JP6646087B2 - Porous carbon material, method for producing the same, and catalyst for synthesis reaction - Google Patents

Description

  The present invention relates to a porous carbon material, a method for producing the same, and a catalyst for a synthesis reaction.

  Porous carbon materials typified by activated carbon include plant raw materials (eg, wood pulp, coconut husk, rice hull, etc.), mineral raw materials (eg, coal, tar, petroleum pitch, etc.), and synthetic resins. The activated carbonized material is treated with a gas or a chemical at a high temperature to activate the carbonized material, whereby micropores are formed and obtained. These micropores are formed in a network inside the carbon, and the micropores generate a large surface area. Therefore, the porous carbon material has excellent adsorption ability. Therefore, the porous carbon material has been widely used for various uses such as removal of offensive odor, removal of impurities in liquid, and recovery and removal of solvent vapor.

  The porous carbon material is used as a carrier in a catalyst in addition to such uses. By supporting a metal or a metal compound on the porous carbon material, a heterogeneous catalyst can be obtained. For example, activated carbon supporting a metal or a metal compound is used as a catalyst in the synthesis of vinyl acetate or the synthesis of vinyl chloride.

Relates the catalyst support is a porous carbon material, for example, as a catalyst carrier for fuel cell electrodes, the measured sheet resistance under a pressure of 75.4kgf / cm ² is at 250mΩ / cm ² or less, the average diameter of the mesopores A mesoporous carbon having a thickness of 2 to 20 nm has been proposed (for example, see Patent Document 1). Further, it has been proposed to use a supported catalyst in which metal catalyst particles are supported on a catalyst carrier for an electrode of a fuel cell.

  Further, it has been proposed to use platinum-supported carbon, which is a porous carbon material carrying platinum, for the selective reduction of nitro groups in nitroaromatic compounds (for example, see Patent Document 2).

  However, many supported catalysts useful for selective hydrogenation reduction are not known, and there is a need for a new synthesis reaction catalyst usable for selective hydrogenation reduction and a porous carbon material usable therefor.

JP 2006-321712 A International Publication No. 2009/060886 pamphlet

An object of the present invention is to achieve the following objects.
That is, an object of the present invention is to provide a porous carbon material useful as a carrier for a catalyst for selective hydrogenation reduction, a method for producing the same, and a synthesis reaction catalyst using the porous carbon material. I do.

The means for solving the above problems are as follows. That is,
<1> A porous carbon material having a specific resistance of 10 Ω · cm to 10,000 Ω · cm at a packing density of 0.4 g / cc.
<2> The porous carbon material according to <1>, wherein a half width (2θ) of a diffraction peak (10X) (38 ° to 49 °) by X-ray diffraction is 4.3 ° or more and 5.5 ° or less. It is.
<3> The porous carbon material according to any one of <1> to <2>, which is derived from a plant.
<4> The porous carbon material according to any one of <1> to <3>, which is derived from rice husk.
<5> The porous carbon material according to any one of <1> to <4>, which is a carrier for a catalyst.
<6> A synthesis reaction catalyst comprising: the porous carbon material according to any one of <1> to <5>; and a metal or a metal compound supported on the porous carbon material. .
<7> The synthesis reaction catalyst according to <6>, wherein the metal or the metal compound is palladium.
<8> The synthesis reaction catalyst according to any one of <6> to <7>, which is used for a hydrogenation reduction reaction.
<9> The synthesis reaction catalyst according to any one of <6> to <8>, which is used in a hydrogenation reduction reaction of a compound having two or more groups capable of hydrogenation reduction.
<10> A method for producing a porous carbon material for producing the porous carbon material according to any one of <1> to <5>,
A method for producing a porous carbon material, comprising removing a silicon component from a raw material containing a silicon component by an acid treatment or an alkali treatment, and then performing a carbonization treatment.
<11> The method for producing a porous carbon material according to <10>, wherein an activation treatment is performed after the carbonization treatment.
<12> The method for producing a porous carbon material according to <11>, wherein the activation treatment is performed at a temperature of 700 ° C to 1,000 ° C.

  According to the present invention, the above object can be achieved, a porous carbon material useful as a carrier for a catalyst for selective hydrogenation reduction, a method for producing the same, and a synthesis reaction using the porous carbon material Can be provided.

FIG. 1 is a flowchart of an example of a method for producing a porous carbon material.

