the same manner as in Example 1. The improvement rate of the conversion rate relative to Example 3 was also calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid (raw material) was 21%, and the improvement rate of the conversion rate relative to Example 3 was -34%. The selectivity for carbon monoxide was 99.93% or higher, and the hydrogen concentration was 644 ppm.

[0039] (Comparative Example 2) As the solid acid catalyst to be packed into the column, 32 g (49 mL) of zeolite catalyst (manufactured by Tosoh Corporation, Si / Al atomic ratio: 3, total pore volume of micropores: 0.24 cm³) was used. 3 The reaction was carried out in the same manner as in Example 1, except that ( / g) was used, to produce carbon monoxide. The conversion rate of formic acid (raw material), the selectivity for carbon monoxide, and the hydrogen concentration were then determined in the same manner as in Example 1. The improvement rate of the conversion rate relative to Example 3 was also calculated. The results are shown in Table 1. As shown in Table 1, the conversion rate of formic acid (raw material) was 22%, and the improvement rate of the conversion rate relative to Example 3 was -31%. The selectivity for carbon monoxide was 99.99% or higher, and the hydrogen concentration was 90 ppm.

[0040] [Table 1]

[0041] Figure 2 shows the relationship between the total pore volume of micropores and the hydrogen concentration in the solid acid catalysts of Examples 1-3 or Comparative Example 1. From the results shown in Table 1 and Figure 2, it was found that the hydrogen concentration in carbon monoxide was significantly lower in Examples 1-3 compared to Comparative Example 1. From this, it can be concluded that the total pore volume of micropores in a solid acid catalyst is 0.23 cm³. 3 When the amount is less than / g, the total pore volume of the micropores in the solid acid catalyst becomes 0.23 cm³. 3It was confirmed that the hydrogen concentration in the carbon monoxide produced can be sufficiently reduced compared to cases where the concentration exceeds / g, without the need for a purification process to remove hydrogen.

[0042] Furthermore, Figure 3 shows the relationship between the total pore volume of micropores and the conversion rate of the raw materials in the solid acid catalysts of Examples 1-3 or Comparative Examples 1-2. From the results shown in Table 1 and Figure 3, it was found that Examples 1-3 showed a significantly higher conversion rate of the raw materials compared to Comparative Examples 1-2. From this, the total pore volume of the micropores in the solid acid catalyst is 0.20 cm³. 3 When the amount is less than / g, the total pore volume of the micropores in the solid acid catalyst becomes 0.20 cm³. 3 It was confirmed that the conversion rate of the raw material can be further improved compared to cases where the value exceeds / g. [Explanation of Symbols]

[0043] 1... Reactor, 1a... Inlet, 1b... Outlet, 2... Solid acid catalyst, 3, 4... Flow channels, 10... Carbon monoxide production apparatus.

Claims

1. The process includes a step of generating carbon monoxide by the decomposition reaction of at least one of the raw materials, formic acid or alkyl formate, in the presence of a solid acid catalyst. The solid acid catalyst is a proton-type zeolite, In the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.23 cm³. ３ A method for producing carbon monoxide that is less than or equal to / g.

2. In the solid acid catalyst, the total pore volume of the pores is 0.20 cm³. ３ A method for producing carbon monoxide according to claim 1, wherein the amount is less than or equal to / g.

3. In the solid acid catalyst, the total pore volume of the pores is 0.19 cm³. ３ A method for producing carbon monoxide according to claim 2, wherein the amount is less than or equal to / g.

4. 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.

5. A method for producing carbon monoxide according to any one of claims 1 to 4, wherein the decomposition reaction of the raw material is carried out at 100 to 300°C.

6. A carbon monoxide production apparatus that generates carbon monoxide by the decomposition reaction of at least one of formic acid or alkyl formate as a raw material in the presence of a solid acid catalyst, The reactor comprises a solid acid catalyst and a reactor that generates carbon monoxide by a decomposition reaction of the raw materials in the presence of the solid acid catalyst, The solid acid catalyst is a proton-type zeolite, In the solid acid catalyst, the total pore volume of pores having a pore diameter of 2 nm or less is 0.23 cm³. ３ A carbon monoxide production apparatus that produces carbon monoxide at a concentration of less than / g.

7. In the solid acid catalyst, the total pore volume of the pores is 0.20 cm³. ３ A carbon monoxide production apparatus according to claim 6, wherein the amount is less than or equal to / g.

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