Supported nanomaterial, preparation method thereof, and method for synthesizing 6ppd by using the same as catalyst

Abstract

The application discloses a supported nanomaterial, a preparation method thereof, and a method for synthesizing 6PPD by using the supported nanomaterial as a catalyst. The preparation method of the supported nanomaterial comprises the following steps: obtaining a mixture containing a nitrogen source, a carbon source and a noble metal source; and performing calcination I, calcination II and acid pickling on the mixture to obtain the supported nanomaterial; the atmosphere of the calcination I and the calcination II is nitrogen; the conditions of the calcination I comprise that the temperature is 555 DEG C to 855 DEG C, and the time is 2h to 6h; the conditions of the calcination II comprise that the temperature is 955 DEG C to 1155 DEG C, and the time is 2h to 4h. The noble metal element is modified on the nitrogen-doped carbon nanosheet by a pyrolysis one-step method. The supported nanomaterial is used as the catalyst for producing 6PPD, and the copper damage problem in the industrial production can be solved, and the ketone to alcohol side reaction phenomenon can be reduced. The catalyst has high activity and high selectivity in the catalytic hydrogenation for preparing 6PPD, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology, specifically relating to supported nanomaterials and their preparation methods, as well as methods for synthesizing 6PPD as a catalyst. Background Technology

[0002] 6PPD is a rubber antioxidant, also known as antioxidant 4525. Its chemical name is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine. It is a low-toxicity, solvent-resistant, and highly efficient p-phenylenediamine antioxidant. In natural and synthetic rubber, it has good resistance to ozone and flexural aging, heat and oxidation, and corrosion from metals such as copper and manganese. Therefore, it is widely used in tires, cables, and other industrial rubber products.

[0003] Currently, methods for synthesizing 6PPD include reductive amination, Schiff base hydrogenation, phenol-amine condensation, hydroxylamine reductive alkylation, and quinone imine condensation. The reductive amination method is the primary process used for industrial production both domestically and internationally. This method uses 4-aminodiphenylamine and methyl isobutyl ketone as raw materials, and obtains the target product 6PPD through hydrogen reduction amination under specific temperature, pressure, and catalyst conditions. This method utilizes a clean hydrogenation process, produces less waste, and has a high product yield.

[0004] Chinese invention patent application CN152146542A synthesizes 6PPD using a two-step method of condensation and hydrogenation. The catalyst mentioned is a nickel, palladium, or platinum catalyst, and the mass of the catalyst is 2-15% of the total mass of methyl isobutyl ketone.

[0005] Chinese invention patent application CN152265176A discloses a continuous production process for 6PPD antioxidants, which can be used for the production of antioxidants at a rate of 7555 t / a or higher. This process involves a condensation hydrogenation reaction of 4-aminodiphenylamine and methyl isobutyl ketone. The process is characterized by the use of a gas-liquid-solid fixed-bed hydrogenation reactor, a reaction temperature of 165–235 °C, a pressure of 5.5–6.5 MPa, a ketone-amine ratio of 2–4:1, a hydrogen-to-oil ratio of 2555–5555:1, and the use of a nickel-based hydrogenation catalyst.

[0006] Chinese invention patent application 159665964A discloses a method for improving the selectivity of 6PPD preparation. This method involves adding a catalyst passivator to the raw material system for preparing the antioxidant to reduce catalytic activity, thereby improving the selectivity of the antioxidant 6PPD.

[0007] In China, the reductive amination method for 6PPD generally uses copper-based catalysts. While inexpensive and suitable for continuous fixed-bed production, copper-based catalysts suffer from poor selectivity, severe ketone-to-alcohol conversion in the side reaction, and significant copper loss, limiting the product's application. Therefore, developing a highly efficient and clean noble metal catalyst for the synthesis of 6PPD is of great significance. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing a noble metal supported catalyst, using glucose, dicyandiamine, and chloroplatinic acid as raw materials, and further preparing a nitrogen-doped carbon nanosheet catalyst supported on metal Pt particles by pyrolysis. This catalyst is then used as a hydrogenation catalyst in the continuous catalytic reduction amination of p-phenylenediamine to prepare the antioxidant 6PPD, solving the problems of copper loss leading to copper damage and the side reaction ketone-to-alcohol conversion in existing antioxidant production processes.