(Porous carbon material)
The porous carbon material of the present invention has a specific resistance of 10 Ω · cm to 10,000 Ω · cm at a packing density of 0.4 g / cc.

The present inventors have intensively studied a catalyst useful for selective hydrogenation-reduction reaction of a compound having two or more hydrogenation-reducible groups, and a carrier thereof.
As a result, in the porous carbon material which is a carrier of the catalyst, the specific resistance at a packing density of 0.4 g / cc was set to 10 Ω · cm to 10,000 Ω · cm, thereby using the porous carbon material. The inventors have found that a selective hydrogenation-reduction reaction is possible in a supported catalyst, and have completed the present invention.

Specifically, the present inventors prepared a palladium-supported catalyst using a porous carbon material having a changed specific resistance value, and performed a hydrogenation reduction reaction of 4-chlorostyrene using the catalyst.
In addition, 4-chlorostyrene was used as a model compound for confirming the selectivity of a catalyst in a selective hydrogenation-reduction reaction of a compound having two or more hydrogeno-reducible groups.
In the hydrogenation reduction reaction of 4-chlorostyrene, a hydrogenation reduction reaction of a vinyl group bonded to a benzene ring and a hydrogenation reduction reaction of a 4-chloro group occur. A hydrogenation reduction reaction of a vinyl group bonded to a benzene ring is more likely to occur than a hydrogenation reduction reaction of a 4-chloro group. Therefore, in the hydrogenation-reduction reaction of 4-chlorostyrene, 1-chloro-4-ethylbenzene and ethylbenzene are mainly synthesized. Here, when the selectivity is low, even when it is desired to synthesize 1-chloro-4-ethylbenzene, a considerable amount of ethylbenzene is synthesized as a by-product.
The present inventors have found that by setting the specific resistance value of the porous carbon material to a specific range, the selectivity in the hydrogenation reduction reaction can be improved.

<Specific resistance value>
At a packing density of 0.4 g / cc, the porous carbon material has a specific resistance value of 10 Ω · cm to 10,000 Ω · cm, and preferably 10 Ω · cm to 1,000 Ω · cm. .
When the specific resistance value is less than 10 Ω · cm, the selectivity of the hydrogenation reduction reaction in a supported catalyst using the porous carbon material is reduced. When the specific resistance exceeds 10,000 Ω · cm, the reaction rate of the hydrogenation reduction reaction in the supported catalyst using the porous carbon material decreases.

The specific resistance value can be measured, for example, by the following method.
An acrylic cylinder having a diameter of 9.0 mm and a length of 17 mm is filled with a porous carbon material to a packing density of 0.4 g / cc. Then, a digital multimeter (VOAC7412, manufactured by Iwasaki Communication Equipment Co., Ltd.) is connected to the electrodes attached to both ends in the length direction of the cylinder, and the measurement is performed.
Here, the reason why the packing density of the porous carbon material was set to 0.4 g / cc is that the density was 0.4 g / cc when the porous carbon material was appropriately filled.

<Half width>
In the porous carbon material, the half width (2θ) of the diffraction peak (10X) (38 ° to 49 °) by X-ray diffraction is preferably 4.3 ° or more and 5.5 ° or less.

  Here, “10X” means a pseudo peak of graphite near the 101 plane.

  The X-ray diffraction measurement and the measurement of the half-value width can be performed by a known X-ray diffractometer, and can be performed by, for example, PHILIPS X'Pert manufactured by PANalytical.

  The half width (2θ) can be adjusted by, for example, the presence or absence of heat treatment of the porous carbon material.

<Pore volume>
The porous carbon material has many pores. The pores are classified into mesopores, micropores, and macropores. Here, mesopores refer to pores having a pore size of 2 nm to 50 nm, micropores refer to pores having a pore size smaller than 2 nm, and macropores refer to pores having a pore size larger than 50 nm.

<< Mesopore volume >>
As the mesopore volume is not particularly limited and may be appropriately selected depending on the purpose, 0.15 cm ³ / g or more 1.00 cm ³ / g or less is preferred, 0.20 cm ³ / g or more 0. more preferably not more than ^{60cm 3 / g, 0.20cm 3 /} g or more 0.50 cm ³ / g or less is particularly preferred.

