Method for separating 2,5-dichlorophenol and 2,4-dichlorophenol

A technology of dichlorophenol and alkali metal, which is applied in the field of separation of 2,5-dichlorophenol and 2,4-dichlorophenol, can solve problems such as complex process and separation cost, and achieve wide sources, simple operation and low cost. low effect

Active Publication Date: 2018-01-19
SICHUAN FOURSTAR BIOTECH RANDD CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention aims to solve the problems that 2,4-dichlorophenol and 2,5-dichlorophenol cannot be completely separated, the separation cost is high, and the process is complicated in the prior art, and a new method for separating 2,5-dichlorophenol is proposed. The method of phenol and 2,4-dichlorophenol has the advantages of simple operation and low cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The method for separating 2,5-dichlorophenol and 2,4-dichlorophenol, comprises the following steps:

[0033] A. Add xylene to the mixture of 2,5-dichlorophenol and 2,4-dichlorophenol, then add sodium hydroxide solution dropwise, keep stirring at 40°C, then raise the temperature and divide the water to reach the moisture content of the system 900ppm. After cooling to room temperature, filter with suction to obtain a filtrate and a filter cake. The filter cake is acidified to obtain 2,5-dichlorophenol; the filtrate is removed from the organic solvent to obtain a mixed solution for future use;

[0034] B. Add ammonia solution dropwise to the mixed solution obtained after removing xylene in step A, suction filter after stirring, then add xylene to the filter cake for recrystallization to obtain 2,4-dichlorophenol.

Embodiment 2

[0036] The method for separating 2,5-dichlorophenol and 2,4-dichlorophenol, comprises the following steps:

[0037] A. Add toluene to the mixture of 2,5-dichlorophenol and 2,4-dichlorophenol, then dropwise add potassium hydroxide solution, keep stirring at 80°C, then raise the temperature and divide the water until the water content of the system is 800ppm. After cooling to room temperature, filter with suction to obtain a filtrate and a filter cake. The filter cake is acidified to obtain 2,5-dichlorophenol; the filtrate is removed from the organic solvent to obtain a mixed solution for future use;

[0038] B. Add ammonia solution dropwise to the mixed solution obtained after removing toluene in step A, suction filter after stirring, then add toluene to the filter cake for recrystallization to obtain 2,4-dichlorophenol.

[0039] In this embodiment, the mass concentration of the potassium hydroxide solution is 10%, and the amount of potassium hydroxide is 0.8 times the sum of ...

Embodiment 3

[0041] The method for separating 2,5-dichlorophenol and 2,4-dichlorophenol, comprises the following steps:

[0042] A. Add benzene to the mixture of 2,5-dichlorophenol and 2,4-dichlorophenol, then add potassium carbonate solution dropwise, keep stirring at 60°C, then raise the temperature and divide the water until the moisture content of the system is 860ppm . After cooling to room temperature, filter with suction to obtain a filtrate and a filter cake. The filter cake is acidified to obtain 2,5-dichlorophenol; the filtrate is removed from the organic solvent to obtain a mixed solution for future use;

[0043] B. Add ammonia solution dropwise to the mixed solution obtained after debenzene removal in step A, suction filter after stirring, then add benzene to the filter cake for recrystallization to obtain 2,4-dichlorophenol.

[0044] In this embodiment, the mass concentration of the potassium carbonate solution is 50%, and the amount of potassium substances in the potassium c...

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PUM

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Abstract

The invention discloses a method for separating 2,5-dichlorophenol from 2,4-dichlorophenol, and belongs to the technical field of fine chemical engineering. According to the method disclosed by the invention, after the 2,5-dichlorophenol is separated through steps of dissociation, extraction, dewatering, sedimentation, filter and the like, the 2,4-dichlorophenol is separated through steps of forming salt by ammonia water, recrystallizing and the like, and the purpose of completely separating the 2,5-dichlorophenol from the 2,4-dichlorophenol is realized through setting specific parameters of each working procedure; the method has the advantages that the operation is simple and convenient, and the cost is low.

Description

technical field [0001] The invention relates to a method for separating 2,5-dichlorophenol and 2,4-dichlorophenol, belonging to the technical field of fine chemicals. Background technique [0002] Dichlorophenol is an important class of organic intermediates. Among many dichlorophenol compounds, 2,5-dichlorophenol and 2,4-dichlorophenol play a very prominent role. 2,5-Dichlorophenol is a key intermediate of the herbicide dicamba, a nitrogen fertilizer synergist and a leather antifungal agent. 2,4-Dichlorophenol is an important fine chemical product, mainly used in pesticides, medicines and auxiliary products. [0003] Dichlorophenol produced by hydrolysis of 1,2,4-trichlorobenzene has three isomers: 2,5-dichlorophenol, 2,4-dichlorophenol and 3,4-dichlorophenol. 3,4-dichlorophenol can be separated by rectification because its boiling point is about 40°C higher than that of 2,5-dichlorophenol and 2,4-dichlorophenol, while 2,5-dichlorophenol and 2,4- Dichlorophenol is diffic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/86C07C39/30
CPCC07C37/86C07C39/30
Inventor 齐鸿李舟梁剑宋剑峰田成刚张蕾张华王蕾
Owner SICHUAN FOURSTAR BIOTECH RANDD CORP
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