Method for synthesizing 4, 4 '-diaminodiphenyl ether through catalytic transfer hydrogenation
By using iron salt and aqueous activated carbon as catalysts in an inert gas atmosphere, 4,4’-dinitrobenzene ether is converted into 4,4’-diaminodiphenyl ether, the problems of high cost and dust pollution in the existing methods are solved, and an efficient and environmentally friendly production process is achieved.
Patent Information
- Application Number
- CN202510036636.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2025-04-15
AI Technical Summary
The existing catalytic hydrogenation and catalytic transfer hydrogenation synthesis of 4,4’-diaminodiphenyl ether methods have problems such as high cost, high energy consumption, serious dust pollution and low product purity.
Under an inert gas atmosphere, 4,4’-dinitrobenzene ether and hydrogen donor hydrazine hydrate were dispersed in a solvent, iron salt and aqueous activated carbon were added as catalysts, and catalytic transfer hydrogenation was performed to synthesize 4,4’-diaminodiphenyl ether.
It realizes efficient conversion of 4,4’-dinitrobenzene ether, reduces production costs and energy consumption, simplifies the subsequent purification process, reduces dust pollution, and has mild reaction conditions and is easy to operate.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for synthesizing 4,4'-diaminodiphenyl ether by catalytic transfer hydrogenation. Background Art
[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.
[0003] 4,4'-diaminodiphenyl ether is an important fine chemical intermediate. It can be used in the industry to produce high-temperature resistant engineering plastics such as polyimide, polyetherimide, polyesterimide and other polymer materials. It can also be used as a raw material and cross-linking agent for synthetic polymers such as high-performance epoxy resins and polyurethanes. At the same time, it is also used to replace carcinogenic benzidine in the production of azo dyes, reactive dyes and fragrances. Therefore, it is of great significance to study the synthesis method of 4,4'-diaminodiphenyl ether.
[0004] The preparation of 4,4'-diaminodiphenyl ether can be achieved by reducing the nitro group in 4,4'-dinitrodiphenyl ether, mainly using catalytic hydrogenation reduction and catalytic transfer hydrogenation reduction. Among them, catalytic hydrogenation reduction is a technology commonly used in industry. It uses supported precious metals such as Pt / C or Pd / C as catalysts and hydrogen as a reducing agent. It undergoes high-pressure hydrogenation reaction in a non-protonic solvent N,N'-dimethylacetamide to form a crude product, which is then purified by vacuum sublimation, recrystallization and other purification processes to form a pure product. This synthesis method not only uses expensive catalysts and reaction solvents, but also cannot ensure that the raw material 4,4'-dinitrodiphenyl ether is completely converted into 4,4'-diaminodiphenyl ether, resulting in a decrease in product purity. A process of vacuum sublimation and recrystallization purification must be used first; production efficiency decreases, energy consumption increases, and toxic dust pollution is serious. Catalytic transfer hydrogenation reduction of 4,4'-dinitrodiphenyl ether to synthesize 4,4'-diaminodiphenyl ether is a technology that uses hydrogen donor raw materials instead of hydrogen to achieve hydrogenation under the catalysis of a specific catalyst. Its characteristics are that hydrogenation is completed under normal pressure conditions, high-pressure reaction equipment is not required, and the operation is simple. However, catalytic transfer hydrogenation to synthesize 4,4'-diaminodiphenyl ether usually uses precious metal catalysts such as Pd and Pt, which increases production costs. Therefore, it is urgent to develop new hydrogenation reduction technologies to achieve efficient and green production of 4,4'-diaminodiphenyl ether. Summary of the invention
[0005] In order to overcome the above problems, the present invention provides a method for synthesizing 4,4'-diaminodiphenyl ether by catalytic transfer hydrogenation.
[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:
[0007] The present invention provides a method for synthesizing 4,4'-diaminodiphenyl ether by catalytic transfer hydrogenation, comprising the following steps:
[0008] In an inert gas atmosphere, the raw material 4,4'-dinitrodiphenyl ether and a hydrogen donor are dispersed in a solvent, and iron salt and water-containing activated carbon are added as catalysts to catalyze transfer hydrogenation to synthesize 4,4'-diaminodiphenyl ether.
