CN117443380A - Biochar-supported iron catalyst and application thereof - Google Patents

Abstract

The invention discloses a biochar-supported iron monoatomic catalyst and application thereof, wherein Phellinus linteus mycelium is used as a biochar pyrolysis precursor, iron ions are complexed on the surface of the biochar pyrolysis precursor, and the biochar-supported iron monoatomic catalyst is obtained by pyrolysis in an inert gas atmosphere. 4-hydroxy-2-butanone and different aniline compounds are used as reaction substrates, a biochar-supported iron single-atom catalyst is used, acetone or butanone is used as a solvent, and the N-alkylation product is obtained by reaction at room temperature in a nitrogen atmosphere. The invention uses Phellinus as a pyrolysis precursor of a carbon carrier for the first time to prepare the monoatomic catalyst. The biochar single-atom catalyst prepared by the invention has the appearance similar to that of a carbon nano tube. The invention uses the iron monoatomic catalyst for catalyzing the alcohol amination reaction of aniline and 4-hydroxy-2-butanone for the first time.

Description

A biochar-loaded iron catalyst and its application

Technical field

The present invention relates to the alcohol amination reaction of biochar-supported iron single atom catalyst, aniline compounds and 4-hydroxy-2-butanone.

Background technique

As an important structural fragment, the CN bond exists in many biologically active molecules and pharmaceutical molecules, and is widely used in the fields of fine chemicals and medicine, such as the synthesis of β-amino acids, β-aminoalcohols, and 1,3-diaminoalkanes. , lactam, nikkomycin, etc. There are many methods to synthesize CN bonds, such as halogenated hydrocarbon substitution reaction, Aza-Michael addition reaction, aromatic halogenated hydrocarbon coupling reaction, Mannich reaction, homoenol or allyl alcohol oxidative amination reaction, etc. Direct substitution of alcoholic hydroxyl groups with amines is one of the important methods for preparing CN bonds. The raw materials are easily available, and the by-product is H ₂ O. It is environmentally friendly and has high atom economy. However, whether it is thermodynamic or kinetic properties, hydroxyl is not a good leaving group and needs to be converted into halogenated hydrocarbons, p-toluenesulfonate, sulfonate, etc. in advance. The direct substitution reaction of alcoholic hydroxyl group is Selected by the Drug Roundtable as one of the top ten key research areas for green chemistry.

In 1981, Grigg and Watanabe almost simultaneously reported the reaction of rhodium, iridium and ruthenium catalyzing the direct substitution of alcoholic hydroxyl groups with amines, starting the study of direct substitution of alcoholic hydroxyl groups with amines. Since then, a variety of methods for directly substituting alcoholic hydroxyl groups with catalytic amines have been reported. The catalysts involve metal salts or complexes such as silver, gold, iridium, palladium, rhenium, ruthenium, cobalt, copper, iron, manganese, and nickel, bimetallic catalytic systems and Non-metal catalytic systems (enzymes, aldehydes, ketones, iodine, carbon materials and organophosphines) have also been reported.

In this invention, for the first time, a biochar-supported iron single-atom catalyst is used to catalyze the alcohol amination reaction of 4-hydroxy-2-butanone and aniline compounds. The method of the invention is fast, simple, environmentally friendly, low-cost and easy to industrialize. The prepared biochar-loaded iron single-atom catalyst has good stability and has good application prospects in the field of alcohol amination reaction.

Contents of the invention

The invention discloses a biochar-supported iron single-atom catalyst and its use for catalyzing the alcohol amination reaction of 4-hydroxy-2-butanone and aniline compounds. In the method, Phellinus linteum mycelium is used as the biochar heat The decomposed precursor is ultrasonically dispersed in physiological saline, complexed with iron ions on the surface, freeze-dried and pyrolyzed at high temperature in an inert gas atmosphere to obtain a biochar-loaded iron single-atom catalyst.

Using 4-hydroxy-2-butanone and different aniline compounds as reaction substrates, using biochar-supported iron single-atom catalyst, acetone or butanone as solvent, react in a nitrogen atmosphere at room temperature to obtain N-alkyl chemical products. The present invention uses Phellinus linteus as the pyrolysis precursor of the carbon carrier to prepare a single-atom catalyst for the first time. The biochar single-atom catalyst prepared by the invention has a morphology similar to carbon nanotubes. In the present invention, an iron single-atom catalyst is used for the first time to catalyze the alcohol amination reaction of aniline and 4-hydroxy-2-butanone.

