Preparation process of p-bromofluoro benzene

A technology of bromofluorobenzene and fluorobenzene, which is applied in the field of preparation of binary halogenated aromatics, can solve the problem of high energy consumption and achieve the effect of simple operation process

Active Publication Date: 2008-03-26
宗铿
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this method is that to maintain a very low temperature, low-temperature cryogenic equipment is required, and the energy consumption is extremely high

Method used

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  • Preparation process of p-bromofluoro benzene
  • Preparation process of p-bromofluoro benzene
  • Preparation process of p-bromofluoro benzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] (Embodiment 1) In the five-necked glass reaction flask that communicates with the atmosphere with electric stirrer, thermometer, balance funnel, vent tube and reflux condenser of 1000 milliliters, add 500 grams of liquid fluorobenzene earlier, and make balance funnel and The outlet of the ventilation pipe is located under the liquid level of fluorobenzene; use a cold water bath to control the reaction temperature at 2±2°C; while stirring, add 2 grams of iron powder as a catalyst into the reaction flask, and add it into the reaction flask through the balance funnel 23 grams of liquid bromine make the material in the reaction bottle begin to carry out the initiating reaction of bromination reaction, and liquid bromine reacts with fluorobenzene to generate hydrogen bromide and p-bromofluorobenzene, and the by-product is o-bromofluorobenzene; the initiating reaction is carried out after 15 minutes , start to pass chlorine gas into the reaction system in the reaction flask th...

Embodiment 2

[0041]The rest are the same as in Example 1, except that the iron powder added as a catalyst in the bromination reaction is 1 gram, and the temperature of the bromination reaction is controlled at 15±2° C. After the reaction, 868 grams of finished product were obtained, and the yield of fluorobenzene was 93%. The contents of relevant components are shown in Table 1.

Embodiment 3

[0043] The rest are the same as in Example 1, except that the iron powder added as a catalyst in the bromination reaction is 0.5 g, and the reaction temperature of the bromination reaction is controlled at 25±2° C. The 858 grams of finished products obtained after the reaction have a fluorobenzene yield of 91.5%, and the contents of relevant components are shown in Table 1.

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Abstract

The present invention discloses preparation process of p-bromofluoro benzene. Liquid fluoro benzene and elementary substance bromine as reactants are made to produce bromination in the presence of catalyst to produce p-bromofluoro benzene and hydrogen bromide. The preparation process features that chlorine gas is introduced into the reaction system for oxidation reaction with hydrogen bromide to produce oxide of hydrogen chloride and hydrogen bromide, and the oxide of hydrogen bromide further reacts with fluoro benzene to produce p-bromofluoro benzene. After the bromination, the product is used as final product or post-treated to eliminate at least one of produced hydrogen chloride, p-chlorofluoro benzene and m-bromofluoro benzene for raised purity of p-bromofluoro benzene product. The process has the advantages of low liquid bromine consumption and low cost.

Description

technical field [0001] The invention relates to a preparation method of a binary halogenated aromatic hydrocarbon in organic matter. Background technique [0002] 4-Bromofluorobenzene is an important intermediate in the synthesis of fine chemical products such as pharmaceuticals, pesticides and dyes, and is widely used in industrial production. There are two main methods for preparing p-bromofluorobenzene. One method is to make fluorobenzene become p-nitrofluorobenzene after nitration reaction, then reduce p-nitrofluorobenzene to obtain p-fluoroaniline, and p-fluoroaniline, sodium nitrite and dilute sulfuric acid are frozen at low temperature to obtain diazonium salt, diazo The salt is then reacted with cuprous bromide to produce p-bromofluorobenzene. This method has long technical route, high energy consumption, huge equipment, high cost, low product conversion rate and serious pollution. Another method is the direct bromination method of fluorobenzene, which adopts the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C25/13C07C17/00
Inventor 宗铿李志刚张云明
Owner 宗铿
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