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Preparation method of 2, 4-dichloro-5-fluoro-3-nitrobenzoic acid

A technology of nitrobenzoic acid and fluoroacetophenone, which is applied in the preparation of nitro compounds, organic chemistry, etc., can solve the problems of high cost and low product yield, achieve less three wastes, high product purity, and be conducive to industrialization Effect

Active Publication Date: 2014-07-16
FUXIN RUIGUANG FLUORINE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the low yield and high cost of the two-step synthesis of 2,4-dichloro-5-fluoro-3-nitrobenzyl with 2,4-dichloro-5-fluoroacetophenone as raw material in the prior art problem, the present invention provides a method for one-step synthesis of 2,4-dichloro-5-fluoro-3-nitrobenzoic acid with high product purity, high yield, easy access to raw materials, simple industrial process, and low cost, and its The reaction mother liquor can be recycled to reduce the environmental pollution of subsequent treatment

Method used

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  • Preparation method of 2, 4-dichloro-5-fluoro-3-nitrobenzoic acid

Examples

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Embodiment 1

[0025] Add 80 grams (0.8mol) of concentrated sulfuric acid into a 250ml three-necked flask with a stirrer and a reflux pipe, utilize ice-cooled concentrated sulfuric acid, and add 28.93 grams (0.45 mol) fuming nitric acid, after the addition, the temperature of the mixed solution in the three-necked flask was raised to 103°C, and 10.46 grams (0.05mol) of 2,4-dichloro-5-fluoroacetophenone, which had been melted in advance, was added dropwise, The dropwise addition temperature was controlled at 103-110°C. After the dropwise addition was completed, it was kept at 103°C for 3 hours, cooled to 10°C and filtered, and the filtrate was recovered for later use. The filter cake was washed with water and then recrystallized with toluene to obtain 2,4-dichloro-5 - 11.61 g of fluoro-3-nitrobenzoic acid, with a purity of 99.3%, and a yield of 90.8% based on 2,4-dichloro-5-fluoroacetophenone.

Embodiment 2

[0027] Add 55 grams (0.55mol) of concentrated sulfuric acid into a 250ml three-necked flask with a stirrer and a reflux pipe, utilize ice-cooled concentrated sulfuric acid, and add 19.29 grams (0.3 mol) fuming nitric acid, after the addition, the temperature of the mixed solution in the three-necked flask was raised to 103°C, and 10.46 grams (0.05mol) of 2,4-dichloro-5-fluoroacetophenone, which had been melted in advance, was added dropwise, The dropwise addition temperature was controlled at 103-110°C. After the dropwise addition was completed, it was kept at 106°C for 3 hours, cooled to 10°C and filtered, and the filtrate was recovered for later use. The filter cake was washed with water and then recrystallized with toluene to obtain 2,4-dichloro-5 - Fluoro-3-nitrobenzoic acid 11.67 g, purity 99%, yield 91% based on 2,4-dichloro-5-fluoroacetophenone

Embodiment 3

[0029] Add 80 grams (0.8mol) of concentrated sulfuric acid into a 250ml three-necked flask with a stirrer and a reflux pipe, utilize ice-cooled concentrated sulfuric acid, and add 29.84 grams (0.45 mol) fuming nitric acid, after the addition, the temperature of the mixed solution in the three-necked flask was raised to 103°C, and 10.46 grams (0.05mol) of 2,4-dichloro-5-fluoroacetophenone, which had been melted in advance, was added dropwise, The dropwise addition temperature is controlled at 103-110°C. After the dropwise addition is completed, it is kept at 110°C for 3 hours, cooled to 10°C and filtered, and the filtrate is recovered for later use. After the filter cake is washed with water, it is recrystallized with toluene to obtain 2,4-dichloro-5- Fluoro-3-nitrobenzoic acid 11.46 g, purity 99.7%, yield 90% based on 2,4-dichloro-5-fluoroacetophenone

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Abstract

The invention relates to a preparation method of 2, 4-dichloro-5-fluoro-3-nitrobenzoic acid and belongs to the technical field of chemical engineering, and particularly belongs to the field of chemical synthesis. The preparation method of 2, 4-dichloro-5-fluoro-3-nitrobenzoic acid comprises the following step: carrying out a reaction on 2, 4-dichloro-5-fluoroacetophenone and fuming nitric acid in concentrated sulfuric acid, wherein the molar ratio of 2, 4-dichloro-5-fluoroacetophenone, fuming nitric acid and concentrated sulfuric acid is 1:(6-15):(11-25). The product prepared by the method provided by the invention is high in purity and yield, and the method is less in three waste, simple to operate and beneficial for industrialization.

Description

technical field [0001] The invention relates to a preparation method of 2,4-dichloro-5-fluoro-3-nitrobenzoic acid, which belongs to the technical field of chemical industry, and specifically belongs to the field of chemical synthesis. Background technique [0002] 2,4-dichloro-5-fluoro-3-nitrobenzoic acid, mainly used in the manufacture of anti-infective drug ciprofloxacin, its structural formula is: [0003] [0004] Its synthesis method is a two-step synthesis method using 2,4-dichloro-5-fluoroacetophenone as a raw material. This type of method first uses an oxidant to oxidize the raw material, and then uses nitric acid to carry out a two-step method for nitration, for example: 2 , the total synthesis of 4-dichloro-5-fluorobenzoic acid and 2,4-dichloro-5-fluorobenzoyl acetate (organic fluorine industry (4); P13, 162007) and Chinese patent CN87106482 disclosed A method for synthesizing 2,4-dichloro-5-fluoro-3-nitrobenzoic acid through sodium hypochlorite oxidation and c...

Claims

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Application Information

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IPC IPC(8): C07C205/58C07C201/08
Inventor 姜殿平韩晓东李成斌
Owner FUXIN RUIGUANG FLUORINE CHEM
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