A method for synthesizing an organic amine

Abstract

The application discloses a synthesis method of an organic amine, which comprises the following steps: under the condition that a reducing agent and a catalyst exist, performing a reduction reaction on a reactant to generate the organic amine; wherein the reactant is selected from nitro compounds or nitrile compounds; and the reducing agent and the catalyst are physically contacted and combined together in the process of the reduction reaction. In the synthesis method, the reaction system can complete the conversion of nitro groups and cyano groups into amino groups under normal temperature and pressure, the composition and device structure are simple, and the synthesis method provides a convenient and efficient path for the synthesis of the organic amine.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology. More specifically, it relates to a method for synthesizing organic amines. Background Technology

[0002] Organic amines are an important class of nitrogen-containing compounds used in the manufacture of pesticides, dyes, pharmaceuticals, and surfactants. Industrially, organic amines are mainly synthesized through alcohol amination, aldehyde / ketone reductive amination, catalytic hydrogenation of nitro compounds, and iron powder reduction of nitro compounds. Among these, alcohol amination, reductive amination, and catalytic hydrogenation require high temperatures and pressures, consuming large amounts of fossil fuels and posing significant safety hazards. Iron powder reduction requires strongly acidic media, generating substantial waste and exhibiting poor atom economy. Achieving green synthesis of organic amines under mild conditions is a continuous pursuit of both academia and industry. Utilizing electrical or light energy to continuously provide electrons to catalysts, driving the reduction reactions of nitro or nitrile compounds, has broken through the limitations of synthesizing organic amines at room temperature and pressure. Currently, the synthesis of organic amines relies on continuous and substantial external energy inputs such as heat, light, and electricity. How to achieve efficient synthesis of organic amines under mild conditions remains a critical problem that urgently needs to be solved. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a method for efficiently producing organic amines under normal temperature and pressure conditions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: On one hand, the present invention provides a method for synthesizing organic amines, comprising the following steps: Under the presence of a reducing agent and a catalyst, the reactants undergo a reduction reaction to produce organic amines; The reactants are selected from nitro compounds or nitrile compounds; During the reduction reaction, the reducing agent and the catalyst come into physical contact and combine.

[0005] Further, the nitro compound is selected from aliphatic and / or aromatic compounds containing one or more nitro groups. Exemplary examples include, but are not limited to, nitromethane, nitrobenzene, 1,3-dinitrobenzene, 4-nitrotoluene, 2-nitrochlorobenzene, 4-nitrochlorobenzene, 4-nitroanisole, 4-nitrotrifluorotoluene, 4-nitroaniline, 4-nitrobenzyl alcohol, 2-nitrobiphenyl, 2-bromo-5-fluoronitrobenzene, 2-bromo-5-chloronitrobenzene, 2-bromo-3-nitrotoluene, etc.

[0006] Further, the nitrile compounds are selected from aliphatic and / or aromatic compounds containing one or more cyano groups. Exemplary examples include, but are not limited to, acetonitrile, cyclopropionitrile, benzonitrile, 4-methylphenylacetonitrile, 1-pentanitrile, cyclobutanitrile, 1,3-malonidonitrile, 1,4-butanitrile, 1,5-pentanitrile, 1,6-adiponitrile, 2-chlorobenzonitrile, 2-aminobenzonitrile, 4-fluorobenzonitrile, 4-methylbenzonitrile, 2,4-difluorobenzonitrile, 2-chloro-4-fluorobenzonitrile, 2-aminophenylacetonitrile, 4-methylphenylacetonitrile, etc.

[0007] Furthermore, the reactants are dissolved in a solvent to form a solution before undergoing a reduction reaction, wherein... The solvent is water, an organic solvent, or a mixture of water and an organic solvent; The concentration of the reactants in the solution is 0.001 mol / L. -1 Between the concentrations of the target concentration and the saturation concentration.