[0009] This invention provides a method for preparing supported nanomaterials, obtaining a mixture containing a nitrogen source, a carbon source, and a noble metal source; the mixture is subjected to calcination I, calcination II, and acid washing to obtain the supported nanomaterials; the atmosphere for calcination I and calcination II is nitrogen; the conditions for calcination I include: temperature 555℃~855℃; time 2h~6h; the conditions for calcination II include: temperature 955℃~1155℃; time 2h~4h.

[0010] Optionally, the calcination process employs a two-step heating method, first heating at 3-8°C for 1 minute... -1 The heating rate is increased to the temperature of calcination I, and the temperature is held for 1-3 hours; then the temperature is increased at 8-15℃ / min. -1 The heating rate is increased to the temperature of calcination II, and the temperature is maintained for 1-3 hours;

[0011] Optionally, first at 5℃ min -1 The heating rate was increased to the temperature of calcination I, and the temperature was held for 2 hours; then the temperature was increased at 15℃ / min. -1 The heating rate was increased to the temperature of calcination II, and the temperature was maintained for 2 hours;

[0012] Optionally, the temperature of calcination I is 555°C; the temperature of calcination II is 955°C.

[0013] Optionally, the nitrogen source is selected from at least one of dicyandiamine and uric acid.

[0014] Optionally, the carbon source is selected from monosaccharide or polysaccharide compounds, preferably at least one of glucose and fructose.

[0015] Optionally, the noble metal source is selected from at least one of platinum metal source and palladium metal source; preferably, it is at least one of platinum chloride, platinum acetate, platinum nitrate or chloroplatinic acid.

[0016] Optionally, the acid used in the pickling is an inorganic acid, preferably at least one of sulfuric acid, hydrochloric acid, and nitric acid.

[0017] Optionally, the concentration of the acid solution is 2M to 15M.

[0018] Optionally, the molar ratio of the nitrogen source to the carbon source is 1 to 35:1; the molar ratio of the carbon source to the noble metal source is 1 to 155:1; calculated based on the number of moles of carbon in the carbon source, the number of moles of nitrogen in the nitrogen source, and the number of moles of noble metal in the noble metal source, respectively.

[0019] Optionally, the mixture also contains water, and the mixture is freeze-dried before calcination I;

[0020] The mass concentration of the precious metal source in the water is 3% to 35%, calculated based on the mass of the precious metal in the precious metal source.

[0021] Another aspect of the present invention provides a supported nanomaterial obtained by the above preparation method.

[0022] Optionally, the supported nanomaterial includes a support and an active component; the support is nitrogen-doped graphitized carbon nitride with porous nanosheets; the surface and / or interior of the nitrogen-doped graphitized carbon nitride are loaded with the active component; the active component is a noble metal element.

[0023] Optionally, the precious metal is selected from at least one of Pt and Pd.

[0024] Optionally, the molar ratio of the nitrogen-doped graphitized carbon nitride to the active component is 1 to 255:1.

[0025] Optionally, the specific surface area of ​​the nitrogen-doped graphitized carbon nitride is 955–1355 m². 2 / g.

[0026] Optionally, the nitrogen-doped graphitized carbon nitride has a pore volume of 5.8–1.8 g / ml.

[0027] Optionally, the nitrogen-doped graphitized carbon nitride has a pore size of 1.5 to 4.5 nm.

[0028] Optionally, the ash content of the nitrogen-doped graphitized carbon nitride is 1% to 5%.

[0029] In another aspect, the present invention provides a catalyst containing either the supported nanomaterial obtained by any of the above preparation methods, or containing any of the above supported nanomaterials.