The mesopore volume can be measured, for example, using the following device.
The nitrogen adsorption isotherm can be measured using 3Flex manufactured by Micromeritex Japan GK, and can be calculated by the BJH method.
The BJH method is a method widely used as a pore distribution analysis method. When the pore distribution analysis is performed based on the BJH method, first, nitrogen is adsorbed and desorbed on the porous carbon material as an adsorbed molecule to obtain a desorption isotherm. Then, based on the obtained desorption isotherm, the thickness of the adsorbing layer when the adsorbing molecules are gradually attached and detached from the state where the pores are filled with the adsorbing molecules (for example, nitrogen), and the pores generated at that time. obtains an inner diameter (twice the core radius) of calculating the pore radius r _p according to the following equation (1) to calculate the pore volume based on the following equation (2). Then, the pore radius and the pore volume variation rate relative to the pore diameter (2r _p) from the pore volume _(dV p / dr _p) pore distribution curve is obtained by plotting the (Nippon Bel Co. Ltd. BELSORP-mini And BELSORP analysis software manuals, pages 85 to 88).

_{r p = t + r k (} 1)
_{V pn = R n · dV n} -R n · dt n · c · ΣA pj (2)
^{_{However, R n = r pn 2 /}} (r kn-1 + dt n) 2 (3)

here,
r _p: pore radius r _k: when the adsorption layer having a thickness of t in the pressure on the inner wall of the pores in the pore radius r _p is adsorbed core radius (inside diameter / 2)
V _pn : pore volume at the time of the n-th attachment / detachment of nitrogen dV _n : change amount at that time dt _n : change of the thickness t _n of the adsorption layer when the n-th attachment / detachment of nitrogen occurs Amount r _kn : core radius at that time c: fixed value r _pn : pore radius at the time of the nth attachment / detachment of nitrogen. ΣA _pj represents an integrated value of the area of the wall surface of the pore from j = 1 to j = n−1.

[Specific measurement method of mesopore volume]
A mesopore volume can be measured using 30 mg of a porous carbon material prepared using 3FLEX set under conditions for measuring a relative pressure (P / P0) in the range of 0.0000001 to 0.995.

<Raw materials for porous carbon materials>
The raw material of the porous carbon material is preferably a plant-derived material. That is, the porous carbon material is preferably derived from a plant. When it is derived from a plant, it becomes easy to adjust the mesopore volume value to the above-mentioned desired value. Another advantage is that it is derived from plants in that the environmental load is small.

  The plant-derived material is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include rice husk such as rice (rice), barley, wheat, rye, hee, millet, and the like. Straw, reed, and stem wakame can be mentioned. Furthermore, for example, vascular plants, fern plants, bryophytes, algae, and seaweed vegetated on land can be mentioned. In addition, these materials may be used alone as a raw material, or may be used by mixing a plurality of types. The shape and form of the plant-derived material are not particularly limited, and may be, for example, chaff or straw itself, or may be a dried product. Furthermore, in the processing of foods and beverages such as beer and Western liquor, those subjected to various treatments such as a fermentation treatment, a roasting treatment, and an extraction treatment can also be used. In particular, from the viewpoint of recycling industrial waste, it is preferable to use straw or chaff after processing such as threshing. These processed straws and rice husks can be obtained in large quantities and easily from, for example, agricultural cooperatives, alcoholic beverage manufacturers, and food companies.

  The use of the porous carbon material is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include an adsorbent and a carrier for a catalyst. Among them, the porous carbon material can be suitably used as a carrier for a catalyst.

  The method for producing the porous carbon material is not particularly limited and may be appropriately selected depending on the purpose. However, the method for producing a porous carbon material described below is preferable.

(Method of manufacturing porous carbon material)
In one example of the method for producing a porous carbon material of the present invention, a carbonizing treatment is performed after removing the silicon component from a raw material containing the silicon component by an acid treatment or an alkali treatment. That is, an example of a method for producing a porous carbon material includes a silicon component removing element treatment and a carbonization treatment in this order.

  The method for producing a porous carbon material of the present invention includes, for example, a silicon component removal treatment and a carbonization treatment, preferably an activation treatment, and further includes other treatments such as heat treatment as necessary.

  The specific resistance value of the porous carbon material can be adjusted by appropriately changing conditions such as the carbonization treatment, the activation treatment, and the heat treatment.

