A green synthesis method of 2-aminothiophene

Abstract

The invention discloses a green synthesis method of 2-aminothiophene, relates to the field of 2-aminothiophene synthesis technology, including: using a green solvent system as a reaction medium; using thiophene compounds as raw materials, adopting amination reaction, carrying out amination reaction; reacting under the reaction conditions of a temperature range of 70-80 ° C and a reaction time of 5-6 hours; after the reaction is completed, separating by a purification method; removing the solvent by suction filtration and vacuum drying, obtaining the final 2-aminothiophene, and identifying the product. The present invention proposes a green synthesis technology, by using a green solvent system and a non-metallic nitrogen source, and combining microwave heating, online monitoring and automatic control technology, the accuracy and efficiency of the reaction can be greatly improved, energy consumption and environmental pollution can be reduced, and in addition, the method optimizes the purification step, ensures the high purity and high yield of the final product, and therefore has a large industrial application prospect and environmental significance.

Description

Technical Field

[0001] The invention relates to the technical field of 2-aminothiophene synthesis, and in particular to a green synthesis method of 2-aminothiophene. Background Art

[0002] 2-Aminothiophene, as an important thiophene derivative, is widely used in organic synthesis, medicinal chemistry, materials science and other fields. The traditional synthesis method of 2-aminothiophene usually involves harsh reaction conditions, such as high temperature, solvent contamination, etc., and often uses toxic metal catalysts or chemicals, which not only increases production costs, but also imposes a heavy burden on the environment.

[0003] In recent years, with the promotion of the concept of green chemistry, researchers have been committed to developing more environmentally friendly, economical and efficient synthesis methods. The core concept of green synthesis methods is to minimize the use and generation of harmful substances, avoid or replace harmful solvents, and reduce energy consumption. Especially in the synthesis process, the selection of green solvent systems, non-metallic nitrogen sources, and the optimization of reaction conditions can not only help to improve the purity and yield of the product, but also reduce the impact on the environment. In this context, the use of water and ethanol as green solvent systems and the amination reaction of non-metallic nitrogen sources such as ammonia gas and ammonia water to prepare 2-aminothiophene in a green synthesis manner has important scientific research and industrial value, especially in combination with microwave heating technology, real-time online monitoring technology and automated control systems. These innovative synthesis methods can significantly improve reaction efficiency, shorten reaction time, and ensure high selectivity and high yield of the reaction. Summary of the invention

[0004] In order to solve the above technical problems, a green synthesis method of 2-aminothiophene is provided. The technical solution solves the above problems.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A green synthesis method of 2-aminothiophene, comprising:

[0007] Use green solvent system as reaction medium;

[0008] Using thiophene compounds as raw materials, adopting an amination reaction, using non-metallic nitrogen sources, including ammonia gas and ammonia water, to carry out an amination reaction;

[0009] The reaction is carried out under the reaction conditions of a temperature range of 70-80°C and a reaction time of 5-6 hours;

[0010] After the reaction is complete, it is separated by purification methods, including filtration, extraction and crystallization;

[0011] The solvent was removed by suction filtration and vacuum drying to obtain the final 2-aminothiophene, and the product was identified to confirm its structure and purity.

[0012] Preferably, the use of a green solvent system as a reaction medium specifically includes:

[0013] First, a suitable green solvent system is selected, wherein the green solvent includes water and ethanol as the solvent for the reaction;

[0014] Use molecular sieves for dehydration and solvent filtration to ensure that the solvent used does not contain solid impurities;

[0015] According to the reaction amount, the thiophene compound is added to the solvent to be uniformly dissolved.