In the above technical solution, 2-5g (preferably 3-4g) Phellinus linteum mycelium is first ultrasonically dispersed in 150mL physiological saline, and then a molar amount of iron ions of 2-6mmol (preferably 5-5.5mmol) is added to the dispersion. Soluble iron salts complex iron ions on the surface at 60-100°C (preferably 80-90°C).

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

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

In the above technical solution, the pyrolysis temperature of Phellinus linteum mycelium is 600-1000°C (preferably 700-800°C), and the time is 1-4h (preferably 1-2h).

In the above technical solution, the inert atmosphere is one of nitrogen or argon; the air flow rate of 1g of dried Phellinus linteus mycelium through the inert atmosphere is 10-30mL/min; the temperature rise rate from room temperature to the pyrolysis temperature is 2- 5°C/min; the cooling rate from the pyrolysis temperature to 40°C after pyrolysis is 2-5°C/min; the prepared biochar-loaded iron single-atom catalyst has a morphology similar to carbon nanotubes. Iron is dispersed in the form of single atoms on the biochar carrier.

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

In the above technical solution, the different aniline compounds are aniline, 2-chloroaniline, 3-bromoaniline, 4-fluoroaniline, 2-methylaniline, 3-methoxyaniline, 4-nitroaniline, 4-tris Fluoromethylaniline

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

Due to the application of the above solution, the present invention has the following advantages compared with the existing technology:

1. This invention uses Phellinus linteum mycelium as the pyrolysis precursor of the carbon carrier for the first time to prepare biochar-loaded iron single-atom catalyst without using non-renewable carbon sources, expensive templates, activators and heteroatom sources. Biochar The supported iron single-atom catalyst can be recycled and reused;

2. This reaction does not require the addition of additional alkaline additives;

3. The reaction is carried out at room temperature without heating;

4. The reaction has good selectivity and no other by-products.

Description of the drawings

Figure 1. Catalyst (Cat-700) scanning electron microscope spectrum;

Figure 2. Catalyst (Cat-700) spherical aberration corrected transmission electron microscope spectrum.

Detailed ways

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

Example

Example 1 Preparation method of biochar-supported iron single-atom catalyst

In a 250 mL round-bottomed flask, add the magnetic stirrer rotor, 3 g of Phellinus linteum mycelium and 150 mL of physiological saline, and perform ultrasonic treatment (power 40 kw, time 30 min). Stir magnetically at room temperature, slowly add 5 mmol ferric chloride, and continue stirring for 30 minutes. Then stir for 12 hours at 80°C. Cool to room temperature, centrifuge (10000r/min, 10min), collect Phellinus linteus mycelium, wash it 3 times with deionized water, and freeze-dry. Put 1 g of the freeze-dried material prepared in the above steps into a quartz boat, place the quartz boat in a tube furnace, and circulate nitrogen at room temperature for 30 minutes (gas flow rate is 10 mL/min). Then, keeping the nitrogen gas flow rate constant, the temperature was raised to 700°C (the heating rate from room temperature to the pyrolysis temperature was 5°C/min). Still keeping the nitrogen gas flow rate unchanged, after maintaining pyrolysis at 700°C for 1 hour, slowly cool down to 30°C (cooling rate is 5°C/min).

The black solid in the quartz boat was ground into powder in an agate mortar, and the biochar-supported iron single-atom catalyst (labeled Cat-700) was obtained with a mass yield of 27% (relative to Phellinus linteum mycelium).

The preparation methods of Cat-800 and Cat-900 are the same as the preparation process of Cat-700 mentioned above. The only difference lies in the pyrolysis temperature. The pyrolysis temperatures of Cat-800 and Cat-900 are 800°C and 900°C respectively, and the yields are 28% and 27% respectively.

The elemental composition and atomic percentage content on the surface of the biochar-supported iron single-atom catalyst were analyzed using X-ray photoelectron spectroscopy. The surface of the biochar-supported iron single-atom catalyst is composed of carbon, nitrogen, oxygen, phosphorus and iron. The content of carbon element is the largest, exceeding 84at%; followed by nitrogen element, with a content of 6.35-7.07at%; and the content of oxygen element The content of phosphorus is 5.61-6.15at%; the content of phosphorus is 1.32-1.71at%; the content of iron is the least (0.77-0.96at%). The element content on the surface of biochar-supported iron single-atom catalysts prepared at different pyrolysis temperatures is different.

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

Cat-700 scanning electron microscope (Figure 1) shows that the morphology of biochar-supported iron single-atom catalyst is very similar to that of carbon nanotubes. The spherical aberration-corrected transmission electron microscope spectrum (Figure 2) shows that iron elements are evenly distributed on the biochar carrier, and uniformly dispersed bright spots can be observed, indicating the atomic-level distribution of iron elements.

