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Preparation for 3, 4-dichloro phenyl isocyanate

A technology of phenyl dichloroisocyanate and dichloroaniline, applied in 3 fields, can solve problems such as low product content and low yield, and achieve the effects of reducing side reactions, reducing the occurrence of side reactions, and providing product conversion rates

Active Publication Date: 2008-10-01
JIANGSU ANPON ELECTROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional process is to add 3,4-dichloroaniline and o-dichlorobenzene into the reactor, pass dry hydrogen chloride gas under stirring until saturated, and then pass phosgene at 110-160°C, or directly pass it into Phosgene, until the solution becomes clear, then pass through phosgene for 20 to 30 minutes. After passing through, the fine-quality 3,4-dichloroisocyanate phenyl ester is obtained by rectification. This method has low product content and low yield, and is generally not more than 80%

Method used

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  • Preparation for 3, 4-dichloro phenyl isocyanate

Examples

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Effect test

Embodiment 1

[0031] In a 500L dissolution kettle, add 100 kg of xylene and 50 kg of 3,4-dichloroaniline, start stirring, open the steam valve, slowly raise the temperature to 40°C, and then stir for 30 minutes to 1 hour until the solid 3,4- After the dichloroaniline is completely dissolved, it is pumped into the high-level metering tank. In a 500L reaction kettle, add 215 kg of xylene and lower the temperature at the same time. Pass 10 kg of phosgene through the phosgene introduction tube. When the temperature drops to -5°C, start to add 3,4-dichloroaniline solution dropwise for 2 hours. After dripping, stir for another 1.5 hours, raise the temperature to 130°C at a heating rate of 20°C / hour, then add phosgene until the material is in a clear and transparent state, stop passing through the phosgene, drive the phosgene with nitrogen for 1 hour, and rectify to obtain the pure product 56.6 kg, the product purity is 98.5%, based on 3,4-dichloroaniline, the total yield of 3,4-dichloroisocyanate...

Embodiment 2

[0033] In a 500L dissolution kettle, add 110 kg of chlorinated benzene and 55 kg of 3,4-dichloroaniline, start stirring, open the steam valve, slowly raise the temperature to 50°C, and stir for another 30 minutes to 1 hour, until the solid 3,4 - After the dichloroaniline is completely dissolved, pour it into the high metering tank. In the 500L reaction kettle, add 240 kg of chlorinated benzene, and at the same time lower the temperature, pass 10 kg of phosgene through the phosgene introduction tube, and when the temperature drops to -5 °C, start to drop 3,4-dichloroaniline solution, 1.8 After hours of dripping, stir for another 1.5 hours, raise the temperature to 125°C at a heating rate of 20°C / hour, then add phosgene until the material is clear and transparent, stop passing through the phosgene, drive the phosgene with nitrogen for 1 hour, and rectify to obtain the pure product 62.3 kg, the product purity is 98.7%, based on 3,4-dichloroaniline, the total yield of 3,4-dichloro...

Embodiment 3

[0035] In a 500L dissolution kettle, add 120 kg of o-dichlorobenzene and 60 kg of 3,4-dichloroaniline, start stirring, open the steam valve, slowly raise the temperature to 55°C, and then stir for 30 minutes to 1 hour until the solid is 3, After 4-dichloroaniline is completely dissolved, put it into the high-level metering tank. In a 500L reaction kettle, add 250 kg of o-dichlorobenzene, while lowering the temperature, pass 12 kg of phosgene through the phosgene introduction tube, and when the temperature drops to 0°C, start to add 3,4-dichloroaniline solution dropwise, 1.6 After hours of dripping, stir for another 1.5 hours, raise the temperature to 135°C at a heating rate of 20°C / hour, then add phosgene until the material is in a clear and transparent state, stop passing through the phosgene, drive the phosgene with nitrogen for 1 hour, and rectify to obtain the pure product 68.6 kg, the product purity is 98.7%, based on 3,4-dichloroaniline, the total yield of 3,4-dichlorois...

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Abstract

The invention discloses a method for preparing 3, 4-dichloro phenyl isocyanate. The method takes 3, 4-dichloroaniline as raw material and xylene, or benzene chloride, o (p) dichlorobenzene and other organic solvents which do not react chemically with phosgene as a reaction solvent, goes through two steps of phosgenation reaction under low temperature and high temperature and distillation to obtain products with purity over 98 percent. The technique of two steps of phosgenation reaction under low temperature and high temperature can effectively reduce side reaction and improve reaction efficiency; the total yield of the invention achieves over 97 percent calculated by 3, 4-dichloroaniline.

Description

technical field [0001] The invention relates to a synthesis method of organic compounds, in particular to a preparation method of 3,4-dichloroisocyanate phenyl. Background technique [0002] 3,4-dichloroisocyanate phenyl (3,4-DCPI) is mainly used in urea herbicides (such as Diuron, Liguron, Triburon, Mizam), the insecticide Midin FF Intermediates in the synthesis of pesticides and certain pharmaceuticals. [0003] 3,4-Phenyl dichloroisocyanate is a white solid with a pungent odor, easily soluble in toluene, xylene, n-butane and other organic solvents, and its aqueous solution is acidic. It is an important organic intermediate, which can be used in medicine and pesticide intermediates. The traditional process is to add 3,4-dichloroaniline and o-dichlorobenzene into the reactor, pass dry hydrogen chloride gas under stirring until saturated, and then pass phosgene at 110-160°C, or directly pass it into Phosgene, until the solution becomes clear, then pass through phosgene fo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/12C07C263/10
Inventor 姜育田
Owner JIANGSU ANPON ELECTROCHEM
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