Method and device for preparing amide compounds through catalysis of blast furnace tail gas

Abstract

The invention discloses a method and a device for preparing amide compounds through catalysis of blast furnace tail gas, and belongs to the technical field of organic synthesis. The method comprises the following steps: S1, separating and purifying CO2 and N2 in the blast furnace tail gas to obtain high-purity CO2 and N2, and specifically comprises the following steps: mixing the blast furnace tail gas and oxygen, heating, dedusting, drying, absorbing and purifying CO2 to obtain high-purity CO2, and enabling the residual gas to pass through a hot copper net to obtain high-purity N2; s2, by taking the CuPd electrode as a cathode, constructing an electrochemical reaction system which comprises the cathode, an anode, a catholyte and an anolyte and is powered by a direct-current power supply; and S3, CO2 and N2 are introduced into the catholyte, and after electrochemical reaction, separation and purification of products are carried out to obtain the amide compounds. According to the method, CO2 and N2 in the blast furnace tail gas are purified to serve as raw materials for C-N bond electrocatalytic reduction to prepare the amide compound, resource utilization of the blast furnace tail gas is achieved, and meanwhile the environment is protected.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and particularly relates to a method and device for catalytically preparing amide compounds by using blast furnace tail gas. Background Art

[0002] As one of the most common and important functional groups in organic chemistry, the amide bond appears not only as a key linker in polypeptides, proteins, bioactive compounds, agrochemicals and polymers, but also widely exists in about 25% of the drugs on the market. Amide compounds are important industrial solvents, used in the pharmaceutical industry for the production of vitamins, hormones, and also for the manufacture of chlordimeform. The common methods for preparing amide compounds at present are as follows: (1) Condensation reaction of carboxylic acid and amine: Under the action of a condensing agent such as N-N-dicyclohexylcarbodiimide (DCC), carboxylic acid reacts with amine to form amide. Or the carboxylic acid is first converted into an active ester and then reacted with amine. (2) Reaction of acyl chloride and amine: The reaction activity of acyl chloride is high and it reacts rapidly with amine. For example, acetyl chloride reacts with ethylamine, and the chlorine atom in acetyl chloride is replaced by the amino group in ethylamine to form N-ethylacetamide. (3) Reaction of acid anhydride and amine: This reaction proceeds under mild conditions without the need for a condensing agent, but the reaction conditions and raw material ratios need to be controlled. For example, the reaction of acetic anhydride and aniline produces acetanilide. (4) Hydrolysis of nitrile: Nitrile can be hydrolyzed under acidic or basic conditions to obtain amide, but the reaction conditions need to be controlled. If the reaction is strong enough, it will be further hydrolyzed to obtain carboxylic acid. For example, Chinese Patent CN114634444A discloses a method for preparing amide compounds, in which an organic solution of acyl chloride or acyl chloride derivative is mixed with aniline or an organic solution of aniline, heated to react, and after cooling, filtering and drying, an amide compound product is obtained. Although the above methods can prepare amide, the process is complex, the reaction conditions are difficult to control, and most of the raw materials are organic reagents, which may cause environmental pollution.

[0003] On the other hand, in the field of iron and steel smelting, the components of blast furnace tail gas are CO 2 、CO and N 2 , as well as very small amounts of hydrogen and methane. If these gases are directly discharged without control, the concentration of CO 2 in the atmosphere will be significantly increased, causing a series of environmental problems such as global warming and ocean acidification, which is not conducive to the realization of the dual-carbon goal. Therefore, it is necessary to control the discharge of blast furnace tail gas. At present, the treatment of blast furnace tail gas mainly removes solid substances such as soot and particulate matter through dust removal operations and then directly discharges it, without resource utilization of gases such as CO 2 , and at the same time, these gases also cause serious damage to the ecological environment after entering the atmosphere.

[0004] Therefore, there is provided a method for using CO 2 and N in blast furnace tail gas2 The method for preparing amide compounds has important economic and environmental protection values. Summary of the Invention

[0005] Aiming at the deficiencies of the above prior art, one of the objectives of the present invention is to provide a method for catalytically preparing amide compounds by using blast furnace tail gas. The method of the present invention purifies CO 2 and N 2 in the blast furnace tail gas and uses them as raw materials for electrocatalytic reduction of C-N bonds to prepare amide compounds, realizing the resource utilization of blast furnace tail gas and protecting the environment at the same time.