  The method for producing the porous carbon material is a method for producing the porous carbon material of the present invention.

<Silicon component removal treatment>
The silicon component removal treatment is not particularly limited as long as the silicon component is removed from a raw material containing the silicon component by an acid treatment or an alkali treatment, and may be appropriately selected depending on the purpose. A method of immersing the raw material in an aqueous solution or an alkaline aqueous solution may be used.

  Examples of the raw material containing the silicon component include the raw materials for the porous carbon material described above.

  Through the silicon component removal treatment, the volume of mesopores and the volume of micropores are easily adjusted in the carbonization treatment and the activation treatment.

<Carburizing treatment>
The carbonization treatment is not particularly limited as long as the raw material subjected to the silicon component removal treatment is carbonized (carbonized) to obtain a carbide (carbonaceous substance), and may be appropriately selected depending on the purpose. it can.
The carbonization (carbonization) generally means that an organic substance (in the present invention, for example, a plant-derived material) is heat-treated to be converted into a carbonaceous substance (see, for example, JIS M0104-1984). In addition, as an atmosphere for carbonization, an atmosphere in which oxygen is blocked can be given, and specifically, a vacuum atmosphere, an inert gas atmosphere such as a nitrogen gas or an argon gas can be given. The heating rate up to the carbonization temperature may be 1 ° C./min or more, preferably 3 ° C./min or more, more preferably 5 ° C./min or more under such an atmosphere. The upper limit of the carbonization time may be 10 hours, preferably 7 hours, more preferably 5 hours, but is not limited thereto. The lower limit of the carbonization time may be a time during which the raw material is surely carbonized.

  The temperature of the carbonization treatment is not particularly limited and may be appropriately selected depending on the purpose. However, the temperature is preferably 600 ° C or higher, more preferably 600 ° C or higher and 1,000 ° C or lower.

<Activation treatment>
The activation treatment is not particularly limited as long as it is a treatment for activating the carbide, and can be appropriately selected depending on the purpose. Examples thereof include a gas activation method and a chemical activation method.
Here, activation refers to developing a pore structure of a carbon material and adding pores.

The gas activation method uses oxygen, water vapor, carbon dioxide gas, air, or the like as an activator and, under such a gas atmosphere, for example, at 700 ° C. or more and 1,000 ° C. or less, for several ten minutes to several hours, By heating, a microstructure is developed by the volatile components and carbon molecules in the carbide. The heating temperature may be appropriately selected based on the type of plant-derived material, the type and concentration of gas, and the like, but is preferably 750 ° C or more and 1,000 ° C or less.
The chemical activation method is, instead of oxygen and water vapor used in the gas activation method, activated using zinc chloride, iron chloride, calcium phosphate, calcium hydroxide, magnesium carbonate, potassium carbonate, sulfuric acid, etc., and washed with hydrochloric acid. This is a method of adjusting the pH with an alkaline aqueous solution and drying.

  The time for the activation treatment is not particularly limited and can be appropriately selected depending on the purpose. However, the time is preferably 0.5 to 20 hours, more preferably 1 to 10 hours.

<Heat treatment>
The heat treatment is not particularly limited as long as it is a treatment of heating the carbide after the activation treatment, and can be appropriately selected depending on the purpose. By this treatment, the carbon density of the carbide can be increased, and the electrical conductivity of the manufactured porous carbon material can be improved.

The temperature of the heat treatment is not particularly limited and may be appropriately selected depending on the purpose. For example, the temperature may be 1200 ° C or higher, or 1200 ° C or higher and 2800 ° C or lower. The temperature may be 1,200 ° C. or more and 2,700 ° C. or less, or 1,200 ° C. or more and 2,500 ° C. or less.
In addition, when manufacturing the porous carbon material of the present invention, the heat treatment may not be performed.

  The time of the heat treatment is not particularly limited and can be appropriately selected depending on the purpose. However, the time is preferably from 1 hour to 24 hours, more preferably from 5 hours to 15 hours.

The heat treatment is preferably performed in the presence of a reducing gas to reduce the load on the furnace. Examples of the reducing gas include a hydrogen gas, a carbon monoxide gas, and a vapor of an organic substance (for example, methane gas).
The reducing gas is preferably used together with an inert gas. Examples of the inert gas include a nitrogen gas, a helium gas, and an argon gas.

