A method for preparing 1h-imidazole-4-carboxylic acid based on a supported copper-based catalyst

Abstract

This invention relates to the field of organic synthesis technology, specifically disclosing a method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst. The method includes the following steps: preparing a supported copper-based catalyst; adding imidazolium-4,5-dicarboxylic acid and a solvent to a reaction flask, stirring and heating, then adding the catalyst, performing a first stirring reaction, followed by slow heating and a second stirring reaction, monitoring the reaction progress until the reactants have reacted completely, and cooling to room temperature; adding deionized water to the reaction solution, stirring and washing, then cooling to room temperature, filtering the reaction solution, washing the precipitate, and drying to obtain the target product, 1H-imidazolium-4-carboxylic acid. This invention uses imidazolium-4,5-dicarboxylic acid as the starting material, and synthesizes the target product through a decarboxylation reaction under a self-made catalyst. The reaction conditions are mild, the process is simple and easy to control, with few side reactions and high safety, significantly improving the purity and yield of the product.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and specifically to a method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst. Background Technology

[0002] 1H-Imidazole-4-carboxylic acid, also known as imidazole-4-carboxylic acid, is an organic compound with the chemical formula C4H4N2O2. It is soluble in acidic aqueous solutions and appears as a transparent, colorless liquid. 1H-Imidazole-4-carboxylic acid is not only an important intermediate in the synthesis of imidazole drugs with broad pharmacological activities, but it also possesses significant biological activity itself. It can be used to synthesize imidazole-functionalized polypropyleneimine dendritic compounds, thus having important chemical application value.

[0003] Patent application number 201210037792.0 discloses the following technical solution: a method for preparing 1H-imidazolium-4-carboxylic acid, using ethyl acetylglycine as a raw material, which undergoes cyclization with potassium thiocyanate to obtain ethyl 2-mercapto-4-imidazolium carboxylate; catalytic desulfurization is performed using a catalyst to obtain desulfurized ethyl imidazolium-4-carboxylate, which is then hydrolyzed to obtain the target compound 1H-imidazolium-4-carboxylic acid. In the above scheme, ethyl 2-mercapto-4-imidazolium carboxylate contains sulfur, which easily leads to catalyst poisoning when using catalytic hydrogenation reduction to remove the sulfidation group. A large amount of catalyst is required to complete the reaction, increasing the reaction cost.

[0004] Patent application number 201610108975.5 discloses the following technical solution: a method for preparing 1H-imidazolium-4-carboxylic acid, comprising the following steps: dissolving bismuth nitrate and sodium tungstate in deionized water, homogenizing, transferring to a hydrothermal reaction vessel, sealing, placing in an oven, reacting, cooling to room temperature, washing, drying, and grinding to obtain bismuth tungstate powder; adding CTAB to distilled water, stirring, adding tetraethyl orthosilicate and bismuth tungstate powder, continuing stirring, aging, filtering, washing, drying, and calcining. A composite catalyst was obtained. Ethyl 2-mercapto-1H-imidazolium-4-carboxylate and an ethanol solution were added to a three-necked flask, followed by the composite catalyst, stirring, cooling, and dropwise addition of hydrogen peroxide solution. The mixture was then heated, rotary evaporated, stirred, allowed to stand, and filtered to obtain ethyl 1H-imidazolium-4-carboxylate. Ethyl 1H-imidazolium-4-carboxylate was dissolved in distilled water, heated, stirred, and sodium hydroxide solution was added with continued stirring. After filtration, the mixture was concentrated by rotary evaporation, washed, dried, and recrystallized to obtain 1H-imidazolium-4-carboxylic acid. This invention has a high yield and low cost. However, the above reaction also involves a desulfatization process, and the reaction generates a large amount of waste liquid, resulting in numerous side reactions, poor safety, and high costs.

[0005] In summary, it is necessary to provide a method for preparing 1H-imidazol-4-carboxylic acid that is safe, easy to control, has few side reactions, and is low in cost. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst, which addresses the shortcomings of the existing technology. This invention uses imidazolium-4,5-dicarboxylic acid as the starting material and carries out a decarboxylation reaction under a self-made catalyst to synthesize the target product. The reaction conditions are mild, the process is simple and easy to control, there are few side reactions, and the safety is high, which greatly improves the purity and yield of the product.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst includes the following steps:

[0009] (1) Preparation of supported copper-based catalysts:

[0010] Copper nitrate trihydrate was added to a glucose solution and stirred. The resulting reaction solution was transferred to an autoclave for reaction. After the reaction was completed, the reaction solution was cooled to room temperature and filtered. The precipitate was dried. The dried solid was first calcined in an air atmosphere in a muffle furnace to obtain component A. Activated carbon and anhydrous copper chloride were mixed and ground. The resulting mixed powder was calcined a second time in a nitrogen atmosphere in a muffle furnace to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst.

