Synthesis method of N-(2, 4-dichloro-5-nitrophenyl) acetamide
Through the improved synthesis method, N-(2,4-dichloroaniline, reaction with acetic anhydride and triethylamine, combined with mixed acid solution of concentrated sulfuric acid and concentrated nitric acid, the N-(2,4-dichloro-5- was successfully improved by using the reaction of 2,4-dichloroaniline, acetic anhydride and triethylamine, combined with mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. The yield of nitrophenyl)acetamide reduces production costs and sulfuric acid usage and reduces pollution.
Patent Information
- Application Number
- CN202411348016.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2024-12-31
AI Technical Summary
In the prior art, the synthetic yield of N-(2,4-dichloro-5-nitrophenyl)acetamide is relatively low, the production cost is high, and the amount of sulfuric acid is large, resulting in serious environmental pollution.
2,4-dichloroaniline reacts with acetic anhydride and triethylamine to form N-acetyl-N-(2,4-dichlorophenyl)acetamide, and then adds it dropwise to concentrated sulfuric acid, concentrated nitric acid and The mixed acid solution composed of fumed nitric acid was stirred and filtered at room temperature, then crystallized in ice water, and purified using a mixed solution of distilled water and ethanol water.
It improves synthetic yield, reduces production costs, and reduces sulfuric acid usage and reduces environmental pollution.
Smart Images
Figure CN119219514A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide, belonging to the technical field of organic synthesis. Background Art
[0002] Sulfonamidone is a triazolinone herbicide with a chemical name of N-(2,4-dichloro-5-(4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl)phenyl)methanesulfonamide. There are many synthetic routes for sulfonamidone. Among them, Chinese invention patent ZL2021113152229 discloses a method for preparing sulfonamidone. Compared with other synthetic routes, this method has a higher yield, lower cost and is easy to implement. N-(2,4-dichloro-5-nitrophenyl)acetamide is an important intermediate for preparing sulfonamidone by this method. In the patent document, 2,4-dichloroaniline is used as a raw material, and N-(2,4-dichloro-5-nitrophenyl)acetamide is obtained by mixed acid nitration and acetylation. The path is as follows:
[0003]
[0004] In the method, the yield of the mixed acid nitration step is 80%, the yield of the acetylation step is 95%, and the total yield of N-(2,4-dichloro-5-nitrophenyl)acetamide is about 76%. The total yield is somewhat low, resulting in high production costs. In addition, a large amount of sulfuric acid is used in the synthesis process, resulting in serious pollution. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide, which can improve the reaction yield, reduce the production cost, reduce the amount of sulfuric acid used, and alleviate the pollution to the environment.
[0006] To achieve the above object, the present invention adopts the following technical solution:
[0007] A method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide comprises the following steps:
[0008] (1) adding 2,4-dichloroaniline, acetic anhydride and triethylamine into a reaction container, heating the reaction under nitrogen protection, and separating and purifying the obtained reaction product to obtain N-acetyl-N-(2,4-dichlorophenyl)acetamide;
[0009] (2) N-acetyl-N-(2,4-dichlorophenyl)acetamide is added dropwise to a mixed acid solution consisting of concentrated sulfuric acid, concentrated nitric acid and fuming nitric acid in a volume ratio of 10:5:1, and the mixture is stirred at room temperature for reaction. The obtained reaction mixture is added to an ice-water mixture, stirred, and filtered to collect a solid product. The solid product is washed with distilled water and then crystallized in a mixed solution of ethanol and water to obtain the product.
[0010] Furthermore, in step (1), the reaction temperature is 110-130° C. and the reaction time is 6-10 h.
[0011] Furthermore, in step (1), the separation and purification method is: first distilling the obtained reaction product to remove the generated acetic acid, excess acetic anhydride and triethylamine, then adding water to the residue, then extracting with ethyl acetate three times, combining the ethyl acetate layers, washing the ethyl acetate layers with saturated brine, and then drying with anhydrous sodium sulfate, filtering, and then removing the ethyl acetate by rotary evaporation.
