Polyazole-derived carbon-coated metal catalysts, preparation and use thereof

Abstract

The application discloses a polypyrrone-derived carbon-coated metal catalyst and a preparation and application thereof. The catalyst prepared by the application provides a nitrogen-doped carbon layer by polypyrrone, which not only provides protection for an active center, but also promotes electron transmission between carbon layers by the conductive property of the polypyrrone-derived carbon layer itself. The polypyrrone-derived carbon-coated metal catalyst is applied to a catalytic hydrogenation reaction of chloronitrobenzene containing sulfur-containing poisons, and shows excellent activity, selectivity and stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of polyazole derivative carbon-coated metal catalyst and its preparation and application in chloronitrobenzene catalytic hydrogenation reaction containing sulfur poison. BACKGROUND

[0002] Selective hydrogenation reaction is widely used in the field of chemistry and fuel, so it is very important to researchers. O-chloroaniline is an important intermediate of organic chemical raw material, which is colorless to light yellow oily liquid, and plays an important role in fine chemical production and industrial production such as pesticide, medicine, solvent, preservative, etc. The product is in high demand at home and abroad, and has certain economic value.

[0003] The existing technology for preparing o-chloroaniline is mainly to synthesize o-chloroaniline by catalytic hydrogenation with o-chloronitrobenzene as raw material. A widely accepted hydrogenation reaction mechanism was published in 1898. There are two acceptable pathways for the hydrogenation reaction of chloronitrobenzene, direct and condensation, as shown in Figure 4 .

[0004] In the direct hydrogenation reaction process, chloronitrobenzene is preferentially generated under the action of hydrogen to generate chloronitrobenzene and chlorophenyl hydroxylamine, and then dehydrated to generate chloroaniline. If the catalyst activity is strong, it will further dechlorinate or deaminate to generate aniline or chlorobenzene. In short, the direct hydrogenation reaction process is the reduction and conversion process of NO2 in chloronitrobenzene. In the condensation reaction process, chloronitrobenzene and chlorophenyl hydroxylamine will be condensed and reduced to generate dichloroazoxypbenzene, dichloroazobenzene and dichloro thiozene intermediates, and then they are converted into chloroaniline by hydrogenation.

[0005] At present, the reported processes for producing o-chloroaniline mainly include the following: iron filings reduction method can be used for the reduction of nitro group in a series of aromatic nitro compounds. This method is simple and has low equipment requirements, but it produces a large amount of waste heat, consumes a large amount of iron powder, is harmful to the environment and difficult to realize continuous production, and has problems such as difficult product separation and low production efficiency; sulfide alkali reduction method is a method commonly used in industrial production, and the process is mature. Although this method has relatively mild reaction conditions and easy product separation, it is still difficult to solve the environmental hazards of large amount of alkali liquor; catalytic hydrogenation reduction method is the mainstream method in recent years, because direct hydrogenation almost does not produce by-products, it is relatively green and clean, and there is no discharge of large amount of alkali or acid liquor.

[0006] In the catalytic hydrogenation reaction, the selection of catalyst has important influence on the solution of the above existing problems. The supported metal nanoparticle catalyst is an important catalyst in the hydrogenation of aromatic nitro compounds, such as Pd, Pt, Co, Ni, etc. However, this catalyst also has many problems. First, from the reaction substrate, nitroaromatics are easy to produce many by-products, such as chloronitrobenzene, which is easy to produce nitrobenzene, aniline and other by-products in the reaction process. Among them, the dechlorination not only reduces the selectivity of the reaction, but also has corrosive to the equipment. Second, from the catalyst itself, the supported catalyst is easy to appear agglomeration, sintering, poisoning, active center loss and other problems, which leads to permanent deactivation of the catalyst and increases the production cost.