[0016] Preferably, the amination reaction using thiophene compounds as raw materials and using non-metallic nitrogen sources, including ammonia gas and ammonia water, specifically includes:

[0017] Selecting thiophene compounds, gaseous ammonia and water-soluble ammonia sources;

[0018] Select a mixed solvent of water and ethanol and use microwave-assisted heating technology to increase the reaction rate;

[0019] Ammonia water is added to the reaction system, the reaction temperature is controlled between 70-80°C, and the reaction is carried out in a green solvent system to fully dissolve the ammonia source and the thiophene compound. The ammonia source and the thiophene compound form an active intermediate in the solvent, and an amination reaction is carried out through nucleophilic attack to form an aminothiophene compound;

[0020] The pH value of the reaction system is maintained at 8-11 through acid-base adjustment, and a non-ionic surfactant is added to the reaction system to increase the contact area between the ammonia source and the thiophene compound.

[0021] Preferably, the reaction is carried out under the reaction conditions of a temperature range of 70-80° C. and a reaction time of 5-6 hours, specifically comprising:

[0022] The reaction time is between 5 and 6 hours, which is adjusted according to the reaction rate of the reactants;

[0023] Use real-time infrared spectroscopy online monitoring technology to monitor the reaction progress and automatically optimize the reaction time;

[0024] During the stirring process, ultrasonic stirring is used to improve the contact efficiency of the reactants, the power output is set, and a heating system with uniform temperature distribution is used to avoid local overheating;

[0025] An automated pH control system was introduced to adjust the pH in real time. During the reaction, samples were taken regularly by thin layer chromatography to analyze the reaction progress. The real-time pH adjustment formula was:

[0026] pH = pH set +ΔpH

[0027] Where, pH set is the set target pH value, and ΔpH is the pH change caused by the acid and base additives.

[0028] Preferably, the use of real-time infrared spectroscopy online monitoring technology to monitor the reaction progress and automatically optimize the reaction time specifically includes:

[0029] Use FTIR online monitoring, equipped with fiber optic connection, to collect infrared spectral data from the reactor in real time;

[0030] Add the substrate, catalyst and solvent to the reactor, set the initial temperature and pressure, start the reaction, and the FTIR instrument scans the solution in the reactor through a specific infrared wavelength range to capture the changes in the absorption peaks of the chemical substances during the reaction. FTIR can record these changes in real time;

[0031] The FTIR system sets the scanning frequency and automatically collects data at regular intervals;

[0032] By changing the FTIR spectrum, we can identify the changes in the characteristic absorption peaks of reactants and products, and infer the consumption rate of reactants and the generation rate of products by the changes in the intensity of the absorption peaks.

[0033] The absorbance is quantitatively analyzed by the standard curve method to obtain real-time data of the reaction process;

[0034] According to the FTIR data and concentration changes, the relationship curve between the reactant concentration and time is drawn, and the reaction time is fitted by analyzing the curve of the reactant concentration changing with time;

[0035] Automatically adjust reaction time based on changes in reaction rate constants and reactant concentrations.

[0036] Preferably, the automatic adjustment of the reaction time according to the change of the reaction rate constant and the reactant concentration specifically includes:

[0037] When the preset target concentration or the maximum product generation amount is reached, the FTIR system sends a signal to indicate that the reaction has reached the optimal point, thereby automatically stopping the reaction, optimizing the reaction time, and avoiding overreaction;

[0038] Combined with the PLC controller automatic control system, the real-time FTIR data is fed back to the control system of the reactor, and the heating and cooling rates are automatically adjusted according to the reaction progress;

[0039] Based on the reaction progress data, the optimal time point for the reaction is automatically calculated to maximize product yield.

[0040] Preferably, the optimal time point for automatically calculating the reaction using the maximized product yield specifically includes:

[0041] The optimal reaction time is solved by the gradient descent optimization algorithm, where the gradient descent optimization algorithm formula is:

[0042]

[0043] In the formula, t new is the updated time value, t oid is the current time value, δ is the learning rate, [A0] is the initial concentration of reactant A, k is the reaction rate constant, is the exponential decay term, and e is the base of the natural logarithm.