[0009] In one or more embodiments, the hydrogen donor is selected from hydrazine hydrate, anhydrous hydrazine or ammonium formate, preferably hydrazine hydrate.
[0010] Preferably, the content of hydrazine hydrate is 80-85%; the molar ratio of the raw material 4,4'-dinitrodiphenyl ether to hydrazine hydrate is 1.0:3.0-1.0:4.5.
[0011] In one or more embodiments, the solvent is an alcohol solvent, and the alcohol solvent is selected from methanol, ethanol or 2-methoxyethanol, preferably methanol.
[0012] In one or more embodiments, the concentration of the raw material 4,4'-dinitrodiphenyl ether in the solvent is 1.00 to 1.25 mol / L.
[0013] In one or more embodiments, the iron salt is selected from one or more of ferric chloride, ferric sulfate or ferric acetate, preferably ferric chloride.
[0014] In one or more embodiments, the molar amount of the iron salt is 0.05-0.5% of the raw material 4,4'-dinitrodiphenyl ether.
[0015] In one or more embodiments, the water content of the hydrous activated carbon is 40-75%, and preferably, the water content of the hydrous activated carbon is 50-70%.
[0016] In one or more embodiments, the molar ratio of the raw material 4,4'-dinitrodiphenyl ether to the aqueous activated carbon is 1.0:0.2 to 1.0:2.0.
[0017] In one or more embodiments, the temperature of the catalytic transfer hydrogenation reaction is 30 to 80° C., and the reaction time is 4 to 10 hours.
[0018] In one or more embodiments, the method for purifying and obtaining 4,4'-diaminodiphenyl ether after catalytic transfer hydrogenation reduction comprises:
[0019] After catalytic transfer hydrogenation reduction, the mixture is filtered while hot, and the filtrate is cooled and crystallized to obtain 4,4'-diaminodiphenyl ether.
[0020] In one or more embodiments, the inert gas is selected from nitrogen or argon.
[0021] The beneficial effects of the present invention are:
[0022] (1) The present invention provides a method for synthesizing 4,4'-diaminodiphenyl ether by catalytic transfer hydrogenation, comprising: dispersing a raw material 4,4'-dinitrodiphenyl ether and a hydrogen donor hydrazine hydrate in a solvent under an inert gas atmosphere, adding an iron salt and water-containing activated carbon as catalysts, and catalytic transfer hydrogenation to synthesize 4,4'-diaminodiphenyl ether. The synthesis method provided by the present invention is not only simple to operate and has mild reaction conditions, but also can achieve efficient conversion of the raw material 4,4'-dinitrodiphenyl ether, and the post-treatment process is simple. After the reaction is completed, the 4,4'-diaminodiphenyl ether product can be obtained by hot filtration and cooling and crystallization of the filtrate.
[0023] (2) The present invention adopts a normal pressure catalytic transfer hydrogenation reaction, does not require high pressure reaction equipment, does not use expensive precious metals as catalysts, and does not use aprotic reaction solvents, which effectively reduces the reaction cost.
[0024] (3) The present invention uses water-containing activated carbon as a co-catalyst, which has the advantages of being able to quickly form an efficient catalytic center with iron salts, thereby increasing the reduction reaction rate, and on the other hand, because its gaps do not contain oxygen molecules, the nitro group reduction in the raw material is more thorough, effectively increasing the reduction conversion rate. Therefore, the purification process of 4,4'-diaminodiphenyl ether in the present invention is simpler, does not require reduced pressure sublimation, reduces energy consumption, reduces dust pollution, and is green and environmentally friendly.
[0025] (4) After the catalytic transfer hydrogenation reaction is completed in the present invention, only hot filtration and cooling of the filtrate for crystallization are required to obtain the 4,4'-diaminodiphenyl ether product. There is no need to use a purification method of reduced pressure sublimation followed by crystallization, which reduces energy consumption and improves production efficiency. It is an environmentally friendly green production process. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.