[0008] Furthermore, the organic solvent is chosen to effectively dissolve the reaction substrate, is miscible with water to form a homogeneous and transparent solution, and is not prone to reaction itself, such as methanol, ethanol, isopropanol, ethylene glycol dimethyl ether, tetrahydrofuran, etc.

[0009] For example, in the mixture of water and organic solvent, the volume fraction of water is between 0% and 100%, but does not include 100%.

[0010] Furthermore, the solution is weakly acidic, alkaline, or neutral. By controlling the acidity or alkalinity of the solution, the oxidizing agent can be continuously oxidized, providing electrons for the reaction and suppressing side reactions, ensuring that nitro compounds or nitrile compounds are efficiently and selectively reduced to organic amines.

[0011] Furthermore, the acidity or alkalinity of the solution can be adjusted by adding a pH adjuster. For example, the pH adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, acetic acid, sodium acetate, sodium dihydrogen phosphate, and sodium monohydrogen phosphate.

[0012] Preferably, the solution is alkaline, and the solution contains OH-. - Concentration at 0.2 mol L -1 That's all. Sufficient OH- - It can initiate rapid electron transfer, efficiently completing the multi-electron conversion from nitro and cyano groups to amino groups: R-NO2+6e - +4H₂O→R-NH₂+6OH - ;R-CN+4e - +4H₂O→R-CH₂NH₂+4OH - For preferred reducing agents (e.g., aluminum), it reacts under strongly alkaline conditions (Al–3e).- +4OH - →Al(OH)4 - OH provides electrons to the system. - Concentration is the key factor determining the rate of electron transport. In OH... - When the concentration is insufficient, the oxidation of the reducing agent is slow, severely hindering electron transfer and negatively impacting the reduction reactions of nitro and cyano groups. Near neutral conditions, reducing agents, such as aluminum, undergo the reaction Al–3e⁻. - +3OH - →Al(OH)3, forming Al(OH)3, which is sparingly soluble in water, covering the aluminum surface and hindering aluminum oxidation, thus preventing the reaction from continuing. Under acidic conditions, aluminum can undergo the reaction Al–3e-. - →Al 3+ However, this reaction requires a strongly acidic environment to reach an acceptable rate. In this environment, the proton reduction reaction competes with the reduction of nitro or cyano groups, leading to a significant decrease in reaction selectivity. Therefore, the preferred reaction conditions are strongly alkaline (OH- in the solution). - Concentration at 0.2 mol L -1 (Above) and below.

[0013] Furthermore, the work function of the reducing agent is lower than that of the catalyst, and The reduction potential of the reducing agent is lower than that of the catalyst compared to RHE.

[0014] Under these conditions, electrons can be directionally transferred from the reducing agent to the catalyst. This method utilizes the difference in work function between the reducing agent and the catalyst to induce electron transfer from the reducing agent to the catalyst, driving the reduction of nitro (-NO2) or cyano (-CN) groups adsorbed on the catalyst surface to amino (-NH2), thereby achieving the synthesis of organic amines.

[0015] Furthermore, the work function of the reducing agent is below 4.5 eV, and the reduction potential is below -0.5 V relative to RHE; Furthermore, the reducing agent is selected from one or more of elemental aluminum, magnesium, gallium, and zinc, alloys of two or more of them, or composites of two or more of them. In this case, the spontaneous and directional electron transfer from the reducing agent to the catalyst is even better.

[0016] Preferably, the reducing agent is any one of elemental aluminum, an alloy, or a composite material. The advantages of using aluminum as a reducing agent are its wide availability, low cost, strong driving force for the reduction reaction, and the large number of electrons provided per unit mass of aluminum, thus ensuring efficient and continuous electron supply for the reaction.

[0017] Furthermore, the reducing agent has a large surface area, a smooth surface, and a shape that is easy to spread and bend. Taking aluminum as an example, its source can be high-purity aluminum foil, aluminum wire, or waste aluminum cans, lunch boxes, and packaging paper, to achieve resource utilization of waste metals. If there are oxides on the surface of these reducing agents, the oxides on the surface of the reducing agent will be dissolved first during the reaction process, so they have no effect on the reaction and no pretreatment operations such as grinding or polishing are required.