[0044] Preferably, after the reaction is completed, separation is performed by a purification method, including filtration, extraction and crystallization, specifically including:

[0045] Select filter paper and prepare filtering device according to the size of the solid matter to be separated;

[0046] The reaction solution is poured into a funnel, where solid impurities are trapped by the filter paper, resulting in a clear filtrate containing the target product dissolved in the liquid;

[0047] The reactants and by-products adhere to the solid matter, and the filter residue is washed with a solvent;

[0048] Use a separatory funnel to mix the reaction solution and the solvent. After shaking, let the mixture stand to form two layers of liquid. Use a separatory funnel to separate the different liquid layers, perform repeated extractions, and separate the pure target product from the solution by crystallization.

[0049] Preferably, the solvent is removed by suction filtration and vacuum drying to obtain the final 2-aminothiophene, and the product is identified to confirm its structure and purity, which specifically includes:

[0050] The filtered product is transferred to a vacuum dryer, and the temperature and vacuum conditions are set to gradually remove the solvent and accelerate the evaporation of the solvent;

[0051] The 2-aminothiophene product was identified to confirm its structure and purity.

[0052] Preferably, the identification and confirmation of the structure and purity of the 2-aminothiophene product specifically includes:

[0053] H NMR spectroscopy analysis:

[0054] Take a sample of 2-aminothiophene, dissolve it in a deuterated solvent, and measure the sample using a nuclear magnetic resonance spectrometer;

[0055] Observe the chemical shift of hydrogen atoms and confirm the characteristic signals of hydrogen atoms in the amino group and benzene ring in 2-aminothiophene;

[0056] The number of hydrogen atoms was inferred based on the relative peak areas of different hydrogen atoms;

[0057] The structure was further confirmed based on the coupling constants between hydrogen atoms;

[0058] The spectrum of 2-aminothiophene shows a signal of amino hydrogen in the 3-5 ppm range and a signal of aromatic hydrogen on the thiophene ring in the 7-8 ppm region;

[0059] Infrared spectroscopy analysis:

[0060] The sample was pressed into a thin film, dissolved in a solvent, and then scanned by an infrared spectrometer;

[0061] Observing the characteristic absorption peaks of the amino group and the thiophene ring, the IR spectrum of 2-aminothiophene shows the typical absorption peaks of the amino group and the thiophene ring;

[0062] Mass spectrometry analysis: The 2-aminothiophene sample was analyzed by a mass spectrometer to obtain a mass spectrum of its molecular weight and fragment ions;

[0063] According to different fragmentation patterns, different fragment ion peaks are observed to confirm their structures;

[0064] HPLC analysis:

[0065] The 2-aminothiophene sample is dissolved in a solvent and analyzed by HPLC. HPLC is used to detect the purity of the 2-aminothiophene sample and check whether there are impurity peaks. By comparing with the standard, the retention time of the target compound is confirmed. Pure 2-aminothiophene should show a single peak without other interfering peaks.

[0066] Melting point determination: The melting point of 2-aminothiophene was determined using a melting point apparatus. The melting point of 2-aminothiophene was 94-96°C, which was close to the value in the literature, indicating that the sample had a high purity.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The present invention proposes that green synthesis technology has significant advantages in synthesizing 2-aminothiophene, especially in terms of environmental friendliness, reaction efficiency, product purity, etc. By using a green solvent system and a non-metallic nitrogen source, and combining microwave heating, online monitoring and automatic control technology, the accuracy and efficiency of the reaction can be greatly improved, and energy consumption and environmental pollution can be reduced. In addition, the method optimizes the purification step and ensures the high purity and high yield of the final product, so it has great industrial application prospects and environmental significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a step flow framework diagram of the present invention. DETAILED DESCRIPTION

[0070] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0071] Reference Figure 1 As shown, a green synthesis method of 2-aminothiophene comprises:

[0072] Step 1:

[0073] First, a suitable green solvent system is selected, wherein the green solvent includes water and ethanol as the solvent for the reaction;

[0074] Use molecular sieves for dehydration and solvent filtration to ensure that the solvent used does not contain solid impurities;

[0075] According to the reaction amount, the thiophene compound is added to the solvent to be uniformly dissolved.

