Method for preparing nitroaniline by ammonolysis of meta-position oil based on micro-flow field reaction technology

Abstract

The invention belongs to the field of chemical synthesis, and relates to a method for preparing nitroaniline by ammonolysis of meta-position oil based on a micro-flow field reaction technology. Mixing meta-position oil with ammonia water and a catalyst to obtain a mixed solution; and pumping the mixed solution into a micro-flow field reactor of the micro-flow field reaction device, and carrying out ammonolysis reaction to obtain nitroaniline. According to the method, nitroaniline is synthesized through single feeding of the micro-flow field reaction device, the selectivity of nitroaniline is high, the total yield reaches 99.2%, and the total purity of the product is not lower than 99.0%. The nitroaniline is synthesized by adopting the micro-flow field reaction device, so that the reaction time can be greatly shortened, the fastest reaction time can reach 12s, the reaction yield is improved, and the method is energy-saving and environment-friendly. According to the synthesis method provided by the invention, continuous production can be carried out through a micro-flow field reaction technology, the production capacity is high, the product quality is excellent, and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of chemical synthesis and relates to a method for ammonolysis of m-position oil to prepare nitroaniline based on microfluidic reaction technology. Background Art

[0002] The raw material m-position oil involved in the present invention is a mixture formed by o-nitrochlorobenzene (mass fraction 30%), m-nitrochlorobenzene (mass fraction 40%), and p-nitrochlorobenzene (mass fraction 30%). Most of the m-position oil is treated as solid waste. Nitroaniline is an extremely important intermediate in the dye industry. Existing production methods of nitroaniline include ammonolysis, nitration, hydrogenation reduction, etc. Among them, ammonolysis uses nitrochlorobenzene as the raw material and conducts a reaction under high temperature and high pressure in a concentrated ammonia water medium; most ammonolysis reactions use excessive ammonia water, and ammonia water needs to be continuously introduced during the reaction. The disadvantages of this process are: (1) There are safety hazards in the ammonolysis reaction under high temperature and high pressure conditions, and the safety is low; (2) Since the product is at a high temperature for a long time, part of the product will be coked, the appearance of the product is poor, and the quality is not high; (3) During the reaction process, a large amount of ammonia gas is generated, which will cause a drastic change in pressure and make the reaction difficult to control. In addition, the reactions of nitration and catalytic hydrogenation to prepare nitroaniline require extremely dangerous materials such as concentrated acids and hydrogen gas, and there are great safety hazards at high temperatures, and the yield is not high.

[0003] The prior art CN 114181089 A discloses a method for continuously synthesizing p-nitroaniline. In this method, the reaction temperature is relatively high, there are safety hazards, and the safety is low; two-phase feeding is required, and the reaction equipment is relatively complex and the cost is high. The prior art CN 111635322 A discloses a method for preparing 2,4-dinitroaniline using a microreactor. This method requires two-phase feeding, the reaction equipment is relatively complex, and the operation is cumbersome; the temperature of the aminolysis reaction is as high as 200°C, and the ammonia water also needs to be preheated and continuously introduced, there are safety hazards, and the safety is low.

[0004] The purpose of the present invention is to provide a safe and efficient method for synthesizing nitroaniline, which solves the problems of low production efficiency, unstable product quality, and poor safety in equipment scaling in the existing nitroaniline preparation process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for ammonolysis of m-position oil to prepare nitroaniline based on microfluidic reaction technology in view of the deficiencies of the prior art.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] The present invention discloses a method for preparing nitroaniline by ammonolysis of meta oil based on microfluidic reaction technology. The meta oil is mixed with ammonia water and a catalyst to obtain a mixed solution; the mixed solution is pumped into a microfluidic reactor of a microfluidic reaction device for ammonolysis reaction, and nitroaniline is obtained.

[0008] Among them, the nitroaniline is a mixture of o-nitroaniline, m-nitroaniline and p-nitroaniline.

[0009] In some embodiments, the meta oil is a composition of o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene; in the meta oil, the mass fraction of o-nitrochlorobenzene is 10% - 80%, the mass fraction of m-nitrochlorobenzene is 10% - 80%, and the mass fraction of p-nitrochlorobenzene is 10% - 80%.

[0010] Among them, in the meta oil, the total mass fraction of o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene is 100%.

[0011] In some embodiments, preferably, the meta oil is a composition of o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene; in the meta oil, the mass fraction of o-nitrochlorobenzene is 30%, the mass fraction of m-nitrochlorobenzene is 40%, and the mass fraction of p-nitrochlorobenzene is 30%.