[0018] Furthermore, the catalyst has a work function above 4.2 eV and a reduction potential below 0.5 V relative to RHE.

[0019] Furthermore, the catalyst is selected from elemental iron, copper, titanium, lead, carbon, or... Alloys of two or more of the following: iron, copper, titanium, lead, and carbon, or Copper-zinc alloy One or more of them.

[0020] By selecting the appropriate catalyst, this method achieves high yield and selectivity in the synthesis of organic amines.

[0021] Furthermore, the reactants are nitro compounds, and in the reaction of reducing nitro compounds to synthesize organic amines, the catalyst is selected from iron or copper-zinc alloys (e.g., H62 brass, where the mass fractions of Cu and Zn are 62% and 38%, respectively). Under these conditions, the method exhibits optimal selectivity and yield for the synthesis of organic amines.

[0022] Furthermore, the reactants are cyano compounds, and in the reaction of reducing cyano compounds to synthesize organic amines, the catalyst is selected from copper-zinc alloys (e.g., H62 brass, where the mass fractions of Cu and Zn are 62% and 38%, respectively). Under these conditions, the method exhibits optimal selectivity and yield for organic amines.

[0023] Furthermore, the catalyst has a large surface area, a flat and clean surface, stable chemical properties, and a regular shape, such as stainless steel mesh or brass sheet; the oxide layer on the surface can be removed by grinding, polishing, or other methods before use.

[0024] Furthermore, the catalyst includes, but is not limited to, physical bonding with the reducing agent in the form of metal foil, metal rod, metal block, or metal strip. Preferably, the catalyst is physically bonded with the reducing agent in the form of metal foil, which results in higher reaction efficiency.

[0025] Furthermore, the physical contact bonding method includes, but is not limited to, entanglement. It can be understood that in solution, the reducing agent and the catalyst maintain a state of physical contact bonding.

[0026] Furthermore, the area of ​​the reducing agent bonded to the catalyst is 0-100% of the catalyst area, excluding 0% and 100%. By controlling the area of ​​the physical contact between the reducing agent and the catalyst, the electron transfer rate during the reaction can be effectively improved.

[0027] Furthermore, the area of ​​physical contact between the reducing agent and the catalyst is, but is not limited to, 0.1%~95%, 0.1%~90%, 1%~80%, 1%~60%, 1%~40% of the catalyst area.

[0028] Furthermore, the contact area between the catalyst and the solution is 0% to 100% of the catalyst area, excluding 0% and 100%. By controlling the contact area between the catalyst and the solution, the yield of synthesized organic amines can be significantly improved.

[0029] Furthermore, the contact area between the reducing agent and the solution is 1% to 100% of the reducing agent's area.

[0030] Furthermore, in the method of the present invention, the amount of catalyst and reducing agent used is sufficient to ensure that the reaction proceeds completely. In some preferred embodiments, the catalyst and reducing agent are completely immersed in the solution.

[0031] Furthermore, the reaction temperature is from 0 °C to the boiling point of the solvent to ensure that the solution does not solidify due to excessively low temperature or volatilize due to excessively high temperature.

[0032] Preferably, the reaction of reducing nitro compounds to synthesize organic amines is carried out at room temperature (20~30 °C). Heat is released during the reaction, causing the reaction rate to accelerate significantly after a period of time. Therefore, this reaction does not require heating. If necessary, the rate of addition of the reducing agent can be controlled, the contact area between the reducing agent / catalyst and the reaction solution can be reduced, or the reaction system can be cooled to prevent the volatilization of reaction components due to excessively high temperatures.

[0033] Preferably, alkyl nitriles, including acetonitrile, are not easily hydrolyzed, and the reaction is carried out at room temperature (20~30 °C).

[0034] Preferably, aryl nitriles such as benzonitrile are readily hydrolyzed, and the reaction is preferably carried out at 5 °C to suppress the side reaction of nitrile hydrolysis to form amides.

