A biochar-supported iron catalyst and its use

Abstract

The application discloses a kind of biochar loaded iron monatomic catalyst and application thereof, adopt morel fungus filament as biochar pyrolysis precursor, surface complex iron ion, obtain biochar loaded iron monatomic catalyst in inert gas atmosphere high temperature pyrolysis.4-hydroxy-2-butanone and different aniline compounds are used as reaction substrate, using biochar loaded iron monatomic catalyst, acetone or butanone is solvent, in nitrogen atmosphere, N-alkylation product is obtained at room temperature reaction.This application first uses morel fungus as the pyrolysis precursor of carbon carrier and prepares monatomic catalyst.The biochar monatomic catalyst prepared in the application has similar morphology of carbon nanotube.The application first uses iron monatomic catalyst to catalyze aniline and 4-hydroxy-2-butanone alcohol amine reaction.

Description

Technical Field

[0001] This invention relates to the amination of aniline compounds and 4-hydroxy-2-butanone using iron single-atom catalysts supported on biochar. Background Technology

[0002] CN bonds, as important structural segments, exist in numerous bioactive and pharmaceutical molecules and are widely used in fine chemicals and pharmaceuticals, such as in the synthesis of β-amino acids, β-amino alcohols, 1,3-diaminoalkanes, lactams, and nicotinic acid. Many methods exist for synthesizing CN bonds, including haloalkanes substitution reactions, Aza-Michael addition reactions, aromatic haloalkanes coupling reactions, Mannich reactions, and oxidative amination reactions of high-enols or allyl alcohols. Direct substitution of the hydroxyl group with an amine is one of the important methods for preparing CN bonds; the raw materials are readily available, the byproduct is H₂O, making it environmentally friendly and highly atom-economical. However, the hydroxyl group is not a good leaving group in terms of either thermodynamic or kinetic properties, requiring prior conversion to a haloalkanes, p-toluenesulfonates, or sulfonates. The direct substitution reaction of the hydroxyl group is... The Drug Roundtable Conference was selected as one of the top ten key research areas in green chemistry.

[0003] In 1981, Grigg and Watanabe almost simultaneously reported the direct substitution of hydroxyl groups in alcohols with rhodium, iridium, and ruthenium, initiating research on this topic. Since then, various methods for the direct substitution of hydroxyl groups in alcohols with amines have been reported, using catalysts including metal salts or complexes of silver, gold, iridium, palladium, rhenium, ruthenium, cobalt, copper, iron, manganese, and nickel. Bimetallic and nonmetallic catalytic systems (enzymes, aldehydes, ketones, iodine, carbon materials, and organophosphorus compounds) have also been reported.

[0004] This invention marks the first application of biochar-supported iron single-atom catalysts to catalyze the amination reaction of 4-hydroxy-2-butanone and aniline compounds. The method of this invention is rapid, simple, environmentally friendly, low-cost, and easily industrialized. The prepared biochar-supported iron single-atom catalyst exhibits good stability and shows promising application prospects in the field of amination reactions. Summary of the Invention

[0005] This invention discloses a biochar-supported iron single-atom catalyst and its use in catalyzing the amination reaction of 4-hydroxy-2-butanone and aniline compounds. The method uses Phellinus linteus mycelium as a biochar pyrolysis precursor, which is ultrasonically dispersed in physiological saline, and iron ions are complexed on the surface. After freeze-drying, the biochar-supported iron single-atom catalyst is obtained by high-temperature pyrolysis in an inert gas atmosphere.

[0006] Using 4-hydroxy-2-butanone and various aniline compounds as reaction substrates, and employing an iron single-atom catalyst supported on biochar, with acetone or butanone as solvent, the reaction is carried out under a nitrogen atmosphere at room temperature to yield N-alkylated products. This invention is the first to use *Sanghuang* fungus as a pyrolysis precursor for preparing a single-atom catalyst. The biochar single-atom catalyst prepared in this invention exhibits a morphology similar to carbon nanotubes. This invention is also the first to use an iron single-atom catalyst to catalyze the amination reaction of aniline and 4-hydroxy-2-butanone.

[0007] In the above technical solution, 2-5g (preferably 3-4g) of Phellinus linteus mycelium is first ultrasonically dispersed in 150mL of physiological saline, and then 2-6mmol (preferably 5-5.5mmol) of soluble iron salt is added to the dispersion to complex iron ions on the surface under the conditions of 60-100℃ (preferably 80-90℃).

