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Preparation method of 2,4-dichlorotoluene

A technology of dichlorotoluene and o-chlorotoluene, which is applied in 2 fields, can solve the problems of high product cost, and achieve the effects of low production cost, favorable resource recycling and high product yield

Active Publication Date: 2011-11-09
山东福尔有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

And the yield of this method can only reach 40%, and the product cost is also relatively high

Method used

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  • Preparation method of 2,4-dichlorotoluene
  • Preparation method of 2,4-dichlorotoluene
  • Preparation method of 2,4-dichlorotoluene

Examples

Experimental program
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Effect test

Embodiment 1

[0014] Add 3 mol of hydrogen chloride into a 1000 ml three-necked flask equipped with mechanical stirring, a reflux condenser, and a thermometer, then add 1 mol of 5-chloro-2-methylaniline dropwise into the three-necked flask, stir to form off-white particles, and cool to -10 Slowly add 1 mol of sodium nitrite after ℃, control the feeding speed so that the temperature is not higher than 10 ℃, after the addition, stir until the system is brownish red. Then thermal decomposition is carried out, the temperature is controlled at 15°C, and the following chemical reactions occur in the system:

[0015]

[0016] After the reaction is completed, first separate the lower organic phase, absorb the unreacted hydrogen chloride with a graphite absorption tower for recovery, wash the organic phase with water until neutral, remove a small amount of o-chlorotoluene generated in the reaction at 180-198 °C, and then carry out Rectification, collecting 198 ~ 201 ° C fractions to obtain 152 gr...

Embodiment 2

[0024] Add 2 mol of hydrogen chloride into a 1000 ml three-necked flask equipped with mechanical stirring, reflux condenser, and thermometer, then add 1.5 mol of 5-chloro-2-methylaniline dropwise into the three-necked flask, stir into off-white particles, and cool to - Slowly add 2 mol of potassium nitrite after 10°C, control the feeding speed so that the temperature is not higher than 10°C, and stir until the system is brown-red after adding. Then thermal decomposition is carried out, the temperature is controlled at 40°C, and the following chemical reactions occur in the system:

[0025]

[0026] After the reaction is completed, first separate the lower organic phase, absorb the unreacted hydrogen chloride with a graphite absorption tower, and recover it. Distillation, collecting 196 ~ 201 ° C fractions to obtain 227 grams of fractions.

[0027] With 2,4-dichlorotoluene as the standard, gas chromatography analysis. The analysis results are shown in Table 3 and Table 4. ...

Embodiment 3

[0034] Add 1 mol of hydrogen chloride into a 1000 ml three-necked flask equipped with mechanical stirring, reflux condenser, and thermometer, then add 2 mol of 5-chloro-2-methylaniline dropwise into the three-necked flask, stir to form off-white particles, and cool to -10 After ℃, slowly add 2 mol of ammonium nitrite, control the feeding speed so that the temperature is not higher than 10 ℃, after the addition, stir until the system is brown-red. Then thermal decomposition is carried out, the temperature is controlled at 60°C, and the following chemical reactions occur in the system:

[0035]

[0036] After the reaction is completed, first separate the lower organic phase, absorb the unreacted hydrogen chloride with a graphite absorption tower for recovery, wash the organic phase with water until neutral, remove a small amount of o-chlorotoluene generated in the reaction at 180-198 °C, and then carry out Rectify, collect fractions at 198-201°C, and obtain 303.5 grams of fra...

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Abstract

The invention discloses a preparation method of 2,4-dichlorotoluene, which comprises the following steps: mixing 5-chloro-2-methylaniline with an acid, stirring, cooling to -10-15 DEG C, adding nitrites, controlling the adding speed of the nitrites to allow the temperature to be no more than 15 DEG C, stirring, controlling the temperature to be 15-60 DEG C, and performing a thermal decomposition reaction; after the thermal decomposition reaction, separating an organic phase at the lower layer, and recovering unreacted acids by a graphite absorption tower; washing the organic phase with water to neutrality, performing distillation, removing o-chlorotoluene generated during the reaction at 180-198 DEG C, performing rectification, collecting fractions at 198-201 DEG C to obtain 2,4-dichlorotoluene. The preparation method of 2,4-dichlorotoluene of the invention has high product yield, and low production cost.

Description

technical field [0001] The invention relates to a preparation method of 2,4-dichlorotoluene. Background technique [0002] 2,4-Dichlorotoluene is used in the production of 2,4-dichlorobenzaldehyde, 2,4-dichlorobenzonitrile, and intermediates for the preparation of herbicides and dyes. In the prior art, the preparation of 2,4-dichlorotoluene is mainly in the prior art, mainly is to obtain through chlorination reaction with toluene as raw material, expresses as follows with chemical reaction formula: [0003] [0004] Where X is one of Cu, Fe, Sb and Al, and Solvent is chloroform, dichloromethane, water, etc. or no solvent. And the yield of the method can only reach 40%, and the product cost is relatively high. Contents of the invention [0005] The purpose of this invention is to provide a kind of preparation method of the 2,4-dichlorotoluene that product yield is high, production cost is low. [0006] The preparation method of 2,4-dichlorotoluene provided by the pres...

Claims

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Application Information

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IPC IPC(8): C07C25/08C07C17/35
Inventor 于俊田张玲孙志国王洛
Owner 山东福尔有限公司
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