5-Fluoro-2-nitroaniline is an organic compound with specific chemical structure and physical properties. This compound has high lipophilicity and is easy to penetrate the cell membrane. In addition, the product has low toxicity, giving it certain advantages in distribution and metabolism in the body.
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5-Fluoro-2-nitroaniline is an important nitrogen-containing aromatic compound widely used in fields such as medicine, dyes, materials, etc. The following introduces various synthesis methods of 5-fluoro-2-nitroaniline.
Method 1:
Synthesis of 5-fluoro-2-nitroaniline through reduction reaction. The following are the detailed steps of this method and its corresponding chemical equations.
1、 Prepare reaction raw materials and equipment
The required raw materials include 5-fluoro-2-nitrophenol, alcohol solvent (such as ethanol), sodium borohydride, and dilute acid (such as dilute nitric acid). The required equipment includes beakers, mixers, heaters, droppers, crystallization vessels, electronic scales, etc.
2、 Operating Steps
Step 1: Dissolve 5-fluoro-2-nitrophenol in an alcohol solvent to form an organic phase.
The corresponding chemical equation is: C6H4FNO2 (s)+CH3CH2OH (aq) → C6H4FNO2 (aq)+CH3CH2OH (aq)
In this step, 5-fluoro-2-nitrophenol (C6H4FNO2) is dissolved in ethanol (CH3CH2OH) to form a homogeneous solution.
Step 2: Add sodium borohydride as a reducing agent to the organic phase and heat the reaction system to the desired temperature.
The corresponding chemical equation is: C6H4FNO2 (aq)+NaBH4 (aq) → C6H4FNO2H (aq)+NaOH (aq)+H2 (g)
In this step, sodium borohydride (NaBH4) is used as a reducing agent to reduce 5-fluoro-2-nitrophenol (C6H4FNO2) to 5-fluoro-2-nitroaniline alcohol (C6H4FNO2H). At the same time, sodium hydroxide (NaOH) and hydrogen gas (H2) are generated.
Step 3: Maintain a certain period of time to allow the reaction to proceed fully. It can be observed that the color of the organic phase gradually changes.
The corresponding chemical equation is: C6H4FNO2H (aq)+NaOH (aq) → C6H4FNO2 (aq)+NaNO2 (aq)+H2O (l)
In this step, 5-fluoro-2-nitroaniline alcohol (C6H4FNO2H) reacts with sodium hydroxide (NaOH) to generate 5-fluoro-2-nitroaniline (C6H4FNO2) and sodium nitrite (NaNO2). At the same time, water (H2O) is generated.
Step 4: When the reaction is nearing completion, take a small amount of reaction solution for testing to confirm that the reduction reaction has been completed. If there are still unreduced nitro groups, sodium borohydride can be added and heated until all are reduced.
The corresponding chemical equation is: C6H4FNO2 (aq)+NaBH4 (aq) → C6H4FNO2H (aq)+NaOH (aq)+H2 (g)
In this step, if there is still unreduced 5-fluoro-2-nitrophenol (C6H4FNO2), sodium borohydride (NaBH4) can be added and heated until all are reduced to 5-fluoro-2-nitroaniline alcohol (C6H4FNO2H).
Step 5: After the reaction is completed, cool the reaction solution to room temperature.
The corresponding chemical equation is: C6H4FNO2H (aq)+NaOH (aq) → C6H4FNO2 (aq)+NaNO2 (aq)+H2O (l)
In this step, the reaction system is cooled to room temperature to further react with 5-fluoro-2-nitroaniline alcohol (C6H4FNO2H) to generate 5-fluoro-2-nitroaniline (C6H4FNO2).
Step 6: Add dilute acid to the cooled reaction solution for acidification treatment. This step is to convert sodium borohydride into the corresponding acid and release hydrogen gas.
The corresponding chemical equation is: NaBH4 (aq)+HCl (aq) → B (OH) 3 (s)+NaCl (aq)+H2 (g)
In this step, dilute acid (such as dilute hydrochloric acid and nitric acid) is added to convert the remaining sodium borohydride into boric acid (B (OH) 3), while releasing hydrogen gas (H2).
Step 7: Wash the reaction product with a mixture of ethanol and water to remove unreacted alcohol solvents and possible impurities.
