Metal catalyst and method for hydrogenolysis of cyclic compound using same

Abstract

A cyclic compound having a five-membered ring structure included in a saturated cyclic compound serving as a hydrogen carrier is selectively hydrogenolyzed. A metal catalyst for use in hydrogenolysis of a cyclic compound having a five-membered ring structure, the cyclic compound being included in a saturated cyclic compound serving as a hydrogen carrier, the metal catalyst comprising: a silica-based carrier as a catalyst carrier; and iridium or rhodium as a metal supported on the catalyst carrier.

Description

[Technical field]

[0001] The present invention relates to a metal catalyst for hydrogenolysis of a cyclic compound having a five-membered ring structure and a method for hydrogenolysis of a cyclic compound using the metal catalyst. [Background technology]

[0002] As is well known, the Organic Chemical Hydride Method is a traditional method for storing and transporting hydrogen (see non-patent literature 1, 2). The Organic Chemical Hydride Method includes, for example, a hydrogenation reaction (hydrogen storage reaction) in which aromatic compounds such as toluene react with hydrogen, and a dehydrogenation reaction (hydrogen production reaction) in which aromatic compounds such as toluene are recovered by generating hydrogen from saturated cyclic compounds such as methylcyclohexane (hydrogenated aromatics). According to the Organic Chemical Hydride Method, saturated cyclic compounds into which hydrogen is introduced can be stored and transported in a liquid state at normal temperature and pressure, and the required amount of hydrogen can be extracted by dehydrogenation of saturated cyclic compounds at places where hydrogen is used. Saturated cyclic compounds such as methylcyclohexane or aromatic compounds such as toluene generated after hydrogen is extracted from saturated cyclic compounds are repeatedly used as hydrogen carriers (hydrogen carriers).

[0003] It is well known that in the hydrogenation reaction and dehydrogenation reaction of the organic chemical hydride method, various by-products (impurities) are generated in addition to the target product (see Patent Document 1). [Prior art literature] [Patent Literature]

[0004] [Non-patent document 1] Okada Yoshimi, Energy and Resources, Vol. 39, No. 3, 168 (2018) [Non-patent document 2] Okada Yoshimi, Bulletin of the Tokyo High Pressure Gas Association, July, August, and September 2019 [Non-patent document 3] Cui Xieli, Ishii Mika, Nanba Tetsuya, Tsujimura Taku, Takaaki Taniguchi, 46th Petroleum and Petrochemical Symposium, Lecture Draft, 2A03 (2016) [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-269522 [Summary of the invention] [Problems to be solved by the invention]

[0005] In the above-mentioned organic chemical hydride method, the ratio of impurities mixed in the hydrogen carrier gradually increases by repeating hydrogenation reaction and dehydrogenation reaction. Therefore, it is considered that such impurities can be removed (separated) from the hydrogen carrier by distilling the hydrogen carrier containing impurities.

[0006] In particular, as impurities that may be mixed into the hydrogen carrier, there are cyclic compounds having a five-membered ring structure such as cyclopentane generated in the dehydrogenation reaction (hereinafter referred to as five-membered ring structure compounds.) (See Non-Patent Document 3). Since the boiling points of such five-membered ring structure compounds are relatively close to the boiling points of the hydrogen carrier, it is not easy to separate these five-membered ring structure compounds from the hydrogen carrier by distillation.

[0007] Therefore, after intensive research, the inventors of the present application developed a metal catalyst that can selectively hydrogenolyze a five-membered ring structure compound mixed with a hydrogen carrier, and as a result, the five-membered ring structure compound can be converted from the hydrogen carrier into light hydrocarbons that are hydrogenolyzed and can be easily separated.

[0008] In view of the above situation, an object of the present invention is to provide a metal catalyst capable of selectively hydrogenolyzing a cyclic compound having a five-membered ring structure contained in a saturated cyclic compound serving as a hydrogen carrier, and a method for hydrogenolysis of a cyclic compound using the metal catalyst.

Methods to solve the problem

[0009] In order to solve the above-mentioned problems, one embodiment of the present invention is a metal catalyst for use in the hydrogenolysis of a cyclic compound having a five-membered ring structure, wherein the cyclic compound is contained in a saturated cyclic compound used as a hydrogen carrier, and the metal catalyst comprises: a silica-based carrier as a catalyst carrier; and iridium or rhodium as a metal supported on the catalyst carrier.

[0010] According to this mode, the cyclic compound having a five-membered ring structure contained in the saturated cyclic compound used as a hydrogen carrier can be selectively hydrogenolyzed. In other words, when the cyclic compound having a five-membered ring structure is mixed in the hydrogen carrier and hydrogenolyzed, the hydrogenolysis can be appropriately performed while suppressing the loss of the hydrogen carrier (i.e., unintended chemical reaction).

[0011] In the above embodiment, it is preferred that the metal supported on the catalyst carrier is iridium, and the metal contains 0.1 to 5% by weight of iridium.

[0012] According to such an embodiment, by supporting an appropriate amount of iridium on the catalyst carrier, hydrogenolysis of a cyclic compound having a five-membered ring structure can be stably performed.

[0013] In the above embodiment, it is preferred that the metal supported on the catalyst carrier is rhodium, and the metal contains 0.5 to 2% by weight of rhodium.

[0014] According to such an embodiment, by supporting an appropriate amount of rhodium on the catalyst carrier, hydrogenolysis of a cyclic compound having a five-membered ring structure can be stably performed.

[0015] In the above aspect, the silica-based support preferably contains amorphous silica.

[0016] According to such an embodiment, by using a silica-based support having an appropriate structure as a catalyst support, hydrogenolysis of a cyclic compound having a five-membered ring structure can be stably performed.

[0017] In the above aspect, the silica-based support preferably contains MFI zeolite.

[0018] According to such an embodiment, by using a silica-based support having an appropriate structure as a catalyst support, hydrogenolysis of a cyclic compound having a five-membered ring structure can be stably performed.