[0011] (2) Catalytic decarboxylation reaction:

[0012] Imidazole-4,5-dicarboxylic acid and solvent were added to a reaction flask, stirred and heated, then the above catalyst was added, and a stirring reaction was carried out once. After that, the temperature was slowly increased and a stirring reaction was carried out a second time. During the reaction, the reactants were monitored until the reaction was completed, and then cooled to room temperature.

[0013] (3) Post-processing:

[0014] Deionized water was added to the reaction solution, and the mixture was stirred and washed. The solution was then cooled to room temperature, filtered, and the precipitate was washed and dried to obtain the target product, 1H-imidazol-4-carboxylic acid.

[0015] Preferably, in step (1), the concentration of the glucose solution is 0.001-0.01 g / ml, and the amount of copper nitrate trihydrate added is 1-3% of the mass of the glucose solution.

[0016] Preferably, in step (1), the stirring and mixing conditions are: 1000-1500 rpm, room temperature, 1-3 h.

[0017] Preferably, in step (1), the reaction conditions are 120℃ and 10-20h.

[0018] Preferably, in step (1), the temperature of the first calcination is 250℃, the heating rate during calcination is 3-5℃ / min, and the calcination time is 1-2h.

[0019] Preferably, in step (1), the amount of activated carbon and cuprous chloride added is 1-3% and 10-20% of the mass of copper nitrate trihydrate, respectively.

[0020] Preferably, in step (1), the conditions for secondary calcination are: 250℃, a heating rate of 3-8℃ / min during calcination, and a calcination time of 10-12h.

[0021] Preferably, in step (2), the solvent is dimethylacetamide.

[0022] Preferably, in step (2), the ratio of imidazole-4,5-dicarboxylic acid, catalyst, and solvent is (30-35)g:(0.01-0.012)g:(60-100)ml.

[0023] Preferably, in step (2), the conditions for one stirring reaction are: 300-600 rpm, 45-55℃, 7-8h.

[0024] Preferably, in step (2), the conditions for the secondary stirring reaction are: 300-600 rpm, 85-95℃, and 7-8h.

[0025] Preferably, in step (3), the temperature during the stirring and washing process is 40-45℃ and the time is 20-30min.

[0026] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. This invention provides a novel method for synthesizing 1H-imidazolium-4-carboxylic acid. Using imidazolium-4,5-dicarboxylic acid as the starting material, the target product is generated by decarboxylation under the catalysis of a self-made supported copper-based catalyst. The process is simple, the conditions are mild, and there are few side reactions. With the addition of a small amount of catalyst, the yield of the product is as high as 95% or more.

[0028] 2. The supported copper-based catalyst prepared in this invention uses porous activated carbon as a support and copper oxide and cuprous chloride as catalytic active components, significantly improving the dispersibility of the active components. In the catalyst, cuprous chloride can donate electrons during the reaction, promoting reactant activation. In the decarboxylation reaction, the presence of cuprous chloride helps lower the energy barrier and accelerate decarboxylation. Copper oxide, as a catalyst, has excellent oxidizing ability and can promote the oxidation process of reaction intermediates. With the assistance of cuprous chloride, copper oxide can effectively capture the intermediates generated in the reaction, thereby further improving the selectivity of the reaction and the product yield. Moreover, the surface of copper oxide contains abundant active sites, which helps in the adsorption and activation of reactants. In summary, cuprous chloride and copper oxide form a good synergy in the reaction, allowing the catalytic reaction to proceed under relatively mild conditions, ensuring high product yield and reaction safety.

[0029] 3. In preparing the supported copper-based catalyst, this invention first uses glucose as a carbon template and reducing agent, and copper nitrate trihydrate as a copper source. Under certain conditions, the reaction yields porous carbon-supported copper oxide as component A. Then, activated carbon is used as a reducing agent, and copper chloride is used as a precursor material. The mixture is treated at a certain temperature, and the copper chloride is reduced to cuprous chloride to obtain component B. Component A and component B are mixed to obtain the catalyst. The catalyst prepared by this invention has high catalytic activity, good stability, and still has good catalytic activity after multiple cycles. Attached image description:

[0030] Figure 1 The target product in Example 1 1 H-NMR spectrum (DMSO, 400MHz);

[0031] Figure 2 1H-imidazol-4-carboxylic acid standard 1 H-NMR spectrum (DMSO, 400MHz). Detailed Implementation

[0032] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0034] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0035] Unless otherwise specified, all raw materials used in the following embodiments are commercially available, and all conditions described are conventional conditions in the art.