[0012] In some embodiments, preferably, the meta oil is a composition of o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene; in the meta oil, the mass fraction of o-nitrochlorobenzene is 30%, the mass fraction of m-nitrochlorobenzene is 40%, and the mass fraction of p-nitrochlorobenzene is 30%.

[0013] In some embodiments, the mass fraction of NH 3 in the ammonia water is 5% - 30%; and / or, the catalyst is any one or a combination of several of cuprous chloride, copper chloride and tetrabutylammonium chloride.

[0014] In some embodiments, preferably, the mass fraction of NH 3 in the ammonia water is 20% - 30%, and further preferably 28%.

[0015] In some embodiments, preferably, the catalyst is any one or a combination of two of cuprous chloride and tetrabutylammonium chloride, and further preferably cuprous chloride.

[0016] In some embodiments, in the mixed solution, the concentration of the meta oil is 0.10 mmol / mL - 2.00 mmol / mL; and / or, the molar ratio of the meta oil to NH 3 in the ammonia water is 1:(5 - 50); and / or, the molar ratio of the meta oil to the catalyst is (1 - 5000):1.

[0017] In some embodiments, preferably, in the mixed solution, the concentration of m-xylene is 0.50 mmol / mL to 1.00 mmol / mL, and more preferably 0.70 mmol / mL to 0.90 mmol / mL.

[0018] In some embodiments, preferably, the molar ratio of the m-xylene to NH 3 in the ammonia water is 1:(10 - 20), more preferably 1:(15 - 20), still more preferably 1:(16 - 20), and most preferably 1:18.

[0019] In some embodiments, the molar ratio of the m-xylene to the catalyst is (100 - 2000):1, and more preferably (100 - 1000):1.

[0020] In some embodiments, the mixed solution further includes a solvent; the solvent is any one or a combination of several of dichloromethane, 1,2-dichloroethane, acetone, benzene, toluene, ether, methyl tert-butyl ether, acetonitrile, tetrahydrofuran, chloroform, cyclohexane, and petroleum ether; and / or, in the mixed solution, the concentration of m-xylene is 0.10 mmol / mL to 2.00 mmol / mL.

[0021] In some embodiments, preferably, the mixed solution further includes a solvent; the solvent is tetrahydrofuran; and / or, in the mixed solution, the concentration of m-xylene is 0.50 mmol / mL to 1.00 mmol / mL, and more preferably 0.70 mmol / mL to 0.90 mmol / mL.

[0022] In some embodiments, the flow rate of pumping the mixed solution into the microfluidic reactor of the microfluidic reaction device is 0.010 mL / min to 50.000 mL / min.

[0023] In some embodiments, preferably, the flow rate of pumping the mixed solution into the microfluidic reactor of the microfluidic reaction device is 0.050 mL / min to 50.000 mL / min, and more preferably 0.056 mL / min, 0.084 mL / min, or 50 mL / min.

[0024] In some embodiments, for the ammonolysis reaction, the reaction temperature is 140°C to 190°C; and / or, for the ammonolysis reaction, the reaction pressure is 1 MPa to 10 Mpa.

[0025] In some embodiments, preferably, for the ammonolysis reaction, the reaction temperature is 160°C to 180°C, and more preferably 160°C or 180°C.

[0026] In some embodiments, preferably, for the ammonolysis reaction, the reaction pressure is 2 MPa to 5 MPa, more preferably 2 MPa to 4 MPa, and even more preferably 3.5 MPa.

[0027] In some embodiments, in the microfluidic reactor, the reaction residence time is 12 s to 10 h.

[0028] In some embodiments, preferably, in the microfluidic reactor, the reaction residence time is 12 s to 5 h, more preferably 12 s to 3 h.

[0029] In some embodiments, the microfluidic reaction device includes a connecting pipeline, a plunger pump, a microfluidic reactor, and a receiver; wherein, the plunger pump, the microfluidic reactor, and the receiver are connected in series through the connecting pipeline; a back pressure valve is provided on the microfluidic reactor.

[0030] Specifically, the pipeline in the plunger pump is a spherical structure pipeline or a cardiac structure pipeline.

[0031] Wherein, the pipeline in the plunger pump is a spherical structure pipeline or a cardiac structure pipeline, which is used to enhance mass transfer.

[0032] Wherein, the temperature of the microfluidic reactor is controlled by oil bath heating.

[0033] Wherein, the microfluidic reactor is a tubular reactor, and the pipeline material is stainless steel.

[0034] Wherein, the inner diameter of the pipeline of the microfluidic reactor is 0.5 mm to 5 mm, and the length is 0.5 m to 40 m.