[0019] In order to solve the above-mentioned problems, one embodiment of the present invention is a hydrogenolysis method, which uses a metal catalyst to hydrogenolyze a cyclic compound with a five-membered ring structure contained in a saturated cyclic compound used as a hydrogen carrier, generates an aromatic compound and a cyclic compound with a five-membered ring structure as an impurity thereof through a dehydrogenation reaction of the saturated cyclic compound, performs a hydrogenation reaction on the aromatic compound mixed with the impurity, and hydrogenolyzes the mixture of the saturated cyclic compound and the impurity generated by the hydrogenation reaction of the aromatic compound using the metal catalyst.

[0020] According to such an aspect, in a system based on an organic chemical hydride method, a cyclic compound having a five-membered ring structure contained in a saturated cyclic compound serving as a hydrogen carrier can be selectively hydrogenolyzed.

[0021] In the above embodiment, the hydrogenolysis is performed by supplying the mixture of the saturated cyclic compound and the impurity together with 50 to 99.8 mol % of hydrogen to the metal catalyst whose catalyst layer is maintained at a temperature of 150° C. to 300° C.

[0022] According to such an embodiment, the mixture of the saturated cyclic compound and the impurities is hydrogenolyzed together with 50 to 99.8 mol % of hydrogen at an appropriate catalyst temperature, so that the cyclic compound having a five-membered ring structure can be stably hydrogenolyzed. [Effects of the invention]

[0023] According to the above aspect, the cyclic compound having a five-membered ring structure contained in the saturated cyclic compound serving as a hydrogen carrier can be selectively hydrogenolyzed.

Brief Description of the Drawings

[0024] Figure 1 It is a schematic block diagram showing the structure of a hydrogen storage and transportation system in an embodiment. Figure 2This is a specification showing the relationship between the by-products of the dehydrogenation reaction of methylcyclohexane and their boiling points. Figure 3 This is a diagram illustrating the hydrogenolysis of methylcyclopentane. [Specific implementation method]

[0025] The following describes a method for hydrogenolysis of a cyclic compound having a five-membered ring structure (hereinafter referred to as a five-membered ring structure compound) using a metal catalyst according to an embodiment of the present invention with reference to the drawings. Here, the metal catalyst and the method for hydrogenolysis using the metal catalyst are described as being applicable to a method based on Figure 1 An example of a hydrogen storage and transportation system 1 using an organic chemical hydride method is shown.

[0026] The hydrogen storage and transportation system 1 includes a hydrogenation plant 2 for generating a saturated cyclic compound as an organic hydride by adding hydrogen to an aromatic compound, and a dehydrogenation device 3 for generating hydrogen and an aromatic compound by dehydrogenating the saturated cyclic compound. Here, an example is described in which methylcyclohexane (abbreviated as "MCH" as needed) is used as the saturated cyclic compound and toluene (abbreviated as "TOL" as needed) is used as the aromatic compound.

[0027] The hydrogenation device 2 has a hydrogenation reaction device 11 that generates methylcyclohexane by performing a hydrogenation reaction of adding hydrogen (H2) to toluene based on a known method. The hydrogenation device 2 is provided with a storage device 4. The storage device 4 has an MCH storage tank 12 that stores the methylcyclohexane generated by the hydrogenation reaction device 11. In addition, the storage device 4 has a TOL storage tank 13 for storing toluene transported from the dehydrogenation device 3 side (i.e., the storage device 5).

[0028] The dehydrogenation device 3 has a dehydrogenation reaction device 21 that generates hydrogen and toluene by performing a dehydrogenation reaction of methylcyclohexane based on a known method. The dehydrogenation device 3 is provided with a storage device 5. The storage device 5 has a TOL storage tank 22 for storing toluene generated by the dehydrogenation reaction device 21. In addition, the storage device 5 has an MCH storage tank 23 for storing methylcyclohexane transported from the hydrogenation device 2 side (storage device 4).

[0029] In the hydrogen storage and transportation system 1, the methylcyclohexane stored in the MCH storage tank 12 is transported to the dehydrogenation equipment 3 by known transportation means (ships, vehicles, pipelines, etc.) and stored in the MCH storage tank 23. The methylcyclohexane stored in the MCH storage tank 23 is used for the dehydrogenation reaction of the dehydrogenation reaction device 21. On the other hand, the toluene stored in the TOL storage tank 22 is transported to the hydrogenation device 2 by known transportation means and stored in the TOL storage tank 13. The toluene stored in the TOL storage tank 13 is used for the hydrogenation reaction of the hydrogenation reaction device 11. Thus, methylcyclohexane and toluene are repeatedly used as hydrogen carriers.

[0030] like Figure 2 As shown in (A), in the dehydrogenation reaction of the dehydrogenation reaction device 21, in addition to hydrogen and toluene, by-products including five-membered ring structure compounds are also generated. Such five-membered ring structure compounds include dimethylcyclopentanes (for example, 1,1-dimethylcyclopentane, 1,3-cis-dimethylcyclopentane, 1,3-trans-dimethylcyclopentane, and 1,2-trans-dimethylcyclopentane) and ethylcyclopentane. On the other hand, Figure 2 As shown in (B), since the boiling point of the five-membered ring structure compound is relatively close to the boiling points of methylcyclohexane and toluene as hydrogen carriers, it is not easy to separate them from the hydrogen carrier by distillation.

[0031] The five-membered ring structure compound generated in the dehydrogenation reaction device 21 is stored in the TOL storage tank 22 in a state of being mixed with toluene, and then sent to the hydrogenation device 2 through the TOL storage tank 13. Therefore, the methylcyclohexane generated in the hydrogenation device 2 may contain the five-membered ring structure compound derived from the above-mentioned dehydrogenation reaction as an impurity. The five-membered ring structure compound is returned to the dehydrogenation equipment 3 in a state of being mixed with methylcyclohexane, and circulates in the hydrogen storage and transportation system 1. It should be noted that the five-membered ring structure compound can be generated not only by the dehydrogenation reaction of the dehydrogenation reaction device 21, but also by the hydrogenation reaction of the hydrogenation reaction device 11.