[0006] The above objective of the present invention is achieved by the following technical solutions:

[0007] A method for catalytically preparing amide compounds by using blast furnace tail gas, comprising the following steps:

[0008] S1. Separate and purify CO 2 and N 2 in the blast furnace tail gas to obtain high-purity CO 2 and N 2 . The specific operation is as follows: Mix the blast furnace tail gas and oxygen and then heat them. After dust removal and drying, carry out the absorption and purification of CO 2 to obtain high-purity CO 2 . Pass the remaining gas through a heated copper mesh to obtain high-purity N 2 ;

[0009] S2. Construct an electrochemical reaction system with a CuPd electrode as the cathode, including a cathode, an anode, a cathode electrolyte, an anode electrolyte and a DC power supply;

[0010] S3. Introduce CO 2 and N 2 into the cathode electrolyte. After the electrochemical reaction, carry out the separation and purification of the products to obtain amide compounds.

[0011] The present invention first separates and purifies high-purity CO 2 and high-purity N 2 from the blast furnace tail gas, and then through an electrochemical reaction, enables CO 2 and N 2 to undergo a C-N bond coupling reaction on the cathode surface, realizing the co-reduction of CO 2 and N 2 and forming amide compounds such as amides, imides, and lactams with amide bonds; solving the problems of environmental pollution and complex processes in the prior art for preparing amide compounds using organic reagents, and at the same time realizing the resource utilization of blast furnace tail gas.

[0012] The present invention uses CO in the blast furnace tail gas2 and N 2 Purification can ensure the smooth progress of the electrochemical reaction and avoid CO in the exhaust gas 2 Too low a concentration is not conducive to the reaction.

[0013] The present invention electrocatalytically reduces CO 2 and N 2 The reaction principle for preparing amide compounds is: on the cathode surface, CO 2 Reduced intermediates CO*, COH*, CO-CO*, CH 2 * etc. (superscript * indicates that the intermediate is adsorbed on the cathode surface) and N 2 The reduced intermediates N*, NH*, NH 2 * etc. CN coupling occurs, i.e. CO 2 A C and N in the reducing intermediate 2 One N in the reduced intermediate forms a new chemical bond under the action of the cathode electrode, and then catalytic reduction produces amide chemicals such as amide, imide, lactam, etc. The specific products and electrochemical reaction formulas are shown in Table 1.

[0014] Table 1

[0015]

[0016] Preferably, in step S3, CO is introduced into the cathode electrolyte. 2 and N 2 A mixed gas having a flow rate of 20 to 50 mL / min.

[0017] Preferably, the cathode electrolyte is NaHCO 3 , the anolyte is water.

[0018] Preferably, the electrochemical reaction time is 5 to 20 hours.

[0019] Preferably, the voltage of the DC power supply is -0.8~-2V.

[0020] Preferably, the anode is a CuFeNi alloy.

[0021] Another object of the present invention is to provide a device for catalytically preparing amide compounds using blast furnace tail gas, comprising:

[0022] The electrocatalytic unit comprises an electrolytic cell and a DC power supply, wherein a proton exchange membrane is arranged in the electrolytic cell, and the proton exchange divides the electrolytic cell into a cathode cell and an anode cell, wherein an anode cell is provided with an anode and an anode electrolyte, and wherein a cathode cell is provided with a cathode and a cathode electrolyte;

[0023] Blast furnace tail gas treatment unit, which includes: a tail gas storage cylinder, a dust remover, a dryer, a CO 2 absorption tower, a CO 2 desorption tower, a CO 2 storage tank, the tail gas storage cylinder has a heating function, and the CO 2 outlet end of the absorption tower is also provided with a glowing copper mesh, and the other end of the glowing copper mesh is connected to an N 2 storage tank.