[0076] Step 2:

[0077] Selecting thiophene compounds, gaseous ammonia and water-soluble ammonia sources;

[0078] Select a mixed solvent of water and ethanol and use microwave-assisted heating technology to increase the reaction rate;

[0079] Ammonia water is added to the reaction system, the reaction temperature is controlled between 70-80°C, and the reaction is carried out in a green solvent system to fully dissolve the ammonia source and the thiophene compound. The ammonia source and the thiophene compound form an active intermediate in the solvent, and an amination reaction is carried out through nucleophilic attack to form an aminothiophene compound;

[0080] The pH value of the reaction system is maintained at 8-11 through acid-base adjustment, and a non-ionic surfactant is added to the reaction system to increase the contact area between the ammonia source and the thiophene compound.

[0081] Step 3:

[0082] The reaction time is between 5 and 6 hours, which is adjusted according to the reaction rate of the reactants;

[0083] Use FTIR online monitoring, equipped with fiber optic connection, to collect infrared spectral data from the reactor in real time;

[0084] Add the substrate, catalyst and solvent to the reactor, set the initial temperature and pressure, start the reaction, and the FTIR instrument scans the solution in the reactor through a specific infrared wavelength range to capture the changes in the absorption peaks of the chemical substances during the reaction. FTIR can record these changes in real time;

[0085] The FTIR system sets the scanning frequency and automatically collects data at regular intervals;

[0086] By changing the FTIR spectrum, we can identify the changes in the characteristic absorption peaks of reactants and products, and infer the consumption rate of reactants and the generation rate of products by the changes in the intensity of the absorption peaks.

[0087] The absorbance is quantitatively analyzed by the standard curve method to obtain real-time data of the reaction process;

[0088] According to the FTIR data and concentration changes, the relationship curve between the reactant concentration and time is drawn, and the reaction time is fitted by analyzing the curve of the reactant concentration changing with time;

[0089] Automatically adjust the reaction time according to the changes in the reaction rate constant and reactant concentration;

[0090] When the preset target concentration or the maximum product generation amount is reached, the FTIR system sends a signal to indicate that the reaction has reached the optimal point, thereby automatically stopping the reaction, optimizing the reaction time, and avoiding overreaction;

[0091] Combined with the PLC controller automatic control system, the real-time FTIR data is fed back to the control system of the reactor, and the heating and cooling rates are automatically adjusted according to the reaction progress;

[0092] Based on the data of reaction progress, the optimal time point of the reaction is automatically calculated using the maximum product yield;

[0093] The optimal reaction time is solved by the gradient descent optimization algorithm, where the gradient descent optimization algorithm formula is:

[0094]

[0095] In the formula, t new is the updated time value, t oid is the current time value, δ is the learning rate, [A0] is the initial concentration of reactant A, k is the reaction rate constant, is the exponential decay term, and e is the base of the natural logarithm;

[0096] During the stirring process, ultrasonic stirring is used to improve the contact efficiency of the reactants, the power output is set, and a heating system with uniform temperature distribution is used to avoid local overheating;

[0097] An automated pH control system was introduced to adjust the pH in real time. During the reaction, samples were taken regularly by thin layer chromatography to analyze the reaction progress. The real-time pH adjustment formula was:

[0098] pH = pH set +ΔpH

[0099] Where, pH set is the set target pH value, and ΔpH is the pH change caused by the acid and base additives.

[0100] Step 4:

[0101] Select filter paper and prepare filtering device according to the size of the solid matter to be separated;

[0102] The reaction solution is poured into a funnel, where solid impurities are trapped by the filter paper, resulting in a clear filtrate containing the target product dissolved in the liquid;

[0103] The reactants and by-products adhere to the solid matter, and the filter residue is washed with a solvent;

[0104] Use a separatory funnel to mix the reaction solution and the solvent. After shaking, let the mixture stand to form two layers of liquid. Use a separatory funnel to separate the different liquid layers, perform repeated extractions, and separate the pure target product from the solution by crystallization.