[0032] Therefore, the hydrogen storage and transportation system 1 includes a hydrogenolysis device 6 for performing a hydrogenolysis reaction of a five-membered ring structure compound mixed with a hydrogen carrier. The hydrogenolysis device 6 converts the five-membered ring structure compound mixed with methylcyclohexane as an impurity into chain-like light hydrocarbons by selective hydrogenolysis using a metal catalyst (hereinafter referred to as a "hydrogenolysis catalyst").

[0033] The hydrogenolysis device 6 can, for example, extract at least a portion of the product of the hydrogenation reaction (mainly methylcyclohexane, for example, 98wt% or more) generated by the hydrogenation device 2 as a treatment target before being stored in the storage device 4, and perform a hydrogenolysis reaction. In the hydrogenolysis device 6, the five-membered ring structure compound in the product of the hydrogenation reaction is decomposed into lighter hydrocarbons (for example, pentane, hexane, heptane, etc.). These hydrocarbons can be removed (separated) from the methylcyclohexane by distillation or other known treatments. The methylcyclohexane from which the five-membered ring structure compound is removed (or reduced) is mixed again into the product of the hydrogenation device 2.

[0034] It should be noted that the treatment target of the hydrogenolysis device 6 may be methylcyclohexane (including a five-membered ring structure compound as an impurity) extracted from the MCH storage tank 12 of the storage device 4. At this time, the methylcyclohexane from which the five-membered ring structure compound is removed by the hydrogenolysis device 6 is returned to the MCH storage tank 12. In addition, the hydrogenolysis device 6 may be connected to a raw material supply pipeline (not shown) of the dehydrogenation reaction device 21, and constitute a part of the dehydrogenation device 3.

[0035] Alternatively, the treatment target of the hydrogenolysis device 6 may be methylcyclohexane (including a five-membered ring structure compound as an impurity) extracted from the MCH storage tank 23 of the storage device 5. In this case, the methylcyclohexane from which the five-membered ring structure compound is removed by the hydrogenolysis device 6 is returned to the MCH storage tank 23. In addition, the hydrogenolysis device 6 may be connected to a discharge pipeline (not shown) of a product of the hydrogenation reaction device 11, and constitute a part of the hydrogenation device 2.

[0036] As the hydrogenolysis device 6, for example, a fixed bed flow-type reaction device can be used. The hydrogenolysis device 6 is equipped with a temperature regulator (for example, an electric heater or a heat exchanger using a heat medium). In the hydrogenolysis reaction of the hydrogenolysis device 6, it is preferred that the temperature of the catalyst layer composed of the hydrogenolysis catalyst is maintained, for example, in the range of 150°C to 300°C by its temperature regulator. The metal catalyst of this embodiment can exhibit good catalytic performance even if the temperature of the catalyst layer is below 200°C. In addition, the reaction raw materials for the hydrogenolysis reaction preferably include, for example, a mixture of methylcyclohexane and a five-membered ring structure compound and 50 to 99.8 mol% of hydrogen.

[0037] Furthermore, as a hydrogenolysis catalyst for the hydrogenolysis device 6, for example, a hydrogenolysis catalyst comprising silica as a catalyst carrier and iridium or rhodium as a metal supported on the catalyst carrier can be used. When iridium is used, the hydrogenolysis catalyst preferably contains 0.1 to 5% by weight of iridium. The hydrogenolysis catalyst more preferably contains 0.5 to 2% by weight of iridium. Furthermore, when rhodium is used, the hydrogenolysis catalyst preferably contains 0.5 to 2% by weight of rhodium. As a silica-based carrier as a catalyst carrier, it is preferred to mainly use amorphous silica or MFI-type zeolite.

[0038] The organic hydride used in the hydrogen storage and transportation system 1 may be an organic compound that reversibly releases hydrogen at least by a catalyst reaction, and is not limited to the above-mentioned methylcyclohexane. In the hydrogen storage and transportation system 1, as the organic hydride, a monocyclic hydrogenated aromatic compound such as methylcyclohexane and cyclohexane, a bicyclic hydrogenated aromatic compound such as tetralin, decalin, methyldecalin, or a tricyclic hydrogenated aromatic compound such as tetradecahydroanthracene may be used alone, or a mixture of two or more thereof may be used. For toluene obtained by the dehydrogenation reaction of methylcyclohexane, when the organic hydride is changed, other aromatic compounds corresponding thereto may also be used.

[0039] Hereinafter, preferred embodiments of the hydrogenolysis catalyst of the present invention and the method for hydrogenolysis of a five-membered ring structure compound using the same will be specifically described based on Examples 1 to 7 and Comparative Example 1.

[0040] The premise of the above-mentioned hydrogenolysis device 6 is to use a hydrogenolysis catalyst to hydrogenolyze a five-membered ring structure compound that is mixed into the product of the hydrogenation reaction of the hydrogenation device 2 as an impurity (or generated as a by-product of the reaction). The reaction raw material of the hydrogenolysis device 6 (that is, the target of the hydrogenolysis reaction) is a mixture of methylcyclohexane and a five-membered ring structure compound generated by the hydrogenation reaction of toluene. In Examples 1-6 and Comparative Example 1, methylcyclopentane (abbreviated as "MCP" as necessary) is used as a model compound of the five-membered ring structure compound contained in the reaction raw material (that is, mixed). And, in Example 7, ethylcyclopentane (abbreviated as "ECP" as necessary) is used as a model compound of the five-membered ring structure compound.

[0041] For example Figure 3 As shown, in the hydrogenolysis of methylcyclopentane (MCP), MCP is cracked at positions (1) to (3), and chain compounds (hexane, 2-methylpentane, 3-methylpentane, etc.) according to the cracking positions can be generated. In addition, these chain compounds can be further decomposed to generate C1-C5 alkanes. The products of these hydrogenolysis reactions are different from the five-membered ring structure compounds and can be easily separated from methylcyclohexane by distillation or other known treatments. Similarly, the products of the hydrogenolysis reactions of ethylcyclopentane and other five-membered ring compounds are also easily separated from methylcyclohexane.

