Clean production process of dicamba synthesis midbody

A clean production and chemical synthesis technology, applied in the preparation of organic compounds, organic chemistry, chemical instruments and methods, etc., can solve problems such as difficult to fully react, environmental impact, etc., and achieve the effect of increasing reaction yield

Active Publication Date: 2013-03-13
JIANGSU YOUJIA CHEM +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this way, the whole phenol synthesis process produces a large amount of waste salt and a large amount of waste acid, which has

Method used

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  • Clean production process of dicamba synthesis midbody

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Embodiment 1

[0021] Synthesis of diazotization: clean production process of 2,5-dichlorophenol synthesis in the production of dicamba, first stir 90g of 2,5-dichloroaniline and 540g of 60% dilute sulfuric acid under reflux for 2 hours, and cool the reaction solution To 0-5°C, add 187.5g of 40% nitrosylsulfuric acid, stir for 1.5 hours, control the molar ratio of 2,5-dichloroaniline at 1:1.05, and pass the diazonium solution generated by the reaction with nitrosylsulfuric acid 60%-70% sulfuric acid is hydrolyzed at a high temperature of 140°C, and the obtained 2,5-dichlorophenol gas is condensed and separated, and then centrifuged and dehydrated to obtain a solid product. Part of the waste sulfuric acid obtained from hydrolysis is recovered by high vacuum distillation and directly applied to diazotization to synthesize dilute sulfuric acid, and the other part is mixed with SO produced by other processes of the company. 2 Tail gas synthesis of 40% nitrosyl sulfuric acid is then applied to di...

Embodiment 2

[0025] Diazotization synthesis: 2,5-dichlorophenol synthesis clean production process in the production of dicamba, first stir 90g of 2,5-dichloroaniline and 720g of 50% dilute sulfuric acid under reflux for 2 hours, then cool the reaction solution To 0-5 ℃, put in 393g of 20% nitrosyl sulfuric acid, stir for 2 hours, the molar ratio of 2,5-dichloroaniline is controlled at 1:1.1, and the diazonium solution generated by the reaction with nitrosyl sulfuric acid is passed into 60%-70% sulfuric acid is hydrolyzed at a high temperature of 150°C, and the obtained 2,5-dichlorophenol gas is condensed and separated, and then centrifuged and dehydrated to obtain a solid product. The dilute sulfuric acid obtained by hydrolysis is oxidized and recovered by 35% hydrogen peroxide, and part of it is directly applied and diazotized to form dilute sulfuric acid, and the other part is mixed with SO produced by other processes of the company. 2 Tail gas synthesis of 20% nitrosyl sulfuric acid is...

Embodiment 3

[0029] Diazotization synthesis: 2,5-dichlorophenol synthesis clean production process in dicamba production, first stir 90g of 2,5-dichloroaniline and 810g of 40% dilute sulfuric acid under reflux for 2 hours, then cool the reaction solution To 0-5°C, add 142.3g of 60% nitrosyl sulfuric acid and stir for 2 hours. The molar ratio of 2,5-dichloroaniline is controlled at 1:1.2. %-70% sulfuric acid is hydrolyzed at a high temperature of 170°C, and the obtained 2,5-dichlorophenol gas is condensed and separated, and then centrifuged to dehydrate to obtain a solid product. The dilute sulfuric acid obtained by hydrolysis is extracted and recovered with chloroform, and part of it is directly applied mechanically and diazotized to synthesize dilute sulfuric acid, and the other part is mixed with SO produced by other processes of the company. 2 Tail gas synthesis of 60% nitrosyl sulfuric acid is then applied to diazotization synthesis, and the yield of 2,5-dichlorophenol in this example ...

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Abstract

The invention relates to a clean production process of a dicamba synthesis midbody, and provides a clean production method of 2,5-dichlorophenol. The clean production process comprises the following steps: stirring 30-70% of dilute sulfuric acid and 2,5-dichloroaniline in a backflow state for 1-2hours, wherein the weight ratio of the dilute sulfuric acid to the 2,5-dichloroaniline is (6:1)-(9:1); after the reaction, cooling the reaction liquid to 0-5 DEG C, and dropping 10-60% nitroso-sulfuric acid and stirring for 2 hours to obtain diazonium liquid, wherein the molar ratio of the 2,5-dichloroaniline to the nitroso-sulfuric acid is 1:(1.0-1.5); carrying out pyrohydrolysis on the synthesized diazonium liquid at 140-170 DEG C to obtain 2,5-dichlorophenol; and carrying out diazotization synthesis on part of the hydrolyzed dilute sulfuric acid subjected to recovery processing as batch charging of dilute sulfuric acid, and synthesizing the other part of the dilute sulfuric with SO2 to be 10-60% nitroso-sulfuric acid, and then applying to diazotization synthesis. According to the synthesis process, no waste salt or phenolic wastewater are generated during diazotization reaction, the reaction yield is as high as 95%, and diazonium liquid is subjected to pyrohydrolysis and the dilute sulfuric acid can be recycled, so that the cycle use of the two can be achieved. The clean production process belongs to a clean and environment-friendly production process.

Description

technical field [0001] The invention relates to a method for producing herbicides and dyes, in particular to a synthesis process of phenol in the production of dicamba. Background technique [0002] In the entire production process of the herbicide dicamba, the first is the diazotization synthesis process. 2,5-dichloroaniline and concentrated sulfuric acid are reacted under reflux conditions. The aqueous solution completes the diazotization reaction, and the diazonium solution is hydrolyzed to obtain the intermediate 2,5-dichlorophenol. However, after reacting 2,5-dichlorophenol with dilute sulfuric acid, it reacts with sodium nitrite at low temperature to obtain diazo solution and a large amount of sodium bisulfate, and after hydrolysis of the diazo solution, phenol and a large amount of waste sulfuric acid are obtained. In this way, the whole phenol synthesis process produces a large amount of waste salt and a large amount of waste acid, which has a great impact on enviro...

Claims

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Application Information

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IPC IPC(8): C07C39/30C07C37/045
Inventor 戚明珠王东朝孔勇汪国庆解春满郭玉波
Owner JIANGSU YOUJIA CHEM
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