[0105] Step 5:

[0106] The filtered product is transferred to a vacuum dryer, and the temperature and vacuum conditions are set to gradually remove the solvent and accelerate the evaporation of the solvent;

[0107] The 2-aminothiophene product was identified to confirm its structure and purity.

[0108] Preferably, the identification and confirmation of the structure and purity of the 2-aminothiophene product specifically includes:

[0109] H NMR spectroscopy analysis:

[0110] Take a sample of 2-aminothiophene, dissolve it in a deuterated solvent, and measure the sample using a nuclear magnetic resonance spectrometer;

[0111] Observe the chemical shift of hydrogen atoms and confirm the characteristic signals of hydrogen atoms in the amino group and benzene ring in 2-aminothiophene;

[0112] The number of hydrogen atoms was inferred based on the relative peak areas of different hydrogen atoms;

[0113] The structure was further confirmed based on the coupling constants between hydrogen atoms;

[0114] The spectrum of 2-aminothiophene shows a signal of amino hydrogen in the 3-5 ppm range and a signal of aromatic hydrogen on the thiophene ring in the 7-8 ppm region;

[0115] Infrared spectroscopy analysis:

[0116] The sample was pressed into a thin film, dissolved in a solvent, and then scanned by an infrared spectrometer;

[0117] Observing the characteristic absorption peaks of the amino group and the thiophene ring, the IR spectrum of 2-aminothiophene shows the typical absorption peaks of the amino group and the thiophene ring;

[0118] Mass spectrometry analysis: The 2-aminothiophene sample was analyzed by a mass spectrometer to obtain a mass spectrum of its molecular weight and fragment ions;

[0119] According to different fragmentation patterns, different fragment ion peaks are observed to confirm their structures;

[0120] HPLC analysis:

[0121] The 2-aminothiophene sample is dissolved in a solvent and analyzed by HPLC. HPLC is used to detect the purity of the 2-aminothiophene sample and check whether there are impurity peaks. By comparing with the standard, the retention time of the target compound is confirmed. Pure 2-aminothiophene should show a single peak without other interfering peaks.

[0122] Melting point determination: The melting point of 2-aminothiophene was determined using a melting point apparatus. The melting point of 2-aminothiophene was 94-96°C, which was close to the value in the literature, indicating that the sample had a high purity.

[0123] In summary, the advantages of the present invention are:

[0124] By choosing water and ethanol as reaction solvents, the use of toxic and harmful solvents is avoided, which conforms to the principle of green chemistry. This solvent system has the advantages of low toxicity, good biodegradability and low cost.

[0125] Using non-metallic nitrogen sources such as ammonia gas or ammonia water to replace traditional metal catalysts or nitrogen sources avoids metal pollution problems and helps reduce by-products in the reaction process;

[0126] Microwave-assisted heating can accelerate the reaction rate and improve the selectivity of the product. Microwave heating has the characteristics of rapid and uniform heating, which can effectively avoid side reactions caused by uneven temperature, thereby improving the overall efficiency of the reaction.

[0127] Combined with ultrasonic stirring and uniform heating system, the contact efficiency of reactants can be further improved, making the reaction more efficient;

[0128] Using FTIR technology to monitor the changes in absorption peaks during the reaction in real time can accurately track the progress of the reaction, optimize the reaction time in a timely manner, avoid overreaction, and improve product quality and yield;

[0129] Through the automated pH control system, the pH value of the reaction system can be adjusted in real time to ensure the smooth progress of the amination reaction. Combined with the real-time data feedback of FTIR, the PLC controller can automatically adjust the heating and cooling rates of the reactor, making the reaction process more precise, further improving the reaction efficiency, and reducing energy consumption;

