A method for synthesizing formamide by electrocatalytic C-N coupling

Abstract

The present invention discloses a method for synthesizing formamide through electrocatalytic C-N coupling. Using small carbon-containing molecules and small nitrogen-containing molecules as raw materials, and RuCu single-atom alloy as an electrocatalyst, formamide is prepared through an electrochemical reaction. The method for synthesizing formamide through electrocatalytic C-N coupling solves the problem that traditional formamide synthesis methods need to be carried out under high-temperature and high-pressure reaction conditions, resulting in a large amount of energy consumption and greenhouse gas emissions, causing environmental pollution.

Description

Technical Field

[0001] The present invention belongs to the technical field of formamide synthesis methods, and particularly relates to a method for synthesizing formamide through electrocatalytic C-N coupling. Background Art

[0002] Amides and their derivatives are an important class of organic compounds commercially, and are widely used as intermediates in the manufacture of chemicals as well as polymers and biological compounds. Among them, formamide (HCONH2), as an important chemical raw material, has been widely used in the fields of organic synthesis, pharmaceuticals, plastics, pesticides, etc. At present, the industrial synthesis of formamide mainly includes the following methods: methanol esterification amination method, methanol carbonylation amination method, methanol dehydrogenation amination method, CO2 and methanol hydrocondensation amination method, and syngas direct synthesis-amination method. The above synthesis methods all need to be carried out under high-temperature and high-pressure reaction conditions, resulting in a large amount of energy consumption and greenhouse gas emissions, causing environmental pollution. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for synthesizing formamide through electrocatalytic C-N coupling, which solves the problems that the traditional formamide synthesis method needs to be carried out under high-temperature and high-pressure reaction conditions, resulting in a large amount of energy consumption and greenhouse gas emissions, causing environmental pollution.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A method for synthesizing formamide through electrocatalytic C-N coupling, characterized in that carbon-containing and nitrogen-containing small molecules are used as raw materials, and RuCu single-atom alloy is used as a catalyst to prepare formamide through an electrochemical reaction.

[0006] A method for synthesizing formamide through electrocatalytic C-N coupling, characterized in that the catalyst includes a carrier and Cu and Ru supported on the carrier; wherein the carrier is titanium oxide nanowires, and both Cu and Ru are active substances. Based on the mass of the carrier, the mass percentage of Cu is 1%-30%, and the mass percentage of Ru is 0.01%-9%.

[0007] A method for synthesizing formamide through electrocatalytic C-N coupling, characterized in that the titanium oxide carrier is in the form of nanowires or nanoporous structures.

[0008] The preparation method of the electrocatalyst is as follows:

[0009] S1. Disperse the titanium oxide carrier in ultrapure water and stir ultrasonically to obtain solution A;

[0010] S2. Add a CuCl2·2H2O solution to solution A and stir to obtain solution B;

[0011] S3. Place the B solution in a liquid nitrogen environment for freeze-drying to obtain C powder;

[0012] S4. Place the C powder in an atmosphere furnace with H2 / Ar flowing through, then heat it at 150 °C - 350 °C for 1 h - 3 h, and finally cool it to room temperature to obtain D powder;

[0013] S5. Disperse the D powder in ultrapure water and stir it ultrasonically to obtain E solution;

[0014] S6. Add RuCl3 solution to the E solution and stir to obtain F solution

[0015] S7. Place the F solution in a liquid nitrogen environment for freeze-drying to obtain the catalyst.

[0016] A method for electrocatalytic C-N coupling to synthesize formamide, characterized in that the carbon-containing small molecules include carbon dioxide, carbon monoxide, etc.

[0017] A method for electrocatalytic C-N coupling to synthesize formamide, characterized in that the nitrogen-containing small molecules include nitrogen, nitric oxide, nitrite, nitrate, etc.

[0018] The beneficial effects of the present invention are as follows: The method for electrocatalytic C-N coupling to synthesize formamide of the present invention has the advantages of high yield, Faraday efficiency, and mild reaction conditions; compared with the traditional synthesis method, the electrocatalytic synthesis of the present invention is a low-energy-consuming green conversion method. Under normal temperature and pressure, rich and cheap carbon-containing small molecules and nitrogen-containing small molecules are used as raw materials to drive the synthesis of formamide, and renewable energy such as wind energy and solar energy can be combined, which conforms to the concept of green sustainable development and is a green, environmentally friendly and efficient synthesis method. Description of the Drawings

[0019] The present invention is further described with the help of the drawings, but the embodiments in the drawings do not constitute any limitation to the present invention.