The scanning electron microscopy spectra of Cat-800 and Cat-900 show that the morphology of the biochar-supported iron single-atom catalyst is very similar to that of carbon nanotubes. The spherical aberration-corrected transmission electron microscope spectrum shows that iron elements are evenly distributed on the biochar carrier, and evenly dispersed bright spots can be observed, indicating the atomic-level distribution of iron elements.

Preparation of other biochar-supported iron single-atom catalysts: The preparation process used is consistent with the preparation process of Cat-700 mentioned above. The difference is that the amount of metal iron salt is changed when preparing biochar-loaded iron single-atom catalysts (2- 6mmol), that is, the addition amount of metal iron salt is replaced from 5mmol with 2mmol, 3mmol, 4mmol, and 6mmol respectively, and biochar-supported iron single-atom catalyst can be prepared. Scanning electron microscopy spectra show that the morphology of biochar-supported iron single-atom catalyst is very similar to that of carbon nanotubes. The spherical aberration-corrected transmission electron microscope spectrum shows that iron elements are evenly distributed on the biochar carrier, and uniformly dispersed bright spots can be observed, indicating the atomic-level distribution of iron elements.

Example 2 4-(phenylamino)-2-butanone

Magnets, 20 mg biochar-loaded iron single atom catalyst (Cat-700), 1 mmol 4-hydroxy-2-butanone, 1 mmol aniline (R is hydrogen) and 2 mL acetone were added in sequence to a 25 mL reaction bottle. The reaction system was at The reaction was stirred for 8 hours in a nitrogen atmosphere at room temperature. The reaction solution was evaporated under reduced pressure, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-(phenylamino)- 2-Butanone, yield 83% (135.5 mg), yellow oil. ¹ H NMR (400MHz, CDCl ₃ ) 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, CDCl ₃ )δ208.16,147.83,129.45,117.74,113.15,42.73,38.48 ,30.38.HRMS(ESI)for C ₁₀ H ₁₃ NO,calcd:163.0993,found:163.0984.

Example 2’

The process is the same as in Example 2, 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%.

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

The process is the same as in Example 2. The difference from the above process is that when the dosage of the biochar-loaded iron single atom catalyst is 10 mg or 30 mg, the yields of 4-(phenylamino)-2-butanone are 51% and 51% respectively. 84%;

Example 3 4-((2-chlorophenyl)amino)-2-butanone

Add magnetons, 20 mg biochar-supported iron single atom catalyst (Cat-800), 0.5 mmol 4-hydroxy-2-butanone, 1 mmol 2-chloroaniline and 2 mL methyl butanone in sequence into a 25 mL reaction bottle. The reaction system is at room temperature. The reaction was stirred for 9 hours in a nitrogen atmosphere, the reaction solution was evaporated under reduced pressure, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((2-chlorophenyl) )Amino)-2-butanone, yellow oil, yield 80% (79.1 mg). ¹ H NMR (400MHz, CDCl ₃ ) 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, CDCl ₃ ) 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.

Example 4 4-((3-bromophenyl)amino)-2-butanone

Magnets, 20 mg biochar-supported iron single atom catalyst (Cat-900), 1 mmol 4-hydroxy-2-butanone, 0.5 mmol 3-bromoaniline and 2 mL acetone were added in sequence to the 25 mL reaction bottle. The reaction system was at room temperature. The reaction was stirred for 12 hours in a nitrogen atmosphere. The reaction solution was evaporated under reduced pressure, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((3-bromophenyl) Amino)-2-butanone, yellow oil, yield 77% (93.2 mg). ¹ H NMR (400MHz, CDCl ₃ ) δ6.97 (t, J = 8.0 Hz, 1H), 6.76 (d, J = 8.0 Hz, 1H), 6.68 (s, 1H), 6.47 (d, J = 8.2 Hz ,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, CDCl ₃ )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.

Example 5 4-((4-fluorophenyl)amino)-2-butanone

Magnets, 20 mg biochar-loaded iron single atom catalyst (Cat-700), 1 mmol 4-hydroxy-2-butanone, 1 mmol 4-fluoroaniline and 2 mL acetone were added in sequence to the 25 mL reaction bottle. The reaction system was filled with nitrogen at room temperature. The reaction was stirred in the atmosphere for 9 hours, the reaction solution was decompressed, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((4-fluorophenyl)amino )-2-butanone, yellow oil, yield 77% (139.5 mg). ¹ H NMR (400MHz, CDCl ₃ ) 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); ¹³ C NMR(101MHz,CDCl ₃ )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.