[0036] Activated carbon: 200 mesh, purchased from Chengde Xingyuan Activated Carbon Co., Ltd. (China).

[0037] The product yield is calculated as follows:

[0038] Yield (%) of 1H-imidazol-4-carboxylic acid = (actual yield / theoretical yield) × 100%.

[0039] Example 1

[0040] A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst includes the following steps:

[0041] S1. Preparation of supported copper-based catalysts:

[0042] Add copper nitrate trihydrate (1% of the glucose solution mass) to 60 ml of a 0.002 g / ml glucose solution. Stir and mix at room temperature and 1000 rpm for 2 h. Transfer the resulting reaction solution to an autoclave and react at 120 °C for 12 h. After the reaction is complete, cool the reaction solution to room temperature and filter. Dry the precipitate.

[0043] The dried solid was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in air for 1 hour to obtain component A. Activated carbon and anhydrous copper chloride were mixed and ground (the amount of activated carbon and cuprous chloride added was 2% and 15% of the mass of copper nitrate trihydrate, respectively). The resulting mixed powder was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in nitrogen atmosphere for 12 hours to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst.

[0044] S2, catalytic decarboxylation reaction:

[0045] 31g of imidazole-4,5-dicarboxylic acid and 60ml of dimethylacetamide were added to a reaction flask and stirred at 500rpm to raise the temperature to 50°C. Then, 0.01g of the above-mentioned supported copper-based catalyst was added and the reaction was carried out for 8 hours. After that, the temperature was raised to 90°C and stirred at 500rpm for 8 hours. During the reaction, the reaction of the raw materials was monitored until the reaction was completed. The mixture was then cooled to room temperature to obtain the reaction solution.

[0046] S3, Post-processing:

[0047] Add 60 ml of deionized water to the above reaction solution, stir and wash at 300 rpm and 40 °C for 30 min, then cool to room temperature, filter the reaction solution, wash the precipitate and dry it to obtain 21.2 g of the target product 1H-imidazol-4-carboxylic acid, with a yield of 95.2%. 1 HNMR (400MHz, DMSO), δ: 7.63 (5-H); 7.73 (2-H).

[0048] from Figure 1 and Figure 2 It can be seen that the product obtained by this invention is 1H-imidazol-4-carboxylic acid.

[0049] Example 2

[0050] A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst includes the following steps:

[0051] S1. Preparation of supported copper-based catalysts:

[0052] Add copper nitrate trihydrate (2% of the glucose solution mass) to 60 ml of glucose solution with a concentration of 0.009 g / ml. Stir and mix for 3 h at room temperature and 1500 rpm. Transfer the resulting reaction solution to an autoclave and react at 120 °C for 12 h. After the reaction is complete, cool the reaction solution to room temperature and filter. Dry the precipitate.

[0053] The dried solid was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in air for 1 hour to obtain component A. Activated carbon and anhydrous copper chloride were mixed and ground (the amount of activated carbon and cuprous chloride added was 3% and 15% of the mass of copper nitrate trihydrate, respectively). The resulting mixed powder was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in nitrogen atmosphere for 12 hours to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst.

[0054] S2, catalytic decarboxylation reaction:

[0055] 31g of imidazole-4,5-dicarboxylic acid and 60ml of dimethylacetamide were added to a reaction flask. The mixture was stirred at 500rpm and heated to 50°C. Then, 0.011g of the above-mentioned supported copper-based catalyst was added and the reaction was carried out for 8 hours. The temperature was then raised to 90°C and stirred at 500rpm for 8 hours. The reaction was monitored until the reactants were fully reacted. The mixture was then cooled to room temperature to obtain the reaction solution.

[0056] S3, Post-processing:

[0057] Add 60 ml of deionized water to the above reaction solution, stir and wash at 300 rpm and 42 °C for 30 min, then cool to room temperature, filter the reaction solution, wash the precipitate and dry it to obtain 21.3 g of the target product 1H-imidazol-4-carboxylic acid, with a yield of 95.5%.