[0042] Table 1 lists the catalyst samples used in Examples 1-7 and Comparative Example 1. Although described in detail later, in Example 1, a catalyst in which rhodium (Rh) was loaded on amorphous silica as a catalyst carrier was used. In Examples 2, 4, 7, Example 3, and Example 5, catalysts in which different loading amounts of iridium (Ir) were loaded on amorphous silica were used. Furthermore, in Example 6, a catalyst sample in which iridium (Ir) was loaded on MFI-type zeolite as a catalyst carrier was used. In Example 6, a pure silica MFI-type zeolite that did not substantially contain aluminum or other metals as heteroelements was used. Furthermore, as Comparative Example 1, a catalyst sample in which amorphous silica loaded with platinum (Pt) was used.

[0043]

Table 1

[0044] Table 2 shows the reaction raw materials used in Examples 1 to 7 and Comparative Example 1.

[0045]

Table 2

[0046] In Examples 1, 2 and Comparative Example 1, as reaction raw materials, the performance of each catalyst sample when methylcyclopentane (MCP) as a five-membered ring structure compound and methylcyclohexane (MCH) as a hydrogen carrier were supplied to the reaction device together with hydrogen was evaluated. As shown in Table 2, in Examples 1, 2 and Comparative Example 1, when MCP was used as the reaction raw material, the hydrogen / MCP ratio (mol / mol) in the reaction raw material was 28. And, when MCH was used as the reaction raw material, the hydrogen / MCH ratio (mol / mol) in the reaction raw material was 28.

[0047] In Example 3-6, assuming the actual raw material of the hydrogenolysis device, a mixed raw material of 10 mol% of methylcyclopentane as a five-membered ring structure compound and 90 mol% of methylcyclohexane as a hydrogen carrier was prepared, and the performance of each catalyst sample when it was supplied to the reaction device together with hydrogen was evaluated. As shown in Table 2, in Example 3-6, the hydrogen / (MCP+MCH) ratio (mol / mol) in the reaction raw material was 30.3.

[0048] In Example 7, a mixed raw material consisting of 10 mol% of ethylcyclopentane (ECP) as a five-membered ring structure compound and 90 mol% of methylcyclohexane (MCH) as a hydrogen carrier was prepared, and the performance of the catalyst sample when it was supplied to the reaction device together with hydrogen was evaluated. As shown in Table 2, in Example 7, the hydrogen / (ECP+MCH) ratio (mol / mol) in the reaction raw material was 28.

[0049] In Examples 1-7, it is assumed that the hydrogenolysis reaction is carried out in a mild temperature range of about 200° C. in the catalyst layer, and (Ir) and rhodium (Rh) are used as active species to selectively promote the hydrogenolysis reaction of the carbon-carbon bond cracking of the five-membered ring structure compound in the coexistence of hydrogen. In addition, a silica-based material that does not exhibit solid acidity that may cause side reactions such as isomerization reactions is used as a catalyst carrier.

[0050] (Example 1) Preparation method of 1.0wt%-Rh / SiO2 catalyst In a 300 mL eggplant-shaped flask, 0.0767 g of rhodium chloride trihydrate (RhCl3·3H2O, containing 39.1 wt% of Rh) and 150 mL of pure water were added, and after being fully dissolved by ultrasonic irradiation, amorphous silica powder (AEROSIL (registered trademark) 380, Japan AEROSIL (Strain), BET specific surface area 380 m 2 / g) 3.0g, stirred at room temperature for 1 hour, and impregnated with silica to make the loading rate of Rh metal 1wt%. After evaporating to dryness at 40°C using an evaporator, the recovered product was transferred to an oven and dried overnight at 80°C to recover the powder. After the powder was pressed and molded, it was appropriately crushed and sieved to make the particle size of 500-600μm. In the reduction treatment of the catalyst, about 1.0g of the whole-grain catalyst was loaded into a fixed bed circulation device, heated to 400°C over 30 minutes under nitrogen flow (30mL / min), then switched to hydrogen flow (50mL / min) for 5 hours of reduction treatment, and the hydrogen flow atmosphere was maintained and cooled to room temperature to obtain a 1.0wt%-Rh / SiO2 catalyst.

[0051] Performance evaluation test method of 1.0wt%-Rh / SiO2 catalyst [Hydrogenolysis of methylcyclopentane (MCP)] The performance evaluation test of the above 1.0wt%-Rh / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst is to load 100.0mg of 1.0wt%-Rh / SiO2 catalyst into a fixed bed flow reactor, heat it to 400℃ under helium flow (30mL / min) for 30 minutes, and then switch to hydrogen flow (50mL / min) and carry out reduction treatment for 1 hour. After the reduction treatment, the hydrogenolysis reaction of MCP is carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCP=28mol / mol, W / F (ratio of catalyst amount to MCP flow rate)=28.5g-cat.h / mol, reaction temperature 200℃, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC (gas chromatograph with hydrogen flame ionization detector) to determine the MCP conversion rate (%) and product selectivity (C-%) as indicators of catalyst performance (for the results, refer to Table 3 described below).

[0052] [Hydrogenolysis of methylcyclohexane (MCH)] The performance evaluation test of the above 1.0wt%-Rh / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst was to load 100.0 mg of the 1.0wt%-Rh / SiO2 catalyst into a fixed bed flow reactor, heat it to 400°C over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) and carry out a reduction treatment for 1 hour. After the reduction treatment, the hydrogenolysis reaction of MCH was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCH=28mol / mol, W / F (ratio of catalyst amount to MCH flow rate)=28.5g-cat.h / mol, reaction temperature 200°C, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and the conversion rate (%) of MCP and the selectivity (C-%) of the product were determined by FID-GC analysis as indicators of catalyst performance (for the results, refer to Table 3 described later).

[0053] (Example 2) Preparation method of 1.0wt%-Ir / SiO2 catalyst 0.0604 g of iridium chloride·n-hydrate (IrCl3·nH2O, containing 49.7 wt% of Ir) and 150 mL of pure water were added to a 300 mL eggplant-shaped flask, and after being fully dissolved by ultrasonic irradiation, amorphous silica powder (AEROSIL380, Japan AEROSIL (Strain), BET specific surface area 380 m2) was added as a carrier. 2 / g) 3.0g and stirred at room temperature for 1 hour to impregnate the silica so that the loading rate as metal is 1wt%. After evaporating to dryness at 40°C using an evaporator, the recovered product is transferred to an oven and dried overnight at 80°C to recover the powder. The powder is pressed and molded and then appropriately crushed, and the granules are sieved to a particle size of 500-600μm. In the reduction treatment of the catalyst, about 1.0g of the granulated catalyst is loaded into a fixed bed circulation device, and the temperature is raised to 400°C over 30 minutes under nitrogen flow (30mL / min), and then switched to hydrogen flow (50mL / min) and a reduction treatment is carried out for 5 hours, and then the hydrogen flow atmosphere is maintained and cooled to room temperature to obtain a 1.0wt% -Ir / SiO2 catalyst.