[0035] The method described in this invention does not require inert gas protection and can operate in an open air atmosphere.

[0036] Furthermore, the reaction time ranges from 5 minutes to 100 hours, with the specific reaction time determined by factors such as the reaction scale, the concentration of each component of the raw materials, and the contact area of ​​the solution.

[0037] Furthermore, the method also includes the steps of extracting the product into an organic phase after the reaction, and then further drying, concentrating, performing column chromatography, and recrystallizing to obtain a high-purity product.

[0038] The beneficial effects of this invention are as follows: 1) In the synthesis method provided by the present invention, the reaction system completes the conversion of nitro and cyano groups to amino groups at room temperature and pressure. The composition and device structure are simple, providing a convenient and efficient route for the synthesis of organic amines. 2) In the method provided by the present invention, the raw materials are inexpensive and readily available, and widely available metal materials are used as reducing agents and catalysts, thereby reducing the production cost of organic amines; 3) The method provided by this invention realizes the synthesis of various nitro compounds and nitrile compounds into organic amines, exhibiting excellent yield, stability and structural universality, and has high application value. Attached Figure Description

[0039] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0040] Figure 1 A photograph showing the tightly bound reducing agent (aluminum foil) and catalyst (brass sheet).

[0041] Figure 2 The product aniline is shown 1 H NMR.

[0042] Figure 3 The product aniline is shown 13 C NMR.

[0043] Figure 4 The product 4-methylaniline is shown. 1 H NMR.

[0044] Figure 5 The product 4-methylaniline is shown. 13 C NMR.

[0045] Figure 6 This shows the reduction of nitromethane to monomethylamine. 1 H NMR.

[0046] Figure 7 The yields of 1 ethylamine are shown for different acetonitrile concentrations.

[0047] Figure 8 Showing monoethylamine sulfate 1 H NMR.

[0048] Figure 9 Showing monoethylamine sulfate 13 C NMR.

[0049] Figure 10 The yields of 1,4-butanediamine at different concentrations of 1,4-butanedione are shown.

[0050] Figure 11 The product benzylamine is shown. 1 H NMR.

[0051] Figure 12 The product benzylamine is shown. 13 C NMR. Detailed Implementation

[0052] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1 A method for synthesizing aniline under mild conditions, the specific steps of which are as follows: Cut a 10 cm long, 2 cm wide H62 brass sheet (0.04 mm thick) with scissors. Tightly wrap a 12 cm long, 1 cm wide, 0.018 mm thick aluminum foil around the brass sheet (e.g., ...). Figure 1 As shown in the figure, the aluminum foil was inserted into 40 mL of a solution containing 0.05 M nitrobenzene and 1.0 M NaOH in a water:methanol (volume ratio) ratio of 3:1, and the reaction was started at room temperature (25 °C). When the aluminum foil was completely dissolved, a new aluminum foil was placed over and wrapped around a brass sheet, and the sheet was completely immersed in the reaction solution to continue the reaction. When 1.0 g of Al foil was consumed, the nitrobenzene was completely consumed, and the only organic product was aniline.

[0054] In this example, the conversion rate of nitrobenzene was 100%, and the yield of aniline was 100%.

[0055] Example 2 The specific steps for synthesizing aniline under mild conditions are as follows: The reducing agent was replaced with 1.0 g Mg from Al foil and inserted into 40 mL of a solution containing 0.05 M nitrobenzene, 0.9 M acetic acid, and 0.1 M sodium acetate in a water:methanol (volume ratio) of 3:1 (initial pH=4). Other conditions and steps were the same as in Example 1, and the yield of aniline was 44%.

[0056] Example 3 The specific steps for synthesizing aniline under mild conditions are as follows: The catalyst was replaced with an iron sheet measuring 10 cm in length and 2 cm in width from H62 brass sheet. Other conditions and steps were the same as in Example 1, and the yield of aniline was 100%.