Example 6 4-(o-toluidine)-2-butanone

Magnets, 20 mg of biochar-loaded 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 in sequence to the 25 mL reaction bottle. The reaction system was placed in a nitrogen atmosphere at room temperature. The reaction was stirred for 9 hours, the reaction solution was decompressed, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-(o-toluidine)-2-butanone. , yellow oil, yield 71% (125.9mg). ¹ H NMR (400MHz, CDCl ₃ ) 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, CDCl ₃ ) 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:177.115 5, found:177.1153.

Example 7 4-((3-methoxyphenyl)amino)-2-butanone

Add magnetons, 20 mg biochar-loaded iron single atom catalyst (Cat-800), 1 mmol 4-hydroxy-2-butanone, 1 mmol m-methoxyaniline and 2 mL butanone in sequence to the 25 mL reaction bottle. The reaction system is at room temperature. The reaction was stirred for 8 hours in a nitrogen atmosphere, and the reaction solution was desolvated under reduced pressure. The residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((3-methoxy). Phenyl)amino)-2-butanone, yellow oil, yield 89% (172.0 mg). ¹ H NMR (400MHz, CDCl ₃ ) δ7.08 (t, J = 8.1 Hz, 1H), 6.27 (d, J = 8.1 Hz, 1H), 6.24 (d, J = 8.1 Hz, 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, CDCl ₃ )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 NO ₂ ,calcd:193.1101,found:193.1117.

Example 8 4-((4-nitrophenyl)amino)-2-butanone

Add magnets, 20 mg biochar-supported iron single atom catalyst (Cat-800), 1 mmol 4-hydroxy-2-butanone, 1 mmol p-nitroaniline and 2 mL butanone in sequence to the 25 mL reaction bottle. The reaction system is at room temperature. The reaction was stirred for 12 hours in a nitrogen atmosphere. The reaction solution was decompressed and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((4-nitrophenyl) )Amino)-2-butanone, yellow solid, melting point 89-91°C, yield 50% (104.1 mg). ¹ H NMR (400MHz, CDCl ₃ ) 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,CDCl ₃ )δ207.59,153.22,137.74,126.50,111.09,42.14,37.67,30.32.HRMS( ESI) for C ₁₀ H ₁₂ N ₂ O ₃ ,calcd:208.0844,found:208.0839.

Example 9 4-((4-trifluoromethylphenyl)amino)-2-butanone

Add magnetons, 20 mg biochar-supported iron single atom catalyst (Cat-700), 1 mmol 4-hydroxy-2-butanone, 1 mmol p-trifluoromethylaniline and 2 mL acetone into the 25 mL reaction bottle in sequence. The reaction system is at room temperature. The reaction was stirred for 12 hours in a nitrogen atmosphere, the reaction solution was evaporated under reduced pressure, and the residue was treated with column chromatography (eluent, ethyl acetate/petroleum ether = 1:4, volume ratio) to obtain 4-((4-trifluoromethyl) (Phenyl)amino)-2-butanone, yellow solid, melting point 89-91°C, yield 49% (113.3 mg). ¹ H NMR (400MHz, CDCl ₃ ) δ7.38 (d, J = 8.5 Hz, 2H), 6.57 (d, J = 8.5 Hz, 2H), 4.36 (s, 1H), 3.46 (s, 2H), 2.76 (t, J=6.0Hz, 2H), 2.19 (s, 3H); ¹³ C NMR (101MHz, CDCl ₃ ) δ 207.87, 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 F ₃ NO,calcd:231.0872,found:231.0869.

Comparative ratio

1. Compared with other solvents, the acetone or butanone solvent used in the present invention has obvious advantages, and the yield of the product is significantly higher than other solvents. The specific data are shown in Table 2 (except for different solvents (the dosage is 2 mL respectively), the other The process and conditions are the same as in Example 2).

Table 2 Isolation yields of 4-(phenylamino)-2-butanone in different solvents

2. The reaction process and conditions are the same as those of Example 2, except that no catalyst is used in the reaction process; compared with the reaction results without using a catalyst, the biochar-loaded iron single-atom catalyst used in the present invention has obvious Advantages, detailed data are shown in Table 3 (except that the biochar-supported iron single-atom catalyst is not added, the others are the same as Example 2).

Table 3 Isolation yields of 4-(phenylamino)-2-butanone in different solvents

3. Compared with the palladium-catalyzed oxidative amination reaction of homoenol (Chem. Commun. 2017, 53, 10422-10425) or allyl alcohol (J. Org. Chem. 2018, 83, 3941-3951), the present invention Has the following advantages:

(1) This reaction uses biochar-supported iron single-atom catalyst and does not require expensive palladium catalyst;

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

(3) The reaction is carried out at room temperature without heating.