[0007] Catalyst poisoning refers to the phenomenon that the catalytic activity of the catalyst decreases due to the action of some compounds, which are called poisons. The main reason for this phenomenon is that the poisons occupy the active sites of the catalyst in the form of physical adsorption or chemical bond, or even react with the active center to generate another substance. This greatly reduces the adsorption and catalytic effect of the catalyst on the reactants, or even completely loses. Yasser Jangjou group found the generation of ammonium sulfate and copper sulfate in the study of SO2 poisoning of Cu-SAPO-34 in NH3-SCR, and the decomposition temperature of copper sulfate needs to be higher than 480℃. They prolonged the poisoning time of the active site by introducing an additive that is easy to react with SO2, but the formation of sulfate salt leads to permanent deactivation of the catalyst. Ruiben Jin group studied the reaction of low-temperature selective catalytic reduction of NO with NH3 in the presence of SO2 using Mn-Ce / TiO2 as catalyst. The study shows that the generation and deposition of (NH4)2SO3 and NH4HSO4 are the main reasons for the deactivation of the catalyst.

[0008] The coated catalyst is a method of using high molecular polymer to wrap the active center to form a core-shell structure to prevent the poison from contacting the active center and increase the stability of the catalyst. This method can also prevent the agglomeration and loss of metal nanoparticles. Because the carbon layer through which the electrons can pass has a threshold, the activity of the catalyst will be greatly reduced. Based on the above analysis, it is urgent to find a catalyst with high activity, high selectivity and high stability for complex catalytic hydrogenation system rich in poisons. SUMMARY

[0009] One of the purposes of the present application is to provide a preparation method of a poly-pyrrole derived carbon coated metal catalyst, which provides a nitrogen doped carbon layer from poly-pyrrole, not only provides protection for the active center, but also promotes electron transfer between carbon layers due to the conductive properties of the poly-pyrrole derived carbon layer itself.

[0010] The second purpose of the present application is to provide a poly-pyrrole derived carbon coated metal catalyst.

[0011] The third object of the present application is to provide the application of the poly-pyrrole derived carbon-coated metal catalyst in the catalytic hydrogenation reaction of chloronitrobenzene containing sulfur-containing poisons, which has excellent activity, selectivity and stability.

[0012] To achieve the above-mentioned objects, the present application adopts the following technical solutions:

[0013] In the first aspect, the present application provides a preparation method of a poly-pyrrole derived carbon-coated metal catalyst, which is carried out according to the following steps:

[0014] Step one: according to the equal volume impregnation method, the carbon material is stirred uniformly in water, then the metal precursor aqueous solution is added, stirred uniformly, and placed in a water bath at 50-80℃ for drying;

[0015] Step two: the product prepared in step one is placed in a hydrogen atmosphere and kept at 250-400℃ for 3-5h for reduction, and the temperature rising rate is 1-5℃ / min, to obtain M / C, wherein M represents metal;

[0016] Step three: the ligand 1,4-bis(diphenylphosphino)butane is added to water and stirred for 10-24h, then the M / C product of step two is added, and placed in a microwave synthesis instrument at 60-140℃ for 2-5h to facilitate the full capture of metal particles by 1,4-bis(diphenylphosphino)butane;

[0017] Step four: the pyrrole monomer is mixed with water by stirring to obtain a monomer solution;

[0018] Step five: an aqueous solution of ferric chloride is prepared;

[0019] Step six: the product obtained in step three is poured into the monomer solution obtained in step four, and ultrasonic treatment is performed for 10-20min, and stirring is performed to mix them uniformly, and the temperature is kept at 0-5℃;

[0020] Step seven: the aqueous solution of ferric chloride obtained in step five is placed in the solution of step six, stirring is started, the temperature is controlled at 0-5℃, and the solution is kept for 8-12h, then filtered, and dried in an oven at 70-100℃;

[0021] Step eight: the product obtained in step seven is calcined in an inert gas atmosphere, and the obtained product is a poly-pyrrole derived carbon-coated metal catalyst, which is named as M / C@PPy-X, wherein "M" represents metal, "X" represents the calcination temperature, "@" represents coating, " / " represents loading, and "PPy" represents poly-pyrrole.

[0022] As a preference, the feeding ratio of 1,4-bis(diphenylphosphino)butane, M / C, pyrrole, and ferric chloride is 1.5-3 g: 1 g: 0.20-0.35 mL: 1-3 g, more preferably 2-3 g: 1 g: 0.25-0.30 mL: 1.5-2.5 g, and further more preferably 2.2-2.3 g: 1 g: 0.28 mL: 1.5-2.5 g.

[0023] As a preference, in step one, the metal precursor is chloroplatinic acid, and the loading of platinum in M / C (based on 100% of the mass of M / C) is 1-5 wt%, more preferably 3 wt%.