[0012] Furthermore, in step (2), the amount of the mixed acid solution used per gram of N-acetyl-N-(2,4-dichlorophenyl)acetamide is 3 to 4 ml.
[0013] Furthermore, in step (2), the stirring reaction is carried out for 3 to 5 hours.
[0014] Furthermore, in step (2), in the mixed solution of ethanol and water, the volume ratio of ethanol to water is 3:1.
[0015] The synthetic route of the present invention is as follows:
[0016]
[0017] Beneficial effects of the invention: The invention discloses a method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide, which uses 2,4-dichloroaniline as a starting material, acetylates amino groups, and then nitrates them with mixed acid to synthesize N-(2,4-dichloro-5-nitrophenyl)acetamide. The method is easy to implement, and the raw materials involved are cheap and easy to obtain. Compared with the existing technology for synthesizing N-acetyl-N-(2,4-dichlorophenyl)acetamide, the method improves the synthesis yield, reduces the production cost of the target product, and reduces the amount of sulfuric acid used, thereby alleviating pollution. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is the hydrogen spectrum of the product N-acetyl-N-(2,4-dichlorophenyl)acetamide synthesized in Example 1;
[0019] Figure 2 The carbon spectrum of the product N-acetyl-N-(2,4-dichlorophenyl)acetamide synthesized in Example 1;
[0020] Figure 3 This is the mass spectrum of the product N-acetyl-N-(2,4-dichlorophenyl)acetamide synthesized in Example 1. DETAILED DESCRIPTION
[0021] The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.
[0022] Example 1
[0023] A method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide comprises the following steps:
[0024] (1) Synthesis of N-acetyl-N-(2,4-dichlorophenyl)acetamide
[0025] Add 32.40 g (0.20 mol) of 2,4-dichloroaniline, 47 ml (0.50 mol) of acetic anhydride and 69.5 ml (0.50 mol) of triethylamine into a 250 ml three-necked flask, stir and mix evenly. Heat to 120°C under nitrogen protection and react for 8 hours. After the reaction is completed, distill to remove the generated acetic acid, excess acetic anhydride and triethylamine, add 150 ml of water to the residue, extract three times with 100 ml of ethyl acetate respectively, combine the ethyl acetate layers, wash once with 100 ml of saturated brine, dry the ethyl acetate layer with anhydrous sodium sulfate, filter, and rotary evaporate to remove ethyl acetate to obtain 48.15 g of colorless oily product N-acetyl-N-(2,4-dichlorophenyl) acetamide, with a purity of 92% and a yield of 90%.
[0026] Figure 1 is the hydrogen spectrum of the synthetic product, 1 H NMR (500MHz, CDCl3) δ7.55 (1H, s, -C6H-), 7.33 (1H, d, -C6H-), 7.19 (1H, d, -C6H-), 2.26 (6H, s, -CH3CO-); Figure 2 is the carbon spectrum of the synthetic product, 13 C NMR (500MHz, CDCl3) δ171.69(-C=O-), 128.59~135.83(-C6H3-), 26.21(-CH3-); Figure 3 The gas chromatography-mass spectrometry mass spectrum of the synthetic product, m / z: 245, 247, C 10 H9Cl2NO2 m / z calculated: 245, 247.
[0027] Depend on Figures 1 to 3 It can be concluded that the synthetic product is N-acetyl-N-(2,4-dichlorophenyl)acetamide.
[0028] (2) Synthesis of N-(2,4-dichloro-5-nitrophenyl)acetamide
[0029] 100 ml of concentrated sulfuric acid, 50 ml of concentrated nitric acid and 10 ml of fuming nitric acid were added to a 250 ml single-necked flask, and the mixture was stirred and mixed evenly under ice-water cooling to form a mixed acid solution; 48.15 g (0.18 mol, purity 92%) of N-acetyl-N-(2,4-dichlorophenyl)acetamide synthesized in step 1) was added dropwise to the mixed acid solution, and the reaction was continued under stirring at room temperature for 4 hours after the addition was completed. The obtained reaction mixture was slowly added to 500 g of ice-water mixture and stirred. A large amount of light yellow solid precipitated. The solid was collected by filtration, and the filter cake was rinsed once with 100 ml of distilled water. The solid was taken out and crystallized in ethanol / water (ethanol / water volume ratio of 3:1) to obtain 42.59 g (0.17 mol) of N-(2,4-dichloro-5-nitrophenyl)acetamide, with a yield of 95%.