[0024] In the present invention, high-purity CO 2 and high-purity N 2 are separated and purified from blast furnace tail gas through the blast furnace tail gas treatment unit, and then the separated high-purity CO 2 and high-purity N 2 are introduced into the electrocatalytic unit, and CO 2 and N 2 undergo a C-N bond coupling reaction on the cathode surface to achieve the co-reduction of CO 2 and N 2 and finally obtain amide compounds.

[0025] Preferably, throttle valves are provided at the outlet ends of the CO 2 storage tank and the N 2 storage tank.

[0026] Preferably, the device further includes a product separation unit, which includes: an extraction tower and a crystallizer. The extraction tower is provided with a heavy-phase feed inlet and a light-phase discharge outlet. The heavy-phase feed inlet is connected to the cathode cell, and the light-phase discharge outlet is connected to the crystallizer. In the present invention, the cathode electrolyte after the electrochemical reaction is extracted and crystallized through the product separation unit to obtain amide compounds.

[0027] Preferably, the crystallizer is provided with a regenerated extraction liquid outlet, and the extraction tower is provided with a light-phase feed inlet, and the regenerated extraction liquid outlet is connected to the light-phase feed inlet.

[0028] Preferably, the device further includes an oxygen storage tank. The feed inlet of the oxygen storage tank is connected to the oxygen outlet at the top of the cathode cell, and the discharge outlet of the oxygen storage tank is connected to the tail gas storage cylinder. By adopting the above technical solution, the by-product O 2 produced in the anode cell can be directly used for blast furnace ironmaking or oxidizing CO in the blast furnace tail gas, reducing the production cost of O 2 .

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) The method of the present invention separates and purifies CO 2 and N 2As a raw material for electrocatalytic reduction of C-N, the effective utilization of waste resources is realized.

[0031] (2) The method of the present invention uses CO 2 and N 2 as raw materials, and realizes the co-reduction of CO 2 and N 2 through an electrochemical reaction to produce amide compounds. The preparation process is simple, and at the same time, the use of organic reagents can be avoided.

[0032] (3) In the method of the present invention, oxygen is produced at the anode, which can be directly used for blast furnace ironmaking or oxidizing CO in blast furnace tail gas, reducing the production cost of O 2

[0033] (4) The device of the present invention can catalytically produce amide compounds from blast furnace tail gas, realizing the resource utilization of blast furnace tail gas, and at the same time providing a new way to produce amide compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of the device for catalytically producing amide compounds from blast furnace tail gas according to the present invention;

[0035] Figure 2 is the Faraday efficiency of different products in Examples 2 to 6;

[0036] Figure 1 In the figure: 1. electrolytic cell; 11. proton exchange membrane; 12. cathode cell; 13. anode cell; 14. electrolyte discharge port; 15. oxygen outlet; 16. gas inlet; 17. anode liquid inlet; 18. anode liquid outlet; 19. extraction tower; 20. heavy phase feed port; 21. light phase discharge port; 22. heavy phase discharge port; 23. light phase feed port; 24. reduction liquid storage tank; 30. crystallizer; 31. regenerated extraction liquid outlet; 40. oxygen storage tank; 41. blast furnace; 42. tail gas storage cylinder; 43. dust collector; 44. dryer; 50. CO 2 absorption tower; 51. CO 2 inlet; 52. flue gas outlet; 53. CO 2 stripping tower; 54. CO 2 outlet; 55. copper mesh; 56. N 2 gas storage tank; 57. CO 2 gas storage tank; 58. second throttle valve; 59. first throttle valve; 60. mixing bottle; 61. third throttle valve; 62. anode liquid storage tank; 63. anode tank inlet; 64. anode tank outlet; 65. anode liquid circulation pump. DETAILED DESCRIPTION OF THE INVENTION

[0037] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0038] An embodiment of the present invention provides a method for catalytically preparing amide compounds from blast furnace tail gas, including the following steps:

[0039] S1. Separate and purify CO 2 and N 2 in the blast furnace tail gas to obtain high-purity CO 2 and N 2 . The specific operation is as follows: Mix the blast furnace tail gas and oxygen and then heat it. After dust removal and drying, carry out the absorption and purification of CO 2 to obtain high-purity CO 2 . Pass the remaining gas through a hot copper mesh to obtain high-purity N 2 ;

[0040] S2. Construct an electrochemical reaction system with a CuPd electrode as the cathode, including a cathode, an anode, a cathode electrolyte, an anode electrolyte, and a DC power supply;

[0041] S3. Introduce CO 2 and N 2 into the cathode electrolyte. After the electrochemical reaction, separate and purify the product to obtain amide compounds.