[0008] In the above technical solution, the ultrasonic dispersion pretreatment time is 20-50 min, preferably 30-40 min; the ultrasonic treatment power is 40-100 kW; the time for surface complexation of iron ions is 12-24 h; after the surface of the Phellinus linteus mycelium is complexed with iron ions, it is cooled to room temperature, centrifuged, the Phellinus linteus mycelium is collected, washed with water, and then freeze-dried.

[0009] In the above technical solution, the soluble manganese salt is one of ferric chloride, ferric nitrate, or ferric sulfate.

[0010] In the above technical solution, the pyrolysis temperature of Phellinus linteus mycelium is 600-1000℃ (preferably 700-800℃), and the time is 1-4h (preferably 1-2h).

[0011] In the above technical solution, the inert atmosphere is either nitrogen or argon; the gas flow rate of 1g of dried Phellinus linteus mycelium through the inert atmosphere is 10-30 mL / min; the heating rate from room temperature to the pyrolysis temperature is 2-5℃ / min; the cooling rate from the pyrolysis temperature to 40℃ after pyrolysis is 2-5℃ / min; the prepared biochar-supported iron single-atom catalyst has a morphology similar to carbon nanotubes. Iron is dispersed in single-atom form on the biochar support.

[0012] In the above technical solution, under a nitrogen atmosphere, an iron single-atom catalyst supported on biochar catalyzes the alcohol amination reaction of 4-hydroxy-2-butanone and different aniline compounds to prepare 4-(N-phenyl)-2-butanone compounds.

[0013] In the above technical solutions, the different aniline compounds are aniline, 2-chloroaniline, 3-bromoaniline, 4-fluoroaniline, 2-methylaniline, 3-methoxyaniline, 4-nitroaniline, and 4-trifluoromethylaniline.

[0014] In the above technical solution, the concentration of 4-hydroxy-2-butanone in the solvent is 0.5-1 mol / L, preferably 0.5 mol / L; the concentration of aniline compounds in the solvent is 0.5-1 mol / L, preferably 0.5 mol / L. The molar ratio of 4-hydroxy-2-butanone to aniline compounds is 1:2-2:1, preferably 1:1. The amount of biochar-supported iron single-atom catalyst is 10-30 mg, preferably 20 mg. The reaction time is 4-12 h, preferably 8 h.

[0015] Due to the application of the above-described solution, the present invention has the following advantages compared with existing technologies:

[0016] 1. This invention is the first to use Phellinus linteus mycelium as a pyrolysis precursor for preparing biochar-supported iron single-atom catalysts. It eliminates the need for non-renewable carbon sources, expensive templates, activators, and heteroatom sources. The biochar-supported iron single-atom catalysts can be recycled and reused.

[0017] 2. This reaction does not require the addition of any alkaline additives;

[0018] 3. This reaction is carried out at room temperature and requires no heating;

[0019] 4. The reaction has good selectivity and produces no other byproducts. Attached Figure Description

[0020] Figure 1 Scanning electron microscope image of the catalyst (Cat-700);

[0021] Figure 2 Aberration-corrected transmission electron microscopy (TEM) spectra of the catalyst (Cat-700). Detailed Implementation

[0022] The present invention will be described in detail below with reference to the embodiments, but the scope of the present invention is not limited to the following embodiments.

[0023] Example

[0024] Example 1: Preparation method of biochar-supported iron single-atom catalyst

[0025] In a 250 mL round-bottom flask, add a magnetic stirrer rotor, 3 g of *Sanghuang* mycelium, and 150 mL of physiological saline, and sonicate (40 kW, 30 min). Stir magnetically at room temperature, slowly add 5 mmol of ferric chloride, and continue stirring for 30 min. Then, stir at 80 °C for 12 h. Cool to room temperature, centrifuge (10000 r / min, 10 min), collect the *Sanghuang* mycelium, wash three times with deionized water, and freeze-dry. Take 1 g of the freeze-dried material prepared in the above steps and place it in a quartz boat. Place the quartz boat in a tube furnace and purge with nitrogen at room temperature for 30 min (gas flow rate 10 mL / min). Then, maintaining a constant nitrogen gas flow rate, raise the temperature to 700 °C (heating rate from room temperature to pyrolysis temperature is 5 °C / min). Continue maintaining a constant nitrogen gas flow rate and pyrolyze at 700 °C for 1 h, then slowly cool to 30 °C (cooling rate is 5 °C / min).