[0054] Performance evaluation test method of 1.0wt%-Ir / SiO2 catalyst [Hydrogenolysis of methylcyclopentane (MCP)] The performance evaluation test of the above 1.0wt%-Ir / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst was to load 100.0 mg of the 1.0wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400°C over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) and carry out a reduction treatment for 1 hour. After the reduction treatment, the hydrogenolysis reaction of MCP was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCP=28mol / mol, W / F (ratio of catalyst amount to MCP flow rate)=28.5g-cat.h / mol, reaction temperature 200°C, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and the conversion rate (%) of MCP and the selectivity (C-%) of the product were determined by FID-GC analysis as indicators of catalyst performance (for the results, refer to Table 3 described later).

[0055] [Hydrogenolysis of methylcyclohexane (MCH)] The performance evaluation test of the 1.0wt%-Ir / SiO2 catalyst prepared according to the above process was carried out according to the following steps. The pretreatment of the catalyst is to load 100.0mg of the 1.0wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400℃ over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) and carry out a reduction treatment for 1 hour. After the reduction treatment, the hydrogenolysis reaction of MCH was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCH=28mol / mol, W / F (ratio of catalyst amount to MCH flow rate)=28.5g-cat.h / mol, reaction temperature 200℃, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and the conversion rate (%) of MCP and the selectivity (C-%) of the product were determined by FID-GC analysis as indicators of catalyst performance.

[0056] (Example 3) Preparation method of 0.5wt%-Ir / SiO2 catalyst 0.0302 g of iridium chloride n-hydrate (IrCl3·nH2O, containing 49.7 wt% of Ir) and 150 mL of pure water were added to a 300 mL eggplant-shaped flask, and after being fully dissolved by ultrasonic irradiation, amorphous silica powder (AEROSIL380, Japan AEROSIL (Strain), BET specific surface area 380 m 2 / g) 3.0g, stirred at room temperature for 1 hour, and impregnated the silica to make the loading rate of Ir metal 0.5wt%. After evaporating to dryness at 40°C using an evaporator, the recovered product was transferred to an oven and dried overnight at 80°C to recover the powder. The powder was pressed and properly crushed, and sieved to make the particle size of 500-600μm. In the reduction treatment of the catalyst, about 1.0g of the granulated catalyst was loaded into a fixed bed circulation device, and the temperature was raised to 400°C over 30 minutes under nitrogen flow (30mL / min), and then switched to hydrogen flow (50mL / min) and carried out a reduction treatment for 5 hours, and then the hydrogen flow atmosphere was maintained and cooled to room temperature to obtain a 0.5wt%-Ir / SiO2 catalyst.

[0057] Performance evaluation test method of 0.5wt%-Ir / SiO2 catalyst [Hydrogenolysis reaction of a mixed raw material of methylcyclopentane (MCP) and methylcyclohexane (MCH)] The performance evaluation test of the above 0.5wt%-Ir / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst is to load 201.0 mg of 0.5wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400°C over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) for 1 hour of reduction treatment. After the reduction treatment, the hydrogen flow rate of MCP and MCH mixed raw materials was 40mL / min, H2 / (MCP+MCH) = 30.3mol / mol (H2:MCP:MCH = 30.3:0.1:0.9), W / F (ratio of catalyst amount to (MCP+MCH) flow) = 62.1g-cat.h / mol, reaction temperature 200°C, and total pressure 0.1MPa. The hydrogenolysis reaction of the mixed raw materials was carried out for a specified time. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC to determine the conversion rate (%) of MCP, the conversion rate (%) of MCH, and the selectivity of the product (C-%) as indicators of catalyst performance (for the results, refer to Table 4 described below).

[0058] (Example 4) Preparation method of 1.0wt%-Ir / SiO2 catalyst A 1.0 wt%-Ir / SiO2 catalyst was obtained in the same manner as the catalyst in Example 2.

[0059] Performance evaluation test method of 1.0wt%-Ir / SiO2 catalyst [Hydrogenolysis reaction of a mixed raw material of methylcyclopentane (MCP) and methylcyclohexane (MCH)] The performance evaluation test of the above 1.0wt%-Ir / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst is to load 202.0mg of 1.0wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400℃ over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) for 1 hour of reduction treatment. After the reduction treatment, the hydrogenolysis reaction of the mixed material of MCP and MCH was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / (MCP+MCH)=30.3mol / mol (H2:MCP:MCH=30.3:0.1:0.9), W / F (ratio of catalyst amount to (MCP+MCH) flow)=62.4g-cat.h / mol, reaction temperature 200℃, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC to determine the conversion rate (%) of MCP, the conversion rate (%) of MCH, and the selectivity of the product (C-%) as indicators of catalyst performance (for the results, refer to Table 4 described below).

[0060] (Example 5) Preparation method of 2.0wt%-Ir / SiO2 catalyst 0.1208 g of iridium chloride n-hydrate (IrCl3·nH2O, containing 49.7 wt% of Ir) and 150 mL of pure water were added to a 300 mL eggplant-shaped flask, and after being fully dissolved by ultrasonic irradiation, amorphous silica powder (AEROSIL380, Japan AEROSIL (Strain), BET specific surface area 380 m 2 / g) 3.0g, stirred at room temperature for 1 hour, and impregnated with silica to make the loading rate of Ir metal 0.5wt%. After evaporating to dryness at 40°C using an evaporator, the recovered product was transferred to an oven and dried overnight at 80°C to recover the powder. The powder was pressed and properly crushed, and sieved to make the particle size of 500-600μm. In the reduction treatment of the catalyst, about 1.0g of the granulated catalyst was loaded into a fixed bed circulation device, heated to 400°C over 30 minutes under nitrogen flow (30mL / min), then switched to hydrogen flow (50mL / min) and carried out a reduction treatment for 5 hours, and then the hydrogen flow atmosphere was maintained and cooled to room temperature to obtain a 2.0wt%-Ir / SiO2 catalyst.