[0042] In some embodiments, CO 2 and N 2 are mixed to form a mixed gas and then introduced into the cathode electrolyte. The flow rate of the mixed gas is 20-50 mL / min. The cathode electrolyte is NaHCO 3 , the anode electrolyte is water, the voltage of the DC power supply is -0.8 to -2 V, and the time of the electrochemical reaction is 5-20 hours.

[0043] In the electrochemical reactions of the following embodiments, there is no strict limit on the dosage ratio of CO 2 and N 2 . The final products contain amides, imides, and lactams.

[0044] Example 1

[0045] This example provides a device for catalytically preparing amide compounds from blast furnace tail gas, as Figure 1 shown, including:

[0046] An electrocatalytic unit, which includes an electrolytic cell 1. A proton exchange membrane 11 is provided inside the electrolytic cell 1. The proton exchange membrane 11 divides the electrolytic cell 1 into a cathode chamber 12 and an anode chamber 13. An anode (not shown in the figure) is provided inside the anode chamber 13, and a cathode (not shown in the figure) is provided inside the cathode chamber 12;

[0047] A blast furnace tail gas treatment unit, which includes: a tail gas storage cylinder 42 with a preheating function, the outlet end of which is connected to the inlet end of a dust collector 43, and the gas collected inside the tail gas storage cylinder 42 flows into the dust collector 43; the outlet end of the dust collector 43 is connected and communicated with the inlet end of a dryer 44, and the outlet end of the dryer 44 is connected to the 2 CO at the bottom end of the absorption tower 50 2 inlet 51 is connected and communicated, and 2 the bottom liquid outlet of the absorption tower 50 is connected and communicated with the 2 desorption tower 53, and 2 the CO of the desorption tower 53 2 outlet 54 is connected to the 2 gas storage tank 57, and 2 the flue gas outlet 52 at the top of the absorption tower 50 is connected to a glowing copper mesh 55, and the other end of the glowing copper mesh 55 is connected to the 2 gas storage tank 56, and 2 a first throttle valve 59 is provided at the outlet end of the gas storage tank 56, and 2 a second throttle valve 58 is provided at the outlet end of the gas storage tank 57, and 2 the N in the gas storage tank 56 and 2 the 2 CO in the gas storage tank 57 2 respectively flow into a mixing bottle 60 through the first throttle valve 59 and the second throttle valve 58, and the mixing bottle 60 is connected to the gas inlet 16 of the cathode chamber 12 through a third throttle valve 61.

[0048] During use, the blast furnace tail gas in the blast furnace 41 enters the tail gas storage cylinder 42 with a heating function, and then after passing through the dust collector 43 and the dryer 44, it enters the 2 CO 2 absorption tower 50 and the 2 CO 2 desorption tower 53 for 2 absorption and purification of CO. Ethanolamine solution is installed in the 2 absorption tower 50 to capture 2 CO, and high-purity CO 2 enters the 2 gas storage tank 57. At the same time, the remaining gas in the 2 absorption tower 50 is discharged through the flue gas outlet 52, and high-purity nitrogen is obtained after passing through the glowing copper mesh 55 and enters the 2They are mixed through the second throttle valve 58 and the first throttle valve 59 respectively, and then enter the mixing bottle 60 with a heating function. Finally, they enter the cathode cell 12 through the third throttle valve 61 via the gas inlet 16. An aqueous solution is added to the anode cell 13. The anode is connected to the positive pole of the power supply, and the cathode is connected to the negative pole of the power supply. The electrolysis voltage is controlled to carry out the electrolysis reaction. The C-N bond coupling reaction occurs on the surface of the cathode electrode in the cathode cell 12 to achieve the 2 co-reduction of 2 CO and N, and form high-value-added product classes such as amides, imides, and lactams with amide bonds, thereby realizing the resource utilization of blast furnace tail gas.