[0026] The black solid inside the quartz boat was ground into powder in an agate mortar to obtain a biochar-supported iron single-atom catalyst (labeled Cat-700) with a mass yield of 27% (relative to Phellinus linteus mycelium).

[0027] The preparation methods for Cat-800 and Cat-900 are the same as those for Cat-700, with the only difference being the pyrolysis temperature. The pyrolysis temperatures for Cat-800 and Cat-900 are 800℃ and 900℃, respectively, with yields of 28% and 27%.

[0028] The elemental composition and atomic percentage of the surface of biochar-supported iron single-atom catalysts were analyzed using X-ray photoelectron spectroscopy. The surface of the biochar-supported iron single-atom catalysts consisted of carbon, nitrogen, oxygen, phosphorus, and iron, with carbon having the highest content (over 84 at%), followed by nitrogen (6.35–7.07 at%), oxygen (5.61–6.15 at%), phosphorus (1.32–1.71 at%), and iron (0.77–0.96 at%). The elemental composition of the surface of the biochar-supported iron single-atom catalysts varied depending on the pyrolysis temperature.

[0029] Table 1. Surface element content of biochar-supported iron single-atom catalysts

[0030]

[0031] Cat-700 Scanning Electron Microscope Figure 1 The morphology of the biochar-supported iron single-atom catalyst is very similar to that of carbon nanotubes. (Aberration-corrected transmission electron microscopy images) Figure 2The results show that iron is evenly distributed on the biochar carrier, and uniformly dispersed bright spots can be observed, indicating that the iron is distributed at the atomic level.

[0032] Scanning electron microscopy (SEM) spectra obtained with Cat-800 and Cat-900 microscopes show that the morphology of the iron single-atom catalyst supported on biochar is very similar to that of carbon nanotubes. Aberration-corrected transmission electron microscopy (TEM) spectra show that iron is uniformly distributed on the biochar support, and uniformly dispersed bright spots can be observed, indicating that the iron is distributed at the atomic level.

[0033] Preparation of other biochar-supported iron single-atom catalysts: The preparation process was consistent with that of Cat-700, except that the amount of iron salt used (2-6 mmol) was varied. Specifically, instead of 5 mmol, 2 mmol, 3 mmol, 4 mmol, and 6 mmol of iron salt were added, and all resulted in biochar-supported iron single-atom catalysts. Scanning electron microscopy (SEM) images showed that the morphology of the biochar-supported iron single-atom catalysts was very similar to that of carbon nanotubes. Aberration-corrected transmission electron microscopy (TEM) images showed that iron was uniformly distributed on the biochar support, and uniformly dispersed bright spots were observed, indicating an atomic-level distribution of iron.

[0034] Example 2: 4-(phenylamino)-2-butanone

[0035]

[0036] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-700), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of aniline (R is hydrogen) and 2 mL of acetone were added sequentially. The reaction system was stirred at room temperature under a nitrogen atmosphere for 8 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution buffer: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-(phenylamino)-2-butanone in 83% (135.5 mg) as a yellow oil. 1 H NMR (400MHz, CDCl3) δ7.17(t,J=7.8Hz,2H),6.73(t,J=7.3Hz,1H),6.63(d,J=8.2Hz,2H),3.40(t,J=6.1Hz,2H),2.74(t,J=6.1Hz,2H),2.14(s,3H); 13 C NMR(101MHz, CDCl3)δ208.16,147.83,129.45,117.74,113.15,42.73,38.48,30.38.HRMS(ESI)for C 10 H 13NO,calcd:163.0993,found:163.0984.

[0037] Example 2'

[0038] The process is the same as in Example 2 above, except that when 2 mL of butanone (instead of 2 mL of acetone) is used as the solvent, the yield of 4-(phenylamino)-2-butanone is 81%.

[0039] The process is the same as in Example 2 above, except that the yields of 4-(phenylamino)-2-butanone are 60%, 71%, 83%, and 87% when the reaction time is 4h, 6h, 10h, and 12h, respectively.

[0040] The process is the same as in Example 2 above, except that when the amount of iron single-atom catalyst supported on biochar is 10 mg or 30 mg, the yield of 4-(phenylamino)-2-butanone is 51% and 84%, respectively.