[0027] Figure 1 1H-NMR diagram of 4,4'-diaminodiphenyl ether prepared in Example 1;
[0028] Figure 2 This is the 13C-NMR chart of 4,4'-diaminodiphenyl ether prepared in Example 1. DETAILED DESCRIPTION
[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.
[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0031] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.
[0032] Example 1
[0033] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether, 0.0001 mol ferric chloride (hexahydrate), and 0.045 mol activated carbon (water content 65%) were dispersed in 45 mL methanol, the reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content 85%) was added dropwise to the reaction system, the reaction was controlled to proceed at 70-80°C, and the reaction progress was monitored by TLC. When the raw material 4,4'-dinitrodiphenyl ether was completely converted into the product, the reaction time was about 6 hours, the heating was stopped, the reaction mixture was filtered while hot, and 4,4'-diaminodiphenyl ether was obtained by cooling and crystallization, with a yield of 96% and a melting point of 189-190°C.
[0034] Figure 1 The 4,4'-diaminodiphenyl ether prepared in this embodiment 1 H-NMR spectrum. Figure 1 It can be seen that the single peak at 4.78 ppm is attributed to the hydrogen on -NH2, and two groups of double peaks appear at 6.51 and 6.62 ppm, which are respectively attributed to the hydrogen on the benzene ring connected to -NH2 and -O-.
[0035] Figure 2 The 4,4'-diaminodiphenyl ether prepared in this embodiment 13 C-NMR spectrum. Figure 2 It can be seen that the two characteristic peaks at 148.85ppm and 144.55ppm are attributed to the benzene ring carbon atoms connected to -O- and -NH2, and the two absorption peaks at 115.23ppm and 119.39ppm are attributed to two groups of unsubstituted benzene ring carbon atoms.
[0036] Comparative Example 1
[0037] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether, 0.0001 mol ferric chloride (hexahydrate) and 0.045 mol activated carbon (water-free) were dispersed in 45 mL methanol, the reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content of 85%) was added dropwise to the reaction system. The reaction was controlled to be carried out at 70-80°C. After the reaction was carried out for 6 hours, it was found that about 80% of the 4,4'-dinitrodiphenyl ether was completely converted into 4,4'-diaminodiphenyl ether product, and the rest was intermediate reduction products. The reduction reaction was not completely completed even if the reaction time was continued to be extended.
[0038] Comparative Example 2
[0039] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether and 0.0001 mol ferric chloride (hexahydrate) were dispersed in 45 mL methanol, the reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content of 85%) was added dropwise to the reaction system. The reaction was controlled to be carried out at 70-80°C. After the reaction was carried out for 6 hours, it was found that only about 20% of the 4,4'-dinitrodiphenyl ether was completely converted into the 4,4'-diaminodiphenyl ether product, and the rest were raw materials and intermediate reduction products. If the reaction time was further extended, the reduction reaction could not be completely completed.
[0040] Comparative Example 3
[0041] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether and 0.045 mol activated carbon (containing 65% water) were dispersed in 45 mL methanol. The reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content of 85%) was added dropwise to the reaction system. The reaction was controlled at 70-80°C. After the reaction was carried out for 6 hours, it was found that almost no 4,4'-diaminodiphenyl ether product was formed.
[0042] By comparing Example 1 with Comparative Example 1, it can be seen that the synergistic catalytic transfer hydrogenation of aqueous activated carbon and iron salt to synthesize 4,4'-diaminodiphenyl ether is significantly better than that of anhydrous activated carbon. This is attributed to the fact that aqueous activated carbon can quickly form highly active catalytic centers with iron salts to accelerate the reduction reaction. At the same time, the gaps in the aqueous activated carbon do not contain oxygen, which makes the reduction of 4,4'-dinitrodiphenyl ether more thorough and improves the conversion rate. By comparing Example 1 with Comparative Examples 2 and 3, it can be found that although the aqueous activated carbon itself has almost no catalytic effect on the transfer hydrogenation reaction, its synergistic catalytic effect on the iron salt is very significant.