[0030] In another aspect, the present invention provides a method for the hydrogenation catalytic preparation of 6PPD from p-phenylenediamine, the method comprising contacting methyl isobutyl ketone and p-aminodiphenylamine with any of the above-mentioned catalysts to react.

[0031] Optionally, the molar ratio of methyl isobutyl ketone to p-aminodiphenylamine is 2 to 5.5:1.

[0032] Optionally, the reaction conditions include: a temperature of 85℃ to 195℃, preferably 85℃ to 125℃; a reaction pressure of 5.6 to 2.5 MPa, preferably 5.4 to 2.5 MPa; and a time of 1 to 2 hours.

[0033] Optionally, the reaction is carried out in a fixed bed or a reaction vessel.

[0034] Optionally, in the reaction, the conversion rate of 4-aminodiphenylamine is 93% to 99%, the selectivity of 6PPD is 95% to 99%, and the ketol ratio is 85 / 15 to 97 / 3.

[0035] In a preferred embodiment, glucose, dicyandiamine, and platinum salts are used as raw materials. First, graphitized carbon nitride (g-C3N4) nanosheets are generated at 555°C under nitrogen atmosphere. Then, using g-C3N4 as a structural template, it decomposes at 955°C to produce a large amount of nitrogen, which is incorporated into the graphene-like carbon nanosheet substrate. The loose, porous sheet-like structure facilitates the exposure of more active sites.

[0036] As a preferred embodiment, the preparation of supported nanomaterials comprises the following steps:

[0037] (1) Add 5g dicyandiamine, 5.5g glucose and 5.58g (1mmol) chloroplatinic acid to 355mL DI, dissolve and stir evenly, then freeze dry to obtain powder sample.

[0038] (2) Place the powdered sample in a crucible and pyrolyze it in a nitrogen atmosphere using a two-step programmed temperature rise method: First, heat the sample to 555℃ at a heating rate of 5℃ / min. -1 Maintain at this temperature for 2 hours; then at 15°C for 1 minute. -1 The temperature was increased to 955℃, and carbonized at this temperature for 2 hours to obtain the carbonized sample.

[0039] (3) The carbonized sample was placed in 2M H2SO4 and stirred overnight. The acid-washed sample was rinsed with plenty of water until the waste liquid was neutral, and dried at 85°C for later use. The obtained sample was NC / Pt (1 mmol).

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. The catalyst described in this invention is used for the hydrogenation reduction preparation of antioxidant 6PPD. It has a high conversion rate of 4-aminodiphenylamine, high selectivity for 6PPD, low side reaction of ketone to alcohol, and the reaction process does not require a solvent recovery step, thus reducing solvent consumption and recovery costs.

[0042] 2. Compared with copper-based catalysts, the catalyst described in this invention can avoid copper damage caused by catalyst loss when used to synthesize 6PPD. Attached Figure Description

[0043] Figure 1 SEM image of carbon nanosheets without metal nanoparticles prepared in step (2) of Example 1;

[0044] Figure 2 SEM image of NC / Pt prepared in Example 1. Detailed Implementation

[0045] The present invention will now be described in detail with reference to the embodiments. (The percentage content in the following comparative examples and embodiments is by mass percentage).

[0046] This invention employs a specific method: using carbon nitride as a sacrificial template, a catalyst supported on metal nanoparticles is prepared. Its porous, sheet-like structure facilitates the exposure of more active sites, thereby improving the conversion rate and selectivity of the hydrogenation reaction.

[0047] The conversion rate of 4-aminodiphenylamine is calculated as: the amount of 4-aminodiphenylamine consumed in the reaction / the total amount of 4-aminodiphenylamine in the raw materials before the reaction. The amount of 4-aminodiphenylamine consumed in the reaction is calculated by subtracting the amount of 4-aminodiphenylamine remaining in the reaction solution after the reaction from the total amount of 4-aminodiphenylamine in the raw materials before the reaction.

