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Synthesis method of 2-methyl-4-nitrobenzoic acid

A technology of nitrobenzoic acid and synthesis method, which is applied in the field of synthesizing 2-methyl-4-nitrobenzoic acid, can solve the problems of non-sustainable development, non-compliance with green chemistry, serious environmental pollution, etc., and achieve reaction Improved safety, improved cleanliness, and reduced environmental pollution

Inactive Publication Date: 2013-11-27
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above oxidation methods seriously pollute the environment and do not meet the requirements of green chemistry.
When the environment-friendly dilute nitric acid is used for oxidation, harsh reaction conditions (such as high temperature, high pressure, etc.) are usually required, the requirements for equipment are high, and there are great safety hazards
It can be seen that with the development of environmental economy, the traditional production method of 2-methyl-4-nitrobenzoic acid does not have sustainable development, and a more environmentally friendly method is urgently needed to replace

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 100 mL three-necked flask, add 4-nitro-o-xylene (0.76 g, 5.0 mmol), azobisisobutyronitrile (0.04 g, 0.25 mmol), cetyltrimethylammonium bromide (0.018 g , 0.05 mmol), 10% nitric acid (3.17 g, 5.0 mmol), magnetically stirred, reacted at 50 °C, followed the reaction progress by TLC. After the reaction, it was lowered to room temperature. 2,4-Dinitrotoluene (0.10 g) was added as an internal standard, extracted three times with ethyl acetate (5 mL×3), the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Liquid chromatographic analysis was carried out, and the mass of product 2-methyl 4-nitrobenzoic acid calculated by internal standard method was 0.55 g, and the yield was 60.4%.

Embodiment 2

[0023] In a 100 mL three-necked flask, add 4-nitro-o-xylene (0.75 g, 5.0 mmol), azobisisoheptanonitrile (0.31 g, 1.24 mmol), tetrabutylammonium chloride (0.07 g, 0.25 mmol) , 30% nitric acid (5.21 g, 24.8 mmol), magnetically stirred, reacted at 100 °C, followed the reaction progress with TLC. After the reaction, it was lowered to room temperature. 2,4-Dinitrotoluene (0.10 g) was added as an internal standard, extracted three times with ethyl acetate (5 mL×3), the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Liquid chromatographic analysis was carried out, and the mass of product 2-methyl 4-nitrobenzoic acid calculated by internal standard method was 0.64 g, and the yield was 71.2%.

Embodiment 3

[0025] In a 100 mL three-neck flask, add 4-nitro-o-xylene (0.75 g, 5.0 mmol), N -Hydroxyphthalimide (0.40 g, 2.48 mmol), benzyltriethylammonium chloride (0.11 g, 0.5 mmol), 60% nitric acid (5.21 g, 49.6 mmol), magnetic stirring, at 150 °C The reaction was carried out, and the progress of the reaction was followed by TLC. After the reaction, it was lowered to room temperature. 2,4-Dinitrotoluene (0.10 g) was added as an internal standard, extracted three times with ethyl acetate (5 mL×3), the organic phases were combined, washed with water until neutral, and dried over anhydrous sodium sulfate. Liquid chromatographic analysis was carried out, and the mass of product 2-methyl 4-nitrobenzoic acid calculated by internal standard method was 0.48 g, and the yield was 53.4%.

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Abstract

The invention discloses a synthesis method of 2-methyl-4-nitrobenzoic acid. The method is used for synthesizing the 2-methyl-4-nitrobenzoic acid by taking 4-dimethylnitrobenzene as a basic raw material and dilute nitric acid as an oxidant. A free radical initiator and a phase transfer catalyst which are added in the reaction process can be used for remarkably increasing the reaction yield and ensuring that the yield of the 2-methyl-4-nitrobenzoic acid as an oxidation product is up to 83.5%. The method disclosed by the invention is mild in reaction condition, capable of avoiding high temperature and high pressure, good in selectivity, high in yield and suitable for engineering application.

Description

technical field [0001] The invention relates to a method for synthesizing 2-methyl-4-nitrobenzoic acid, especially a method for selectively oxidizing raw material 4-nitro-o-xylene into 2-methyl-4- Nitrobenzoic acid method. Background technique [0002] 2-Methyl-4-nitrobenzoic acid, as an important pharmaceutical chemical intermediate, can be used to synthesize V2 receptor antagonist-tolvaptan. [0003] At present, the synthesis of 2-methyl-4-nitrobenzoic acid usually adopts the following two routes: (1) hydrolysis of the cyano group of 2-methyl-4-nitrobenzonitrile to carboxyl group (2) 4-amino-2 - Oxidation of the amino group of methylbenzoic acid to the nitro group. However, the synthesis of the above two raw materials requires complex preparation processes. Besides, few studies have been conducted on the preparation of 2-methyl-4-nitrobenzoic acid by selective oxidation of the methyl group of 4-nitro-o-xylene. The reason is that the strong electron-withdrawing effect o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C205/57C07C201/12
Inventor 彭新华唐波魏松波
Owner NANJING UNIV OF SCI & TECH
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