[0024] As a preference, in step one, the standing time is 20-30 h.

[0025] As a preference, in step one, the carbon material used is activated carbon.

[0026] As a preference, in step two, the reduction temperature is 300°C, and the holding time is 4 h.

[0027] As a preference, in step three, the mass ratio of 1,4-bis(diphenylphosphino)butane, water, and M / C is 1.5-3: 5-15: 1, more preferably 2-3: 8-12: 1.

[0028] As a preference, in step four, the volume ratio of pyrrole monomer and water is 1-2: 450-500.

[0029] As a preference, in step four, the stirring time is 4-10 min, most preferably 10 min.

[0030] As a preference, in step five, the mass ratio of anhydrous ferric chloride and water is 1-1.2: 10.

[0031] As a preference, in step six, the ultrasonic time is 15 min, and the holding temperature is 0°C.

[0032] As a preference, in step seven, the holding time at 0°C is 12 h.

[0033] As a preference, in step eight, the selected inert gas is N2, the calcination condition is 600°C for 3 h, and the temperature rising rate is 5°C / min.

[0034] In a second aspect, the present application provides a poly-pyrrole-derivative carbon-coated metal catalyst prepared by the preparation method according to the first aspect.

[0035] In a third aspect, the present application provides an application of the poly-pyrrole-derivative carbon-coated metal catalyst in a catalytic hydrogenation reaction of chloronitrobenzene containing sulfur-containing poisons.

[0036] The chloronitrobenzene according to the present application is one of the following:

[0037]

[0038] Preferred is o-chloronitrobenzene.

[0039] The sulfur-containing poison described in the present application is thiophene.

[0040] As preferred, the application is specifically: in a high-pressure reactor, adding chloronitrobenzene containing sulfur-containing poison, solvent and polypyrrole derivative carbon-coated metal catalyst, after removing air by nitrogen, stirring reaction by hydrogen, generating chloroaniline.

[0041] As preferred, the solvent is ethanol.

[0042] As preferred, the mass amount of polypyrrole derivative carbon-coated metal catalyst is 1-5% of the mass of chloronitrobenzene, and most preferably 2%.

[0043] As preferred, the hydrogen pressure is maintained at 0.8-1.5 MPa, and more preferably the hydrogen pressure is 1.0 MPa, and the reaction temperature is controlled at 50-60℃, and most preferably 60℃.

[0044] As preferred, the stirring rate is 500-1000 rpm.

[0045] Compared with the prior art, the present application has the following advantages:

[0046] (1) The polypyrrole derivative carbon-coated metal catalyst provided by the present application uses high molecular conductive polymer polypyrrole as the carbon source of the shell layer, and applies the high molecular conductive polymer to the thermal catalytic reaction, thereby improving the catalyst activity.

[0047] (2) The polypyrrole derivative carbon-coated metal catalyst provided by the present application is polymerized in situ on the metal surface and completely coats the metal, bypassing the physical properties of polypyrrole that are difficult to melt and dissolve, and indirectly applying polypyrrole, which is different from the partial coating of mesoporous catalysts, and the manufacturing method is simple and the application of polypyrrole is more efficient.

[0048] (3) The polypyrrole derivative carbon-coated metal catalyst provided by the present application uses 1,4-bis(diphenylphosphino)butane as a metal capturing agent during preparation, and uses microwave solid-phase technology to assist in capturing metal particles, which not only makes it easier for pyrrole to adhere to the metal surface, polymerize in situ on the metal surface, and achieve complete coating, but also helps the contact of pyrrole monomers in the solution, increases the polymerization efficiency, and increases the application rate of pyrrole. Pyrrole is biologically harmless and meets the green development concept.

[0049] (4) The polypyrrole derivative carbon-coated metal catalyst provided by the present application uses a direct introduction of pyrrole nitrogen to regulate the activity of the catalyst, and the content of pyrrole nitrogen in the catalyst can be regulated by adjusting the calcination temperature, thereby affecting the catalyst activity.

[0050] (5) The poly-pyrrole derived carbon coated metal catalyst provided by the present application, the poly-pyrrole carbon layer completely coated on the surface of the metal helps the electron transmission between the active metal in the core and the reaction substrate, so that the catalyst has high activity; the outer shell layer protects the core metal, preventing the attack of external poisons on the active center, so that the catalyst has high stability.

