Method for preparing nitrile compound through catalytic oxidation of ether compound
By catalyzing the oxidative cracking of ether compounds with nitrogen-doped mesoporous carbon-supported copper-based single-atom materials, the problem of using highly toxic solvents and generating a large amount of inorganic waste in the traditional nitrile compound synthesis method is solved, and the efficient, environmentally friendly and economical preparation of nitrile compounds is achieved.
Patent Information
- Application Number
- CN202311268185.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-28
- Publication Date
- 2025-03-28
AI Technical Summary
The traditional synthesis methods of existing nitrile compounds have problems with the use of highly toxic solvents, expensive reagents and the production of large amounts of inorganic waste, and lack a green and efficient method of directly oxidizing nitrile with ether compounds as raw materials.
The ether compound is oxidized and cracked by heating and stirring under sealing conditions to form nitrile compounds by using nitrogen-doped mesoporous carbon-supported copper-based single-atom material as a catalyst. This method is suitable for the synthesis of aromatic, heterocyclic and fatty esters, and the catalyst can be recycled.
It has achieved efficient preparation of nitrile compounds, which are characterized by high atomic economy, non-toxic and pollution-free, and environmentally friendly and economical, suitable for industrial applications, and the recycling of catalysts reduces production costs.
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Abstract
Description
Technical Field
[0001] The invention relates to the field of chemistry and chemical engineering, and in particular to a method for preparing nitrile compounds by oxidative cracking of ether compounds. Background Art
[0002] Organic nitriles are an important component of pharmaceuticals, pesticides and fine chemicals. In 2010, more than 30 cyano-containing organic compounds were identified with different medicinal indications, and more than 20 nitrile-containing compounds are available for clinical development. In organic chemistry, nitriles can be used as important intermediates for the production of a large number of heterocycles, and can also be used to synthesize amines, amides, aldehydes and different carboxylic acid derivatives.
[0003] The traditional synthesis methods of nitrile compounds are: 1) nucleophilic substitution of alkyl and aryl halides and the classic Sandmeyer reaction, but usually require the use of highly toxic hydrocyanic acid or metal cyanide. 2) dehydration of amides or aldoximes, elimination of oxime ethers or oxime esters and oxidation of primary amines to corresponding nitriles. 3) preparation of aromatic nitriles using aromatic amines as raw materials; 4) preparation of aromatic nitriles using methyl aromatics as raw materials. However, from the perspective of green chemistry, the use of toxic solvents and expensive reagents, cumbersome operations and the generation of a large amount of inorganic waste limit their widespread application. In view of this, it is very urgent to develop a green, efficient, non-toxic and pollution-free catalytic system for direct ammoxidation of cheap and readily available alcohols to prepare nitriles, which has attracted widespread attention from researchers.
[0004] At the same time, so far, there has been no research reported in the world on the preparation of nitrile by cleavage of the carbon-oxygen bond of ether compounds. The present invention aims to develop a method for preparing nitrile compounds by catalyzing the oxidation cleavage of the carbon-oxygen bond of ether compounds, which can realize the synthesis of aromatic, heterocyclic and aliphatic esters, and can be recycled for many times, and has industrial application prospects. Summary of the invention
[0005] The invention provides a novel preparation method of benzonitrile. The method uses an ether compound as a substrate and oxygen as an oxygen source. Under the action of a catalyst, the ether compound undergoes oxidative cracking to generate a nitrile compound. The substrate has wide applicability and the catalyst can be recycled.
[0006] The technical solution adopted by the present invention is:
[0007] Using ether compounds as substrates and copper-based single-atom materials supported by nitrogen-doped mesoporous carbon as catalysts, adding ammonia sources and oxygen sources, the reaction is carried out for 20-50 hours under sealed conditions with heating and stirring at a certain temperature.
[0008] 1. In the above technical scheme, the preparation method of the copper-based single-atom catalyst supported by nitrogen-doped mesoporous carbon is as follows: weigh a certain amount of silica sol, add it to N,N-dimethylformamide (DMF), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh a certain amount of copper phthalocyanine (II), add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C, evaporate the solvent, obtain a dry solid, and then calcine it at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1 ), calcined and cooled to room temperature to obtain a black powder, soaked in a dilute HF solution for more than 24 hours, finally washed with deionized water until neutral, and dried in an oven at 80°C for 12 hours to obtain the target catalyst Cu-NC-1; wherein the mass content of Cu is 0.1-2wt%, and the mass content of N is 1-5wt%.