[0061] Performance evaluation test method of 2.0wt%-Ir / SiO2 catalyst [Hydrogenolysis reaction of a mixed raw material of methylcyclopentane (MCP) and methylcyclohexane (MCH)] The performance evaluation test of the above 2.0wt%-Ir / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst is to load 204.0mg of 2.0wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400℃ over 30 minutes under helium flow (30mL / min), then switch to hydrogen flow (50mL / min) and carry out reduction treatment for 1 hour. After the reduction treatment, the hydrogen flow rate of MCP and MCH mixed raw materials was 40mL / min, H2 / (MCP+MCH) = 30.3mol / mol (H2:MCP:MCH = 30.3:0.1:0.9), W / F (ratio of catalyst amount to (MCP+MCH) flow rate) = 63.0g-cat.h / mol, reaction temperature 200℃, and total pressure 0.1MPa. The hydrogenolysis reaction of the mixed raw materials was carried out for a specified time. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC to determine the conversion rate (%) of MCP, the conversion rate (%) of MCH, and the selectivity of the product (C-%) as indicators of catalyst performance (for the results, refer to Table 4 described below).

[0062] (Example 6) Preparation method of 1.0wt%-Ir / Silicalite-1 catalyst A catalyst in which 1.0 wt% of Ir is supported on crystalline silicalite-1 (1.0 wt%-Ir / Silicalite-1) was prepared. Silicalite-1 as a carrier was synthesized according to the following steps. In a container made of perfluoroalkoxyalkane (PFA) with a capacity of 80 mL, a specified amount of tetrapropylammonium hydroxide (TPAOH) and fumed silica (Cab-O-SilM5) were added, and stirred in an oil bath at 80°C for 2 hours to obtain a basic gel solution. The molar composition of the basic gel solution was SiO2:TPAOH:H2O=1.0:0.24:10.44. The gel solution was hydrothermally synthesized in an autoclave with a capacity of 23 mL under conditions of autogenous pressure, 135°C, 3 hours, and 20 rpm. Then, the product was recovered by centrifugal separation and dried in an oven at 80°C, and further calcined in a muffle furnace at 550°C to synthesize silicalite-1. Furthermore, XRD analysis confirmed that the synthesized sample had an MFI structure, and nitrogen adsorption isotherm analysis confirmed a BET specific surface area of ​​371 m 2 / g, micropore volume is 0.154cm 3 / g.

[0063] Using the silicalite-1 synthesized by the above steps, a 1.0 wt% -Ir / Silicalite-1 catalyst was prepared according to the following steps. 0.0302 g of iridium chloride n-hydrate (IrCl3·nH2O, containing 49.7 wt% of Ir) and 75 mL of pure water were added to a 200 mL eggplant-shaped flask. After being fully dissolved by ultrasonic irradiation, 1.5 g of silicalite-1 powder synthesized by the above steps was added and stirred at room temperature for 1 hour to impregnate and load silica so that the loading rate of Ir metal was 1.0 wt%. After evaporating to dryness at 40°C using an evaporator, the recovered product was transferred to an oven and dried at 80°C overnight to recover the powder. The powder was pressed and pulverized appropriately, and sieved to size the particles to 500-600 μm. The reduction treatment of the catalyst is as follows: about 1.0 g of the whole-granulated catalyst is loaded into a fixed-bed circulation device, and the temperature is raised to 400°C over 30 minutes under nitrogen flow (30 mL / min), and then switched to hydrogen flow (50 mL / min) and carried out reduction treatment for 5 hours. The hydrogen flow atmosphere is maintained and cooled to room temperature to obtain a 1.0 wt% -Ir / Silicalite-1 catalyst.

[0064] Performance evaluation test method of 1.0wt%-Ir / Silicalite-1 catalyst [Hydrogenolysis reaction of a mixed raw material of methylcyclopentane (MCP) and methylcyclohexane (MCH)] The performance evaluation test of the above 1.0wt%-Ir / Silicalite-1 catalyst was carried out according to the following steps. The pretreatment of the catalyst was that 202.0 mg of the 1.0wt%-Ir / Silicalite-1 catalyst was loaded into a fixed bed flow reactor, heated to 400°C over 30 minutes under helium flow (30 mL / min), and then switched to hydrogen flow (50 mL / min) and reduced for 1 hour. After the reduction treatment, the hydrogenolysis reaction of the mixed raw material of MCP and MCH was carried out for a specified time under the conditions of hydrogen flow rate of 40 mL / min, H2 / (MCP+MCH)=30.3 mol / mol (H2:MCP:MCH=30.3:0.1:0.9), W / F (ratio of catalyst amount to (MCP+MCH) flow)=62.4 g-cat.h / mol, reaction temperature of 200°C, and total pressure of 0.1 MPa. After 5 minutes from the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC to determine the conversion rate (%) of MCP, the conversion rate (%) of MCH, and the selectivity of the product (C-%) as indicators of catalyst performance. (For the results, refer to Table 3 described below).

[0065] (Example 7) Preparation method of 1.0wt%-Ir / SiO2 catalyst A 1.0 wt%-Ir / SiO2 catalyst was obtained in the same manner as the catalyst in Example 2.