[0051] (6) The poly-pyrrole derived carbon coated metal catalyst provided by the present application is applied to a complex catalytic hydrogenation system rich in poisons, and the probe reaction of catalytic hydrogenation of chloronitrobenzene to generate chloroaniline is selected, so that the by-products generated are less, reducing the corrosiveness to the equipment; the catalyst has good stability and can be repeatedly used, effectively reducing the cost of the catalyst; at the same time, the safety during use is high; and the catalyst has high industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a TEM image of Pt / C prepared in Example 1;

[0053] Figure 2 is a TEM image of the poly-pyrrole derived carbon coated metal catalyst prepared in Example 1.

[0054] Figure 3 is an infrared spectrum of Pt / C, Pt / C@poly-pyrrole, Pt / C@poly-pyrrole-500 prepared in Example 17 and poly-pyrrole prepared in Comparative Example 1.

[0055] Figure 4 is the hydrogenation reaction mechanism of chloronitrobenzene. DETAILED DESCRIPTION

[0056] The technical solutions of the present application will be further described below with specific examples. It is necessary to point out that the examples are only used to further illustrate the present application, but cannot be understood as limiting the protection scope of the present application, and the present application is not limited to this in any way.

[0057] In the examples of the present application, the specific conditions not mentioned are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are conventional products that can be obtained by conventional technical means or obtained by purchase.

[0058] The coconut shell activated carbon used in the examples of the present application is purchased from Chengde Tianyuan Activated Carbon Co., Ltd., with a specification of 20-40 mesh and an iodine value of 1000; and the platinum liquid is an aqueous chloroplatinic acid solution.

[0059] Comparative Example 1: Preparation method of poly-pyrrole

[0060] To 125 mL of deionized water, 0.280 mL of pyrrole monomer was added and stirred for 10 min to mix the pyrrole and water uniformly, at the same time, a ferric chloride solution was prepared by dissolving 1.94 g of anhydrous ferric chloride in 20 mL of deionized water. Then the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. The temperature was kept at 0°C for 12 h under stirring. Then it was filtered and dried at 80°C. The polypyrrole was obtained.

[0061] Example 1

[0062] To 10 mL of deionized water, 0.97 g of commercially available coconut shell activated carbon was added and stirred to mix uniformly, then 0.189 mL of platinum solution (0.1579 g Pt / mL) was added and left to stand for 24 h, then dried at 80°C, and then placed in a hydrogen atmosphere and kept at 300°C for 4 h with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h to make it disperse fully, then 1 g of Pt / C was added and placed in a microwave synthesis instrument and kept at 100-140°C for 5 h to facilitate the 1,4-bis(diphenylphosphino)butane to capture the metal particles fully, then centrifuged and washed with benzene and deionized water three times; to 125 mL of deionized water, 0.280 mL of pyrrole monomer was added and stirred for 10 min to mix the pyrrole and water uniformly, then the Pt / C treated by the capturing agent 1,4-bis(diphenylphosphino)butane was placed in the mixed solution of pyrrole and water, and ultrasonic was performed for 15 min and stirring was performed for 30 min to keep the temperature at 0°C; at the same time, a ferric chloride solution was prepared by dissolving 1.94 g of anhydrous ferric chloride in 20 mL of deionized water. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. The temperature was kept at 0°C for 12 h under stirring. Then it was filtered and dried at 80°C. The Pt / C@PPy was obtained. Then the obtained product was calcined at 600°C for 3 h under a nitrogen atmosphere with a heating rate of 5°C / min. Thus a polypyrrole derived carbon coated metal catalyst was prepared, which was recorded as 3%Pt / C@PPy-600.

[0063] The TEM images of Pt / C and 3%Pt / C@PPy-600 prepared in Example 1 are shown in Figure 1 and Figure 2 It can be seen that Pt / C is a typical uncoated supported metal catalyst structure, while in 3%Pt / C@PPy-600, the metal particles are completely coated.