[0009] 2. In the above technical solution, in the ether compound molecule, the benzene ring has one or more of phenyl, naphthyl, furan ring, thiophene ring, and pyridine ring with other substituents;
[0010] The other substituents on the benzene ring are one or more of -CH3, -OCH3, -C(CH3)3, -F, -Cl, -Br, -CF3; in the ether compound having other substituents on the benzene ring, the positions of the other substituents are ortho, meta or para; in the ether compound having other substituents on the benzene ring, the number of the other substituents is 1, 2, 3, 4 or 5;
[0011] 3. In the above technical solution, the molar ratio of the amount of ammonia source added to the amount of the ether compound reactant added is 1-6, preferably 3-5, more preferably 4. The ammonia source used is an amine inorganic compound, including one or more of ammonia water, ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium acetate, and ammonium chloride.
[0012] 4. In the above technical solution, the molar ratio of the amount of catalyst added to the amount of the ether compound reactant fed is 0.02-0.2, preferably 0.08.
[0013] 5. In the above technical solution, the gas pressure used is 0.2-2MPa, the reaction temperature used is 130-200°C, and the reaction time is 20-50h, preferably 1Mpa, 170°C, and 24h.
[0014] 6. In the above technical solution, the oxygen source used is one or both of pure oxygen and air.
[0015] 7. In the above technical scheme, the solvent used for oxidation of the ether compound is one or more of toluene, tert-amyl alcohol, 1,4-dioxane, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, n-heptane, methanol, and ethanol. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a scanning electron microscope (SEM) image of the Cu-NC-8 nitrogen-doped mesoporous carbon-supported copper-based catalyst prepared as described below.
[0017] Figure 2 This is a transmission electron microscope (TEM) image of the Cu-NC-8 nitrogen-doped mesoporous carbon-supported copper-based catalyst prepared as described below. DETAILED DESCRIPTION
[0018] The following examples will help to understand the present invention, but the present invention is not limited thereto.
[0019] The preparation method of the nitrogen-doped mesoporous carbon-supported copper-based single-atom catalyst used in the following examples is:
[0020] 1) Cu-NC-8: Weigh 8 mmol of silica sol, add it to 20 ml of N,N-dimethylformamide (DMF), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh 1 mmol of copper phthalocyanine (II), add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C (specifically 180°C in this case), evaporate the solvent, and obtain a dry solid, which is then calcined at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1 ), calcined and cooled to room temperature to obtain a black powder, which was soaked in a 18% by mass HF solution for more than 24 hours, and finally washed with deionized water until neutral, and dried in an oven at 80°C for 12 hours to obtain the target catalyst Cu-NC-8 with a porous structure.
[0021] 2) Cu-NC-13: Weigh 13 mmol silica sol, add it to 20 ml N,N-dimethylformamide (DMF), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh 1 mmol copper phthalocyanine (II), add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C (specifically 180°C in this case), evaporate the solvent, and obtain a dry solid, which is then calcined at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1), calcined and cooled to room temperature to obtain a black powder, which was soaked in a 18% by mass HF solution for more than 24 hours, and finally washed with deionized water until neutral, and dried in an oven at 80°C for 12 hours to obtain the target catalyst Cu-NC-13 with a porous structure.
[0022] 3) Cu-NC-16: Weigh 16 mmol silica sol, add it to 20 ml N,N-dimethylformamide (DMF), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh 1 mmol copper phthalocyanine (II), add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C (specifically 180°C in this case), evaporate the solvent, and obtain a dry solid, which is then calcined at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1 ), calcined and cooled to room temperature to obtain a black powder, which was soaked in a 18% by mass HF solution for more than 24 hours, and finally washed with deionized water until neutral, and dried in an oven at 80°C for 12 hours to obtain the target catalyst Cu-NC-16 with a porous structure.