[0057] Example 4 The specific steps for synthesizing aniline under mild conditions are as follows: The catalyst was replaced with a 20 cm long and 0.6 cm diameter lead rod, and other conditions and steps were the same as in Example 1. The yield of aniline was 94%.

[0058] Example 5 The specific steps for synthesizing aniline under mild conditions are as follows: The reaction was scaled up to 800 mL, with other conditions and steps the same as in Example 1. The resulting mixture was extracted five times with 200 mL of dichloromethane. The organic phases were dried, combined, and concentrated. Silica gel column chromatography with petroleum ether:ethyl acetate (volume ratio) = 10:1 yielded 2.30 g of a golden-yellow liquid, with a yield of 85%.

[0059] 1 H NMR (400 MHz, CDCl3) δ 7.22 (t, J = 7.7 Hz, 2H), 6.82 (t, J = 7.5 Hz, 1H), 6.73 (d, J = 7.8 Hz, 2H), 3.64 (s, 2H), such as Figure 2 As shown.

[0060] 13 C NMR (101 MHz, CDCl3) δ 146.81, 129.65, 118.88, 115.48, as shown Figure 3 As shown, the structure is consistent with the expected structure, proving that high-purity aniline was obtained, indicating that the reaction can be scaled up to the gram scale.

[0061] Example 6 The specific steps for synthesizing 4-methylaniline under mild conditions are as follows: 2.76 g of 4-nitrotoluene (20 mmol) was dissolved in 50 mL of ethanol and mixed with 400 mL of 1.0 M NaOH aqueous solution, and stirred to form a homogeneous and transparent solution. Three sets of aluminum foil, each 15 cm long, 1 cm wide, and 0.018 mm thick, were tightly wound around a brass sheet 20 cm long and 10 cm wide and immersed in the solution. The reaction was initiated at room temperature (25 °C). After the aluminum foil was completely dissolved, new aluminum foil was replaced and wound around the brass sheet, and the sheet was completely immersed in the reaction solution to continue the reaction until 15.4 g of Al was consumed, at which point the reaction was complete. The reaction solution was extracted five times with 200 mL of dichloromethane. The organic phases were combined, dried, concentrated, and subjected to silica gel column chromatography (using n-hexane:ethyl acetate (volume ratio) = 5:1) to obtain 693 mg of yellow solid, with a yield of 32%.

[0062] 1 H NMR (400 MHz, CDCl3) δ 6.99 (d, J = 7.7 Hz, 2H), 6.69-6.57 (m, 2H), 3.54 (s, 2H), 2.27 (d, J = 2.3 Hz, 3H), such as Figure 4 As shown.

[0063] 13 C NMR (101 MHz, CDCl3) δ 144.26, 130.20, 128.24, 115.72, 20.86, as shown Figure 5 As shown, the structure is consistent with the expected structure, proving that high-purity 4-methylaniline has been obtained.

[0064] Example 7 A method for synthesizing monomethylamine under mild conditions, the specific steps of which are as follows: A 12 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wound around a 10 cm long and 2 cm wide brass sheet. The sheet was then immersed in 40 mL of an aqueous solution containing 0.1 M nitromethane and 1.0 M NaOH, and the reaction was initiated at room temperature (25 °C). When the aluminum foil was completely dissolved, new aluminum foil was placed over and wound around the brass sheet, completely immersing it in the reaction solution to continue the reaction. After 1.0 g of Al foil was consumed, 1 ¹H NMR showed that nitromethane was completely consumed, with the only product being monomethylamine. Figure 6 In this example, the conversion rate of nitromethane was 100%, and the yield of monomethylamine was 100%.