[0066] Performance evaluation test method of 1.0wt%-Ir / SiO2 catalyst [Hydrogenolysis reaction of a mixed raw material of ethylcyclopentane (ECP) and methylcyclohexane (MCH)] The performance evaluation test of the above 1.0wt%-Ir / SiO2 catalyst was carried out according to the following steps. The pretreatment of the catalyst is to load 202.0mg of 1.0wt%-Ir / SiO2 catalyst into a fixed bed flow reactor, heat it to 400℃ over 30 minutes under helium flow (30mL / min), then switch to hydrogen flow (50mL / min) and carry out reduction treatment for 1 hour. After the reduction treatment, the hydrogen flow rate of ECP and MCH mixed raw materials was 40mL / min, H2 / (ECP+MCH) = 28mol / mol (H2:ECP:MCH = 28.0:0.1:0.9), W / F (ratio of catalyst amount to (ECP+MCH) flow rate) = 57.6g-cat.h / mol, reaction temperature 200℃, and total pressure 0.1MPa. The reaction was carried out for a specified time. After 5 minutes from the start of the hydrogenolysis reaction, the product was sampled and analyzed by FID-GC to determine the conversion rate (%) of ECP, the conversion rate (%) of MCH, and the selectivity (C-mol%) of the product as indicators of catalyst performance. (For the results, refer to Table 5 described below).

[0067] (Comparative Example 1) Preparation method of 1.0wt%-Pt / SiO2 catalyst As a catalyst sample, a commercially available silica-supported platinum catalyst (1.0 wt % -Pt / SiO 2 ) (Aldrich, 520691-25G) was used.

[0068] 1.0wt%-Pt / SiO2 Catalyst Performance Evaluation Test Method [Hydrogenolysis of methylcyclopentane (MCP)] The performance evaluation test of the commercially available 1.0wt%-Pt / SiO2 catalyst was conducted according to the following steps. The pretreatment of the catalyst was to load 202.0 mg of the 1.0wt%-Pt / SiO2 catalyst into a fixed bed flow reactor, heat it to 400°C over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) for 1 hour of reduction treatment. After the reduction treatment, the hydrogenolysis reaction of MCP was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCP=28mol / mol, W / F (ratio of catalyst amount to MCP flow rate)=28.5g-cat.h / mol, reaction temperature 200°C, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and the conversion rate (%) of MCP and the selectivity (C-%) of the product were determined by FID-GC analysis as indicators of catalyst performance. (For the results, refer to Table 3 described later).

[0069] [Hydrogenolysis of methylcyclohexane (MCH)] The performance evaluation test of the commercially available 1.0wt%-Pt / SiO2 catalyst was conducted according to the following steps. The pretreatment of the catalyst was to load 100.0 mg of the 1.0wt%-Pt / SiO2 catalyst into a fixed bed flow reactor, heat it to 400°C over 30 minutes under helium flow (30mL / min), and then switch to hydrogen flow (50mL / min) and perform a reduction treatment for 1 hour. After the reduction treatment, the hydrogenolysis reaction of MCH was carried out for a specified time under the conditions of hydrogen flow rate 40mL / min, H2 / MCH=28mol / mol, W / F (ratio of catalyst amount to MCH flow rate)=28.5g-cat.h / mol, reaction temperature 200°C, and total pressure 0.1MPa. Five minutes after the start of the hydrogenolysis reaction, the product was sampled and the conversion rate (%) of MCP and the selectivity (C-%) of the product were determined by FID-GC analysis as indicators of catalyst performance. (For the results, refer to Table 3 described later).

[0070] Table 3 shows the performance test results of each catalyst of Examples 1 and 2 and Comparative Example 1. In the performance test of each catalyst, methylcyclopentane (MCP) and methylcyclohexane (MCH) were used as separate reaction raw materials, and hydrogenolysis reactions were carried out under the same conditions.

[0071]

Table 3

[0072] As shown in Table 3, in Comparative Example 1 (1.0 wt% -Pt / SiO2 catalyst), when MCP was used as a raw material, almost no hydrogenolysis reaction occurred, and the conversion rate of MCP was less than 1%. In addition, when MCH was used as a raw material, the conversion rate of MCH was also less than 1%, and the product was all toluene (TOL).

[0073] Therefore, when platinum is used as an active species supported on silica, it exhibits activity in the dehydrogenation aromatization reaction of cyclohexanes (here, methylcyclohexane), but has extremely low activity in the hydrogenolysis reaction of cyclopentanes (here, methylcyclopentane).

[0074] On the other hand, the 1.0 wt% -Rh / SiO2 catalyst of Example 1 showed high activity in the hydrogenolysis reaction of MCP, and the conversion rate of MCP was 53%. The product obtained by hydrogenolysis of MCP was n-hexane (n-C6H 14 (See "n-C6" in the table)), 3-methylpentane (3-CH3-C5H 11 (See "3-MP" in the table)), 2-methylpentane (2-CH3-C5H 11 (See "2-MP" in the table)) When MCH was used as a raw material, almost no hydrogenolysis reaction occurred, the conversion rate of MCH was less than 1%, and the obtained product was only toluene (TOL).

[0075] In the 1.0wt%-Ir / SiO2 catalyst of Example 2, the activity of the hydrogenolysis reaction of methylcyclopentane is further improved than that of Example 1, and the conversion rate of methylcyclopentane reaches 70%. The products obtained by hydrogenolysis of methylcyclopentane are the direct ring-opening products n-hexane, 3-methylpentane, and 2-methylpentane as in Example 1. Moreover, when methylcyclohexane (MCH) is used as a raw material, the hydrogenolysis reaction hardly occurs as in Example 1, the raw material conversion rate is less than 1%, and the only product obtained is toluene.

[0076] From the above, it is understood that rhodium or iridium as active species supported on amorphous silica exhibits high activity in the hydrogenolysis reaction of cyclopentanes, but exhibits low activity in the hydrogenolysis reaction of cyclohexanes.

[0077] Table 4 shows the performance test results of each catalyst of Examples 3 to 6. In the performance test of each catalyst, a hydrogenolysis reaction was carried out under the same conditions using a mixed raw material of methylcyclopentane (MCP) and methylcyclohexane (MCH).

[0078]

Table 4

[0079] In Example 3-5 (Xwt%-Ir / SiO2 catalyst, X=0.5, 1.0, 2.0), performance evaluation was performed using samples with iridium metal loading rates on amorphous silica carriers in the range of 0.5-2.0wt%.