[0058] Example 3

[0059] A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst includes the following steps:

[0060] S1. Preparation of supported copper-based catalysts:

[0061] Add copper nitrate trihydrate (3% of the glucose solution mass) to 60 ml of glucose solution with a concentration of 0.008 g / ml. Stir and mix for 3 h at room temperature and 1200 rpm. Transfer the resulting reaction solution to an autoclave and react at 120 °C for 12 h. After the reaction is complete, cool the reaction solution to room temperature and filter. Dry the precipitate.

[0062] The dried solid was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in air for 1 hour to obtain component A. Activated carbon and anhydrous copper chloride were mixed and ground (the amount of activated carbon and cuprous chloride added was 2% and 20% of the mass of copper nitrate trihydrate, respectively). The resulting mixed powder was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in nitrogen atmosphere for 12 hours to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst.

[0063] S2, catalytic decarboxylation reaction:

[0064] 31g of imidazole-4,5-dicarboxylic acid and 60ml of dimethylacetamide were added to a reaction flask and stirred at 500rpm to raise the temperature to 50°C. Then, 0.012g of the above-mentioned supported copper-based catalyst was added and the reaction was carried out for 8 hours. After that, the temperature was raised to 90°C and stirred at 500rpm for 8 hours. During the reaction, the reaction of the raw materials was monitored until the reaction was completed. The mixture was then cooled to room temperature to obtain the reaction solution.

[0065] S3, Post-processing:

[0066] Add 60 ml of deionized water to the above reaction solution, stir and wash at 300 rpm and 45 °C for 30 min, then cool to room temperature, filter the reaction solution, wash the precipitate and dry it to obtain 21.4 g of the target product 1H-imidazol-4-carboxylic acid, with a yield of 96.0%.

[0067] Example 4

[0068] A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst includes the following steps:

[0069] S1. Preparation of supported copper-based catalysts:

[0070] Add copper nitrate trihydrate (3% of the glucose solution mass) to 60 ml of glucose solution with a concentration of 0.009 g / ml. Stir and mix for 3 h at room temperature and 1400 rpm. Transfer the resulting reaction solution to an autoclave and react at 120 °C for 12 h. After the reaction is complete, cool the reaction solution to room temperature and filter. Dry the precipitate.

[0071] The dried solid was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in air for 1 hour to obtain component A. Activated carbon and anhydrous copper chloride were mixed and ground (the amount of activated carbon and cuprous chloride added was 3% and 20% of the mass of copper nitrate trihydrate, respectively). The resulting mixed powder was placed in a muffle furnace and heated to 250°C at a rate of 5°C / min. It was then calcined in nitrogen atmosphere for 12 hours to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst.

[0072] S2, catalytic decarboxylation reaction:

[0073] 31g of imidazole-4,5-dicarboxylic acid and 60ml of dimethylacetamide were added to a reaction flask and stirred at 600rpm to raise the temperature to 50°C. Then, 0.012g of the above-mentioned supported copper-based catalyst was added and the reaction was carried out for 8 hours. After that, the temperature was raised to 90°C and stirred at 600rpm for 8 hours. During the reaction, the reaction of the raw materials was monitored until the reaction was completed. The mixture was then cooled to room temperature to obtain the reaction solution.

[0074] S3, Post-processing:

[0075] Add 60 ml of deionized water to the above reaction solution, stir and wash at 300 rpm and 45 °C for 30 min, then cool to room temperature, filter the reaction solution, wash the precipitate and dry it to obtain 21.5 g of the target product 1H-imidazol-4-carboxylic acid, with a yield of 96.5%.

[0076] To better verify that the technical solution of the present invention has better effects, the following description takes Example 4 as a reference and combines multiple comparative examples.

[0077] Comparative Example 1

[0078] Compared with Example 4, the difference is that commercially available cuprous chloride and copper oxide were directly used in combination. The ratio of cuprous chloride to copper oxide and other conditions were the same as in Example 4, and the target product 1H-imidazol-4-carboxylic acid was obtained with a yield of 94.9%.

[0079] Comparative Example 2

[0080] Compared with Example 4, the difference is that in step S1, the amount of copper nitrate trihydrate added is 0.5% of the mass of the glucose solution, and other conditions are the same as in Example 4, to obtain the target product 1H-imidazol-4-carboxylic acid with a yield of 90.9%.

[0081] Comparative Example 3

[0082] Compared with Example 4, the difference is that in step S1, the calcination time of component A is 5 hours, and other conditions are the same as in Example 4, yielding the target product 1H-imidazol-4-carboxylic acid with a yield of 88.3%.

[0083] Comparative Example 4

[0084] Compared with Example 4, the difference is that in step S1, the heating rate of component A is 10℃ / min, and other conditions are the same as in Example 4, yielding the target product 1H-imidazol-4-carboxylic acid with a yield of 90.1%.