[0041] Example 3 4-((2-chlorophenyl)amino)-2-butanone

[0042] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-800), 0.5 mmol of 4-hydroxy-2-butanone, 1 mmol of 2-chloroaniline, and 2 mL of butanone were added sequentially. The reaction system was stirred at room temperature under a nitrogen atmosphere for 9 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, v / v) to give 4-((2-chlorophenyl)amino)-2-butanone, a yellow oil, with a yield of 80% (79.1 mg). 1 H NMR (400MHz, CDCl3) δ7.14 (d, J=7.8Hz, 1H), 7.06 (t, J=8.3Hz, 1H), 6.55 (dd, J= 15.8,7.9Hz,2H),4.44(s,1H),3.35(s,2H),2.67(t,J=6.3Hz,2H),2.09(s,3H); 13 C NMR(101MHz, CDCl3)δ207.57,143.63,129.38,127.90,119.54,117.51,111.17,42.66,38.15,30.42.HRMS(ESI) for C 10 H 12 ClNO,calcd:197.0610,found:197.0612.

[0043] Example 4: 4-((3-bromophenyl)amino)-2-butanone

[0044] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-900), 1 mmol of 4-hydroxy-2-butanone, 0.5 mmol of 3-bromoaniline, and 2 mL of acetone were added sequentially. The reaction system was stirred at room temperature under a nitrogen atmosphere for 12 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-((3-bromophenyl)amino)-2-butanone, a yellow oil, with a yield of 77% (93.2 mg). 1 H NMR (400MHz, CDCl3) δ6.97(t,J=8.0Hz,1H),6.76(d,J=8.0Hz,1H),6.68(s,1H),6.47(d ,J=8.2Hz,1H),4.16(s,1H),3.32(t,J=6.1Hz,2H),2.69(t,J=6.1Hz,2H),2.12(s,3H); 13 C NMR(101MHz, CDCl3)δ207.91,149.13,130.54,123.22,120.07,115.19,111.68,42.24,38.03,30.21.HRMS(ESI) for C 10 H 12 BrNO,calcd:241.0103,found:241.0108.

[0045] Example 5 4-((4-fluorophenyl)amino)-2-butanone

[0046] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-700), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of 4-fluoroaniline, and 2 mL of acetone were added sequentially. The reaction system was stirred at room temperature under a nitrogen atmosphere for 9 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-((4-fluorophenyl)amino)-2-butanone, a yellow oil, with a yield of 77% (139.5 mg). 1 H NMR (400MHz, CDCl3) δ7.13 (d, J = 8.7Hz, 2H), 6.32 (d, J = 8.7Hz, 2H), 3.96 (s, 1H), 3.14 (t, J = 6.1Hz, 2H), 2.61 (t, J = 6.1Hz, 2H), 2.05 (s, 3H); 13C NMR(101MHz, CDCl3)δ207.03,146.45,131.07,113.35,108.08,42.24,38.12,30.21.HRMS(ESI)for C 10 H 12 FNO,calcd:181.0905,found:181.0907.

[0047] Example 6: 4-(o-Toluidine)-2-Butanone

[0048] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-900), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of o-toluidine, and 2 mL of acetone were added sequentially. The reaction system was stirred at room temperature under a nitrogen atmosphere for 9 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-(o-toluidine)-2-butanone, a yellow oil, with a yield of 71% (125.9 mg). 1 H NMR (400MHz, CDCl3) δ7.15(t,J=7.7Hz,1H),7.09(d,J=7.2Hz,1H),6.73(t,J=7.3Hz,1H),6.66(d, J=8.0Hz,1H),3.90(s,1H),3.49(t,J=6.1Hz,2H),2.81(t,J=6.1Hz,2H),2.19(s,3H),2.14(s,3H); 13 C NMR(101MHz, CDCl3)δ208.27,145.76,130.33,127.16,122.58,117.20,109.67,42.60,38.38,30.33,17.49.HRMS(ESI) for C 11 H 15 NO,calcd:177.1155,found:177.1153.

[0049] Example 7 4-((3-methoxyphenyl)amino)-2-butanone

[0050] A magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-800), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of m-methoxyaniline, and 2 mL of butanone were added sequentially to a 25 mL reaction flask. The reaction system was stirred under a nitrogen atmosphere at room temperature for 8 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, v / v) to give 4-((3-methoxyphenyl)amino)-2-butanone, a yellow oil, with a yield of 89% (172.0 mg).1 H NMR (400MHz, CDCl3) δ7.08(t,J=8.1Hz,1H),6.27(d,J=8.1Hz,1H),6.24(d,J=8.1Hz,1H ),6.15(s,1H),3.77(s,3H),3.38(t,J=6.1Hz,2H),2.72(t,J=6.1Hz,2H),2.14(s,3H); 13 C NMR(101MHz, CDCl3)δ208.19,160.95,149.20,130.12,106.19,102.72,99.01,55.13,42.61,38.38,30.32.HRMS(ESI) for C 11 H 15 NO2,calcd:193.1101,found:193.1117.

