A preparation method of 9-phenanthroline carboxylic acid

Abstract

The present invention relates to the technical field of organic chemistry, and discloses a preparation method of 9-phenanthrene formic acid, wherein the preparation method comprises the following steps: using phenanthrene as a main raw material, iron bromide or zinc bromide as a catalyst, reacting with hydrobromic acid and hydrogen peroxide at 20 to 50 ° C to generate 9-bromophenanthrene, 9-bromophenanthrene reacts with cyanide under a catalyst to generate 9-nitrile phenanthrene, and then hydrolyzing under alkaline conditions to obtain 9-phenanthrene formic acid. The present invention uses cheap and readily available raw materials such as phenanthrene, hydrobromic acid, hydrogen peroxide and sodium cyanide to prepare 9-phenanthrene formic acid, with low production cost, high conversion rate, good product quality, mild reaction conditions, low equipment requirements, and can be used for large-scale industrial preparation of 9-phenanthrene formic acid.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemistry, and in particular to a method for preparing 9-phenanthroline carboxylic acid. Background Art

[0002] The polycyclic aromatic hydrocarbon (PAH) phenanthrene and its derivatives possess a large π system. When coordinated with metal ions, they can generate weak interactions such as π…π, C—H…π, and hydrogen bonds, resulting in novel structures and unique functionalities. These interactions offer broad potential applications in optical, electrical, and magnetic properties. Currently, organic optoelectronic materials containing PAH structures have garnered significant attention. Materials containing phenanthrene or phenanthrene derivatives are increasingly demonstrating their high photothermal stability and application value.

[0003] The synthetic routes of 9-phenanthroline formic acid reported in the literature can be summarized as follows:

[0004] 1. 9-Phenanthrene carboxylic acid was prepared by reacting phenanthrene and carbon dioxide as starting materials with aluminum tribromide as catalyst in benzene solvent under high temperature and high pressure (Suzuki Y., Hattori T., Okuzawa T., Miyano S. Chemistry Letters, 2002, 102-103).

[0005]

[0006] 2. 9-Phenanthrene methyl sulfide and dichlorocarbene were used as raw materials to prepare 9-phenanthrene carboxylic acid by substitution, oxidation and acidification (Mueller, P., Bernardinelli, G., Pautex, N. Tetrahedron Letters, 1988, 29, 5877-5880).

[0007]

[0008] 3. 9-Phenanthrene carboxylic acid was prepared from 9-chloromethylphenanthrene through substitution and oxidation (Wu, G., Ma, Y., Li, Z., Xu, J. Huaxue Xuebao, 1987, 45, 875-880).

[0009]

[0010] 4. Using phenanthrene as the raw material, 9-phenanthrene formic acid was prepared by bromination, substitution, and acidification (Wang Ligeng, Chen Lujun, Zhang Hualong, et al., A method for preparing 9-bromophenanthrene, CN107151197; Bu Xianhe, Wang Junjie, Liu Chunsen, et al., A method for synthesizing 9-phenanthrene acid, CN101016243).

[0011]

[0012] The above-mentioned synthesis methods have many disadvantages, such as harsh reaction conditions, high reaction difficulty, low conversion rate and yield, difficult post-processing, expensive and dangerous reagents, etc. They can only be synthesized in the laboratory, which is not conducive to industrial production. Summary of the Invention

[0013] The present invention aims to provide a method for preparing 9-phenanthroline formic acid to solve the problems of difficult operation, high pollution, and high cost in the production process of 9-phenanthroline formic acid proposed in the background art. The 9-phenanthroline formic acid synthesis process of the present invention adopts conventional reactions, mild conditions, inexpensive reagents, simple post-processing, and high yield, and is suitable for large-scale industrial production.

[0014] To achieve the above object, the present invention provides the following technical solution: a method for preparing 9-phenanthroline carboxylic acid, the preparation method comprising the following steps:

[0015] 1) Using phenanthrene as the main raw material and iron bromide or zinc bromide as the catalyst, react with hydrobromic acid and hydrogen peroxide at 20-50°C for 3 hours, filter and dry to obtain 9-bromophenanthrene.

[0016] 2) 9-bromophenanthrene is reacted with cyanide in the presence of a catalyst at 50-100°C for 6 hours, concentrated, filtered, and dried to obtain 9-nitrophenanthrene.