[0130] After the reaction is completed, a multi-step purification method such as filtration, extraction and crystallization is used to effectively remove impurities and ensure the purity of the final product. The solvent is removed by vacuum drying to avoid the influence of solvent residue on the purity of the product, thereby obtaining high-purity 2-aminothiophene;

[0131] The product was identified for structure and purity using modern analytical techniques such as nuclear magnetic resonance hydrogen spectrum, infrared spectrum, mass spectrometry and high performance liquid chromatography to ensure product quality. The purity of 2-aminothiophene was further confirmed by melting point determination and compared with literature values ​​to ensure that its quality met the requirements.

[0132] By optimizing the solvent system and reaction conditions, not only can the use and generation of harmful substances be reduced, but also the pollution to the environment can be reduced, which meets the requirements of sustainable development. The automated control and real-time monitoring systems can reduce experimental errors and operational complexity, reduce production costs, and improve the feasibility of industrial production.

[0133] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A green synthesis method of 2-aminothiophene, characterized in that: include: Use green solvent system as reaction medium; Using thiophene compounds as raw materials, adopting an amination reaction, using non-metallic nitrogen sources, including ammonia gas and ammonia water, to carry out an amination reaction; The reaction is carried out under the reaction conditions of a temperature range of 70-80°C and a reaction time of 5-6 hours. The reaction progress is monitored using FTIR online monitoring technology. Combined with the PLC controller automatic control system, the FTIR real-time data is fed back to the control system of the reactor, and the heating and cooling rates are automatically adjusted according to the reaction progress. After the reaction is complete, it is separated by purification methods, including filtration, extraction and crystallization; The solvent was removed by suction filtration and vacuum drying to obtain the final 2-aminothiophene, and the product was identified to confirm its structure and purity.

2. A green synthesis method of 2-aminothiophene according to claim 1, characterized in that: The green solvent system used as the reaction medium specifically includes: First, a suitable green solvent system is selected, wherein the green solvent includes water and ethanol as the solvent for the reaction; Use molecular sieves for dehydration and solvent filtration to ensure that the solvent used does not contain solid impurities; According to the reaction amount, the thiophene compound is added to the solvent to be uniformly dissolved.

3. A green synthesis method of 2-aminothiophene according to claim 2, characterized in that: The method of using thiophene compounds as raw materials, adopting an amination reaction, and using a non-metallic nitrogen source, including ammonia gas and ammonia water, to carry out an amination reaction specifically includes: Selecting thiophene compounds, gaseous ammonia and water-soluble ammonia sources; Select a mixed solvent of water and ethanol and use microwave-assisted heating technology to increase the reaction rate; Ammonia water is added to the reaction system, the reaction temperature is controlled between 70-80°C, and the reaction is carried out in a green solvent system to fully dissolve the ammonia source and the thiophene compound. The ammonia source and the thiophene compound form an active intermediate in the solvent, and an amination reaction is carried out through nucleophilic attack to form an aminothiophene compound; The pH value of the reaction system is maintained at 8-11 through acid-base adjustment, and a non-ionic surfactant is added to the reaction system to increase the contact area between the ammonia source and the thiophene compound.

4. A green synthesis method of 2-aminothiophene according to claim 3, characterized in that: The reaction under the reaction conditions of a temperature range of 70-80° C. and a reaction time of 5-6 hours specifically includes: The reaction time is between 5 and 6 hours, which is adjusted according to the reaction rate of the reactants; Use real-time infrared spectroscopy online monitoring technology to monitor the reaction progress and automatically optimize the reaction time; During the stirring process, ultrasonic stirring is used to improve the contact efficiency of the reactants, the power output is set, and a heating system with uniform temperature distribution is used to avoid local overheating; An automated pH control system was introduced to adjust the pH in real time. During the reaction, samples were taken regularly by thin layer chromatography to analyze the reaction progress. The real-time pH adjustment formula was: pH=pH set +ΔpH Where, pH set is the set target pH value, and ΔpH is the pH change caused by the acid and base additives.