[0065] Example 8 A method for synthesizing monomethylamine under mild conditions, the specific steps of which are as follows: 1.0 mL of nitromethane (18.6 mmol) was dissolved in 240 mL of 1.0 M NaOH aqueous solution. A discarded 330 mL standard aluminum can (115 mm high, 66 mm in diameter) was washed and cut along its height, leaving the side of the can. The surface coating was removed with sandpaper as a reducing agent (5.6 g). The can was tightly wrapped around a 20 cm long and 10 cm wide brass sheet and completely immersed in the reaction solution. The reaction was started at room temperature (25 °C). The reaction was stopped after the aluminum can was completely dissolved. Taking advantage of the volatility of the product monomethylamine, the reaction system was purged with an air flow of 20 mL / min at 70 °C for 2 h. The exhaust gas was absorbed with 0.5 equivalent H2SO4 to obtain 0.88 g of white solid, which was monomethylamine sulfate, with a yield of 59%.

[0066] Examples 9-20 A method for synthesizing organic amines under mild conditions, the specific steps of which are as follows: 1.00 mmol of the nitro compound was dissolved in 10 mL of ethanol and mixed with 30 mL of 1.0 M NaOH aqueous solution, stirring to form a homogeneous and transparent solution. A 10 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wrapped around a 10 cm long and 2 cm wide iron sheet and immersed in the solution. The reaction was initiated at room temperature (25 °C). After the aluminum foil completely dissolved, a new aluminum foil was replaced and wrapped around the iron sheet, then the iron sheet was completely immersed in the reaction solution to continue the reaction until 1.2 g of Al was consumed, at which point the reaction was terminated. The reaction products were analyzed by GC-MS, and the results are shown in Table 1.

[0067] Table 1 shows the conversion rates of different nitro compounds and the yields of organic amines.

[0068] Examples 21-28 A method for synthesizing monoethylamine under mild conditions, the specific steps of which are as follows: A 12 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wound around a 10 cm long and 2 cm wide brass sheet and inserted into 40 mL of an aqueous solution containing acetonitrile and 1.0 M NaOH at different concentrations. The reaction was initiated at room temperature (25 °C). The concentrations of acetonitrile in each example were as follows: 47 mM (Example 21) 95 mM (Example 22) 143 mM (Example 23) 190 mM (Example 24) 237 mM (Example 25) 283 mM (Example 26) 375 mM (Example 27) 467 mM (Example 28) When the aluminum foil is completely dissolved, new aluminum foil is placed over and wrapped around the brass sheet, then completely immersed in the reaction solution to continue the reaction; the reaction is terminated after 1.0 g of Al foil has been consumed. The relationship between the yield of monoethylamine and the concentration of acetonitrile is as follows: Figure 7 As shown.

[0069] Example 29 The specific steps for synthesizing monoethylamine under mild conditions are as follows: The reaction in Example 27 was scaled up to 900 mL, and three polished aluminum cans (total mass 17.5 g) were used instead of aluminum foil as reducing agents; 105 mmol of monoethylamine was obtained, with a yield of 46%; taking advantage of the volatility of the product monoethylamine, the reaction system was heated to 70 °C and decanted at 20 L / min. -1 Air was introduced at a certain rate to separate the monoethylamine, which was then absorbed with 0.5 equivalents of sulfuric acid. The absorbent was evaporated at 50 °C and 20 mbar to obtain 9.86 g of white solid.

[0070] 1 H NMR (400 MHz, D2O) δ 3.05 (q, J = 7.7 Hz, 2H), 1.27 (t, J = 7.8 Hz, 3H), such as Figure 8 As shown.

[0071] 13 C NMR (101 MHz, D2O) δ 35.09, 11.96, as shown Figure 9 As shown, high-purity monoethylamine was obtained, indicating that the reaction can be scaled up to the ten-gram scale.

[0072] Examples 30-33 The specific steps for synthesizing 1,4-butanediamine under mild conditions are as follows: A 12 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wound around a 10 cm long and 2 cm wide brass sheet and immersed in 40 mL of an aqueous solution containing different concentrations of 1,4-butadionitrile and 1.0 M NaOH. The reaction was initiated at room temperature (25 °C). The concentrations of acetonitrile in each example were as follows: 25 mM (Example 30) 50 mM (Example 31) 75 mM (Example 32) 100 mM (Example 33). When the aluminum foil is completely dissolved, new aluminum foil is placed over and wrapped around the brass sheet, then completely immersed in the reaction solution to continue the reaction; the reaction is terminated after 1.0 g of Al foil has been consumed. The relationship between the yield of 1,4-butanediamine and the concentration of acetonitrile is as follows: Figure 10 As shown.