[0049] In some embodiments, the device further includes an oxygen storage tank 40. The oxygen storage tank 40 is connected to the anode cell 13 through the oxygen outlet 15 at the top of the anode cell 13. The oxygen generated by electrolysis in the anode cell 13 enters the oxygen storage tank 40. The other end of the oxygen storage tank 40 is connected to the tail gas storage cylinder 42. The oxygen generated at the anode can be directly used to oxidize CO in the blast furnace tail gas, reducing the 2 production cost. The generated 2 O can also be stored in the oxygen storage tank 40 and supplied to other units (hospitals, factories, etc.), improving the economic benefits of the power plant.

[0050] In some embodiments, the device further includes a product separation unit, which includes an extraction tower 19 and a crystallizer 30. The extraction tower 19 is provided with a heavy-phase feed inlet 20 and a light-phase discharge outlet 21. The cathode cell 12 is provided with an electrolyte discharge outlet 14 at the top. The extraction tower 19 is connected to the cathode cell 12 through the heavy-phase feed inlet 20 and the electrolyte discharge outlet 14, and is connected to the crystallizer 30 through the light-phase discharge outlet 21. The reduced cathode electrolyte in the cathode cell 12 flows into the extraction tower 19 through the electrolyte discharge outlet 14 and the heavy-phase feed inlet 20 in sequence for extraction, and the C-N bond liquid products are extracted and separated. The organic phase of the amide products obtained by extraction enters the crystallizer 30 through the light-phase discharge outlet 21, and the aqueous phase sinks and flows into the reduced liquid storage tank 24 through the heavy-phase discharge outlet 22 at the bottom of the extraction tower 19. The products are crystallized and output in the crystallizer 30, and finally high-value-added amide products such as amides, imides, and lactams are obtained.

[0051] In some embodiments, the crystallizer 30 is provided with a regenerated extraction liquid outlet 31 on the side. The regenerated extraction liquid outlet 31 is connected to the light-phase feed inlet 23 at the bottom of the extraction tower 19. After the amides, imides, and lactam products are separated by recrystallization, the regenerated extraction liquid passes through the bottom light-phase feed inlet 23 from the regenerated extraction liquid outlet 31 and enters the extraction tower 19 again for reuse.

[0052] In some embodiments, the device further includes an anolyte storage tank 62. An anolyte inlet 17 and an anolyte outlet 18 are provided on the anode cell 13. The anolyte tank inlet 63 of the anolyte storage tank 62 is communicated with the anolyte outlet 18 of the anode cell 13, and the anolyte tank outlet 64 of the anolyte storage tank 62 is communicated with the anolyte inlet 17 of the anode cell 13. Meanwhile, the anolyte storage tank 62 and the anode cell 13 are communicated through an anolyte circulation pipeline, and an anolyte circulation pump 65 is provided on the anolyte circulation pipeline; the anolyte storage tank 62 stores anolyte, and the anolyte is an aqueous solution. The anolyte circulation pump 65 can be used to realize the circulating flow of the anolyte between the anolyte storage tank 62 and the anode cell 13.

[0053] The working process of the device for catalytically preparing amide compounds by using blast furnace tail gas according to the present invention is as follows:

[0054] (1) Working process in the C-N electrocatalytic reduction flow cell: The catalytic electrodes for electrocatalytic reduction and oxygen evolution reaction (OER) are respectively installed in the cathode cell 12 and the anode cell 13; CO 2 and N 2 start from the mixing bottle 60 and are controlled by the third throttle valve 61 to be introduced into the cathode cell 12 as reduction raw materials; pure water is introduced into the anode cell 13 as anolyte; the potential of the C-N electrocatalytic reduction electrode is controlled between -0.8 V and -2 V, and the C-N bond coupling reaction occurs on the cathode surface to realize the co-reduction of CO 2 and N 2 to produce amide, imide, and lactam. The oxidation reaction occurs in the anode cell 13 to produce O 2 , and the generated protons pass through the proton exchange membrane 11 to the cathode cell 12 to provide protons for the co-reduction of CO 2 and N 2 . The anolyte circulates in the anode cell 13 under the push of the anolyte circulation pump 65 to maintain the ion balance and the stability of the pH value in the anode cell 13;