[0020] Figure 1 It is a reaction schematic diagram for electrocatalytic C-N coupling to synthesize formamide by the method of the present invention;

[0021] Figure 2 It is a preparation schematic diagram of the RuCu single-atom alloy catalyst used in the present invention;

[0022] Figure 3 It is the yield and Faraday efficiency results of electrocatalytic synthesis of formamide by the RuCu single-atom alloy catalyst through the method of the present invention;

[0023] Figure 4 It is the selectivity and yield results of synthesizing formamide by using different catalysts through the method of the present invention;

[0024] Figure 5 The 1 1H NMR spectra of the electrolytes obtained by the coupling reaction using the RuCu single-atom alloy catalyst at different concentrations of KNO2 through the method of the present invention;

[0025] Figure 6 The 1 1H NMR spectra of the electrolytes obtained by the coupling reaction of nitrate as a nitrogen source with CO using the RuCu single-atom alloy catalyst through the method of the present invention. Detailed implementation manners

[0026] The embodiments of the present invention will be described in detail below. The embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0027] As Figure 1 shown, a method for synthesizing formamide by electrocatalytic C-N coupling of the present invention uses carbon-containing small molecules and nitrogen-containing small molecules as raw materials, and uses a RuCu single-atom alloy as a catalyst to prepare formamide through an electrochemical reaction;

[0028] Figure 2 is a schematic diagram of the synthesis method of the RuCu single-atom alloy in the embodiment. The preparation method of the electrocatalyst is as follows:

[0029] S1. Dispersing a titanium oxide support in ultrapure water and ultrasonically stirring to obtain solution A;

[0030] S2. Adding a CuCl2·2H2O solution to solution A and stirring to obtain solution B;

[0031] S3. Freeze-drying solution B in a liquid nitrogen environment to obtain powder C;

[0032] S4. Placing powder C in an atmosphere furnace into which H2 / Ar is introduced, then heating at 150°C - 350°C for 1 h - 3 h, and finally cooling to room temperature to obtain powder D;

[0033] S5. Dispersing powder D in ultrapure water and ultrasonically stirring to obtain solution E;

[0034] S6. Adding a RuCl3 solution to solution E and stirring to obtain solution F

[0035] S7. Freeze-drying solution F in a liquid nitrogen environment to obtain the catalyst.

[0036] From Figure 3Shows the yield and Faraday efficiency results of electrocatalytic synthesis of formamide over RuCu single-atom alloy catalyst, where the Faraday efficiency is as high as 45.65 ± 0.76%, and the yield reaches 2.48 ± 0.15 mg h -1 mg cat. -1 .

[0037] From Figure 4 The selectivity and yield of formamide over different catalysts show that Cu nanoclusters and RuCu alloy nanoparticles can also achieve formamide synthesis, but their performance is inferior to that of RuCu single-atom alloy.

[0038] Figure 5 Shows the 1 HNMR spectrum of the electrolyte obtained from the coupling reaction over RuCu single-atom alloy under different concentrations of KNO2. It can be seen that electrosynthesis of formamide can also be achieved under low nitrite concentration conditions.

[0039] Figure 6 Shows the 1 1H NMR spectrum of the electrolyte obtained after co-reducing nitrate as the nitrogen source with CO over RuCu single-atom alloy. The spectrum shows that formamide can also be obtained using nitrate as the nitrogen source for the coupling experiment.

[0040] Example 1

[0041] A method for constructing secondary amine compounds by electrocatalytic C-N coupling according to the present invention uses CO and potassium nitrite as raw materials, 1M KNO2 + 1M KOH as the electrolyte, continuously introduces CO into the electrolyte, and uses RuCu single-atom alloy as the catalyst to synthesize formamide through an electrochemical reaction;

[0042] The preparation method of the RuCu single-atom alloy catalyst is as follows:

[0043] S1. Disperse the titanium oxide support in ultrapure water and obtain solution A by ultrasonic stirring;

[0044] S2. Add CuCl2·2H2O solution to solution A and stir to obtain solution B;

[0045] S3. Place solution B in a liquid nitrogen environment for freeze-drying to obtain powder C;

[0046] S4. Place powder C in an atmosphere furnace with H2 / Ar flowing through, then heat at 150 °C - 350 °C for 1 h - 3 h, and finally cool to room temperature to obtain powder D.

[0047] S5. Disperse powder D in ultrapure water and obtain solution E by ultrasonic stirring;

[0048] S6. Add RuCl3 solution to solution E and stir to obtain solution F.

[0049] S7. Place solution F in a liquid nitrogen environment for freeze-drying to obtain the RuCu single-atom alloy catalyst.

[0050] Example 2

[0051] A method for constructing secondary amine compounds by electrocatalytic C-N coupling according to the present invention uses CO and potassium nitrite as raw materials, with an electrolyte of 1M KNO2 + 1M KOH. CO is continuously introduced into the electrolyte, and formamide is synthesized through an electrochemical reaction using Cu nanoclusters and RuCu nanoparticles as catalysts respectively.

[0052] The preparation methods of the Cu nanoclusters and RuCu nanoparticles catalysts are as follows:

[0053] S1. Disperse the titanium oxide support in ultrapure water and stir ultrasonically to obtain solution A.

[0054] S2. Add CuCl2·2H2O solution to solution A and stir to obtain solution B.

[0055] S3. Place solution B in a liquid nitrogen environment for freeze-drying to obtain powder C.

[0056] S4. Place powder C in an atmosphere furnace with H2 / Ar being introduced, then heat at 150°C - 350°C for 1h - 3h, and finally cool to room temperature to obtain the Cu nanocluster catalyst.