We have verified through experiments that the palladium catalyst cannot catalyze the reaction of 4-hydroxy-2-butanone and aromatic amines to produce β-aminoketone under the conditions of this reaction (except for the different catalysts, the others are the same as in Example 1).

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

Compared with the patent "A method for TEMPO and TBN catalyzing N-alkylation reaction (CN201910743878.7)" or the patent "A method for iodine catalyzing the generation of β-aminoketone compounds (CN201811374694.X)", the present invention has The following are obvious differences and advantages: The content of the present invention is that a biochar-supported iron single-atom catalyst catalyzes the alcohol amination reaction of aniline and 4-hydroxy-2-butanone. The catalyst is significantly different from previous technologies; biochar-supported iron The single-atom catalyst can be recycled and reused. After six consecutive uses, the catalytic activity has not dropped significantly. Neither TEMPO/TBN nor iodine catalysts can be recycled and reused.

Claims (9)

1. A biochar-supported iron catalyst characterized by: the Phellinus linteus mycelium is used as a charcoal pyrolysis precursor, the Phellinus linteus mycelium is dispersed in normal saline, then soluble ferric salt is added into the dispersion liquid, and iron ions are complexed on the surface of the Phellinus linteus mycelium; and (3) solid-liquid separation is carried out to collect Phellinus linteus mycelium, washing is carried out, freeze drying is carried out, and then the Phellinus linteus mycelium is pyrolyzed in inert atmosphere to obtain the biochar-loaded iron monoatomic catalyst.

2. The catalyst of claim 1, wherein:

the specific process is that 2-5g (preferably 3-4 g) Phellinus linteus mycelium is firstly ultrasonically dispersed in 150mL physiological saline to obtain dispersion liquid; then, a soluble iron salt having a molar amount of iron ions of 2 to 6mmol (preferably 5 to 5.5 mmol) is added to the dispersion, and the iron ions are surface-complexed under conditions of 60 to 100 ℃ (preferably 80 to 90 ℃).

3. The catalyst according to claim 1 or 2, characterized in that:

the ultrasonic dispersion pretreatment time is 20-50min, preferably 30-40min; the ultrasonic treatment power is 40-100kw;

the time for complexing the iron ions on the surface is 12-24 hours;

after complexing iron ions on the surface of Phellinus linteus mycelium, cooling to room temperature, centrifuging, collecting Phellinus linteus mycelium, washing with water, and freeze drying.

4. The catalyst of claim 1, wherein:

the soluble manganese salt is one or more of ferric chloride, ferric nitrate or ferric sulfate.

5. The catalyst of claim 1, wherein:

the pyrolysis temperature of Phellinus linteus mycelium is 600-1000deg.C (preferably 700-800deg.C) for 1-4 hr (preferably 1-2 hr).

6. The catalyst according to claim 1 or 5, characterized in that:

the inert atmosphere is one or more than two of nitrogen and argon;

1g of dried Phellinus linteus mycelium is introduced into an inert atmosphere at an air flow rate of 10-30mL/min;

the heating rate from room temperature to pyrolysis temperature is 2-5 ℃/min; cooling to room temperature-40 ℃ after pyrolysis to obtain the catalyst, and cooling from the pyrolysis temperature to the room temperature-40 ℃ after pyrolysis at a cooling rate of 2-5 ℃/min.

7. Use of the biochar-supported catalyst of any one of claims 1-6 in an alcohol amination reaction of 4-hydroxy-2-butanone and aniline compounds.

8. The use according to claim 7, characterized in that: the method is characterized in that:

in a nitrogen atmosphere, catalyzing 4-hydroxy-2-butanone and different aniline compounds to perform an alcohol amination reaction by using an iron single-atom catalyst loaded by biochar to prepare 4- (N-phenyl) -2-butanone compounds;

r substituent groups in the formula 1 are one or more than two of hydrogen, halogen (one or more than two of F, cl and Br), methyl, methoxy, nitro and trifluoromethyl, and the number is 1-5.

9. Use according to claim 7 or 8, characterized in that:

the concentration of 4-hydroxy-2-butanone in the solvent is 0.25-1mol/L, preferably 0.5mol/L; the concentration of the aniline compound in the solvent is 0.25-1mol/L, preferably 0.5mol/L;

the molar ratio of the 4-hydroxy-2-butanone to the aniline compound is 1:2-2:1, and the preferable molar ratio is 1:1;

the solvent is acetone and/or butanone;

the dosage of the biochar-supported iron single-atom catalyst in 2mL of solvent is 10-30mg, preferably 15-20mg;

the reaction time is 4 to 12 hours, preferably 6 to 8 hours.