[0048] The selection method for 6PPD is: actual yield of 6PPD in the reactor liquid / (theoretical yield of 6PPD and conversion rate of 4-aminodiphenylamine).

[0049] The ketone-to-alcohol ratio is calculated as the ratio of the mass of methyl isobutyl ketone to the mass of 4-methyl-2-pentanol in the distillate.

[0050] The amount of 4-aminodiphenylamine remaining in the reaction vessel after reaction, the actual yield of 6PPD in the reaction vessel, the mass of methyl isobutyl ketone in the distillate, and the mass of 4-methyl-2-pentanol were analyzed by chromatography.

[0051] The specific surface area, pore volume, and pore size distribution of the catalyst of this invention were determined by low-temperature nitrogen adsorption method, and the specific surface area was the BET specific surface area.

[0052] The ash content of the catalyst of this invention was obtained by testing in accordance with the GB / T12496.3 standard.

[0053] Comparative Example 1: Preparation of NC / Cu Catalyst

[0054] (1) Add 5g dicyandiamine, 5.5g glucose and 5.242g (1mmol) copper nitrate to 355mL DI (deionized water), dissolve and stir evenly, then freeze dry to obtain powder sample.

[0055] (2) Place the powdered sample in a crucible and pyrolyze it in a nitrogen atmosphere using a two-step programmed temperature rise method: First, heat the sample to 555℃ at a heating rate of 5℃ / min. -1 Maintain at this temperature for 2 hours; then at 15°C for 1 minute. -1 The temperature was increased to 955℃, and carbonized at this temperature for 2 hours to obtain the carbonized sample.

[0056] (3) The carbonized sample was placed in 2M H2SO4 and stirred overnight. The acid-washed sample was rinsed with plenty of water until the waste liquid was neutral, and dried at 85°C for later use. The obtained sample was NC / Cu (1 mmol).

[0057] Comparative Application Example 1

[0058] One mmol of the NC / Cu catalyst prepared in Comparative Example 1 was loaded into a high-pressure reactor. Methyl isobutyl ketone (MOH) and 4-aminodiphenylamine (4PPD) were added. The reaction temperature was 85 °C, the pressure was 5.8 MPa, and the molar ratio of MOH to 4-aminodiphenylamine (4PPD) was 5:1. The synthesis of the 4-phenylenediamine antioxidant 6PPD was carried out for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 hours. The distillate (mainly MOH) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 96%, the selectivity of 6PPD was 95%, and the ketone-to-alcohol ratio was 75 / 25.

[0059] Comparative Example 2: Preparation of NC / Ni Catalyst

[0060] (1) Add 5g dicyandiamine, 5.5g amine, 5g glucose and 5.242g (1mmol) nickel nitrate to 355mL DI, dissolve and stir evenly, then freeze dry to obtain powder sample.

[0061] (2) Place the powdered sample in a crucible and pyrolyze it in a nitrogen atmosphere using a two-step programmed temperature rise method: First, heat the sample to 555℃ at a heating rate of 5℃ / min. -1 Maintain at this temperature for 2 hours; then at 15°C for 1 minute. -1 The temperature was increased to 955℃, and carbonized at this temperature for 2 hours to obtain the carbonized sample.

[0062] (3) The carbonized sample was placed in 2M H2SO4 and stirred overnight. The acid-washed sample was rinsed with plenty of water until the waste liquid was neutral, and dried at 85°C for later use. The obtained sample was NC / Ni (1 mmol).

[0063] Comparative Application Example 2

[0064] One mmol of the NC / Ni catalyst prepared in Comparative Example 2 was loaded into a high-pressure reactor. Methyl isobutyl ketone (MBE) and 4-aminodiphenylamine (4PPD) were added. The reaction temperature was 85 °C, the pressure was 5.8 MPa, and the molar ratio of MBE to 4PPD was 5:1. A synthesis experiment of the p-phenylenediamine antioxidant 6PPD was conducted for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 hours. The distillate (mainly MBE) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 85%, the selectivity of 6PPD was 78%, and the ketone-to-alcohol ratio was 68 / 32.