[0051] Example 8 4-((4-nitrophenyl)amino)-2-butanone

[0052] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-800), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of p-nitroaniline, and 2 mL of butanone were added sequentially. The reaction system was stirred under a nitrogen atmosphere at room temperature for 12 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-((4-nitrophenyl)amino)-2-butanone, a yellow solid with a melting point of 89-91 °C, and a yield of 50% (104.1 mg). 1 H NMR (400MHz, CDCl3) δ8.03(d,J=9.0Hz,2H),6.45(d,J=9.2Hz,2H),5.12(s,1H),3.46(q,J=5.9Hz,2H),2.78(t,J=6.0Hz,2H),2.18(s,3H); 13 C NMR(101MHz, CDCl3)δ207.59,153.22,137.74,126.50,111.09,42.14,37.67,30.32.HRMS(ESI)for C 10 H 12 N2O3,calcd:208.0844,found:208.0839.

[0053] Example 9 4-((4-trifluoromethylphenyl)amino)-2-butanone

[0054] In a 25 mL reaction flask, a magnetic magnet, 20 mg of biochar-supported iron single-atom catalyst (Cat-700), 1 mmol of 4-hydroxy-2-butanone, 1 mmol of p-trifluoromethylaniline, and 2 mL of acetone were added sequentially. The reaction system was stirred under a nitrogen atmosphere at room temperature for 12 h. The reaction solution was desolvated under reduced pressure, and the residue was treated by column chromatography (elution: ethyl acetate / petroleum ether = 1:4, volume ratio) to give 4-((4-trifluoromethylphenyl)amino)-2-butanone, a yellow solid with a melting point of 89-91 °C, and a yield of 49% (113.3 mg). 1 H NMR (400MHz, CDCl3) δ7.38(d,J=8.5Hz,2H),6.57(d,J=8.5Hz,2H),4.36(s,1H),3.46(s,2H),2.76(t,J=6.0Hz,2H),2.19(s,3H); 13 C NMR(101MHz, CDCl3)δ207.87,150.34,126.84,126.45,123.75,118.97,112.09,42.41,37.94,30.46.HRMS(ESI) for C 11 H 12 F3NO,calcd:231.0872,found:231.0869.

[0055] Comparative Example

[0056] 1. Compared with other solvents, the acetone or butanone solvent used in this invention has obvious advantages, and the product yield is significantly higher than that of other solvents. For specific data, please refer to Table 2 (except for the different solvents (the amount used is 2 mL each), the other processes and conditions are the same as in Example 2).

[0057] Table 2. Separation yields of 4-(phenylamino)-2-butanone in different solvents

[0058]

[0059]

[0060] 2. The reaction process and conditions are the same as in Example 2, except that no catalyst is used in the reaction process; compared with the reaction results without using a catalyst, the biochar-supported iron single-atom catalyst used in this invention has obvious advantages, and the specific data are detailed in Table 3 (except for the absence of biochar-supported iron single-atom catalyst, the rest is the same as in Example 2).

[0061] Table 3. Separation yields of 4-(phenylamino)-2-butanone in different solvents

[0062]

[0063] 3. Compared with palladium-catalyzed oxidative amination reactions of high-enols (Chem. Commun. 2017, 53, 10422-10425) or allyl alcohols (J. Org. Chem. 2018, 83, 3941-3951), the present invention has the following advantages:

[0064] (1) This reaction uses a single-atom iron catalyst supported on biochar, eliminating the need for expensive palladium catalysts;

[0065] (2) This reaction does not require an oxidizing agent;

[0066] (3) The reaction is carried out at room temperature and does not require heating.

[0067] We have experimentally verified that palladium catalysts cannot catalyze the reaction of 4-hydroxy-2-butanone and aromatic amines to produce β-amino ketones under the conditions of this reaction (except for the catalyst, everything else is the same as in Example 1).