5. A green synthesis method of 2-aminothiophene according to claim 4, characterized in that: The use of real-time infrared spectroscopy online monitoring technology to monitor the reaction process and automatically optimize the reaction time specifically includes: Use FTIR online monitoring, equipped with fiber optic connection, to collect infrared spectral data from the reactor in real time; Add the substrate, catalyst and solvent to the reactor, set the initial temperature and pressure, start the reaction, and the FTIR instrument scans the solution in the reactor through a specific infrared wavelength range to capture the changes in the absorption peaks of the chemical substances during the reaction. FTIR can record these changes in real time; The FTIR system sets the scanning frequency and automatically collects data at regular intervals; By changing the FTIR spectrum, we can identify the changes in the characteristic absorption peaks of reactants and products, and infer the consumption rate of reactants and the generation rate of products by the changes in the intensity of the absorption peaks. The absorbance is quantitatively analyzed by the standard curve method to obtain real-time data of the reaction process; According to the FTIR data and concentration changes, the relationship curve between the reactant concentration and time is drawn, and the reaction time is fitted by analyzing the curve of the reactant concentration changing with time; Automatically adjust reaction time based on changes in reaction rate constants and reactant concentrations.

6. A green synthesis method of 2-aminothiophene according to claim 5, characterized in that: The automatic adjustment of the reaction time according to the change of the reaction rate constant and the reactant concentration specifically includes: When the preset target concentration or the maximum product generation amount is reached, the FTIR system sends a signal to indicate that the reaction has reached the optimal point, thereby automatically stopping the reaction, optimizing the reaction time, and avoiding overreaction; Combined with the PLC controller automatic control system, the real-time FTIR data is fed back to the control system of the reactor, and the heating and cooling rates are automatically adjusted according to the reaction progress; Based on the reaction progress data, the optimal time point for the reaction is automatically calculated to maximize product yield.

7. A green synthesis method of 2-aminothiophene according to claim 6, characterized in that: The method of automatically calculating the optimal time point of the reaction based on the data of the reaction process using the maximized product yield specifically includes: The optimal reaction time is solved by the gradient descent optimization algorithm, where the gradient descent optimization algorithm formula is: Where, t new is the updated time value, t oid is the current time value, δ is the learning rate, [A0] is the initial concentration of reactant A, k is the reaction rate constant, is the exponential decay term, and e is the base of the natural logarithm.

8. A green synthesis method of 2-aminothiophene according to claim 7, characterized in that: After the reaction is completed, separation is performed by a purification method, including filtration, extraction and crystallization, specifically including: Select filter paper and prepare filtering device according to the size of the solid matter to be separated; The reaction solution is poured into a funnel, where solid impurities are trapped by the filter paper, resulting in a clear filtrate containing the target product dissolved in the liquid; The reactants and by-products adhere to the solid matter, and the filter residue is washed with a solvent; Use a separatory funnel to mix the reaction solution and the solvent. After shaking, let the mixture stand to form two layers of liquid. Use a separatory funnel to separate the different liquid layers, perform repeated extractions, and separate the pure target product from the solution by crystallization.

9. A green synthesis method of 2-aminothiophene according to claim 8, characterized in that: The solvent is removed by suction filtration and vacuum drying to obtain the final 2-aminothiophene, and the product is identified to confirm its structure and purity, which specifically includes: The filtered product is transferred to a vacuum dryer, and the temperature and vacuum conditions are set to gradually remove the solvent and accelerate the evaporation of the solvent; The 2-aminothiophene product was identified to confirm its structure and purity.

10. A green synthesis method of 2-aminothiophene according to claim 9, characterized in that: The identification and confirmation of the structure and purity of the 2-aminothiophene product specifically includes: nuclear magnetic resonance hydrogen spectrum analysis, infrared spectrum analysis, mass spectrum analysis, high performance liquid chromatography analysis and melting point determination.

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