[0073] Example 34 The specific steps for synthesizing benzylamine under mild conditions are as follows: A 12 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wound around a 10 cm long and 2 cm wide brass sheet. The sheet was then immersed in 40 mL of a water:methanol (volume ratio) mixture containing 0.05 M benzonitrile and 1.0 M NaOH in a 3:1 ratio (water:methanol). The reaction was initiated at room temperature (25 °C). When the aluminum foil was completely dissolved, a new aluminum foil was placed over and wound around the brass sheet, which was then completely immersed in the reaction solution to continue the reaction. After 1.0 g of Al foil was consumed, GC-MS showed that the reaction was complete, with a yield of 59% for benzylamine and a byproduct benzamide with a yield of 41%.

[0074] Example 35 The specific steps for synthesizing benzylamine under mild conditions are as follows: Aluminum foil was tightly wrapped around a brass sheet and inserted into 40 mL of a water:methanol (volume ratio) mixture containing 0.05 M benzonitrile and 0.5 M NaOH in a ratio of 3:1. Other conditions were the same as in Example 34. The raw material benzonitrile was completely consumed, and the yield of benzylamine was 79%. The byproduct was benzamide, with a yield of 21%.

[0075] Example 36 The specific steps for synthesizing benzylamine under mild conditions are as follows: The reaction was carried out at 50 °C, with other conditions the same as in Example 35. The yield of benzylamine was 3%, and the yield of the byproduct benzamide was 49%.

[0076] Example 37 The specific steps for synthesizing benzylamine under mild conditions are as follows: The reaction was carried out at 5 °C, with other conditions the same as in Example 35. The yield of benzylamine was 94%, and no benzamide was formed.

[0077] Example 38 The specific steps for synthesizing benzylamine under mild conditions are as follows: A magnesium strip measuring 9 cm in length, 0.3 cm in width, and 0.04 mm in thickness was tightly wrapped around an iron sheet measuring 10 cm in length and 2 cm in width. The iron sheet was then immersed in 40 mL of a water:methanol (volume ratio) mixture containing 0.05 M benzonitrile and 1.0 M acetate buffer (pH=4) at a ratio of 3:1. When the magnesium strip was completely dissolved, a new magnesium strip was placed over and wrapped around the iron sheet, and the sheet was completely immersed in the reaction solution to continue the reaction. After consuming 0.40 g of magnesium strip, 331 μmol of benzylamine was produced, with a yield of 17%, and no other byproducts were obtained.

[0078] Example 39 The specific steps for synthesizing benzylamine under mild conditions are as follows: The catalyst was replaced with a copper sheet 10 cm long and 2 cm wide. Other conditions and steps were the same as in Example 38, yielding 198 μmol of benzylamine with a yield of 10% and no other byproducts.

[0079] Example 40 The specific steps for synthesizing benzylamine under mild conditions are as follows: The catalyst was replaced with an H62 brass sheet measuring 10 cm in length and 2 cm in width. Other conditions and steps were the same as in Example 38, yielding 531 μmol of benzylamine with a yield of 27% and no other byproducts.

[0080] Example 41 The specific steps for synthesizing benzylamine under mild conditions are as follows: The reaction described in Example 37 was scaled up 5 times, with all other conditions remaining the same. GC-MS showed that the reaction was complete, and the only organic product was benzylamine. To separate the obtained benzylamine, the reaction solution was extracted five times with 100 mL of dichloromethane. The organic phases were combined, dried, and concentrated to give 485 mg of a yellow liquid, with a yield of 93%.