[0035] Beneficial effects:

[0036] (1) In the prior art, the meta-position oil is mostly treated as solid waste. The microfluidic reaction technology involved in the present invention solves the problems of poor safety, poor mass transfer and heat transfer, long reaction time, and energy waste in the ammonolysis process of meta-position oil in traditional batch reactors. The reaction device is simple to build and has the potential for industrial scale-up. The synthesis method provided by the present invention uses meta-position oil as a raw material, which is cheap and easily available. The final product nitroaniline can be efficiently synthesized in one step from meta-position oil. The operation is simple, environmentally friendly, safe and reliable; the microfluidic reaction device is simple to build and easy to scale up.

[0037] (2) The synthesis method provided by the present invention can continuously produce without interruption through the microfluidic reaction technology, with large production capacity, excellent product quality, and reduced cost.

[0038] (3) The present invention synthesizes nitroaniline using a microfluidic reaction device, which can greatly reduce the reaction time, with the fastest reaching 12 s, improve the reaction yield, and save energy and protect the environment.

[0039] (4) The present invention synthesizes nitroaniline by single-feed in a microfluidic reaction device, with high selectivity of nitroaniline, a total yield reaching 99.2%, and the total purity of the product not less than 99.0%.

[0040] (5) The present invention pumps the single-feed into the microfluidic reactor of the microfluidic reaction device through a plunger pump with a spherical structure pipeline or a core-shaped structure pipeline. Among them, compared with directly pumping the feed by a traditional injection pump, the plunger pump with a spherical structure pipeline or a core-shaped structure pipeline can enhance mass transfer. Meanwhile, under the synergistic effect of the catalyst, the aminolysis reaction temperature can be reduced to 160 - 180 °C, the reaction pressure can be reduced to 3.5 Mpa, the reaction time can be reduced to 12 s, the reaction efficiency is high, and the product quality is high. Description of the Drawings

[0041] The following further specifically describes the present invention in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0042] Figure 1 It is a schematic diagram of the microfluidic reaction device used in the embodiment of the present invention.

[0043] Figure 2 It is a physical setup diagram of the microfluidic reaction device used in the embodiment of the present invention.

[0044] Figure 3 It is a schematic diagram of the spherical structure pipeline or the core-shaped structure pipeline inside the plunger pump used in the embodiment of the present invention. Detailed Embodiments

[0045] According to the following embodiments, the present invention can be better understood. However, those skilled in the art can easily understand that the content described in the embodiments is only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0046] In the following embodiments, the experimental methods are all conventional methods unless otherwise specified; the reagents and materials can all be obtained from commercial channels unless otherwise specified.

[0047] The meta-position oil used in the embodiment of the present invention is the bottom residue (solid waste) in the rectification process of nitrochlorobenzene. The meta-position oil is a composition of o-nitrochlorobenzene (mass fraction 30%), m-nitrochlorobenzene (mass fraction 40%) and p-nitrochlorobenzene (mass fraction 30%); the meta-position oil is provided by Nanjing Chemical Industry Company.

[0048] In the embodiment of the present invention, the synthesis route of synthesizing nitroaniline by ammoniating m - oil is as follows:

[0049]

[0050] The flow chart of the micro - flow field reaction device used in the embodiment of the present invention is shown in Figure 1 , and the micro - flow field reaction device includes a connecting pipeline, a plunger pump, a micro - flow field reactor and a receiver; wherein, the plunger pump, the micro - flow field reactor and the receiver are connected in series through the connecting pipeline; a back - pressure valve is provided on the micro - flow field reactor for adjusting the reaction pressure in the micro - flow field reactor. The specific physical device diagram is shown in Figure 2 .

[0051] Among them, the micro - flow field reactor is a tubular reactor, and the pipeline material is stainless steel.

[0052] Among them, the inner diameter of the pipeline of the micro - flow field reactor is 1.0 mm, and the preferred volume in the embodiment is 10 mL.

[0053] Among them, the temperature of the micro - flow field reactor is controlled by oil - bath heating.

[0054] Among them, the pipeline in the plunger pump is a spherical - structure pipeline or a core - type structure pipeline (see Figure 3 , Figure a is a spherical - structure pipeline; Figure b is a core - type structure pipeline), which is used to enhance mass transfer. The pipeline in the plunger pump used in the embodiment of the present invention is preferably a spherical - structure pipeline.

