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Preparation method of 2-chloride-5-nitrobenzoic acid

A technology of nitrobenzoic acid and nitrotrichlorotoluene, applied in the field of preparation of 2-chloro-5-nitrobenzoic acid, can solve the problems of being unable to meet the needs of use, difficult to achieve higher purity, etc., and achieve side effects Fewer products, reasonable design of process steps, and strong operability

Inactive Publication Date: 2017-02-15
枣阳凤泽环化科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The method for preparing 2-chloro-5-nitrobenzoic acid in the prior art is to adopt the method for refining after nitration of o-chlorobenzoic acid, but more 2-chloro-3-nitrobenzoic acid isomers are produced during nitration , it is difficult to achieve high purity by conventional refining methods, generally only controlled at about 99.0%, which cannot meet the needs of use

Method used

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Examples

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Embodiment 1

[0012] In a 500ml four-neck round-bottomed flask equipped with a mechanical stirring device, a cooling device, a thermometer and a dropping funnel, add concentrated nitric acid and SO with a mass ratio of 1 to 3 3 It is 20% oleum, and the mixing process controls the solution temperature to be lower than 10°C. To the resulting mixture of sulfuric acid and nitric acid was added 2-chlorotrichlorotoluene (2-chlorotrichlorotoluene with concentrated nitric acid and SO 3 The mass ratio of the 20% oleum mixed solution is 1:4), the temperature of the reaction solution is controlled to be between 0 and 10°C, and after the dropwise addition is completed, the temperature is maintained and stirring is continued for 2 hours to complete the reaction. The reaction solution was then poured into ice water and solid precipitation was immediately observed. Dichloromethane was added to the mixture for extraction, and the organic phase was extracted with saturated NaHCO 3 The solution was washed,...

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Abstract

The invention provides a preparation method of 2-chloride-5-nitrobenzoic acid. The preparation method comprises the following steps: mixing concentrated nitric acid and fuming sulphuric acid with the SO3 concentration of 20 percent according to the mass ratio of 1:(2-3), and controlling the temperature of the solution to be less than 10 DEG C in a mixing process; dripping 2-chloride trichlorotoluene, controlling the temperature of reaction liquid to be 0 to 10 DEG C, and continuously stirring at the end of dripping till the reaction is completed; pouring the reaction liquid into ice water, extracting with dichloromethane, washing an organic phase with a saturated sodium bicarbonate solution, and concentrating and drying to obtain 2-chloride-5-nitro trichlorotoluene; preparing concentrated sulfuric acid with the concentration of 85 weight percent, heating to 60 to 65 DEG C, adding the 2-chloride-5-nitro trichlorotoluene in batches, and preserving the heat till the reaction is completed; cooling the reaction liquid, adding water into the reaction liquid for dilution, extracting with ethyl acetate, taking an organic phase, and performing washing and concentration to obtain 2-chloride-5-nitrobenzoic acid. The technological steps are more reasonable in design and high in operability; the number of byproducts is small; the prepared product is relatively high in purity and can meet the requirement on industrial application.

Description

technical field [0001] The invention relates to a preparation method of 2-chloro-5-nitrobenzoic acid. Background technique [0002] The method for preparing 2-chloro-5-nitrobenzoic acid in the prior art is to adopt the method for refining after nitration of o-chlorobenzoic acid, but because more 2-chloro-3-nitrobenzoic acid isomers are produced during nitration , it is difficult to achieve high purity by conventional refining methods, generally only controlled at about 99.0%, which cannot meet the needs of use. SUMMARY OF THE INVENTION [0003] The technical problem to be solved by the present invention is aimed at the deficiencies of the prior art, and provides a production process of 2-chloro-5-nitrobenzoic acid with a more reasonable process and high product purity. [0004] The present invention is realized in this way: [0005] A preparation method of 2-chloro-5-nitrobenzoic acid, comprising the following steps: [0006] (1) Concentrated nitric acid and SO with mas...

Claims

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Application Information

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IPC IPC(8): C07C201/12C07C205/58
CPCC07C201/12C07C201/08C07C205/58C07C205/12
Inventor 陈金勇
Owner 枣阳凤泽环化科技有限公司
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