[0017] 3) 9-Phenytrile is hydrolyzed under alkaline conditions at 60-100°C. After the reaction is completed, a small amount of insoluble impurities are removed by filtration. The filtrate is adjusted to a pH of 2-3 with hydrochloric acid and filtered. Methanol and activated carbon are added to the filter cake, and the mixture is decolorized, recrystallized, and dried to obtain 9-phenanthroline formic acid. The reaction equation is as follows:

[0018]

[0019] Where:

[0020] Cat. is a catalyst;

[0021] OH - A certain base.

[0022] The present invention aims to provide a method for preparing 9-phenanthrene carboxylic acid. The polycyclic aromatic hydrocarbon phenanthrene and its derivatives have a large π system. When coordinated with metal ions, they can produce weak interactions such as π…π, C—H…π, and hydrogen bonds, resulting in novel structures and unique functionalities. These materials have broad potential applications in optical, electrical, and magnetic properties. Currently, organic optoelectronic materials containing polycyclic aromatic hydrocarbon structures have attracted widespread attention. Materials containing phenanthrene or phenanthrene derivatives are increasingly demonstrating their high application value due to their high photothermal stability.

[0023] The synthesis process of 9-phenanthroline carboxylic acid adopts conventional reactions, has mild conditions, inexpensive reagents, simple post-treatment and high yield, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0025] Figure 1 The present invention is a schematic flow diagram of a method for preparing 9-phenanthroline carboxylic acid.

[0026] Figure 2 9-phenanthroline carboxylic acid 1 HNMR spectrum.

[0027] Figure 3 9-phenanthroline carboxylic acid 13 CNMR spectrum. DETAILED DESCRIPTION

[0028] In order to better understand the purpose, process and results of the present invention, the preparation method of 9-phenanthroline carboxylic acid of the present invention is further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited thereto.

[0029] Example 1

[0030] Phenanthrene (17.8 g, 0.100 mol) and hydrobromic acid solution (40.5 g, 0.200 mol) were placed in a reaction flask and stirred. Copper bromide (0.005 mol) was then added dropwise. Hydrogen peroxide (22.7 g, 0.200 mol) was slowly added at 40°C. The reaction was continued for 2 h after addition. TLC analysis revealed no phenanthrene. The reaction solution was cooled to 10°C, filtered, washed with water, and dried to yield 22.5 g of 9-bromophenanthrene.

[0031] 9-Bromophenanthrene (22.5 g, 0.087 mol), 100 ml of ethylene glycol dimethyl ether, and sodium cyanide solution (20 g, 0.131 mol) were placed in a reaction flask and stirred. Benzyltriethylammonium chloride (0.005 mol) was then added and the mixture was incubated at 85°C for 6 h. TLC analysis revealed the absence of 9-bromophenanthrene. The reaction solution was concentrated under reduced pressure to remove the ethylene glycol dimethyl ether, cooled to 20°C, filtered, washed with water, and dried to yield 15.3 g of 9-cyanophenanthrene.

[0032] 9-Phenanthrenenitrile (15.3g, 0.075mol), sodium hydroxide (24.0g, 0.600mol), 10ml of anhydrous ethanol, and 10ml of water were placed in a reaction flask and stirred. The mixture was heated to reflux for 4 hours. TLC analysis revealed no 9-phenanthrenenitrile. After the reaction was completed, the mixture was cooled to room temperature and filtered to remove a small amount of insoluble impurities. The filtrate was adjusted to a pH of 2-3 with hydrochloric acid and filtered. The filter cake was then added with 60ml of methanol and 0.8g of activated carbon. The mixture was heated at reflux for 1 hour to decolorize the mixture. The mixture was filtered while hot. The filtrate was refrigerated (4°C) overnight, filtered, and dried to yield 15.4g of 9-phenanthrenenitrile acid. Total yield: 69.4%, HPLC (liquid chromatography): 99.3%.

[0033] Example 2

[0034] Phenanthrene (20 g, 0.112 mol) and hydrobromic acid solution (45.4 g, 0.224 mol) were placed in a reaction flask and stirred. Zinc bromide (0.006 mol) was then added dropwise. Hydrogen peroxide (25.4 g, 0.224 mol) was slowly added at 30°C. The reaction was continued for 4 hours after addition. TLC analysis showed the absence of phenanthrene. The reaction solution was cooled to 10°C, filtered, washed with water, and dried to obtain 23.6 g of 9-bromophenanthrene.