[0055] (2) Treatment process of blast furnace tail gas: The tail gas obtained from the blast furnace 41 is first stored in the tail gas storage cylinder 42 with a heating function, and O 2 is introduced to oxidize CO to CO 2 . The reacted gas passes through the dust remover 43 to remove particulate matter and dust, enters the dryer 44 to remove moisture, and then enters the CO 2 absorption tower 50 and the CO 2 stripping tower 53 for the absorption and purification of CO 2 , and is stored in the CO 2 gas storage tank 57. The remaining gas (O 2 + N 2 ) in the CO 2 absorption tower 50 is discharged by the CO 2It is discharged from the flue gas outlet 52 at the top of the absorption tower 50 and passes through a hot copper mesh 55 to remove O 2 to obtain high-purity N 2 , which is stored in N 2 gas storage tank 56. Finally, high-purity CO 2 and N 2 are introduced into the cathode cell 12 under the control of the third throttle valve 61 as reaction raw materials; further, the oxygen generated at the anode of the C-N electrocatalytic reduction reactor can also participate in blast furnace smelting as an oxidant.

[0056] (3) Product separation and purification process: CO 2 and N 2 jointly reduce to form a C-N bond product; subsequently, the reduced cathode electrolyte enters the extraction tower 19 to extract and separate the C-N bond liquid product. The organic phase enters the crystallizer 30. While the product crystallizes and is output, the extractant is regenerated and returns to the extraction tower 19 for extraction again.

[0057] Example 2

[0058] This example provides a method for catalytically preparing amide compounds from blast furnace tail gas. This method uses the above device and includes the following steps:

[0059] S1. Use the device as shown in Figure 1 , where the anode is a CuFeNi alloy electrode prepared by chemical reduction method, and the cathode is a CuPd electrode prepared by hydrothermal method;

[0060] S2. Turn on the blast furnace tail gas treatment unit. The blast furnace tail gas enters the tail gas storage cylinder with heating function and is introduced with O 2 to oxidize CO to CO 2 . After the reaction, the gas is dust-removed and dried, and then enters the CO 2 absorption tower and is adsorbed by the ethanolamine solution. The ethanolamine solution absorbing CO 2 is transferred to the CO 2 stripping tower. Under the action of heating, CO 2 is stripped and introduced into the CO 2 gas storage tank for storage; the flue gas after trapping CO 2 is discharged from the flue gas outlet at the top of the CO 2 absorption tower; high-purity nitrogen is obtained after passing through the hot copper mesh and enters the N 2 gas storage tank; then the CO 2 in the CO 2 gas storage tank and the N 2 in the N 2 gas storage tank are mixed and stored in the mixing bottle;

[0061] S3. Introduce the anolyte (specifically water) into the anode cell, introduce the catholyte (specifically NaHCO 3 ), connect the anode to the positive electrode of the power supply and the cathode to the negative electrode of the power supply, control the reaction voltage to be -1.2 V (reference hydrogen electrode potential (V vs RHE)), and introduce the CO 2 and N 2 mixed gas into the cathode cell, with the flow rate of the mixed gas being 50 mL / min;

[0062] S4. C-N coupling reaction occurs between CO 2 and N 2 in the cathode cell to generate a reduced liquid product. Subsequently, the reduced catholyte flows out of the cathode cell and enters the extraction column through the heavy-phase feed port of the extraction column. The extractant extracts amide products such as amides, imides, and lactams in the reduced catholyte. Under the action of gravity and density, the organic phase floats and flows out through the top light-phase discharge port and enters the crystallizer. While the product crystallizes and is output, the extractant is regenerated and returns to the extraction column for extraction again. The aqueous phase sinks and flows into the reduced liquid storage tank through the heavy-phase discharge port at the bottom of the extraction column.