[0055] Example 1:

[0056] Take m - oil (10 mmol, 1.0 eq), cuprous chloride (0.1 mmol, 0.01 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) and mix them to obtain a mixed solution; pump the mixed solution into the micro - flow field reactor (volume 10 mL) of the micro - flow field reaction device at a flow rate of 0.056 mL / min for ammonolysis reaction. The reaction temperature is 180 °C, the reaction pressure is 3.5 MPa, and the reaction residence time in the micro - flow field reactor is 3 h; after the reaction is completed, extract the reaction solution. Ethyl acetate is used as the organic phase and water is used as the aqueous phase. After extraction, take the organic phase to obtain the final product nitroaniline (a mixture of o - nitroaniline, m - nitroaniline and p - nitroaniline), with a yield of 99.2% and a purity of 99.0%.

[0057] Example 2:

[0058] Take m - oil (10 mmol, 1.0 eq), cuprous chloride (0.01 mmol, 0.001 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH3 , 18.0 eq) were mixed to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 0.056 mL / min for an ammonolysis reaction. The reaction temperature was 160 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 3 h; after the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 95.2% and a purity of 99.0%.

[0059] Example 3:

[0060] Take m-position oil (10 mmol, 1.0 eq), copper chloride (0.1 mmol, 0.01 eq), and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) were mixed to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 0.084 mL / min for an ammonolysis reaction. The reaction temperature was 180 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 2 h; after the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 97.4% and a purity of 99.0%.

[0061] Example 4:

[0062] Take m-position oil (10 mmol, 1.0 eq), tetrabutylammonium chloride (0.1 mmol, 0.01 eq), and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) were mixed to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 0.056 mL / min for an ammonolysis reaction. The reaction temperature was 180 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 3 h; after the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 90.2% and a purity of 95.0%.

[0063] Example 5:

[0064] Take m-position oil (10 mmol, 1.0 eq), copper chloride (0.1 mmol, 0.01 eq), 12 mL of 28 wt% ammonia water (0.18 mol NH 3, 18.0 eq) and 2 mL of tetrahydrofuran were mixed to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 0.056 mL / min for ammonolysis reaction. The reaction temperature was 180 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 3 h. After the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 93.6% and a purity of 95.0%.

[0065] Example 6:

[0066] Take m-position oil (10 mmol, 1.0 eq), copper chloride (0.1 mmol, 0.01 eq), and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) and mix them to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 50 mL / min for ammonolysis reaction. The reaction temperature was 180 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 12 s. After the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 90.6% and a purity of 99.0%.

[0067] Example 7:

[0068] Take m-position oil (100 mmol, 1.0 eq), copper chloride (1 mmol, 0.01 eq), and 120 mL of 28 wt% ammonia water (1.8 mol NH 3 , 18.0 eq) and mix them to obtain a mixed solution; the mixed solution was pumped into a microfluidic reactor (volume 10 mL) of a microfluidic reaction device at a flow rate of 0.056 mL / min for ammonolysis reaction. The reaction temperature was 180 °C, the reaction pressure was 3.5 MPa, and the reaction residence time in the microfluidic reactor was 3 h. After the reaction, the reaction solution was extracted, with ethyl acetate as the organic phase and water as the aqueous phase. After extraction, the organic phase was taken to obtain the final product nitroaniline (a mixture of o-nitroaniline, m-nitroaniline, and p-nitroaniline), with a yield of 90.6% and a purity of 99.0%.

[0069] Comparative Example 1:

[0070] The experimental method was the same as that in Example 1, except that a conventional high-pressure autoclave device was used to synthesize nitroaniline.

[0071] Add m - oil (10 mmol, 1.0 eq), copper(I) chloride (0.1 mmol, 0.01 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) into a high - pressure reactor, heat it to 180 °C, pressurize it to 3.5 MPa, and carry out the ammonolysis reaction for 3 h. After the reaction is completed, extract the reaction solution. Use ethyl acetate as the organic phase and water as the aqueous phase. After extraction, take the organic phase to obtain the final product nitroaniline (a mixture of o - nitroaniline, m - nitroaniline and p - nitroaniline), with a yield of 65.6% and a purity of 88.0%.

[0072] Comparative Example 2:

[0073] The experimental method is the same as that in Example 2, except that a conventional high - pressure reactor device is used to synthesize nitroaniline.

[0074] Add m - oil (10 mmol, 1.0 eq), copper(I) chloride (0.01 mmol, 0.001 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) into a high - pressure reactor, heat it to 160 °C, pressurize it to 3.5 MPa, and carry out the ammonolysis reaction for 3 h. After the reaction is completed, extract the reaction solution. Use ethyl acetate as the organic phase and water as the aqueous phase. After extraction, take the organic phase to obtain the final product nitroaniline (a mixture of o - nitroaniline, m - nitroaniline and p - nitroaniline), with a yield of 52.8% and a purity of 88.0%.