[0035] 9-Bromophenanthrene (23.6 g, 0.091 mol), 100 ml of ethylene glycol dimethyl ether, and sodium cyanide solution (27.8 g, 0.182 mol) were placed in a reaction flask and stirred. Tetrabutylammonium bromide (0.005 mol) was then added and the mixture was incubated at 75°C for 6 h. TLC analysis revealed the absence of 9-bromophenanthrene. The reaction solution was concentrated under reduced pressure to remove the ethylene glycol dimethyl ether, cooled to 20°C, filtered, washed with water, and dried to yield 16.6 g of 9-nitrile phenanthrene.

[0036] 9-Phenanthrenenitrile (16.6g, 0.082mol), potassium hydroxide (22.4g, 0.400mol), 10ml of anhydrous ethanol, and 10ml of water were placed in a reaction flask and stirred. The mixture was heated to reflux for 4 hours. TLC analysis revealed no 9-phenanthrenenitrile. After the reaction was completed, the mixture was cooled to room temperature and filtered to remove a small amount of insoluble impurities. The filtrate was adjusted to a pH of 2-3 with hydrochloric acid and filtered. The filter cake was then added with 60ml of methanol and 0.8g of activated carbon. The mixture was heated at reflux for 1 hour to decolorize the mixture. The mixture was filtered while hot. The filtrate was refrigerated (4°C) overnight, filtered, and dried to yield 16.1g of 9-phenanthrenenitrile acid. Total yield: 64.6%, HPLC (liquid chromatography): 99.0%.

[0037] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A method for preparing 9-phenanthroline carboxylic acid, characterized in that: Phenanthrene is used as the main raw material and copper bromide or zinc bromide is used as a catalyst. It reacts with hydrobromic acid and hydrogen peroxide at 20-50°C to generate 9-bromophenanthrene. 9-bromophenanthrene reacts with cyanide in the presence of a catalyst to generate 9-nitrophenanthrene, which is then hydrolyzed under alkaline conditions to obtain 9-phenanthrene formic acid. The reaction equation is as follows: ； Where: Cat. is a catalyst; OH - For a certain base; In the reaction in which 9-bromophenanthrene reacts with cyanide in the presence of a catalyst to generate 9-nitrilephenanthrene, the catalyst is benzyltrimethylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, 18 crown 6, or 15 crown 5.

2. A method for preparing 9-phenanthroline carboxylic acid according to claim 1, characterized in that, The bromination temperature is 30-40°C.

3. A method for preparing 9-phenanthroline carboxylic acid according to claim 1, characterized in that, The amount of the catalyst in the first step reaction is 1-5% (by weight) of phenanthrene.

4. A method for preparing 9-phenanthric acid according to claim 1, characterized in that, The cyanide is sodium cyanide, potassium cyanide, or cuprous cyanide, and the reaction temperature of the second step reaction is 50-100°C.

5. A method for preparing 9-phenanthric acid according to claim 4, characterized in that, The reaction temperature of the second step reaction is 75-85°C.

6. A method for preparing 9-phenanthroline carboxylic acid according to claim 1, characterized in that, The amount of the catalyst in the second step reaction is 1-5% by weight of 9-bromophenanthrene.

7. A method for preparing 9-phenanthroline carboxylic acid according to claim 1, characterized in that, The base is lithium hydroxide, sodium hydroxide, or potassium hydroxide, and the molar ratio of the base to 9-nitrophenanthrene is 3-6:

1.

8. A method for preparing 9-phenanthric acid according to claim 7, characterized in that, The hydrolysis temperature is 60-100°C.

9. A method for preparing 9-phenanthric acid according to claim 8, characterized in that, The hydrolysis temperature is 70-80°C.

10. The method for preparing 9-phenanthroline carboxylic acid according to claim 7, wherein: The purification method of 9-phenanthroline carboxylic acid is as follows: after the reaction is completed, a small amount of insoluble impurities are removed by filtration, the filtrate is added with hydrochloric acid to adjust the pH value to 2-3, filtered, methanol and activated carbon are added to the filter cake, decolorized, recrystallized, and dried to obtain 9-phenanthroline carboxylic acid.

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