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Preparation method of highly selective 3-methyl-2-nitrobenzoic acid

A technology of nitrobenzoic acid and toluic acid is applied in the field of preparation of 3-methyl-2-nitrobenzoic acid, can solve problems such as limited application, and achieves improved cleanliness, reduced environmental pollution and high yield Effect

Inactive Publication Date: 2017-03-15
安徽安生生物化工科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Literature Bulletin of the Chemical Society of Japan; 60 (10); 3659-3662; 1987; 3-methyl-2-nitrobenzene was obtained by using 3-methylbenzoic acid as raw material, nitrogen dioxide and nitric acid as nitrating reagents Formic acid, the yield is 49%. Nitrogen dioxide is used as a nitrating reagent, which limits its application due to the difficulty of transportation and tail gas treatment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add 27.2g of 3-methylbenzoic acid, 50mL of methanol, and 4mL of concentrated sulfuric acid into a 250mL single-necked bottle, and reflux for 2h to 3h. After the reaction was completed, methanol was concentrated to remove, and the organic phase was washed with saturated potassium bicarbonate solution (30 mL×3), purified water (30 mL), and dried to obtain 28.82 g of a yellow liquid with a yield of 96.08% and a purity of 98.64%.

[0027] Add 4.8mL 65% nitric acid (0.07moL) into a 100mL round bottom flask, add dropwise 7.6mL (0.08 moL) acetic anhydride, dropwise, after reaction for 0.5h, mix 7.6mL acetic anhydride, 5.4mL acetic acid, 3.0g 3- Methyl toluate (0.02moL) was mixed and slowly added dropwise to the reaction system. The above operations were all carried out under ice-bath conditions. After dropping, raise the temperature to 30°C and react for 3 hours. After stopping the reaction, distill off the acetic anhydride, nitric acid and the generated glacial acetic acid. P...

Embodiment 2

[0030] Add 109g of 3-methylbenzoic acid, 300mL of methanol, and 8mL of concentrated sulfuric acid into a 250mL single-necked bottle, and reflux for 2h to 3h. After the reaction, methanol was concentrated to remove, the organic phase was washed with saturated sodium carbonate solution (120mL×3), purified water (120mL), and dried to obtain 86.56g of yellow liquid with a yield of 72.72% and a purity of 96.94%.

[0031] Add 2.7mL 65% nitric acid (0.04moL) to a 100mL round bottom flask, add dropwise 3.8mL (0.04 moL) acetic anhydride, dropwise, after 0.5h of reaction, add 3.8mL acetic anhydride, 2.7mL dichloromethane, 3.0 g Methyl 3-methylbenzoate (0.02moL) was mixed and slowly added dropwise to the reaction system. The above operations were all carried out under ice bath conditions. After dropping, raise the temperature to 40°C~50°C and react for 15 minutes. After stopping the reaction, distill off acetic anhydride and glacial acetic acid, pour the concentrated solution into ice wa...

Embodiment 3

[0034] Add 109g of 3-methylbenzoic acid, 370mL of n-butanol, and 80mL of concentrated sulfuric acid into a 250mL single-necked bottle, and reflux for 2h to 3h. After the reaction was completed, n-butanol was removed by concentration, and the organic phase was washed with saturated sodium bicarbonate solution (80 mL×3), purified water (80 mL), and dried to obtain 127.6 g of a yellow liquid with a yield of 75.92% and a purity of 97.34%.

[0035] Add 4.8mL 95% nitric acid (0.11moL) to a 100mL round-bottomed flask, add 8.6mL (0.011moL) acetic anhydride dropwise, and after the reaction for 1.0h, add 5.2mL acetic anhydride, 5.5mL 1,2-dichloro After mixing ethane and 6.72 g of n-butyl 3-methylbenzoate, they were slowly added dropwise into the reaction system, and the above operations were all carried out under ice-bath conditions. After dripping, raise the temperature to 15°C~20°C to react, stop the reaction, distill off acetic anhydride, nitric acid and the generated glacial acetic ...

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Abstract

The invention discloses a preparation method of 3-methyl-2-nitrobenzoic acid. 3-methylbenzoic acid alkyl ester is used as raw material in nitrification, two-grade selectivity and high yield are realized, and the amount of waste acid was reduced. In nitrification product, only 3-methyl 2-nitrobenzoic acid alkyl ester and 3-methyl-4-nitrobenzoic acid alkyl ester are hydrolyzed after separation to obtain 3-methyl 2-Nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid. The process is simple, and suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and specifically relates to a preparation method of 3-methyl-2-nitrobenzoic acid. Background technique [0002] 3-Methyl-2-nitrobenzoic acid is the raw material for the synthesis of 2-amino-5-chloro-N,3-dimethylbenzamide, and is widely used in the pesticide and pharmaceutical markets. [0003] At present, known about the preparation method of 3-methyl-2-nitrobenzoic acid mainly contains following several kinds: [0004] In the literature Qin Tao's master's thesis of Nanjing University of Science and Technology "Study on the Nitration Selectivity of Meta-Substituted Toluene", 3-methyl-2- Methyl nitrobenzoate produces a large amount of waste acid during the reaction, which is difficult to handle. [0005] Literature Tetrahedron Letters, 47 (49): 8651–8652; 2006; 3-methylbenzoic acid was used as raw material, urea mononitrate or nitrourea was used as nitrating reagent to synthesize crude 3-methyl-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/57
CPCC07C67/08C07C201/08C07C201/12C07C201/16C07C69/76C07C205/57
Inventor 李凤和梅文艺边侠玲杨新宇
Owner 安徽安生生物化工科技有限责任公司
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