[0043] Example 2
[0044] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether, 0.0001 mol ferric chloride (hexahydrate), and 0.045 mol activated carbon (water content 65%) were dispersed in 45 mL ethanol, and the reaction mixture was heated to about 70°C. After that, 0.16 mol hydrogen donor hydrazine hydrate (content 85%) was added dropwise to the reaction system, and the reaction was controlled to be carried out at 70-80°C. The reaction progress was monitored by TLC. When the raw material 4,4'-dinitrodiphenyl ether was completely converted into the product, the reaction time was about 6 hours, the heating was stopped, the reaction mixture was filtered while hot, and 4,4'-diaminodiphenyl ether was obtained by cooling and crystallization with a yield of 94%.
[0045] Example 3
[0046] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether, 0.0001 mol ferric chloride (hexahydrate), and 0.045 mol activated carbon (water content 65%) were dispersed in 45 mL 2-methoxyethanol, the reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content 85%) was added dropwise to the reaction system. The reaction was controlled to proceed at 70-80°C, and the reaction progress was monitored by TLC. When 4,4'-dinitrodiphenyl ether was completely converted into the product, the reaction time was about 6 h, the heating was stopped, the reaction mixture was filtered while hot, and 4,4'-diaminodiphenyl ether was obtained by cooling and crystallization with a yield of 92%.
[0047] Example 4
[0048] Under N2 atmosphere, 0.05 mol 4,4'-dinitrodiphenyl ether, 0.00005 mol ferric sulfate (hexahydrate), and 0.045 mol activated carbon (water content 65%) were dispersed in 45 mL methanol, the reaction mixture was heated to about 70°C, and 0.16 mol hydrogen donor hydrazine hydrate (content 85%) was added dropwise to the reaction system. The reaction was controlled to be carried out at 70-80°C. After the reaction was carried out for 6 hours, it was found that about 75% of the 4,4'-dinitrodiphenyl ether was completely converted into the product.
[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for synthesizing 4,4'-diaminodiphenyl ether by catalytic transfer hydrogenation, characterized in that: The steps include: In an inert gas atmosphere, the raw material 4,4'-dinitrodiphenyl ether and a hydrogen donor are dispersed in a solvent, and iron salt and water-containing activated carbon are added as catalysts to catalyze transfer hydrogenation to synthesize 4,4'-diaminodiphenyl ether.
2. The method according to claim 1, characterized in that The hydrogen donor is selected from hydrazine hydrate, anhydrous hydrazine or ammonium formate, preferably hydrazine hydrate.
3. The method according to claim 2, characterized in that The content of the hydrazine hydrate is 80-85%; the molar ratio of the raw material 4,4'-dinitrodiphenyl ether to the hydrazine hydrate is 1.0:3.0-1.0:4.
5.
4. The method according to claim 1, characterized in that The solvent is an alcohol solvent, and the alcohol solvent is selected from methanol, ethanol or 2-methoxyethanol, preferably methanol.
5. The method according to claim 1, characterized in that The concentration of the raw material 4,4'-dinitrodiphenyl ether in the solvent is 1.00-1.25 mol / L.
6. The method according to claim 1, characterized in that The iron salt is selected from one or more of ferric chloride, ferric sulfate or ferric acetate, preferably ferric chloride.
7. The method according to claim 1, characterized in that The molar dosage of the iron salt is 0.05-0.5% of the raw material 4,4'-dinitrodiphenyl ether.
8. The method according to claim 1, characterized in that The water content of the hydrous activated carbon is 40-75%, and the preferred water content of the hydrous activated carbon is 50-70%; The molar ratio of the raw material 4,4'-dinitrodiphenyl ether to the water-containing activated carbon is 1.0:0.2 to 1.0:2.
0.
9. The method according to claim 1, characterized in that The temperature of the catalytic transfer hydrogenation reaction is 30 to 80° C., and the reaction time is 4 to 10 hours.
10. The method according to claim 1, characterized in that The method for purifying and obtaining 4,4'-diaminodiphenyl ether after catalytic transfer hydrogenation reaction comprises: After the catalytic transfer hydrogenation reaction, the mixture is filtered while hot, and the filtrate is cooled and crystallized to obtain 4,4'-diaminodiphenyl ether.