[0065] Example 1: Preparation of NC / Pt catalyst

[0066] (1) 5g dicyandiamine, 5.5g glucose and 5.58g (1mmol) chloroplatinic acid were added to 355mL DI, and after being fully dissolved and stirred evenly, the sample was freeze-dried to obtain a powder sample.

[0067] (2) Place the powdered sample in a crucible and pyrolyze it in a nitrogen atmosphere using a two-step programmed temperature rise method: First, heat the sample to 555℃ at a heating rate of 5℃ / min. -1 Maintain at this temperature for 2 hours; then at 15°C for 1 minute. -1 The temperature was increased to 955℃, and carbonized at this temperature for 2 hours to obtain the carbonized sample.

[0068] Figure 1 In the image, a and b are SEM images of the local morphology of carbon nanosheets without metal Pt particles; c is a SEM image of the local morphology of carbon nanosheets without metal Pt particles at 155K magnification; and d is a SEM image of the local morphology of carbon nanosheets without metal Pt particles at 185K magnification.

[0069] from Figure 1 It is evident that the carbonized sample exhibits an ultrathin structure.

[0070] (3) The sample loaded with metal particles was placed in 2M H2SO4 and stirred overnight. After acid washing, the sample was rinsed with plenty of water until the waste liquid was neutral, and then dried at 85°C for later use. The obtained sample was NC / Pt (1 mmol).

[0071] Figure 2In the image, a is a SEM image of NC / Pt nanosheets at 5K magnification; b is a SEM image of NC / Pt nanosheets at 55K magnification.

[0072] Figure 2 It can be seen that the prepared NC / Pt porous Pt particles are uniformly loaded in the carbon nanosheets.

[0073] Table 1. NC / Pt analysis results of the catalyst.

[0074] NC / Pt <![CDATA[Specific surface area, m 2 / g]]> Pore ​​volume, g / ml Average aperture, Ash content, % Example 1 1216 5.88 3.54 1.54

[0075] Application Example 1

[0076] 1 mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone (Methyl isobutyl ketone) and 4-aminodiphenylamine (4PPD) were added. The reaction temperature was 85 °C, the pressure was 5.8 MPa, and the molar ratio of Methyl isobutyl ketone to 4-aminodiphenylamine (4PPD) was 5:1. The reaction time was 2 h. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 h. The distillate (mainly Methyl isobutyl ketone) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 93%, the selectivity of 4-aminodiphenylamine (4PPD) was 95%, and the ketone-to-alcohol ratio was 85 / 15.

[0077] Application Example 2

[0078] Two mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone and 4-aminodiphenylamine were added. The reaction temperature was 85°C, the pressure was 5.8 MPa, and the molar ratio of methyl isobutyl ketone to p-aminodiphenylamine was 5:1. The synthesis of p-phenylenediamine antioxidant 6PPD was carried out. The liquid in the reactor was distilled under reduced pressure, and the distillate (mainly methyl isobutyl ketone) was recovered and reused. The reactor liquid was analyzed by chromatography, and the reaction conversion rate of 4-aminodiphenylamine was 95%, the selectivity was 95%, and the ketone-to-alcohol ratio was 89 / 11.

[0079] Application Example 3

[0080] 3 mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone (Methyl isobutyl ketone) and 4-aminodiphenylamine (4-aminodiphenylamine) were added. The reaction temperature was 85 °C, the pressure was 5.8 MPa, and the molar ratio of Methyl isobutyl ketone to 4-aminodiphenylamine (4-aminodiphenylamine) was 5:1. The synthesis of the 4-phenylenediamine antioxidant 6PPD was carried out for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 hours. The distillate (mainly Methyl isobutyl ketone) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 97%, the selectivity of 6PPD was 96.5%, and the ketone-to-alcohol ratio was 92 / 8.