The corresponding chemical equation is: C6H4FNO2+HCl (aq) → C6H4FNO2Cl (aq)+NaCl (aq)+H2O (l)
In this step, the reaction product is washed with a mixture of ethanol and water to remove unreacted alcohol solvents and possible impurities. At the same time, dissolve the generated sodium chloride in water.
Step 8: Cool the washed solution naturally in a crystallization dish until the crystals precipitate.
Method 2:
The above method is a chemical reaction process for synthesizing 5-fluoro-2-nitroaniline, which mainly involves the amination reaction between amino compounds and CN bonds. The following are the detailed steps of this method and its corresponding chemical equations:
1、 Prepare reaction raw materials and equipment
The required raw materials include 2-amino-5-fluorobenzoic acid ethyl ester, catalysts (such as ferrous salts and copper salts), sodium hydroxide, solvents (such as ethanol), etc. The required equipment includes a reactor, stirrer, thermometer, dropper, crystallization vessel, etc.
2、 Synthesis steps
Step 1: Add 2-amino-5-fluorobenzoic acid ethyl ester and an appropriate amount of solvent to the reaction kettle, and stir evenly. In this step, 2-amino-5-fluorobenzoic acid ethyl ester is the starting material, which is a compound containing amino and carboxyl groups.
Step 2: Add catalysts, such as ferrous or copper salts, and heat the reaction system to the desired temperature. In this step, the role of the catalyst is to promote the reaction.
Step 3: Maintain a certain period of time to allow the reaction to proceed fully. Changes in the color of the reaction system can be observed. This is due to the ongoing reaction, which has produced some new chemical substances.
Step 4: When the reaction is nearing completion, take a small amount of reaction solution for testing to confirm that the ammonolysis reaction has been completed. If there are still amino compounds that have not been ammoniated, the catalyst can be added and heated until they are fully ammoniated. In this step, confirming the completion of the reaction through testing is to ensure that the reaction is complete, avoid wasting raw materials, and reduce yield.
Step 5: Add alkaline substances such as sodium hydroxide to the reaction system and continue heating the reaction. In this step, alkaline substances are added to neutralize potential acidic substances, ensuring the progress of the reaction and the stability of the product.
Step 6: Under the abnormal action of sodium salt, the reaction generates the product 5-fluoro-2-nitroaniline. In this step, the amino group is converted into nitro group through the action of sodium salt, thereby obtaining the target product.
Step 7: Cool the reaction solution to room temperature and filter out impurities such as catalyst. In this step, filtration is used to separate insoluble impurities such as catalysts and obtain a pure reaction solution.
Step 8: Cool the filtrate naturally in a crystallization dish until the crystals precipitate. In this step, the target product is crystallized and precipitated by cooling the filtrate to obtain a solid product.
Step 9: Use an electronic balance to weigh the crystalline product and calculate the yield. In this step, weighing the crystalline product is to determine the quality and yield of the product, in order to evaluate the effectiveness and economic benefits of the reaction.
Step 10: By further purification (such as recrystallization, chromatography, etc.), a higher purity 5-fluoro-2-nitroaniline product can be obtained. In this step, further purification is to improve the purity of the product to meet the requirements of practical applications.
3、 Chemical equation
In the synthesis process of this method, the following chemical equations are mainly involved:
Aminolysis reaction of 2-amino-5-fluorobenzoic acid ethyl ester with catalyst:
C9H10FNO2+catalyst → 2-amino-5-fluorobenzoic acid amine+C2H4O2/C2H6O
Neutralization reaction between sodium hydroxide and acidic substances:
H++OH- → H2O
Nitration reaction of sodium salt with 2-amino-5-fluorobenzoic acid amine:
2-Amino-5-fluorobenzoic acid amine+NaNO2 → C6H5FN2O2+NaOH+H2O
These chemical equations demonstrate the various chemical reaction processes and their interrelationships that occur in this method. These equations can provide a better understanding of the chemical principles and reaction processes of this method. It should be noted that other side reactions and intermediates may also be involved in the actual reaction process, and only the chemical equations of the main reactions are listed here.
The above are various synthesis methods for 5-fluoro-2-nitroaniline, each with its own advantages and disadvantages, and suitable synthesis methods can be selected according to actual needs. Among them, the cost of synthesis through nitrification reaction is lower, but the safety risk is higher, while the cost of synthesis through reduction reaction is higher, but the danger is less, and careful selection is needed.