[0023] The Cu content of 1) is 1%, the Cu content of 2) is 0.7%, and the Cu content of 3) is 0.4%. Figure 1 , 2 For Cu-NC-13, the porous morphology of Cu-NC can be seen, proving its mesoporous structure with a pore size of about 2-50 nm. Figure 2 It can be seen that Cu-NC does not exist in particle form, indicating that there is no copper oxide in it, proving that it is a single-atom catalyst. 1) 2) 3) The Cu content is 0.4-1wt%. See Figure 1 , 2 , we can see the porous morphology of Cu-NC, proving its mesoporous structure. Figure 2 , it can be seen that Cu-NC does not exist in particle form, proving that it is a single-atom catalyst.
[0024] The preparation method of the nitrogen-doped mesoporous carbon-supported unacid-washed copper-based catalyst used in the following example is as follows: weigh a silica sol containing 13 mmol of silicon dioxide, add it to 20 ml of N,N-dimethylformamide (DMF), stir at room temperature, and ultrasonicate until it is uniformly mixed to obtain a mixed solution A; weigh 1 mmol of copper phthalocyanine (II), add it to solution A, stir at room temperature, and ultrasonicate until it is uniformly mixed to obtain a mixed solution B, stir solution B at 170-200°C (specifically 180°C here), evaporate the solvent to obtain a dry solid, and then calcine it at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1), calcined and cooled to room temperature to obtain a black powder, which was dried in an oven at 80°C for 12 h to obtain the target catalyst Cu-NC (not acid-washed).
[0025] The preparation method of the nitrogen-doped mesoporous carbon-supported non-metal catalyst used in the following example is as follows: weigh a silica sol containing 13 mmol of silicon dioxide, add it to 20 ml of N,N-dimethylformamide (DMF), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh 1 mmol of phthalocyanine, add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C (specifically 180°C here), evaporate the solvent, obtain a dry solid, and then calcine it at 900°C in a nitrogen atmosphere for 2 hours (heating rate is 5°C min -1 ), calcined and cooled to room temperature to obtain a black powder, which was soaked in a 18% by mass HF solution for more than 24 hours, and finally washed with deionized water until neutral, and dried in an oven at 80°C for 12 hours to obtain the target catalyst NC.
[0026] Example 1
[0027] Cu-NC (in terms of copper, 8 mol% relative to the raw material), benzyl methyl ether (0.25 mmol), NH3·H2O (1 mmol), and 2 mL of acetonitrile were added to a 5 mL reaction bottle in sequence, and then transferred to a stainless steel high-pressure reactor, filled with oxygen pressure to 1 MPa, and the reactor was placed in a 170°C oil bath. The reaction was stirred at a speed of 550 (rpm) for 24 h. After the reaction was completed, the reactor was cooled to room temperature, the reactor was opened, and internal standard naphthalene (20 mg) was added. The qualitative product was detected by gas chromatography-mass spectrometry. The conversion rate of the quantitative substrate benzyl methyl ether and the yield of the product benzonitrile by gas chromatography internal standard method are shown in Table 1.
[0028] Example 2-23
[0029] Except for the catalyst and dosage, pressure and reaction time, the catalyst activity evaluation is the same as that in Example 1. The reaction conditions and catalytic reaction results are shown in Table 1. It can be seen from Table 1 that the catalyst and dosage, oxygen pressure, ammonia source type, reaction temperature and reaction time have an effect on the catalytic effect. With the increase of reaction temperature (Examples 1 and 2, 3), oxygen source type, pressure (Examples 1 and 4-6) and reaction time (Examples 1 and 7, 8), the yield increases, and the dosage and type of ammonia source (Examples 1 and 24-16), solvent type (Examples 1 and 17-23), the dosage and type of catalyst (Examples 1 and 24-30), the catalytic effect is also different.
[0030] Table 1 Preparation of organic nitrile by oxidative cleavage of benzyl ether
[0031]
[0032]
[0033] The amount of catalyst refers to the amount of copper, relative to the raw material mol%; NC means that it is the same as Cu-NC-13; Examples 31-60
[0034] Except for the different substrates, the catalyst activity evaluation and reaction conditions are the same as those in Example 1, and the reaction time is 24-48 h (specifically 48 h in this case). The substrates and catalytic reaction results are shown in Table 2. Ether compound substrates can all undergo oxidative cleavage to generate corresponding organic nitrile compounds, which indicates the universality of this method.