[0057] S5. Disperse the Cu nanocluster catalyst in ultrapure water and stir ultrasonically to obtain solution D.

[0058] S6. Add RuCl3 solution to solution D and stir to obtain solution E

[0059] S7. Place solution E in a liquid nitrogen environment for freeze-drying to obtain the RuCu nanoparticle catalyst.

[0060] Example 3

[0061] A method for constructing secondary amine compounds by electrocatalytic C-N coupling according to the present invention uses CO and potassium nitrite as raw materials, with electrolytes of 0.1M KNO2 + 1M KOH and 0.01M KNO2 + 1M KOH respectively. CO is continuously introduced into the electrolyte, and formamide is synthesized through an electrochemical reaction using the RuCu single-atom alloy as the catalyst.

[0062] The preparation method of the RuCu single-atom alloy catalyst is as follows:

[0063] S1. Disperse the titanium oxide support in ultrapure water and stir ultrasonically to obtain solution A.

[0064] S2. Add the CuCl₂·2H₂O solution to the A solution and stir to obtain the B solution;

[0065] S3. Place the B solution in a liquid nitrogen environment for freeze-drying to obtain the C powder;

[0066] S4. Place the C powder in an atmosphere furnace with H₂ / Ar being introduced, then heat it at 150 °C - 350 °C for 1 h - 3 h, and finally cool it to room temperature to obtain the D powder.

[0067] S5. Disperse the D powder in ultrapure water and stir it ultrasonically to obtain the E solution;

[0068] S6. Add RuCl₃ solutions with different ratios to the E solution and stir to obtain the F solution

[0069] S7. Place the F solution in a liquid nitrogen environment for freeze-drying to obtain the RuCu single-atom alloy catalyst.

[0070] Example 4

[0071] A method for constructing secondary amine compounds through electrocatalytic C-N coupling according to the present invention uses CO and potassium nitrate as raw materials, the electrolyte is 0.1 M KNO₃ + 1 M KOH, CO is continuously introduced into the electrolyte, and a RuCu single-atom alloy is used as the catalyst to synthesize formamide through an electrochemical reaction;

[0072] The preparation method of the RuCu single-atom alloy catalyst is as follows:

[0073] S1. Disperse the titanium oxide support in ultrapure water and stir it ultrasonically to obtain the A solution;

[0074] S2. Add the CuCl₂·2H₂O solution to the A solution and stir to obtain the B solution;

[0075] S3. Place the B solution in a liquid nitrogen environment for freeze-drying to obtain the C powder;

[0076] S4. Place the C powder in an atmosphere furnace with H₂ / Ar being introduced, then heat it at 150 °C - 350 °C for 1 h - 3 h, and finally cool it to room temperature to obtain the D powder.

[0077] S5. Disperse the D powder in ultrapure water and stir it ultrasonically to obtain the E solution;

[0078] S6. Add the RuCl₃ solution to the E solution and stir to obtain the F solution

[0079] S7. Place the F solution in a liquid nitrogen environment for freeze-drying to obtain the RuCu single-atom alloy catalyst.

[0080] The foregoing description has shown and described several preferred embodiments of the invention. However, as previously mentioned, it should be understood that the invention is not limited to the forms disclosed herein, should not be construed as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the above teachings or the skills or knowledge in the relevant field. Any alterations and changes made by those skilled in the art that do not depart from the spirit and scope of the invention shall fall within the protection scope of the appended claims of the invention.

Claims

1. A method for synthesizing formamide by electrocatalytic C-N coupling, characterized in that, Using carbon monoxide and nitrogen-containing small molecules as raw materials, the nitrogen-containing small molecules being nitrite or nitrate, continuously introducing carbon monoxide into the electrolyte, and using a RuCu single-atom alloy as a catalyst, the catalyst comprising a support and Cu and Ru supported on the support, wherein the support is titanium oxide nanowires, and preparing formamide through an electrochemical reaction.

2. The method for synthesizing formamide by electrocatalytic C-N coupling according to claim 1, wherein Based on the mass of the support, the mass percentage of Cu is 1% - 30%, and the mass percentage of Ru is 0.01% - 9%.

3. A method for synthesizing formamide by electrocatalytic C-N coupling according to any one of claims 1-2, characterized in that, The preparation method of the catalyst is as follows: S1. Disperse the titanium oxide support in ultrapure water and obtain solution A by ultrasonic stirring; S2. Add a CuCl2·2H2O solution to solution A and stir to obtain solution B; S3. Place solution B in a liquid nitrogen environment for freeze-drying to obtain powder C; S4. Place powder C in an atmosphere furnace with H2 / Ar being introduced, then heat at 150°C - 350°C for 1 h - 3 h, and finally cool to room temperature to obtain powder D; S5. Disperse powder D in ultrapure water and obtain solution E by ultrasonic stirring; S6. Add a RuCl3 solution to solution E and stir to obtain solution F; S7. Place solution F in a liquid nitrogen environment for freeze-drying to obtain the catalyst.

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