[0081] 1 H NMR (400 MHz, CDCl3) δ 7.38-7.29 (m, 4H), 7.25 (t, J = 6.8 Hz, 1H), 3.86 (s, 2H), 1.42 (s, 2H), as Figure 11 As shown.

[0082] 13 C NMR (101 MHz, CDCl3) δ 145.40, 129.40, 129.26, 128.38, 128.02, 127.31, 46.96, as shown Figure 12 As shown, the structure is consistent with the expected structure, proving that high-purity benzylamine has been obtained. Examples 42-52 The specific steps for synthesizing organic amines under mild conditions are as follows: 1 mmol of a nitrile compound (as shown in Table 2) was dissolved in 10 mL of ethanol and mixed with 30 mL of 0.5 M NaOH aqueous solution to obtain a homogeneous and transparent solution. A 10 cm long, 1 cm wide, and 0.018 mm thick aluminum foil was tightly wound onto a 10 cm long and 2 cm wide H62 brass sheet and completely immersed in the reaction solution. The reaction was carried out at 5 °C. After the aluminum foil was completely dissolved, new aluminum foil was wound onto the brass sheet and immersed in the reaction solution to continue the reaction until 0.6 g of aluminum foil was consumed. The reaction products were analyzed by GC-MS, and the results are shown in Table 2.

[0083] Table 2 shows the yields of organic amines synthesized from the reduction of different nitrile compounds.

[0084] Comparative Example 1 The specific steps for synthesizing organic amines under mild conditions are as follows: Al foil and H62 brass sheet were placed in 40 mL of a water:methanol (volume ratio) mixture containing 0.05 M benzonitrile and 0.5 M NaOH, respectively, so that the Al foil and brass sheet did not come into contact. Other conditions and steps were the same as in Example 37. The yield of benzoylamine was 1%.

[0085] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for synthesizing an organic amine, characterized in that, Includes the following steps: The reactants are reduced in the presence of a reducing agent and a catalyst to produce organic amines; The reactants are selected from nitro compounds or nitrile compounds; During the reduction reaction, the reducing agent and the catalyst come into physical contact and combine.

2. The synthesis method according to claim 1, characterized in that, The nitro compound is selected from aliphatic and / or aromatic compounds containing one or more nitro groups; and / or The nitrile compounds are selected from aliphatic and / or aromatic compounds containing one or more cyano groups.

3. The synthesis method according to claim 1, characterized in that, The reactants are dissolved in a solvent to form a solution, and then a reduction reaction is carried out. The solvent is water, an organic solvent, or a mixture of water and an organic solvent; The concentration of the reactants in the solution is 0.001 mol / L. -1 Between the concentrations of the target concentration and the saturation concentration.

4. The synthesis method according to claim 1, characterized in that, The work function of the reducing agent is lower than that of the catalyst, and The reduction potential of the reducing agent is lower than that of the catalyst compared to RHE.

5. The synthesis method according to claim 4, characterized in that, The reducing agent has a work function of less than 4.5 eV and a reduction potential of less than -0.5 V relative to RHE.

6. The synthesis method according to claim 5, characterized in that, The reducing agent is selected from one or more of the following: elemental aluminum, magnesium, gallium, and zinc, alloys of two or more, or composites of two or more.

7. The synthesis method according to claim 1, characterized in that, The catalyst has a work function above 4.2 eV and a reduction potential below 0.5 V relative to RHE; Preferably, the catalyst is selected from elemental iron, copper, titanium, lead, carbon, or... Alloys of two or more of the following: iron, copper, titanium, lead, and carbon, or Copper-zinc alloy One or more of them.

8. The synthesis method according to any one of claims 1-7, characterized in that, The area of ​​the reducing agent combined with the catalyst is 0-100% of the catalyst area, excluding 0% and 100%.

9. The synthesis method according to claim 1, characterized in that, The contact area between the catalyst and the solution is 0-100% of the catalyst area, excluding 0% and 100%.

10. The synthesis method according to claim 3, characterized in that, The reaction temperature is from 0 °C to the boiling point of the solvent.

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