[0035] Table 2 Oxidative cleavage of ether compounds substrates
[0036]
[0037]
[0038]
[0039] The invention has high oxidation efficiency, good selectivity and high product yield; it uses oxygen as an oxygen source, is economical and environmentally friendly, and has important significance for the catalytic oxidation method for developing a green economy.
Claims
1. A method for preparing nitrile compounds by catalytic oxidation of ether compounds, characterized in that: Ether compounds, ammonia sources and nitrogen-doped mesoporous carbon-supported copper-based catalysts are added to a solvent, placed in a sealed pressure vessel, and 0.2-2MPaMPa of oxygen source gas is introduced, and the reaction is carried out at 120-200°C for 20-50 hours to oxidatively break the carbon-oxygen bond into the corresponding nitrile compound.
2. The method according to claim 1, characterized in that The nitrogen-doped mesoporous carbon-supported catalyst is a nitrogen-doped mesoporous carbon-supported copper-based single-atom catalyst. The preparation method of the nitrogen-doped mesoporous carbon-supported copper-based single-atom catalyst is as follows: Weigh 1-3g silica sol (preferably 1.25-2g), add it to 40-60mL N,N-dimethylformamide (DMF) (preferably 45-55mL), stir at room temperature, and mix by ultrasound to obtain a mixed solution A; weigh 0.5-1.5mmol copper phthalocyanine (II) (preferably 0.8-1.2mmol), add it to solution A, stir at room temperature, and mix by ultrasound to obtain a mixed solution B, stir solution B at 170-200°C, evaporate the solvent, obtain a dry solid, and then calcine at 800-900°C in a nitrogen atmosphere for more than 2 hours (the heating rate from room temperature to 800-900°C is 3-10°C min -1 ), calcined and cooled to room temperature to obtain a black powder, soaked in 15-30% HF for more than 24 hours, finally washed with deionized water until neutral, and dried in an oven at 80-120°C to obtain the target catalyst Cu-NC; wherein the mass content of Cu is 0.1-2wt%, and the mass content of N is 1-5wt%.
3. The method according to claim 1, characterized in that: The molar ratio of the amount of the catalyst added to the amount of the ether compound reactant added is 0.02-0.2, preferably 0.08-0.
12.
4. The method for preparing nitrile compounds by oxidative cleavage of ether compounds according to claim 1, characterized in that: The ammonia source is an alkaline inorganic compound, including one or more of ammonium sulfate, ammonium carbonate, ammonium chloride, ammonium bicarbonate, and ammonia water; the molar ratio of the added amount of the ammonia source to the ether compound reactant is 1-6, preferably 3-5, and more preferably 4.
5. The method according to claim 1, characterized in that The solvent is one or more of toluene, tert-amyl alcohol, 1,4-dioxane, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, n-heptane, methanol and ethanol.
6. The method according to claim 1, characterized in that The reaction temperature is 130-200° C., preferably 150-170° C.; the gas pressure is 0.2-2.0 MPa, preferably 1.0 MPa; and the reaction time is 8-48 h, preferably 20-50 h.
7. The method according to claim 1 or 2, characterized in that: The ether compound molecules are one or more of the following: Aromatic ethers: R1=-H, -CH3, -OCH3, -C(CH3)3, -F, -Cl, -Br, -CF3, 4-tBu, one or more thereof, the number of which is 1-5, preferably 1-2, the position of the R1 substituent is ortho, meta or para; n=1, 2, 3, one or more thereof; R2=Me, Et, Ph, Bn, naphthalene ring, furan ring, thiophene ring, pyridine ring, phenyl with C1-C6 alkyl substituent, one or more thereof; Heterocyclic ethers: refers to heterocyclic ethers in which the benzene ring in the above structural formula can be replaced by one or more of naphthalene ring, furan ring, thiophene ring and pyridine ring; Fatty ethers: n=one or two or more of 1-6.