[0064] Comparative Example 2: without adding ligand

[0065] The purchased 0.97 g coconut shell activated carbon was placed in 10 mL deionized water, after stirring evenly, 0.189 mL platinum liquid (0.1579 g Pt / mL) was added, and after standing for 24 h, it was dried at 80°C, and then placed in a hydrogen atmosphere at 300°C for 4 h, with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 0.280 mL of pyrrole monomer was added to 125 mL deionized water, and stirred for 10 min to mix the pyrrole and water evenly, then the Pt / C was placed in the mixed solution of pyrrole and water, and ultrasonic was performed for 15 min, and stirring was performed for 30 min, while maintaining the temperature at 0°C; at the same time, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL deionized water to prepare a ferric chloride solution. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. Under stirring, 0°C was maintained for 12 h. Then, it was filtered and dried at 80°C. Subsequently, the obtained product was calcined at 600°C under a nitrogen atmosphere for 3 h, with a heating rate of 5°C / min. A polypyrrole derived carbon coated metal catalyst was prepared, which was recorded as 3% Pt / C@PPy-600.

[0066] Example 2

[0067] The purchased 0.97 g coconut shell activated carbon was placed in 10 mL deionized water, after stirring evenly, 0.189 mL platinum liquid (0.1579 g Pt / mL) was added, and after standing for 24 h, it was dried at 80°C, and then placed in a hydrogen atmosphere at 300°C for 4 h, with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 0.280 mL of pyrrole monomer was added to 125 mL deionized water, and stirred for 10 min to mix the pyrrole and water evenly, then the Pt / C was placed in the mixed solution of pyrrole and water, and ultrasonic was performed for 15 min, and stirring was performed for 30 min, while maintaining the temperature at 0°C; at the same time, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL deionized water to prepare a ferric chloride solution. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. Under stirring, 0°C was maintained for 12 h. Then, it was filtered and dried at 80°C. Subsequently, the obtained product was calcined at 600°C under a nitrogen atmosphere for 3 h, with a heating rate of 5°C / min. A polypyrrole derived carbon coated metal catalyst was prepared, which was recorded as 3% Pt / C@PPy-600.

[0068] Example 3

[0069] The 0.97 g of purchased coconut shell activated carbon was placed in 10 mL of deionized water, after stirring evenly, 0.189 mL of platinum liquid (0.1579 g Pt / mL) was added, and after standing for 24 h, it was dried at 80°C, and then placed in a hydrogen atmosphere at 350°C for 4 h, with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water, stirred for 10 h, then 1 g of Pt / C was added, and placed in a microwave synthesis instrument at 100-140°C for 5 h, to facilitate the full capture of metal particles by 1,4-bis(diphenylphosphino)butane, centrifuged, and washed with benzene and deionized water three times; 0.280 mL of pyrrole monomer was added to 125 mL of deionized water, stirred for 10 min to mix the pyrrole and water evenly, then the Pt / C treated by the capture agent 1,4-bis(diphenylphosphino)butane was placed in the mixed solution of pyrrole and water, and ultrasonic was performed for 15 min, and stirring was performed for 30 min, while maintaining the temperature at 0°C; at the same time, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. Under stirring, 0°C was maintained for 12 h. Then, filtration was performed, and drying was performed at 80°C. Subsequently, the obtained product was calcined at 600°C for 3 h under a nitrogen atmosphere, with a heating rate of 5°C / min. Thus a polypyrrole derived carbon coated metal catalyst was prepared, and was recorded as 3% Pt / C@PPy-600.

[0070] Example 4

[0071] The 0.97 g of purchased coconut shell activated carbon was placed in 10 mL of deionized water, after stirring evenly, 0.189 mL of platinum liquid (0.1579 g Pt / mL) was added, and after standing for 24 h, it was dried at 80°C, and then placed in a hydrogen atmosphere at 400°C for 4 h, with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water, stirred for 10 h, then 1 g of Pt / C was added, and placed in a microwave synthesis instrument at 100-140°C for 5 h, to facilitate the full capture of metal particles by 1,4-bis(diphenylphosphino)butane, centrifuged, and washed with benzene and deionized water three times; 0.280 mL of pyrrole monomer was added to 125 mL of deionized water, stirred for 10 min to mix the pyrrole and water evenly, then the Pt / C treated by the capture agent 1,4-bis(diphenylphosphino)butane was placed in the mixed solution of pyrrole and water, and ultrasonic was performed for 15 min, and stirring was performed for 30 min, while maintaining the temperature at 0°C; at the same time, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. Under stirring, 0°C was maintained for 12 h. Then, filtration was performed, and drying was performed at 80°C. Subsequently, the obtained product was calcined at 600°C for 3 h under a nitrogen atmosphere, with a heating rate of 5°C / min. Thus a polypyrrole derived carbon coated metal catalyst was prepared, and was recorded as 3% Pt / C@PPy-600.

