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A kind of preparation method of 2,5-dichlorophenol

A technology of dichlorophenol and dichlorobenzene, which is applied in two fields, can solve the problems of unsatisfactory catalytic effect, difficult recycling and treatment, high energy consumption, etc., and achieves benefits for subsequent separation and purification work, industrial production, and simple process operation Effect

Active Publication Date: 2017-03-22
XINYI AGRI CHEM PLANT JIANGSU PROV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the hydrolysis method of 1,2,4-trichlorobenzene needs to be obtained by high temperature and high pressure hydrolysis, and a large amount of acid and alkali will be used in the preparation process, resulting in a large amount of industrial waste, and the product is a mixture of isomers. Difficult to separate and purify, high industrial cost
The 2,5-dichloroaniline diazonium hydrolysis method will use a large amount of sulfuric acid and nitrite, which will cause serious corrosion to equipment, high energy consumption, difficulty in recycling and treatment, and pollute the environment. In addition, the substrate 2,5-dichloroaniline The preparation process involves nitrification reaction, and the use of a large amount of sulfuric acid and nitrite not only puts forward higher requirements for equipment, but also aggravates the harm to the environment
[0004] In order to solve this defect, in the prior art, 1,4-dichlorobenzene is used as a raw material to prepare 2,5-dichlorophenol by catalytic oxidation, using heteropolyacid, heteropolyacid salt or its loaded type as catalyst, The reaction route is short, the operation is simple, and there is almost no pollution to the environment, but the catalytic effect is not ideal, the catalyst recovery is difficult, and the subsequent purification process is not disclosed

Method used

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  • A kind of preparation method of 2,5-dichlorophenol
  • A kind of preparation method of 2,5-dichlorophenol
  • A kind of preparation method of 2,5-dichlorophenol

Examples

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Effect test

example 1

[0038] 0.001 parts by weight of V 2 o 5 and 0.01 parts by weight of polyphosphoric acid were added to 1 / 30 parts by weight of acetic acid, stirred at 55°C for 8min, and then 2.7×10 -4 The mass fraction of parts by weight is 20% H 2 o 2 , and continue to stir for 20 minutes to obtain an activation solution;

[0039] Stir 1 part by weight of 1,4-dichlorobenzene and 2 parts by weight of acetic acid at a temperature of 30°C until they are evenly mixed, then add the activation solution to obtain a reaction solution;

[0040] At a temperature of 35°C, 0.20 parts by weight of 20% H 2 o 2 Add dropwise into the reaction solution for 2 hours. After the dropwise addition, continue to stir for 0.5h; then add 0.2 parts by weight of sodium sulfite, stir for 5min, and filter to obtain the filtrate;

[0041] The above-mentioned filtrate is fed into the evaporator at a rate of 6000kg / h. The feed temperature is 25°C and the pressure is 300kPa to remove heavy components such as phosphoric ...

example 2

[0046] 0.002 parts by weight of V 2 o 5 and 0.02 parts by weight of polyphosphoric acid were added to 1 / 5 parts by weight of acetic acid, stirred at 65°C for 10 min, and then added 7.4×10 -4 The mass fraction of parts by weight is 40% H 2 o 2 , after continuing to stir for 25 minutes, the activation solution was obtained;

[0047] Stir 1 part by weight of 1,4-dichlorobenzene and 5 parts by weight of acetic acid at a temperature of 28°C until they are evenly mixed, and then add the activation solution to obtain a reaction solution;

[0048] At a temperature of 72°C, 0.92 parts by weight of 40% H 2 o 2 Add dropwise into the reaction solution for 8 hours. After the dropwise addition, continue to stir for 0.5h; then add 0.98 parts by weight of sodium bisulfite, stir for 5min, and filter to obtain the filtrate;

[0049] The above-mentioned filtrate is fed into the evaporator at a rate of 9000kg / h, the feed temperature is 30°C, and the pressure is 500kPa to remove heavy compon...

example 3

[0054] 0.04 parts by weight of V 2 o 3 and 1 part by weight of polyphosphoric acid were added to 1 / 20 part by weight of acetic acid, stirred at 57°C for 9 minutes, and then 0.016 parts by weight of 70% H 2 o 2 , and continue to stir for 30 minutes to obtain an activation solution;

[0055] Stir 1 part by weight of 1,4-dichlorobenzene and 10 parts by weight of acetic acid at a temperature of 25°C until they are evenly mixed, and then add the activation solution to obtain a reaction solution;

[0056] At a temperature of 50°C, 1.32 parts by weight of 70% H 2 o 2 Add dropwise into the reaction solution for 5 hours. After the dropwise addition, continue to stir for 0.5h; then add 1.72 parts by weight of sodium sulfite, stir for 5min, and filter to obtain the filtrate;

[0057] The above-mentioned filtrate is fed into the evaporator at a rate of 8000kg / h. The feed temperature is 28°C and the pressure is 400kPa to remove heavy components such as phosphoric acid, tar, and cataly...

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Abstract

The invention provides a preparation method of 2, 5-dichlorophenol. The preparation method of the 2, 5-dichlorophenol comprises the following steps of pretreatment of catalyst and assistant agents, 1, 4-dichlorobenzene one-step-method product synthesizing, continuous rectification of 2, 5-dichlorophenol and recycling of a substrate and solvent. By the preparation method, the catalyst and the assistant agents are pretreated, the catalytic performance and the catalytic effect of the catalyst can be improved effectively, the efficiency and the yield of synthesis reaction are improved, the use level of the catalyst and the use level of the assistant agents can be reduced obviously, production cost is reduced, heavy components are reduced, and follow-up separation and purification operation is facilitated. Synthetic reaction products are rectified, separated and purified, the purity of the obtained 2, 5-dichlorophenol is greater than 99.5%, the purify of the 1, 4-dichlorobenzene, the solvent and water which are obtained by recycling is greater than 99%, the recycled raw material and the recycled solvent can be directly used for next synthetic reaction, the production cost is reduced, and environmental protection is facilitated.

Description

technical field [0001] The present invention relates to the preparation method of 2,5-dichlorophenol. More specifically, the present invention relates to a method of efficiently synthesizing 2,5-dichlorophenol by one-step reaction using 1,4-dichlorobenzene as a raw material, and then performing multi-step continuous distillation to obtain high-purity 2,5-dichlorophenol. -Dichlorophenol method. Background technique [0002] 2,5-Dichlorophenol is an important intermediate of pesticides, medicines and dyes, nitrogen fertilizer synergist and leather antifungal agent, etc. Currently, 2,5-dichlorophenol is mostly used in the synthesis of the herbicide 3,6-dichloro-2-methoxybenzoic acid (Dicamba). [0003] The current methods for preparing 2,5-dichlorophenol mainly include 1,2,4-trichlorobenzene hydrolysis and 2,5-dichloroaniline diazo hydrolysis. However, the hydrolysis method of 1,2,4-trichlorobenzene needs to be obtained by high temperature and high pressure hydrolysis, and a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C39/30C07C37/60C07C37/70C07C37/74
CPCC07C37/60C07C37/685C07C37/70C07C37/74C07C39/30
Inventor 刘宇申剑冰时萌萌陈高部朱柳柳方菁晏海江朱青云陈润纪传武张湘宁
Owner XINYI AGRI CHEM PLANT JIANGSU PROV