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Preparation process of 2,4-dichlorophenol

A technology for the preparation of dichlorophenol, which is applied in the preparation of organic compounds, organic compound/hydride/coordination complex catalysts, organic chemistry, etc., and can solve problems such as market influence, high synthesis cost, and limited product use. Reach the effect of reducing production cost and improving efficiency

Inactive Publication Date: 2017-01-25
LIANYUNGANG ZHICHENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The direct chlorination of phenol is a traditional production process at home and abroad. The process is simple and the cost is low. However, because the physical properties of the by-product 2,6-dichlorophenol are very close to those of 2,4-dichlorophenol, it is difficult to separate, resulting in low product purity. , unable to produce 2,4-dichlorophenol with higher purity
The mixed phenol chlorination method uses the by-product mixed phenol in the process of chlorination of phenol to produce o-chlorophenol as a raw material. Although a product with high purity can be obtained, the raw material resources are limited due to the influence of the o-chlorophenol market.
The chlorinated product of ortho-chlorophenol contains 2,6-dichlorophenol, which makes the product purity unable to be improved
The catalytic chlorination of p-chlorophenol is a domestically developed high-purity 2,4-dichlorophenol production process, but the high synthesis cost limits the use of the product

Method used

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Examples

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Comparison scheme
Effect test

preparation example Construction

[0025] A kind of preparation technology of 2,4-dichlorophenol of the present invention, comprises the steps:

[0026] Using phenol as a raw material, using a mixture of boric acid, diphenyl sulfide, and ferric chloride as a catalyst, chlorination with chlorine gas produces crude 2,4-dichlorophenol, and then obtains the target product through rectification, including the following step:

[0027] 1.1 The system maintains a negative pressure of -0.08~-0.09MPa, add phenol and catalyst to the chlorination kettle, and start stirring;

[0028] 1.2 Control the temperature of the material in the chlorination kettle at 10-80°C, feed chlorine gas, and circulate the reaction solution through a circulating pump; stop the reaction when the phenol content is less than 0.5%, and obtain a p-chlorophenol content of more than 65%, ortho-chlorine Monochlorophenol mixture with phenol<20% (by rectification, ≥95% o-chlorophenol and ≥99% p-chlorophenol, and a certain amount of mixed phenol can be ob...

Embodiment 1

[0037] 1. In a 5000 liter chlorination kettle with a tail gas treatment system, after adding ferric chloride, turn on the water flushing pump to vacuum inhale phenol, diphenyl sulfide and boric acid (the content of ferric chloride, diphenyl sulfide and boric acid The molar ratio is 1.0:1.0:1.0), keep the vacuum at -0.005MPa, start to adjust the chlorine flow rate, keep the chlorination temperature at 30-70°C, and start the material circulation pump to start the reaction liquid circulation. Until the central control analysis finds that phenol < 0.5%, it can be regarded as the end of monochlorination. Then increase the vacuum to 0.09MPa (to drive off the remaining hydrogen chloride in the reaction), and use pH test paper to detect that the tail gas does not show acidity, that is, the end of the gas rush; then stop the circulation pump and discharge the crude monochlorophenol into the storage tank. Gas chromatography analysis found 19.8% o-chlorophenol, 0.06% phenol, 2.98% 2,6-di...

Embodiment 2

[0041]1. In a 5000 liter chlorination kettle with a tail gas treatment system, after adding ferric chloride, turn on the water pump to vacuum inhale phenol and catalyst diphenyl sulfide and boric acid (ferric chloride, diphenyl sulfide and boric acid The molar ratio is 1.5:1.5:1.0), keep the vacuum at -0.005MPa, start to adjust the chlorine flow rate, keep the chlorination temperature at 30-70°C, and turn on the circulation pump to start the circulation of the reaction solution. Until the central control analysis finds that phenol < 0.5%, it can be regarded as the end of monochlorination. Then increase the vacuum to 0.09MPa (to drive off the remaining hydrogen chloride in the reaction), and use pH test paper to detect that the tail gas does not show acidity, that is, the end of the gas rush; then stop the circulation pump and discharge the crude monochlorophenol into the storage tank. Gas chromatography analysis found 19.5% o-chlorophenol, 0.05% phenol, 3.06% 2,6-dichloropheno...

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PUM

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Abstract

The invention discloses a preparation process of 2,4-dichlorophenol. The preparation process comprises the following steps: chloridizing phenol or o-chlorophenol serving as a raw material and a mixture which is prepared from boric acid, phenyl sulfide and ferric trichloride and serves as a catalyst to generate a 2,4-dichlorophen coarse product, and rectifying the coarse product to obtain a target product. The mixed catalyst used in the reaction has a positioning effect, so that the content of p-chlorophenol in a chlorinated phenols mixture generated by the reaction is greater than 65 percent, the content of the 2,4-dichlorophenol in di-chlorophenol generated in the reaction is greater than 95 percent, the number of di-chlorophenol impurities generated in the reaction is reduced, and the 2,4-dichlorophenol with the content greater than 99.5 percent and the total yield of 95 percent or above can be obtained by rectification treatment; furthermore, the reaction yield is greatly increased, and the yield of the p-chlorophenol is also increased.

Description

technical field [0001] The invention relates to a process for preparing 2,4-dichlorophenol, which belongs to the field of organic chemical preparation. Background technique [0002] 2,4-Dichlorophenol and p-chlorophenol are important organic chemical intermediates. For example, p-chlorophenol is used in the preparation of pesticides such as fenoxin, mitrafenone, anti-falling agent, tetramine, profenfos, mite egg ester, acarifen, difenate, pharmaceutical clofibrate, and pharmaceutical intermediate p-chlorophenoxyisobutyl Acid, Sodium 5-Chloro-2-Hydroxybenzoate, Antioxidant BHA (Butylated Hydroxyanisole), Dye Fast Pigment Sauce RH, 1,4-Dihydroxyanthraquinone, 1,4-Diaminoanthraquinone, Para-Aminophenol And hydroquinone, an important intermediate of permanent violet; selective solvents in the oil refining industry, ethanol discoloration agents and other organic synthesis raw materials; Intermediates and raw materials of oxazone, ibifos (EPBP), dukesan, glyphate, and the drug t...

Claims

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Application Information

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IPC IPC(8): C07C39/30C07C37/62B01J31/30
CPCC07C37/62B01J21/02B01J27/128B01J31/0217B01J31/30B01J35/19C07C39/30Y02P20/52
Inventor 王耀良
Owner LIANYUNGANG ZHICHENG CHEM
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