[0072] Example 5

[0073] The 0.97 g of purchased coconut shell activated carbon was placed in 10 mL of deionized water, after stirring evenly, 0.189 mL of platinum liquid (0.1579 g Pt / mL) was added, and after standing for 24 h, it was dried at 80°C, and then placed in a hydrogen atmosphere at 300°C for 4 h, with a heating rate of 5°C / min. Thus Pt / C was prepared. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water, stirred for 10 h, then 1 g of Pt / C was added, and placed in a microwave synthesis instrument at 100-140°C for 2.5 h, to facilitate the capture of metal particles by 1,4-bis(diphenylphosphino)butane, centrifuged, and washed with benzene and deionized water three times; 0.280 mL of pyrrole monomer was added to 125 mL of deionized water, stirred for 10 min to mix the pyrrole and water evenly, then the Pt / C treated with the capture agent 1,4-bis(diphenylphosphino)butane was placed in the mixed solution of pyrrole and water, and ultrasonic was applied for 15 min, and stirred for 30 min, while maintaining the temperature at 0°C; at the same time, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring was completed, the prepared ferric chloride solution was quickly poured into the mixed solution of pyrrole monomer. Under stirring, the temperature was maintained at 0°C for 12 h. Then it was filtered and dried at 80°C. Subsequently, the obtained product was calcined at 600°C for 3 h under a nitrogen atmosphere, with a heating rate of 5°C / min. Thus a polypyrrole derived carbon coated metal catalyst was prepared, denoted as 3% Pt / C@PPy-600.

[0074] Example 6

[0075] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 4 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture and sonicated for 15 min, followed by stirring for 30 min, while maintaining the temperature at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was maintained at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0076] Example 7

[0077] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 4 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0078] Example 8

[0079] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 8 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0080] Example 9

[0081] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 10 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0082] Example 10

[0083] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane scavenging agent was then placed in the pyrrole and water mixture, sonicated for 12 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0084] Example 11

[0085] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 16 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0086] Example 12

[0087] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 18 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0088] Example 13

[0089] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture and sonicated for 20 min, followed by stirring for 30 min, maintaining the temperature at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was maintained at 0 °C for 12 h under stirring conditions. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0090] Example 14

[0091] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane scavenging agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and maintained at 5 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was maintained at 5 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0092] Example 15

[0093] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 8 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0094] Example 16

[0095] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane scavenging agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 10 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 600°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-600.

[0096] Example 17

[0097] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane trapping agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C to obtain Pt / C@PPy. The resulting product was then calcined at 500°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-500.

[0098] The infrared spectra of Pt / C, Pt / C@polypyrrole, Pt / C@polypyrrole-500 prepared in Example 17 and the polypyrrole prepared in Comparative Example 1 are shown in Figure 17. Figure 3 Of these, the band at 547 is attributed to the fundamental vibration of the pyrrole ring, the peaks at 1299 and 1038 are attributed to vibrations within the =C–H plane, the peak at 1196 is identified as a C–N stretching vibration, and the peak observed at 920 is attributed to vibrations outside the =C–H plane. Figure 3 It is evident that Pt / C@PPy exhibits a combined peak of polypyrrole and platinum carbon, and the peak intensity is significantly reduced after coating, confirming the formation of polypyrrole. Furthermore, after calcination at 500℃, the platinum carbon peak at approximately 1350℃ disappears.

[0099] Example 18

[0100] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 700°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-700.