[0081] Application Example 4

[0082] The preparation method of the 5 mmol NC / Pt catalyst is the same as in Example 1.

[0083] Five mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor. Methyl isobutyl ketone (MBE) and 4-aminodiphenylamine (4PPD) were added. The reaction was carried out at 85°C and 5.8 MPa, with a molar ratio of MBE to 4PPD of 5:1, for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145°C and 25 kPa for 3 hours. The distillate (mainly MBE) was recovered and reused. Chromatographic analysis of the reactor liquid showed a 99% conversion rate of 4-aminodiphenylamine, a 99% selectivity for 4PPD, and a ketone-to-alcohol ratio of 97 / 3.

[0084] Application Example 5

[0085] 15 mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone (Methyl isobutyl ketone) and 4-aminodiphenylamine (4PPD) were added. The reaction temperature was 85 °C, the pressure was 5.8 MPa, and the molar ratio of Methyl isobutyl ketone to 4-aminodiphenylamine (4PPD) was 5:1. The reaction time was 2 h. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 h. The distillate (mainly Methyl isobutyl ketone) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 99%, the selectivity of 4-aminodiphenylamine was 97%, and the ketone-to-alcohol ratio was 92 / 8.

[0086] Application Example 6

[0087] 25 mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone (Methyl isobutyl ketone) and 4-aminodiphenylamine (4-aminodiphenylamine) were added. The reaction temperature was 125 °C, the pressure was 1.5 MPa, and the molar ratio of Methyl isobutyl ketone to 4-aminodiphenylamine (4-aminodiphenylamine) was 5:1. The synthesis of the 4-phenylenediamine antioxidant 6PPD was carried out for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 hours. The distillate (mainly Methyl isobutyl ketone) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 99%, the selectivity of 6PPD was 98%, and the ketone-to-alcohol ratio was 95 / 15.

[0088] Application Example 7

[0089] 55 mmol of the NC / Pt catalyst prepared in Example 1 was loaded into a high-pressure reactor, and methyl isobutyl ketone (Methyl isobutyl ketone) and 4-aminodiphenylamine (4-aminodiphenylamine) were added. The reaction temperature was 125 °C, the pressure was 1.5 MPa, and the molar ratio of Methyl isobutyl ketone to 4-aminodiphenylamine (4-aminodiphenylamine) was 5:1. The synthesis of the 4-phenylenediamine antioxidant 6PPD was carried out for 2 hours. After the reaction, the liquid in the reactor was distilled under reduced pressure at 145 °C, 25 kPa, and for 3 hours. The distillate (mainly Methyl isobutyl ketone) was recovered and reused. Chromatographic analysis of the reactor liquid showed that the conversion rate of 4-aminodiphenylamine was 99%, the selectivity of 6PPD was 96%, and the ketone-to-alcohol ratio was 93 / 7.

[0090] This invention can be summarized in other specific forms that do not depart from the spirit or essential features of the invention. Therefore, in all respects, the above embodiments of the invention should be considered illustrative only and not limiting, while the claims define the scope of the invention. The foregoing description does not define the scope of the invention; therefore, any changes within the meaning and scope equivalent to the claims should be considered to be included within the scope of the claims.

Claims

1. A method for the hydrogenation catalytic preparation of 6PPD from p-phenylenediamine, characterized in that, The method involves contacting methyl isobutyl ketone and 4-aminodiphenylamine with a catalyst to allow a reaction to occur. The catalyst is a supported nanomaterial; The supported nanomaterial includes a carrier and an active component; The carrier is nitrogen-doped graphitized carbon nitride with porous nanosheets; The nitrogen-doped graphitized carbon nitride has active components loaded on its surface and / or inside. The active component is a noble metal element; The method for preparing the supported nanomaterials is as follows: To obtain a mixture containing a nitrogen source, a carbon source, and a precious metal source; The mixture was subjected to calcination I, calcination II, and acid washing to obtain the supported nanomaterials; The atmosphere for calcination I and calcination II is nitrogen; The conditions for calcination I include: temperature 550 ℃~850 ℃; time 2 h~6 h; The conditions for calcination II include: temperature 900 ℃~1100 ℃; time 2 h~4 h.

