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Production process of 2-chloro-5-nitrobenzoic acid

A technology of nitrobenzoic acid and sodium nitrobenzoate, which is applied in the preparation of nitro compounds, organic chemistry, etc., can solve the problems of being unable to meet the needs of use and difficult to achieve high purity, and achieve strong operability and process Reasonable step design and high purity effect

Inactive Publication Date: 2012-01-25
GUANNAN YISITE CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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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 aci

Method used

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  • Production process of 2-chloro-5-nitrobenzoic acid

Examples

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Effect test

Embodiment 1

[0018] Embodiment 1, a kind of production technology of 2-chloro-5-nitrobenzoic acid, its steps are as follows:

[0019] (1) Nitration: put concentrated sulfuric acid and o-chlorobenzoic acid into the nitrification kettle at a weight ratio of 3.5:1, add nitric acid in the reaction amount dropwise, and control the temperature at 30°C. After checking that there is no o-chlorobenzoic acid residue, the material is discharged into the water analysis kettle, and the 2-chloro-5-nitrobenzoic acid and 2-chloro-3-nitrobenzoic acid crystallization that the reaction generates are separated out, and the crude product is obtained after centrifugal filtration;

[0020] (2) Alkali dissolution: Put the crude product into an alkali dissolution kettle, add water 3.5 times the weight of the crude product, stir and heat up to 60°C, add liquid alkali dropwise to pH=7.5, 2-chloro-5-nitrobenzoic acid and 2- Chloro-3-nitrobenzoic acid is dissolved and reacted with NaOH to generate sodium 2-chloro-5-ni...

Embodiment 2

[0023] Embodiment 2, a kind of production technology of 2-chloro-5-nitrobenzoic acid, its steps are as follows:

[0024] (1) Nitration: put concentrated sulfuric acid and o-chlorobenzoic acid into the nitrification kettle at a weight ratio of 4.5:1, add nitric acid of the reaction amount dropwise, and control the temperature at 40°C. After checking that there is no o-chlorobenzoic acid residue, the material is discharged into the water analysis kettle, and the 2-chloro-5-nitrobenzoic acid and 2-chloro-3-nitrobenzoic acid crystallization that the reaction generates are separated out, and the crude product is obtained after centrifugal filtration;

[0025] (2) Alkali dissolution: Put the crude product into an alkali dissolution kettle, add water 4.5 times the weight of the crude product, stir and heat up to 70°C, add liquid alkali dropwise to pH = 7.5, 2-chloro-5-nitrobenzoic acid and 2- Chloro-3-nitrobenzoic acid is dissolved and reacted with NaOH to generate sodium 2-chloro-5-...

Embodiment 3

[0028] Embodiment 3, a kind of production technology of 2-chloro-5-nitrobenzoic acid, its steps are as follows:

[0029] (1) Nitrification: put concentrated sulfuric acid and o-chlorobenzoic acid into the nitrification kettle at a weight ratio of 4:1, add nitric acid of the reaction amount dropwise, and control the temperature at 35°C. After checking that there is no o-chlorobenzoic acid residue, the material is discharged into the water analysis kettle, and the 2-chloro-5-nitrobenzoic acid and 2-chloro-3-nitrobenzoic acid crystallization that the reaction generates are separated out, and the crude product is obtained after centrifugal filtration;

[0030] (2) Alkali dissolution: Put the crude product into an alkali dissolution kettle, add water 4 times the weight of the crude product, stir and heat up to 65°C, add liquid alkali dropwise to pH=7.5, 2-chloro-5-nitrobenzoic acid and 2- Chloro-3-nitrobenzoic acid is dissolved and reacted with NaOH to generate sodium 2-chloro-5-ni...

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Abstract

The invention relates to a production process of 2-chloro-5-nitrobenzoic acid. The production process is characterized in that 2-chloro-5-nitrobenzoic acid is prepared by the process steps of nitration, alkali dissolution, acid precipitation and the like based on o-chlorobenzoic acid as a raw material; and when nitration is carried out, concentrated sulfuric acid and o-chlorobenzoic acid are added in a nitration kettle in a weight ratio of (3.5-4.5):1 and reaction amount of nitric acid is dropwise added for reaction, so that a crude product is prepared; water and an alkali liquid are added in the crude product so as to carry out alkali dissolution; and acid precipitation is carried out on filtrate so as to obtain the finished product. The production process provided by the invention has reasonable design and strong operability, the purity of the prepared product is high, the chromatographic purity of the product is not less than 99.5%, the yield of the product is above 85%, and the requirement of industrial application can be met.

Description

technical field [0001] The invention relates to a process for preparing 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 more 2-chloro-3-nitrobenzoic acid isomers are produced during nitration , it is difficult to achieve higher purity by conventional refining methods, and generally it can only be controlled at about 99.0%, which cannot meet the needs of use. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a production process of 2-chloro-5-nitrobenzoic acid with more reasonable process and high product purity for the deficiencies in the prior art. [0004] The technical problem to be solved by the present invention is achieved through the following technical solutions. The present invention is a kind of production technology of 2-chloro-5-nitrobenzoi...

Claims

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Application Information

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IPC IPC(8): C07C205/58C07C201/08
Inventor 张守平
Owner GUANNAN YISITE CHEM
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