[0075] Comparative Example 3:

[0076] The experimental method is the same as that in Example 3, except that a conventional high - pressure reactor device is used to synthesize nitroaniline.

[0077] Add m - oil (10 mmol, 1.0 eq), copper(I) chloride (0.1 mmol, 0.01 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) into a high - pressure reactor, heat it to 180 °C, pressurize it to 3.5 MPa, and carry out the ammonolysis reaction for 2 h. After the reaction is completed, extract the reaction solution. Use ethyl acetate as the organic phase and water as the aqueous phase. After extraction, take the organic phase to obtain the final product nitroaniline (a mixture of o - nitroaniline, m - nitroaniline and p - nitroaniline), with a yield of 54.5% and a purity of 85.0%.

[0078] Comparative Example 4:

[0079] The experimental method is the same as that in Example 1, except that a conventional high - pressure reactor device is used to synthesize nitroaniline and no catalyst is added.

[0080] Add m - position oil (10 mmol, 1.0 eq) and 12 mL of 28 wt% ammonia water (0.18 mol NH 3 , 18.0 eq) into the high - pressure reactor, heat it to 180 °C, pressurize it to 3.5 MPa, and carry out the ammonolysis reaction for 3 h; after the reaction is completed, extract the reaction solution to obtain the final product nitroaniline (a mixture of o - nitroaniline, m - nitroaniline and p - nitroaniline), with a yield of 30.3% and a purity of 80.0%.

[0081] The present invention provides an idea and method for preparing nitroaniline by ammonolysis of m - position oil based on micro - flow field reaction technology. There are many methods and ways to specifically implement this technical solution. The above - mentioned is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by the prior art.

Claims

1. A method for preparing nitroaniline by ammonolysis of meta-oil based on microfluidic field reaction technology, characterized in that: The meta-oil is mixed with ammonia water and a catalyst to obtain a mixed solution; the mixed solution is pumped into a microfluidic field reactor of a microfluidic field reaction device to perform an ammonolysis reaction to obtain nitroaniline.

2. The method according to claim 1, characterized in that The meta-oil is a composition of o-nitrochlorobenzene, m-nitrochlorobenzene and p-nitrochlorobenzene; in the meta-oil, the mass fraction of o-nitrochlorobenzene is 10% to 80%, the mass fraction of m-nitrochlorobenzene is 10% to 80%, and the mass fraction of p-nitrochlorobenzene is 10% to 80%.

3. The method according to claim 1, characterized in that The mass fraction of NH3 in the ammonia water is 5% to 30%; and / or, the catalyst is any one or a combination of cuprous chloride, cupric chloride and tetrabutylammonium chloride.

4. The method according to claim 1, characterized in that: In the mixed solution, the concentration of the meta-oil is 0.10mmol / mL to 2.00mmol / mL; and / or, the molar ratio of the meta-oil to NH3 in the ammonia water is 1:(5-50); and / or, the molar ratio of the meta-oil to the catalyst is (1-5000):

1.

5. The method according to claim 1, characterized in that The mixed liquid also includes a solvent; the solvent is any one or a combination of dichloromethane, 1,2-dichloroethane, acetone, benzene, toluene, ether, methyl tert-butyl ether, acetonitrile, tetrahydrofuran, chloroform, cyclohexane and petroleum ether; and / or, in the mixed liquid, the concentration of meta-oil is 0.10 mmol / mL to 2.00 mmol / mL.

6. The method according to claim 1, characterized in that The mixed solution is pumped into the microfluidic reactor of the microfluidic reaction device at a flow rate of 0.010 mL / min to 50.000 mL / min.

7. The method according to claim 1, characterized in that The reaction temperature of the ammonolysis reaction is 140°C to 190°C; and / or the reaction pressure of the ammonolysis reaction is 1MPa to 10Mpa.

8. The method according to claim 1, characterized in that In the microfluidic field reactor, the reaction residence time is 12s to 10h.

9. The method according to claim 1, characterized in that: The microfluidic field reaction device comprises a connecting pipe, a plunger pump, a microfluidic field reactor and a receiver; wherein the plunger pump, the microfluidic field reactor and the receiver are connected in series via a connecting pipe; and a back pressure valve is provided on the microfluidic field reactor.

10. The method according to claim 9, characterized in that The pipeline in the plunger pump is a spherical structure pipeline or a core structure pipeline.

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