An example of a method for producing the porous carbon material will be described with reference to FIG.
FIG. 1 is a flowchart of an example of a method for producing a porous carbon material.
First, a plant is prepared as a raw material (S1). Plants contain a silicon component.
Subsequently, the raw material is subjected to a silicon component removal treatment using an alkali to remove the silicon component from the raw material (S2).
Subsequently, the raw material from which the silicon component has been removed is subjected to a carbonization treatment (S3). Carbide is obtained by subjecting it to a carbonization treatment.
Subsequently, the obtained carbide is subjected to an activation treatment (S4). By subjecting it to the activation treatment, the pore structure in the carbide is developed.
Thus, a porous carbon material is obtained.

(Synthesis reaction catalyst)
The synthesis reaction catalyst of the present invention includes the porous carbon material of the present invention, a metal or a metal compound supported on the porous carbon material, and further includes other components as necessary.

The metal is not particularly limited as long as it is a catalytically active component, and can be appropriately selected depending on the intended purpose. For example, platinum group elements (platinum, iridium, osmium, ruthenium, rhodium, palladium), rhenium, gold , Silver and the like.
The metal compound is not particularly limited as long as it is a catalytically active component, and can be appropriately selected depending on the purpose. Examples thereof include alloys of the metals.
Among these, palladium is preferable as the metal or the metal compound in terms of price and availability.

Examples of a method for supporting the metal or the metal compound on the porous carbon material include the following methods.
(1) The porous carbon material, which is a catalyst carrier, is dispersed in a solution of a metal, which is a catalyst active component, and a reducing agent is further added to reduce metal ions in the solution. Method for Precipitating Metal on Porous Carbon Material (2) Heating and stirring a solution of a metal as a catalytically active component in which the porous carbon material as a catalytic carrier is dispersed to precipitate a catalytically active component on the catalytic carrier After that, filtration, washing, drying, etc. are appropriately performed, and a reduction treatment is performed with hydrogen gas or the like.

  The ratio between the porous carbon material and the metal or metal compound in the synthesis reaction catalyst is not particularly limited, and can be appropriately selected depending on the purpose.

The synthesis reaction catalyst can be suitably used for a hydrogenation reduction reaction. As the hydrogenation reduction reaction, a hydrogenation reduction reaction of a compound having two or more groups capable of hydrogenation reduction is preferable.
At least two hydrogenatable groups in the compound having two or more hydrogenatable groups are different groups. Examples of the group capable of being hydrogenated and reduced include a halogen group and a vinyl group.

(Method of synthesizing compound)
The method for synthesizing the compound of the present invention includes at least a reduction step, and further includes other steps as necessary.

<Reduction process>
The reduction step is not particularly limited as long as it is a step of reducing the compound using the synthesis reaction catalyst of the present invention, and can be appropriately selected depending on the purpose.
Examples of the compound include a compound having a hydride-reducing group, and a compound having two or more hydride-reducing groups is preferable in that a selective hydride-reduction reaction can be performed. . At least two hydrogenatable groups in the compound having two or more hydrogenatable groups are different groups. Examples of the group capable of being hydrogenated and reduced include a halogen group and a vinyl group.

  The amount of the synthesis reaction catalyst used in the method for synthesizing the compound is not particularly limited and may be appropriately selected depending on the intended purpose. 2.0 parts by mass or less, more preferably 1.0 part by mass or more and 3.0 parts by mass or less.

  In the method for synthesizing the compound, heating may be performed, or the reaction may be performed at room temperature.

  The method for synthesizing the compound is preferably performed in the presence of a reducing gas. Examples of the reducing gas include a hydrogen gas, a carbon monoxide gas, and a vapor of an organic substance (for example, methane gas).

  Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

<Raw materials>
Rice husks from Miyagi Prefecture were used as raw materials.

<Alkali treatment>
The alkali treatment (silicon component removal treatment) for removing the silicon component was performed by immersing the rice hulls in a 5.3% by mass aqueous solution of sodium hydroxide at 90 ° C. for 14 hours.

<Carburizing treatment>
The carbonization treatment was performed in a carbonization furnace at 600 ° C. for 3 hours under a nitrogen atmosphere (N ₂ = 30 L / min).

<Activation treatment>
The activation treatment was performed using a rotary kiln and at a predetermined temperature for a predetermined time with steam under nitrogen bubbling (N ₂ = 10 L / min).