[0101] Example 19

[0102] 0.97g of purchased coconut shell activated carbon was placed in 10mL of deionized water, stirred evenly, and then 0.189mL of platinum solution (0.1579g Pt / mL) was added. After standing for 24h, it was dried at 80℃ and then placed in a hydrogen atmosphere at 300℃ for 4h, with a heating rate of 5℃ / min. Pt / C was thus obtained. Then, 2.27 g of ligand 1,4-bis(diphenylphosphino)butane was added to 10 mL of water and stirred for 10 h. Next, 1 g of Pt / C was added, and the mixture was placed in a microwave synthesizer at 100–140 °C for 5 h to allow the 1,4-bis(diphenylphosphino)butane to fully capture the metal particles. The mixture was centrifuged and washed three times with benzene and deionized water. 0.280 mL of pyrrole monomer was added to 125 mL of deionized water and stirred for 10 min to ensure homogeneity of the pyrrole and water. The Pt / C treated with the 1,4-bis(diphenylphosphino)butane capturing agent was then placed in the pyrrole and water mixture, sonicated for 15 min, stirred for 30 min, and kept at 0 °C. Simultaneously, 1.94 g of anhydrous ferric chloride was dissolved in 20 mL of deionized water to prepare a ferric chloride solution. After stirring, the prepared ferric chloride solution was quickly poured into the pyrrole monomer mixture. The mixture was kept at 0 °C for 12 h under stirring. Then, it was filtered and dried at 80 °C. The resulting product was then calcined at 800°C for 3 hours under a nitrogen atmosphere, with a heating rate of 5°C / min. This yielded a polypyrrole-derived carbon-coated metal catalyst, denoted as 3%Pt / C@PPy-800.

[0103] Application Example 1

[0104] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0105] Application Example 2

[0106] In a 250 mL high-pressure reactor, 0.1 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0107] Application Example 3

[0108] In a 250 mL high-pressure reactor, 0.3 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0109] Application Example 4

[0110] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 50 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0111] Application Example 5

[0112] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 55 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0113] Application Example 6

[0114] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of m-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0115] Application Example 7

[0116] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of p-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0117] Application Example 8

[0118] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 0.9 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0119] Application Example 9

[0120] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1.1 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0121] Application Example 10

[0122] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1.3 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0123] Application Example 11

[0124] In a 250 mL high-pressure reactor, 0.2 g of the polypyrrole-derived carbon-coated metal catalyst prepared in Example 1, 10 g of o-chloronitrobenzene, 80 mL of ethanol, and 3000 ppm of thiophene were added sequentially. The reactor was sealed, and the air inside was replaced with nitrogen three times. Then, the nitrogen inside the reactor was replaced with hydrogen five times. The hydrogen pressure inside the reactor was adjusted to 1.5 MPa, and the reactor was heated to 60 °C and stirred (stirring rate 750 rpm) for 2 h. After the reaction was completed, the catalyst was filtered, the organic layer was separated, and the composition of the hydrogenation product in the filtrate was analyzed by high performance gas chromatography. The solvent was filtered out under reduced pressure, washed with deionized water and methanol, and dried to obtain the target product.

[0125] Table 1. Reaction results of application examples 1-11

[0126] Application Examples Catalyst Ortho-chloronitrobenzene conversion Product selectivity 1 3% Pt / C@PPy-600 of Example 1 100.00％ 97.99％ 2 3% Pt / C@PPy-600 of Example 1 100.00％ 94.42％ 3 3% Pt / C@PPy-600 of Example 1 100.00％ 97.33％ 4 3% Pt / C@PPy-600 of Example 1 100.00％ 95.46％ 5 3% Pt / C@PPy-600 of Example 1 100.00％ 96.26％ 6 3% Pt / C@PPy-600 of Example 1 100.00％ 96.78％ 7 3% Pt / C@PPy-600 of Example 1 100.00％ 95.12％ 8 3% Pt / C@PPy-600 of Example 1 100.00％ 96.72％ 9 3% Pt / C@PPy-600 of Example 1 100.00％ 97.76％ 10 3% Pt / C@PPy-600 of Example 1 100.00％ 97.78％ 11 3% Pt / C@PPy-600 of Example 1 100.00％ 97.95％

[0127] Application Examples 12-30

[0128] The experimental conditions were the same as in Application Example 1, except that the catalyst was changed. The experimental results are shown in Table 2.