[0030] Comparative Example 1
[0031] 64.80 g (0.40 mol) of 2,4-dichloroaniline and 300 ml of concentrated sulfuric acid were added to a 500 ml round-bottom flask, and then cooled in an ice-water bath; a mixture of 160 ml of concentrated sulfuric acid and 16 ml of concentrated nitric acid was added dropwise at 0°C, and the reaction was continued at the same temperature for 2 hours after the addition was complete. The reaction mixture was then added to 1500 ml of ice-water mixture, the precipitate was filtered out, and crystallized in an isopropanol / water mixed solvent (the volume ratio of the two in the isopropanol / water mixed solvent was 3:1) to obtain 66.24 g (0.32 mol) of 2,4-dichloro-5-nitroaniline, with a yield of 80%.
[0032] Add 200 ml of dichloromethane, 62.10 g (0.30 mol) of 2,4-dichloro-5-nitroaniline and 66.79 g (0.66 mol) of triethylamine into a 500 ml round-bottom flask and stir evenly. Add 86.35 g (0.33 mol) of acetyl chloride to the flask at room temperature, and continue to react at room temperature for 5 hours after the addition is complete. After the reaction is complete, add the reaction mixture to 200 ml of ice water, separate the liquids, wash the dichloromethane layer twice with 100 ml of saturated brine, wash once with 100 ml of water, dry over anhydrous sodium sulfate, filter, remove the dichloromethane, and crystallize the crude product obtained in ethanol / water (the volume ratio of the two in ethanol / water is 2:1) to obtain 70.97 g (0.285 mol) of N-(2,4-dichloro-5-nitrophenyl) acetamide, with a yield of 95%.
Claims
1. A method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide, characterized in that: The steps include: (1) adding 2,4-dichloroaniline, acetic anhydride and triethylamine into a reaction container, heating the reaction under nitrogen protection, and separating and purifying the obtained reaction product to obtain N-acetyl-N-(2,4-dichlorophenyl)acetamide; (2) N-acetyl-N-(2,4-dichlorophenyl)acetamide is added dropwise to a mixed acid solution consisting of concentrated sulfuric acid, concentrated nitric acid and fuming nitric acid in a volume ratio of 10:5:1, and the mixture is stirred at room temperature for reaction. The obtained reaction mixture is added to an ice-water mixture, stirred, and filtered to collect a solid product. The solid product is washed with distilled water and then crystallized in a mixed solvent of ethanol and water to obtain the product.
2. The method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide according to claim 1, characterized in that: In step (1), the reaction temperature is 110-130° C. and the reaction time is 6-10 h.
3. The method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide according to claim 1, characterized in that: In step (1), the separation and purification method is: first distill the obtained reaction product to remove the generated acetic acid, excess acetic anhydride and triethylamine, then add water to the residue, then extract with ethyl acetate three times, combine the ethyl acetate layers, wash the ethyl acetate layers with saturated brine, and then dry them with anhydrous sodium sulfate, filter, and then remove the ethyl acetate by rotary evaporation.
4. The method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide according to claim 1, characterized in that: In step (2), the amount of the mixed acid solution used per gram of N-acetyl-N-(2,4-dichlorophenyl)acetamide is 3 to 4 ml.
5. The method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide as claimed in claim 1, characterized in that: In step (2), the stirring reaction is carried out for 3 to 5 hours.
6. The method for synthesizing N-(2,4-dichloro-5-nitrophenyl)acetamide according to any one of claims 1 to 5, characterized in that: In step (2), in the mixed solution of ethanol and water, the volume ratio of ethanol to water is 3:1.