<Heat treatment>
The heat treatment was performed at a predetermined temperature and a predetermined time under an argon gas supply (30 L / min).

(Examples 1 to 4)
The treatment of the rice hulls was performed in the order of alkali treatment, carbonization treatment, and activation treatment under the conditions shown in Table 1 to obtain a porous carbon material.

(Comparative Example 1)
The treatment of the rice hulls was performed in the order of alkali treatment and carbonization under the conditions shown in Table 1 to obtain a porous carbon material.

(Comparative Examples 2 to 4)
The treatment of the rice husks was performed under the conditions shown in Table 1, in the order of alkali treatment, carbonization treatment, activation treatment, and heat treatment, to obtain a porous carbon material.

  The following evaluation was performed about the obtained porous carbon material.

<Measurement of specific resistance value>
The specific resistance value of the porous carbon material was measured by the following method.
An acrylic cylinder having a diameter of 9.0 mm and a length of 17 mm was filled with a porous carbon material at a packing density of 0.4 g / cc. Then, measurement was performed by connecting a digital multimeter (VOAC7412, manufactured by Iwasaki Communication Equipment Co., Ltd.) to electrodes attached to both ends in the length direction of the cylinder. The results are shown in Table 2.

<Half width>
For the measurement of the half width (2θ) of (10X) (38 ° to 49 °) by X-ray diffraction, PHILIPS X'Pert manufactured by PANalytical was used. The results are shown in Table 2.

<Mesopore volume>
For measurement of the mesopore volume, a multi-sample high performance specific surface area / pore distribution measuring device 3Flex manufactured by Micromeritics Co., Ltd. was used. The results are shown in Table 2.

<Catalyst performance>
<< Production of palladium carbon catalyst >>
The porous carbon material was immersed in a hydrochloric acid solution adjusted so that Pd metal was 5% by mass with respect to 1 g of the porous carbon material. Then, it was dried under reduced pressure at 100 ° C. for 2 hours. Further, a reduction treatment was performed at 400 ° C. for 3 hours in a hydrogen-containing gas atmosphere. As a result, a palladium carbon catalyst in which palladium was supported on a porous carbon material was obtained.

<< Selective reduction of 4-chlorostyrene >>
The following composition was charged into a 10-ml test tube, and a hydrogenation reaction was carried out for 1 hour by stirring at a rotation speed of 500 rpm while supplying hydrogen gas through a balloon.
The products were 1-chloro-4-ethylbenzene and ethylbenzene, and the reaction yield was calculated based on the amount of 4-chlorostyrene charged. The reaction yield was determined using Agilent 6890N / 5975 MSD (GC / MS). The results are shown in Table 3.
〔composition〕
-4-chlorostyrene: 89.1 mg
-The above palladium carbon catalyst: 1.3 mg
-Heavy methanol as solvent: 1 ml

  The porous carbon materials produced in Examples 1 to 4 were superior to the porous carbon materials produced in Comparative Examples 1 to 4 in selectivity when used as a catalyst.

  The porous carbon material of the present invention can be suitably used as a carrier for a catalyst and the like.

Claims (7)

Having a porous carbon material and a metal or metal compound supported on the porous carbon material,
The porous carbon material charges, the packing density of 0.4 g / cc, the specific resistance value, and a 10 [Omega · cm or more 10,000 · cm or less, and mesopores volume 0.20 cm ³ / g or more 0. A catalyst for a synthesis reaction, which is 50 cm ³ / g or less.   The catalyst for a synthesis reaction according to claim 1, wherein the metal or metal compound is palladium.   3. The synthesis reaction catalyst according to claim 1, which is used in a hydrogenation reduction reaction.   The catalyst for a synthesis reaction according to any one of claims 1 to 3, which is used for a hydrogenation reduction reaction of a compound having two or more groups capable of hydrogenation reduction.   5. The porous carbon material according to claim 1, wherein a half-width (2θ) of a diffraction peak (10X) (38 ° to 49 °) by X-ray diffraction is 4.3 ° or more and 5.5 ° or less. 5. The catalyst for a synthesis reaction according to   The synthesis reaction catalyst according to any one of claims 1 to 5, wherein the porous carbon material is derived from a plant.   The catalyst for a synthetic reaction according to any one of claims 1 to 6, wherein the porous carbon material is derived from rice husk.