[0085] Comparative Example 5

[0086] Compared with Example 4, the difference is that in step S1, the calcination time of component B is 15h, and other conditions are the same as in Example 4, to obtain the target product 1H-imidazol-4-carboxylic acid with a yield of 89.9%.

[0087] Comparative Example 6

[0088] Compared with Example 4, the difference is that in step S1, the catalyst only includes component A, and the other conditions are the same as in Example 4, yielding the target product 1H-imidazol-4-carboxylic acid with a yield of 80.5%.

[0089] Comparative Example 7

[0090] Compared with Example 4, the difference is that in step S1, the catalyst only includes component B, and the other conditions are the same as in Example 4, yielding the target product 1H-imidazol-4-carboxylic acid with a yield of 51.2%.

[0091] In summary, the amount of glucose used, calcination time, and calcination temperature all affect the catalyst's activity during preparation. An excessively high mass ratio of glucose to copper nitrate trihydrate and a prolonged calcination time lead to the formation of more metals during calcination, reducing the amount of copper oxide or cuprous chloride and consequently decreasing the catalyst's catalytic activity. This invention, by optimizing the above preparation conditions, yields a catalyst with high catalytic activity. When used to synthesize 1H-imidazolium-4-carboxylic acid, it achieves a high yield of the target product under relatively mild conditions.

[0092] To verify the cycling stability of the catalyst of the present invention, the supported catalyst prepared in Example 4 was recycled 10 times and reused in the preparation of 1H-imidazolium-4-carboxylic acid. The specific preparation method was the same as in Example 4, yielding 21.1 g of 1H-imidazolium-4-carboxylic acid with a product yield of 95.0%. This demonstrates that the supported copper-based catalyst prepared in this invention still exhibits good catalytic activity after 10 cycles.

[0093] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst, characterized in that, Includes the following steps: (1) Preparation of supported copper-based catalysts: Copper nitrate trihydrate was added to a glucose solution and stirred. The resulting reaction solution was transferred to an autoclave for reaction. After the reaction, the reaction solution was cooled to room temperature and filtered. The precipitate was dried. The dried solid was first calcined in an air atmosphere in a muffle furnace to obtain component A. Anhydrous copper chloride and activated carbon were mixed and ground. The resulting mixed powder was then calcined a second time in a nitrogen atmosphere in a muffle furnace to obtain component B. Component A and component B were mixed to obtain a supported copper-based catalyst. The concentration of the glucose solution was 0.001-0.01 g / ml, and the amount of copper nitrate trihydrate added was 1-3% of the mass of the glucose solution. The temperature of the first calcination was 250℃, the heating rate was 3-5℃ / min, and the calcination time was 1-2 h. The conditions for the second calcination were: 250℃, the heating rate was 3-8℃ / min, and the calcination time was 10-12 h. (2) Catalytic decarboxylation reaction: Imidazole-4,5-dicarboxylic acid and solvent were added to a reaction flask, stirred and heated, then the above catalyst was added, and a stirring reaction was carried out once. After that, the temperature was slowly increased and a stirring reaction was carried out a second time. During the reaction, the reactants were monitored until the reaction was completed, and then the mixture was cooled to room temperature. (3) Post-processing: Deionized water was added to the reaction solution, and the mixture was stirred and washed. The solution was then cooled to room temperature, filtered, and the precipitate was washed and dried to obtain the target product, 1H-imidazol-4-carboxylic acid.

2. The method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst according to claim 1, characterized in that: In step (1), the mixing conditions are: 1000-1500 rpm, room temperature, 1-3 h.

3. The method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst according to claim 1, characterized in that: In step (1), the reaction conditions are 120℃ and 10-20h.

4. The method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst according to claim 1, characterized in that: In step (2), the solvent is dimethylacetamide, and the ratio of the amount of imidazole-4,5-dicarboxylic acid, catalyst and solvent is (30-35) g: (0.01-0.012) g: (60-100) ml.

5. The method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst according to claim 1, characterized in that: In step (2), the conditions for one stirring reaction are: 300-600 rpm, 45-55℃, 7-8h; The conditions for the reaction and / or secondary stirring are: 300-600 rpm, 85-95℃, 7-8 h.

6. The method for preparing 1H-imidazolium-4-carboxylic acid based on a supported copper-based catalyst according to claim 1, characterized in that: In step (3), the temperature during the stirring and washing process is 40-45℃ and the time is 20-30min.

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