Method for preparing 3, 4-dichlorobenzotrifluoride

A technology of dichlorobenzotrifluoride and dichlorotrichlorotoluene, which is applied in the field of preparation of pesticide chemical intermediate products, can solve problems such as inventory backlog, and achieve the effects of less corrosion of equipment, improved economic benefits, and wide sources of raw materials

Inactive Publication Date: 2014-07-02
JIANGSU FENGHUA CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] At present, a large amount of by-product 3,4-dichlorotoluene is produced during the domestic production of 2,4-dichlorotoluene, resulting in a serious inventory backlog

Method used

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  • Method for preparing 3, 4-dichlorobenzotrifluoride
  • Method for preparing 3, 4-dichlorobenzotrifluoride

Examples

Experimental program
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Effect test

Embodiment 1

[0026] 1) Chlorination: Put 800g of 3,4-dichlorotoluene into a 3L reactor, raise the temperature to 115°C, add 40g of catalyst, and start to feed dry chlorine gas with a flow rate of 40-80m 3 / h, the temperature is controlled at 115-117°C, and the reaction time is 24 hours. 3, when the 4-dichlorodichlorotoluene content is less than 0.5%, stop feeding chlorine gas, change into dry air and discharge unreacted chlorine gas, hydrogen chloride gas and gaseous impurities produced in the reaction kettle to obtain 3,4-dichlorotri Chlorotoluene.

[0027] 2) Fluorination: Press 4 moles of 3,4-dichlorobenzotrichloride and 12 moles of anhydrous hydrogen fluoride into a 3L reactor, and check the opening status of each valve. Turn on the stirring, slowly feed steam into the jacket, and when the pressure in the kettle reaches 1.5MPa, open the tail gas discharge valve to exhaust, continue to heat up until the temperature in the kettle is 110°C, and control the pressure in the kettle at 1.5-1...

Embodiment 2

[0031] 1) Chlorination: Put 800g of 3,4-dichlorotoluene into a 3L reactor, raise the temperature to 115°C, add 20g of catalyst, and start to feed dry chlorine gas with a flow rate of 40-80m 3 / h, the temperature is controlled at 120-125°C, and the reaction time is 22 hours. 3, when the 4-dichlorodichlorotoluene content is less than 0.5%, stop feeding chlorine gas, change into dry air and discharge unreacted chlorine gas, hydrogen chloride gas and gaseous impurities produced in the reaction kettle to obtain 3,4-dichlorotri Chlorotoluene.

[0032] 2) Fluorination: Press 4 moles of 3,4-dichlorobenzotrichloride and 14 moles of anhydrous hydrogen fluoride into a 3L reactor, and check the opening status of each valve. Turn on stirring, slowly feed steam into the jacket, and when the pressure in the kettle reaches 1.5MPa, open the exhaust valve to exhaust, continue to heat up until the temperature in the kettle is 115°C, and control the pressure in the kettle to 2.2-2.5MPa at the sa...

Embodiment 3

[0036]1) Chlorination: Put 800g of 3,4-dichlorotoluene into a 3L reactor, raise the temperature to 115°C, add 8g of catalyst, and start to feed dry chlorine gas with a flow rate of 40-80m 3 / h, the temperature is controlled at 115-120°C, and the reaction time is 20 hours. 3, when the 4-dichlorodichlorotoluene content is less than 0.5%, stop feeding chlorine gas, change into dry air and discharge unreacted chlorine gas, hydrogen chloride gas and gaseous impurities produced in the reaction kettle to obtain 3,4-dichlorotri Chlorotoluene.

[0037] 2) Fluorination: Press 4 moles of 3,4-dichlorobenzotrichloride and 13 moles of anhydrous hydrogen fluoride into a 3L reactor, and check the opening status of each valve. Turn on stirring, slowly feed steam into the jacket, and when the pressure in the kettle reaches 1.5MPa, open the exhaust valve to exhaust, and continue to heat up until the temperature in the kettle is 110°C, and at the same time control the pressure in the kettle to 1...

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Abstract

The invention discloses a method for preparing 3, 4-dichlorobenzotrifluoride. The method comprises the following steps: performing chlorination, fluorination, distillation, neutralization and filtration to obtain a finished product of 3, 4-dichlorobenzotrifluoride. In the method disclosed by the invention, 3, 4-dichlorotoluene is used as a raw material, 3, 4-dichlorobenzotrifluoride is synthesized by two steps of chlorination and fluorination, a chlorination reaction is decreased compared with the existing step by step reaction with p-chlorotoluene as a raw material, the new process is simple and convenient to operate and small in equipment corrosion, byproducts and exhaust emission generated by the chlorination reaction in the production are greatly reduced, and the pollutant emission in the production process is reduced. No isomer 2, 4-dichlorobenzotrifluoride of 3, 4-dichlorobenzotrifluoride is generated in the reaction process, so that the product yield is high.

Description

technical field [0001] The invention relates to a method for preparing a pesticide chemical intermediate product, in particular to a method for synthesizing 3,4-dichlorobenzotrifluoride. The method is suitable for using 3,4-dichlorotoluene as a raw material to synthesize 3,4-dichlorotrifluorotoluene through two steps of chlorination and fluorination. Background technique [0002] 3,4-Dichlorobenzotrifluorotoluene (3,4-Dichlorobenzotrifluoride) is a colorless transparent liquid with an odor of halogenated benzene. Insoluble in water, miscible with benzene, toluene, ethanol, ether, halogenated hydrocarbons, etc. 3,4-Dichlorotrifluorotoluene is an important intermediate in organic synthesis. The fluorine atom in its molecular structure makes it have special activity. It is widely used in fine organic synthesis fields such as medicine, pesticide, and dyestuff. Among them, synthetic diphenyl ether herbicides are currently the most used, such as: lactofen, fomesafen, acetoxyfluo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/13C07C17/20C07C17/10
Inventor 张亮李琦郑龙生韩伟彪
Owner JIANGSU FENGHUA CHEM IND
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