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Method for producing by-product hydrobromic acid in synthesis of bromobenzene

A technology of hydrobromic acid and bromobenzene, applied in bromine/hydrogen bromide, chemical instruments and methods, preparation of halogenated hydrocarbons, etc., can solve problems such as deep appearance after being placed for a long time, and achieve the effect of normal appearance

Active Publication Date: 2013-03-13
JIANGSU YOUJIA CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to: solve the technical problems of further improving the comprehensive utilization rate of bromine in the synthesis process of bromobenzene and the high content of free bromine in the by-product hydrobromic acid, and the dark appearance after being placed for a long time

Method used

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  • Method for producing by-product hydrobromic acid in synthesis of bromobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0022] In a 1000L reactor equipped with stirring, with a 4m enamel packing tower and a partial condenser, put 468KG of benzene, and then put in 0.6KG of catalyst anhydrous ferric trichloride, and raise the temperature to 75°C. Drop into 480KG bromine in the bromine dropping tank. Open the top decondenser to feed in and out water, raise the temperature of the synthesis kettle to about 75°C, keep the reflux state in the tower, open the valve at the bottom of the bromine dropping tank in the reaction kettle to add bromine dropwise, and the dropping time is 8hr. During the process, the reaction temperature was gradually increased, and the system always maintained a slight reflux state in the tower. After the dropwise addition, the temperature was maintained at 95-105°C for 2 hours. Tail gas is absorbed by falling film water in three stages in series, adding 240kg of water to each stage, and the absorption temperature is 15~60°C. The synthetic solution is debenzene-removed and ref...

Embodiment 2

[0024] In a 1000L reactor equipped with stirring, with a 4m enamel packing tower and a partial condenser, put 312KG of benzene into it, then put in 0.6kg of iron powder, and raise the temperature to 75°C. Drop into 512KG bromine in the bromine dropping tank. Open the top decondenser to feed in and out water, raise the temperature of the synthesis kettle to about 75°C, keep the reflux state in the tower, open the valve at the bottom of the bromine dropping tank in the reaction kettle to add bromine dropwise, and the dropping time is 10hr. During the process, the reaction temperature is gradually increased, and the system always maintains a slight reflux state in the tower. After the dropwise addition, the reaction temperature is maintained at 100-110°C for 2 hours. Tail gas is absorbed by falling film water in three stages in series, adding 260kg of water to each stage, and the absorption temperature is 15~60°C. The synthetic solution is debenzene and refined to obtain 470.9KG...

Embodiment 3

[0026] In a 1000L reactor equipped with stirring, with a 4m enamel packing tower and a partial condenser, put 312KG of benzene into it, then put in 1.0kg of aluminum trichloride, and raise the temperature to 75°C. Drop into 512KG bromine in the bromine dropping tank. Open the top decondenser to feed in and out water, raise the temperature of the synthesis kettle to about 75°C, keep the reflux state in the tower, open the valve at the bottom of the bromine dropping tank in the reaction kettle to add bromine dropwise, and the dropping time is 10hr. During the process, the reaction temperature is gradually increased, and the system always maintains a slight reflux state in the tower. After the dropwise addition, the reaction temperature is maintained at 100-110°C for 2 hours. Tail gas is absorbed by falling film water in three stages in series, adding 260kg of water to each stage, and the absorption temperature is 15~60°C. The synthetic solution is debenzene and refined to obtai...

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Abstract

The invention provides a method for producing by-product hydrobromic acid in synthesis of bromobenzene. Under the condition of reflowing temperature, by virtue of a separation tower and a total condenser, the bromine vapor volatilized into the tower is continuously eluted by the benzene under the condition of reflowing, so that the aim of improving the comprehensive utilization rate of bromine and the quality of the by-product hydrobromic acid is realized. The method provided by the invention comprises the following specific steps of: 1) adding benzene and a catalyst in a reactor, at the temperature of warming and reflowing, dropping bromine, and obtaining the bromobenzene by debenzolizing and refining the synthesized liquid; and 2) continuously eluting the end gas synthesized in the step 1) by the benzene in the tower, cooling the end gas in a fractional condenser, and conveying the cooled gas in an end gas absorption system. The content of the free benzene in the by-product hydrobromic acid obtained by the method is less than 40PPM, and the by-product hydrobromic acid is a colorless or slightly yellow transparent liquid, and has no various change in appearance after being stored for more than one year.

Description

technical field [0001] The invention relates to a method for recovering HBr gas, a by-product of bromobenzene synthesis, to obtain industrial-grade hydrobromic acid. Background technique [0002] Bromobenzene is an important raw material for the synthesis of the pyrethroid insecticide bifenthrin, and the common method for its synthesis is the substitution reaction of benzene and bromine to obtain bromobenzene. During the benzene bromination reaction, a certain amount of hydrogen bromide gas will be produced. The use of alkali for absorption will produce a large amount of bromine-containing wastewater, and water is often used for absorption in industrial production processes. The comprehensive utilization rate of bromine and the internal quality of recovered hydrogen bromide become the key factors affecting the cost of bromobenzene synthesis products. [0003] The bromobenzene synthesis reaction, reported in the literature, adopts the method of liquid phase dropwise additio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/02C07C17/12C01B7/09
Inventor 徐海鹏王振锋彭达吴春中丁剑剑尹卫东
Owner JIANGSU YOUJIA CHEM
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