[0063] S5. An oxidation reaction occurs at the anode to produce O 2 , and O 2 flows out through the oxygen outlet at the top of the anode cell and enters the oxygen storage tank for storage. Subsequently, it can also be introduced into the tail gas storage cylinder to oxidize CO in the blast furnace tail gas and can also be used for other purposes.

[0064] Example 3

[0065] The method of this example is basically the same as that of Example 2, except that the reaction voltage is controlled to be -0.8 V.

[0066] Example 4

[0067] The method of this example is basically the same as that of Example 2, except that the reaction voltage is controlled to be -0.9 V.

[0068] Example 5

[0069] The method of this example is basically the same as that of Example 2, except that the reaction voltage is controlled to be -1.0 V.

[0070] Example 6

[0071] The method of this example is basically the same as that of Example 2, except that the reaction voltage is controlled to be -1.1 V.

[0072] The Faraday efficiencies of different products in Examples 2 to 6 are as Figure 2As shown, it can be seen from the figure that under the conditions of the reference hydrogen electrode potential (V vs RHE) of -0.9 V and -1 V, the Faraday efficiency of amide substances is the highest.

[0073] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing amide compounds by catalytic use of blast furnace tail gas, characterized in that: The following steps are involved: S1. Separate and purify CO2 and N2 in blast furnace tail gas to obtain high-purity CO2 and N2. The specific operation is as follows: mix the blast furnace tail gas and oxygen and heat them. After dust removal and drying, absorb and purify CO2 to obtain high-purity CO2. The remaining gas passes through a hot copper mesh to obtain high-purity N2. S2. Using the CuPd electrode as the cathode, constructing an electrochemical reaction system including a cathode, an anode, a cathode electrolyte, an anode electrolyte and a DC power supply; S3. CO2 and N2 are introduced into the cathode electrolyte, and the products are separated and purified after electrochemical reaction to obtain amide compounds.

2. The method according to claim 1, characterized in that In step S3, a mixed gas of CO2 and N2 is introduced into the cathode electrolyte, and the flow rate of the mixed gas is 20-50 mL / min.

3. The method according to claim 1, characterized in that The cathode electrolyte is NaHCO3, and the anode electrolyte is water.

4. The method according to claim 1, characterized in that: The voltage of the DC power supply is -0.8~-2V.

5. The method according to claim 1, characterized in that The anode is a CuFeNi alloy.

6. A device for preparing amide compounds by catalytic use of blast furnace tail gas, characterized in that: The device is applied to the method described in any one of claims 1 to 5, comprising: The electrocatalytic unit comprises an electrolytic cell and a DC power supply, wherein a proton exchange membrane is arranged in the electrolytic cell, and the proton exchange divides the electrolytic cell into a cathode cell and an anode cell, wherein an anode cell is provided with an anode and an anode electrolyte, and wherein a cathode cell is provided with a cathode and a cathode electrolyte; The blast furnace tail gas treatment unit comprises: a tail gas storage bottle, a dust collector, a dryer, a CO2 absorption tower, a CO2 analysis tower, and a CO2 gas storage tank which are connected in sequence. The tail gas storage bottle has a heating function. The outlet end of the CO2 absorption tower is also provided with a hot copper mesh, and the other end of the hot copper mesh is connected to a N2 gas storage tank.

7. The device according to claim 6, characterized in that The outlet ends of the CO2 gas storage tank and the N2 gas storage tank are both provided with throttle valves.

8. The device according to claim 6, characterized in that The device also includes a product separation unit, which includes: an extraction tower and a crystallizer. The extraction tower is provided with a heavy phase feed port and a light phase discharge port. The heavy phase feed port is connected to the cathode tank, and the light phase discharge port is connected to the crystallizer.

9. The device according to claim 8, characterized in that The crystallizer is provided with a regeneration extract outlet, the extraction tower is provided with a light phase feed inlet, and the regeneration extract outlet is communicated with the light phase feed inlet.

10. The device according to claim 6, characterized in that The device also includes an oxygen storage tank, a feed inlet of the oxygen storage tank is connected to the oxygen outlet at the top of the cathode cell, and a discharge outlet of the oxygen storage tank is connected to the tail gas storage bottle.

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