[0129] Table 2 Catalyst performance results in Examples 12-29

[0130]

[0131]

[0132] *Reaction conditions are the same as in Application Example 1

[0133] The comparison between Example 1 and Comparative Example 2 shows that using 1,4-bis(diphenylphosphino)butane as a metal scavenger and employing microwave solid-phase technology to assist in the capture of metal particles during catalyst preparation is beneficial for the subsequent in-situ polymerization of pyrrole monomers on the surface of metal particles to form polypyrrole and achieve full coating of the metal particles, thereby improving the catalytic hydrogenation performance of the catalyst.

[0134] Application Example 31

[0135] The experimental conditions were the same as in Application Example 1, and the filtered catalyst was reused in the next reaction. High-performance gas chromatography (HPLC) was used to analyze the composition of the hydrogenation products in the filtrate obtained from each reuse experiment, and the results are shown in Table 3.

[0136] Table 3 Results of application of catalyst in Example 1

[0137]

[0138]

[0139] *The reaction conditions are the same as in Application Example 1.

Claims

1. A method for preparing a polypyrole-derived carbon-coated metal catalyst, characterized by: The preparation method is carried out according to the following steps: Step one: according to the equal volume impregnation method, the carbon material is stirred in water, then the metal precursor aqueous solution is added, stirred uniformly, and then placed in a 50-80°C water bath for evaporation; Step two: the product obtained in step one is placed in a hydrogen atmosphere and kept at 250-400°C for 3-5h for reduction, with a temperature rising rate of 1-5°C / min, to obtain M / C, wherein M represents metal; Step three: the ligand 1,4-bis(diphenylphosphino)butane is added to water and stirred for 10-24h, then the M / C product of step two is added, and placed in a microwave synthesis instrument at 60-140°C for 2-5h to facilitate the full capture of metal particles by 1,4-bis(diphenylphosphino)butane; Step four: pyrrole monomer and water are mixed and stirred to obtain a monomer solution; Step five: an aqueous solution of ferric chloride is prepared; Step six: the product obtained in step three is poured into the monomer solution obtained in step four, and ultrasonic treatment is performed for 10-20min, and then stirred to mix uniformly, while keeping the temperature at 0-5°C; Step seven: the aqueous solution of ferric chloride obtained in step five is added to the solution of step six, and stirring is started, while keeping the temperature at 0-5°C, and kept for 8-12h, then filtered, and dried in an oven at 70-100°C; Step eight: the product obtained in step seven is calcined in an inert atmosphere, and the obtained product is a polypyrrole derivative carbon-coated metal catalyst.

2. The production method according to claim 1, characterized by: The feeding ratio of 1,4-bis(diphenylphosphino)butane, M / C, pyrrole, and ferric chloride is 1.5-3g:1g:0.20-0.35mL:1-3g.

3. The production method according to claim 2, characterized by: The feeding ratio of 1,4-bis(diphenylphosphino)butane, M / C, pyrrole, and ferric chloride is 2-3g:1g:0.25-0.30mL:1.5-2.5g.

4. The production method according to claim 3, characterized by: The feeding ratio of 1,4-bis(diphenylphosphino)butane, M / C, pyrrole, and ferric chloride is 2.2-2.3g:1g:0.28mL:1.5-2.5g.

5. The production method according to claim 1, wherein: In step one, the metal precursor is chloroplatinic acid, and the loading of platinum in M / C is 1-5wt%.

6. The production method according to claim 1, wherein: In step two, the reduction temperature is 300°C, and the holding time is 4h.

7. The production method according to claim 1, wherein: In step four, the stirring time is 4-10min.

8. The production method according to claim 7, characterized by: In step four, the stirring time is 10min.

9. The production method according to claim 1, wherein: In step six, the ultrasonic treatment time is 15min, and the temperature is kept at 0°C.

10. The production method according to claim 1, wherein: In step seven, the holding time at 0°C is 12h.

11. The production method according to claim 1, wherein: In step eight, the selected inert atmosphere is N2, the calcination condition is 600°C for 3h, and the temperature rising rate is 5°C / min.

12. A polypyrrole derivative carbon-coated metal catalyst prepared by the preparation method of claim 1.

13. Use of the polypyrrole derivative carbon-coated metal catalyst of claim 12 in catalytic hydrogenation of chloronitrobenzene containing sulfur-containing poisons.

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