[0068] 4. Compared with the iodine-catalyzed nucleophilic substitution reaction of benzyl alcohol (Synlett 2008, 7, 1045-1049; Tetrahedron Lett. 2007, 48, 8120-8124), this invention has the following advantages: the iodine-catalyzed nucleophilic substitution reaction of benzyl alcohol (Synlett 2008, 7, 1045-1049; Tetrahedron Lett. 2007, 48, 8120-8124) can only react benzyl alcohol with other alcohols to form ether compounds. We have experimentally verified that iodine catalysis cannot catalyze the reaction of benzyl alcohol with amines. The content of this invention is the catalysis of the amination reaction of aniline and 4-hydroxy-2-butanone by a biochar-supported iron single-atom catalyst, which is significantly different from previous techniques.

[0069] Compared with the patents "A method for N-alkylation reaction catalyzed by TEMPO and TBN (CN201910743878.7)" or "A method for iodine-catalyzed generation of β-aminoketone compounds (CN201811374694.X)", the present invention has the following significant differences and advantages: The present invention uses a biochar-supported iron single-atom catalyst to catalyze the alcohol amination reaction of aniline and 4-hydroxy-2-butanone, and the catalyst is significantly different from previous technologies; the biochar-supported iron single-atom catalyst can be recycled and reused, and after six consecutive uses, the catalytic activity does not show a significant decrease, while TEMPO / TBN or iodine catalysts cannot be recycled and reused.

Claims

1. The application of a biochar-supported catalyst in the amination reaction of 4-hydroxy-2-butanone and aniline compounds, characterized in that: Formula 1, In a nitrogen atmosphere, biochar-supported iron single-atom catalysts catalyze the alcohol amination reaction of 4-hydroxy-2-butanone and different aniline compounds to prepare 4-(N-phenyl)-2-butanone compounds. The R substituents in Formula 1 are one or more of hydrogen, F, Cl, Br, methyl, methoxy, nitro, and trifluoromethyl, and the number of them is 1 to 5; The solvent is acetone and / or butanone; The specific preparation method of the biochar-supported catalyst is as follows: Phellinus linteus mycelium is used as a biochar pyrolysis precursor. The Phellinus linteus mycelium is dispersed in physiological saline, and then soluble iron salt is added to the dispersion to complex iron ions on the surface of the Phellinus linteus mycelium. The Phellinus linteus mycelium is collected by solid-liquid separation, washed and freeze-dried, and then pyrolyzed in an inert atmosphere to obtain the biochar-supported iron single-atom catalyst.

2. The application according to claim 1, characterized in that: The specific process is as follows: 2-5 g of Phellinus linteus mycelium is first ultrasonically dispersed in 150 mL of physiological saline to obtain a dispersion; then, 2-6 mmol of soluble iron salt is added to the dispersion, and iron ions are complexed on the surface under conditions of 60-100 ℃.

3. The application according to claim 2, characterized in that: The ultrasonic dispersion pretreatment time is 20-50 min; the ultrasonic treatment power is 40-100 kW. The time for surface-complexed iron ions is 12-24 h; After iron ions are complexed on the surface of Phellinus linteus mycelium, the mixture is cooled to room temperature, centrifuged, and the collected Phellinus linteus mycelium is washed with water and then freeze-dried.

4. The application according to claim 1, characterized in that: The soluble iron salt is one or more of ferric chloride, ferric nitrate, or ferric sulfate.

5. The application according to claim 1, characterized in that: The pyrolysis temperature of Phellinus linteus mycelium is 600-1000 ℃, and the time is 1-4 h.

6. The application according to claim 1 or 5, characterized in that: The inert atmosphere is one or more of nitrogen or argon; The airflow rate of 1 g of dried Phellinus linteus mycelium under an inert atmosphere is 10-30 mL / min; The heating rate from room temperature to the pyrolysis temperature is 2-5 °C / min; after pyrolysis, the catalyst is obtained by cooling to room temperature - 40 °C, and the cooling rate from the pyrolysis temperature to room temperature - 40 °C is 2-5 °C / min.

7. The application according to claim 1, characterized in that: The concentration of 4-hydroxy-2-butanone in the solvent is 0.25-1 mol / L; the concentration of aniline compounds in the solvent is 0.25-1 mol / L; The molar ratio of 4-hydroxy-2-butanone to aniline compounds is 1:2 to 2:1; The amount of iron single-atom catalyst supported on biochar in 2 mL of solvent is 10-30 mg; The reaction time is 4-12 h.

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