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Preparation method of 5-bromo-1,3-dichloro-2-fluorobenzene

A technology of fluorobromobenzene and dichloride, applied in the field of chemical intermediate preparation, can solve the problems of low reaction yield, unstable diazonium salt and the like, and achieve the effects of high purity, improved stability and yield, and easy mass preparation

Active Publication Date: 2014-03-26
ZHEJIANG LINJIANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to too many electron-withdrawing substituents on the 3,5-dichloro-4-fluoroaniline, the obtained diazonium salt is unstable and the reaction yield is low

Method used

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  • Preparation method of 5-bromo-1,3-dichloro-2-fluorobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0026] 900g (5mol) of 3,5-dichloro-4-fluoroaniline and 1350ml of 98% concentrated sulfuric acid are used to form ammonium salt, and 1400g of 30% sodium nitrite aqueous solution are pumped into the tubular type with jacket with two metering pumps respectively. In the diazotization reactor (tube length 5m, inner diameter 7mm), tap water is passed through the jacket to adjust the temperature of the reaction solution in the tube to 15-20°C, the reaction solution stays in the tube for 15s, and then directly enters the bromine-filled tank with agitator. Put 715g (6mol) of cuprous chloride and 1000ml of 48% hydrobromic acid into a three-necked flask, and control the reaction temperature between 100 and 130°C. After the reaction is completed, cool down and extract twice with dimethane. After alkali washing and water washing, dichloromethane was distilled off to obtain crude 3,5-dichloro-4-fluorobromobenzene, which was rectified under reduced pressure to obtain 915g of 3,5-dichloro-4-fl...

Embodiment 2

[0030] Use 900g (5mol) of 3,5-dichloro-4-fluoroaniline and 1350ml of 98% concentrated sulfuric acid to make ammonium salt, and 1400g of 30% sodium nitrite aqueous solution into the jacketed pipe with two metering pumps respectively. In the type diazotization reactor (tube length 10m, inner diameter 7mm), tap water is passed through the jacket to adjust the temperature of the reaction solution in the tube to 15-20°C, the reaction solution stays in the tube for 30s, and directly enters the Put 715g (6mol) of cuprous bromide and 1000ml of 48% hydrobromic acid into a three-necked flask, control the reaction temperature between 100 and 130°C, after the reaction is completed, cool down, extract twice with dimethane, dichloromethane layer After washing with alkali and water, dichloromethane was distilled off to obtain crude 3,5-dichloro-4-fluorobromobenzene, which was rectified under reduced pressure to obtain 865 g of 3,5-dichloro-4-fluorobromobenzene (yield 71 %).

Embodiment 3

[0032] Use 900g (5mol) of 3,5-dichloro-4-fluoroaniline and 1350ml of 98% concentrated sulfuric acid to make ammonium salt, and 1400g of 30% sodium nitrite aqueous solution into the jacketed pipe with two metering pumps respectively. In the type diazotization reactor (the length of the pipe is 15m, the inner diameter is 7mm), tap water is passed through the jacket to adjust the temperature of the reaction liquid in the pipe to 15-20°C, the reaction liquid stays in the pipe for 60s, and directly enters the Put 715g (6mol) of cuprous bromide and 1000ml of 48% hydrobromic acid into a three-necked flask, control the reaction temperature between 100 and 130°C, after the reaction is completed, cool down, extract twice with dimethane, dichloromethane layer After washing with alkali and water, dichloromethane was distilled off to obtain crude 3,5-dichloro-4-fluorobromobenzene, which was rectified under reduced pressure to obtain 610 g of 3,5-dichloro-4-fluorobromobenzene (yield 50 %). ...

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Abstract

The invention discloses a preparation method of 5-bromo-1,3-dichloro-2-fluorobenzene, which comprises the following steps: (1) simultaneously feeding ammonium salt and a sodium nitrite aqueous solution into a tubular reactor for tubular diazotization reaction so as to obtain a diazonium salt intermediate, wherein the ammonium salt is prepared through dissolving 3,5-dichloro-4-fluoroaniline in sulfuric acid; (2) dissolving cuprous bromide in hydrobromic acid, heating to 100-130 DEG C, dropwise adding the diazonium salt intermediate prepared in the step (1) for reaction, and after the complete reaction, performing after-treatment to obtain the 5-bromo-1,3-dichloro-2-fluorobenzene. According to the preparation method, the tubular diazotization reaction technology is adopted to prepare diazonium salt, so that the side reaction including diazonium salt coupling and decomposition and the like can be reduced, the diazotization reaction is enabled to be more stable, and the final yield is improved; in addition, the tubular diazotization reaction technology has a series of advantages of continuity in production, safety, short reaction time, energy saving and the like, and is relatively suitable for industrial production in the future.

Description

technical field [0001] The invention belongs to the field of preparation of chemical intermediates, and in particular relates to a preparation method of 3,5-dichloro-4-fluorobromobenzene. Background technique [0002] 3,5-Dichloro-4-fluorobromobenzene, CAS No. 17318-08-0, the structure shown in formula (I), is an important chemical intermediate, the carbon-bromine bond on the structure can be used Further functionalization to form various fluorine-containing products, which are used in the fields of pesticides and pharmaceuticals. [0003] [0004] Evans et al. reported a method for the preparation of bis(3,5-dichloro-4-fluorobenzene)mercurides using 3,5-dichloro-4-fluorobromobenzene (Journal of the Chemical Society [Section] A : Inorganic, Physical, Theoretical (1967), (10), 1643-8). 3,5-dichloro-4-fluorobromobenzene and mercuric chloride can be heated to obtain bis(3,5-dichloro-4-fluorobenzene)mercury compound, bis(3,5-dichloro-4 -Fluorobenzene) mercuric compound can...

Claims

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Application Information

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IPC IPC(8): C07C25/13C07C17/093
Inventor 尹新易苗义贤富
Owner ZHEJIANG LINJIANG CHEM
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