[0080] As shown in Table 4, the conversion rates of methylcyclopentane (MCP) and methylcyclohexane (MCH) of the catalysts of Examples 3-5 were 8.7-51.3%, and 0.3-5.1%, respectively, both of which increased with the increase in metal loading. In addition, it was confirmed that all catalysts of Examples 3-5 were able to inhibit the hydrogenolysis of methylcyclohexane (MCH) and highly selectively hydrogenolyze MCP. Regarding product distribution, the reaction product derived from MCP was a direct ring-opening product, namely n-hexane (n-C6H 14 (See "n-C6" in the table)), 3-methylpentane (3-CH3-C5H 11 (See "3-MP" in the table)), 2-methylpentane (2-CH3-C5H 11 (See "2-MP" in the table)), the decomposition products are light hydrocarbons (C1-C5), and the reaction products derived from MCH are direct ring-opening products, namely n-heptane (n-C7H 16 (See "n-C7" in the table)), 3-methylhexane (3-CH3-C6H 13 (See "3-MH" in the table)), 2-methylhexane (2-CH3-C6H 13 (Refer to "2-MH" in the table)), the dehydrogenation product is toluene (TOL).

[0081] In the 1.0 wt%-Ir / Silicalite-1 catalyst of Example 6, performance evaluation was performed using a sample in which 1.0 wt% of iridium metal was supported on silicalite-1 (a type of MFI zeolite).

[0082] As shown in Table 4, in the catalyst of Example 6, the conversion rate of MCP is lower than that of Example 4 (1.0wt%-Ir / SiO2 catalyst), but the conversion rate of MCH is very low, 0.1%, indicating that it is a catalyst with excellent selectivity. In addition, the product distribution is the same as that of the above-mentioned Examples 3-5. It should be noted that in Example 6, a catalyst loaded with iridium is used, but it is believed that the same effect can be obtained when a catalyst loaded with rhodium is used.

[0083] Table 5 shows the performance test results of the catalyst of Example 7. In the performance test results of the catalyst, a hydrogenolysis reaction was carried out using a mixed raw material of ethylcyclopentane (ECP) and methylcyclohexane (MCH).

[0084]

Table 5

[0085] As shown in Table 5, the conversion rate of ECP and the conversion rate of MCH of the catalyst of Example 7 were 39.8% and 2.8%, respectively, confirming that the catalyst was able to suppress the hydrogenolysis of MCH and hydrogenolyze ECP with high selectivity. The product distribution was the direct ring-opening product, namely n-heptane (n-C7H 16 (See "n-C7" in the table)), 3-ethylpentane (3-C2H5-C5H 11 (See "3-EP" in the table)), 3-methylhexane (3-CH3-C6H 13 (See "3-MH" in the table)), 2-methylhexane (2-CH3-C6H 13 (See "2-MH" in the table)), 3-methylpentane (3-CH3-C5H 11 (See "3-MP" in the table)), 2-methylpentane (2-CH3-C5H 11 (See "2-MP" in the table)) and the decomposition products, namely light hydrocarbons (C1-C5), and the dehydrogenation product, namely toluene (TOL).

[0086] From the performance test results of each catalyst shown in Tables 3-5 above, it can be seen that the use of a metal catalyst containing iridium or rhodium supported on a silica-based carrier such as amorphous silica or crystalline silica zeolite-1 for hydrogenolysis reaction can highly selectively hydrogenolyze cyclopentanes contained in methylcyclohexane.

[0087] The above is the end of the description of the specific embodiment, but the present invention is not limited to the above embodiment and the modified example, and various modifications can be made. All the constituent elements of the metal catalyst and the cyclic compound hydrogenolysis method using the metal catalyst shown in the above embodiment are not necessarily indispensable, and at least those skilled in the art can make appropriate selections without departing from the scope of the present invention.

[0088] For example, the metal catalyst of the present invention and the method for hydrogenolysis of cyclic compounds using the same are not limited to the hydrogenolysis device 6 provided in the above-mentioned hydrogen storage and transportation system 1. These can be widely applied to hydrogenolysis of cyclic compounds having a five-membered ring structure contained in saturated cyclic compounds.

[0089] Furthermore, as the silica-based support, in addition to the above-mentioned amorphous silica and MFI-type zeolite, for example, mesoporous silica (SBA-15, etc.) can also be used.

Explanation of symbols

[0090] 1: Transportation System 2: Hydrogenation unit 3: Dehydrogenation equipment 4: Storage Devices 5. Storage Devices 6: Hydrogenolysis device 11: Hydrogenation reaction unit 12: MCH storage tank 13: TOL storage tank 21: Dehydrogenation reaction unit 22: TOL storage tank 23: MCH storage tank.

Claims

1. A metal catalyst for hydrogenolysis of a cyclic compound having a five-membered ring structure, wherein the cyclic compound is contained in a saturated cyclic compound used as a hydrogen carrier, wherein the metal catalyst comprises: A silica-based support as a catalyst support; and Iridium or rhodium as the metal supported on the catalyst carrier.

2. The metal catalyst according to claim 1, wherein The metal supported on the catalyst carrier is iridium, The metal contains 0.1 to 5% by weight of iridium.

3. The metal catalyst according to claim 1, wherein The metal supported on the catalyst carrier is rhodium. The metal contains 0.5 to 2 wt% of rhodium.

4. The metal catalyst according to claim 1, wherein The silica-based support includes amorphous silica.

5. The metal catalyst according to claim 1, wherein The silica-based support includes MFI-type zeolite.

6. A hydrogenolysis method, comprising hydrogenolyzing a cyclic compound having a five-membered ring structure contained in a saturated cyclic compound used as a hydrogen carrier using the metal catalyst according to any one of claims 1 to 5, The dehydrogenation reaction of the saturated cyclic compound generates an aromatic compound and a cyclic compound having a five-membered ring structure as an impurity thereof. performing a hydrogenation reaction on the aromatic compound mixed with the impurities, The mixture of the saturated cyclic compound and the impurities generated by the hydrogenation reaction of the aromatic compound is hydrogenolyzed using the metal catalyst.

7. The hydrogenolysis method according to claim 6, wherein The hydrogenolysis is performed by supplying the mixture of the saturated cyclic compound and the impurity together with 50 to 99.8 mol % of hydrogen to the metal catalyst whose catalyst layer is maintained at a temperature of 150° C. to 300° C.

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