2. The method according to claim 1, characterized in that, The roasting process employs a two-step heating method, first with a temperature increase of 3-8 °C for 1 minute. -1 The heating rate is increased to the temperature of calcination I, and the temperature is held for 1-3 hours; then the temperature is increased at 8-15℃ for min. -1 The heating rate is increased to the temperature of calcination II, and the temperature is maintained for 1-3 hours.

3. The method according to claim 2, characterized in that, First at 5 ℃ min -1 The heating rate was increased to the temperature of calcination I, and held for 2 hours; then increased at 10 °C min... -1 The heating rate was increased to the temperature of calcination II, and the temperature was maintained for 2 hours.

4. The method according to claim 2, characterized in that, The temperature of calcination I is 550 ℃; the temperature of calcination II is 900 ℃.

5. The method according to claim 1, characterized in that, The nitrogen source is selected from at least one of dicyandiamine and urea; And / or, the carbon source is selected from monosaccharide or polysaccharide compounds; And / or, the noble metal source is selected from one of a platinum metal source and a palladium metal source; And / or, the acid used in the pickling is an inorganic acid; And / or, the concentration of the acid solution is 2M to 10M.

6. The method according to claim 1, characterized in that, The carbon source is selected from at least one of glucose and fructose; And / or, the noble metal source is selected from at least one of platinum chloride, platinum acetate, palladium nitrate, or chloropalladium acid; And / or, the acid used in the pickling is at least one of sulfuric acid, hydrochloric acid, and nitric acid; And / or, the concentration of the acid solution is 2M to 10M.

7. The method according to claim 1, characterized in that, The molar ratio of nitrogen source to carbon source is 1~50:1; the molar ratio of carbon source to precious metal source is 1~200:1; calculated based on the number of moles of carbon in the carbon source, the number of moles of nitrogen in the nitrogen source, and the number of moles of precious metal in the precious metal source, respectively.

8. The method according to claim 1, characterized in that, The mixture also contains water, and the mixture is freeze-dried before calcination.

9. The method according to claim 8, characterized in that, The mass concentration of the precious metal source in the water is 3% to 30%, calculated based on the mass of the precious metal in the precious metal source.

10. The method according to claim 1, characterized in that, The precious metal is selected from at least one of Pt and Pd; And / or, the molar ratio of the nitrogen-doped graphitized carbon nitride to the active component is 1 to 200:1; And / or, the nitrogen-doped graphitized carbon nitride has a specific surface area of ​​900–1300 m². 2 / g; And / or, the nitrogen-doped graphitized carbon nitride has a pore volume of 0.8–1.8 g / ml; And / or, the nitrogen-doped graphitized carbon nitride has a pore size of 1.5 to 4.5 nm; And / or, the ash content of the nitrogen-doped graphitized carbon nitride is 1% to 5%.

11. The method according to claim 1, characterized in that, The molar ratio of methyl isobutyl ketone to 4-aminodiphenylamine is 2 to 5.5:1; And / or, the reaction conditions include: temperature 80℃~190℃; reaction pressure 0.6~2.0 MPa; reaction time 1~2 h; And / or, the reaction is carried out in a fixed bed or a reaction vessel; And / or, in the reaction, the conversion of 4-aminodiphenylamine is 93%–99%, the selectivity of 6PPD is 90%–99%, and the ketol ratio is 85 / 15–97 / 3.

12. The method according to claim 11, characterized in that, The reaction conditions include: temperature 80℃~120℃; reaction pressure 0.4~2.0MPa.

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