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A kind of preparation method of m-bromophenol

A technology for bromophenol and chemical reaction, applied in the field of preparation of m-bromophenol, can solve the problems of difficulty in product separation and difficult to improve quality, and achieves the effects of mild reaction conditions and improved reaction yield

Active Publication Date: 2021-12-03
开封缘润药业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the bromination reaction is based on the SN1 mechanism, the bromination can obtain a higher yield, but there is still competition with the hydroxyl group, so the yield of the product generally does not exceed 55%, and a large part of it becomes a by-product Resorcinol brings difficulty in product separation and quality improvement

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] A kind of preparation method of m-bromophenol, its process chemical reaction is:

[0017] ,

[0018] It includes the following steps: in a reaction flask equipped with a stirrer, a thermometer, and a dropping funnel, add 400mL of water, 260g of 98% concentrated sulfuric acid, add 138g of m-bromoaniline under cooling, and then add 150mL of water, and cool the reaction solution to 5°C Next, start to add dropwise a solution made of 64.4g of sodium nitrite dissolved in 180mL of water, control the diazotization temperature below 5°C, control the dropwise addition time at 25min, then continue to stir for 10min, add 5g of urea to decompose excess Sodium nitrite, stir for 10 minutes, add 270mL of low-temperature water at 0°C, stir well and set aside;

[0019] In a reaction flask equipped with a stirrer, a thermometer, a dropping funnel, and a distillation device, add 170 g of sodium sulfate catalyst, 200 g of 98% concentrated sulfuric acid, heat up to 125 ° C, dropwise add t...

Embodiment 2

[0022] A kind of preparation method of m-bromophenol, its process chemical reaction is:

[0023] ,

[0024] It includes the following steps: in a reaction flask equipped with a stirrer, a thermometer, and a dropping funnel, add 200 mL of water, 130 g of 98% concentrated sulfuric acid, add 69 g of m-bromoaniline under cooling, and then add 100 mL of water, and cool the reaction solution to 5°C Afterwards, start to add dropwise a solution prepared by dissolving 32.2g of sodium nitrite in 90mL of water, control the diazotization temperature below 5°C, control the dropwise addition time at 25min, then continue stirring for 10min, add 3g of urea to decompose excess Sodium nitrite, stir for 10 minutes, add 270mL of low-temperature water at 0°C, stir well and set aside;

[0025] In a reaction flask equipped with a stirrer, a thermometer, a dropping funnel, and a distillation device, add 100 g of sodium sulfate catalyst, 130 g of 98% concentrated sulfuric acid, heat up to 130 ° C, ...

Embodiment 3

[0028] A kind of preparation method of m-bromophenol, its process chemical reaction is:

[0029] ,

[0030] The method comprises the following steps: in a reaction flask equipped with a stirrer, a thermometer and a dropping funnel, add 300 mL of water, 195 g of 98% concentrated sulfuric acid, add 103.5 g of m-bromoaniline under cooling, and then add 125 mL of water, and cool the reaction solution to 5 Below ℃, start dropwise adding a solution made of 48.3g of sodium nitrite dissolved in 135mL of water, control the diazotization temperature below 5°C, control the dropping time at 25min, then continue to stir for 10min, add 4g of urea to decompose the excess sodium nitrite, stirred for 10 minutes, added 270mL of low-temperature water at 0°C, stirred evenly and set aside;

[0031] In a reaction flask equipped with a stirrer, a thermometer, a dropping funnel, and a distillation device, add 135 g of copper sulfate catalyst, 165 g of 98% concentrated sulfuric acid, heat up to 120...

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PUM

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Abstract

The invention discloses a preparation method of m-bromophenol, which comprises the following steps: diazotization reaction, hydrolysis reaction, and extraction. The invention uses m-bromoaniline as a raw material, through diazo, catalytic hydrolysis, solvent extraction, and vacuum rectification. The high-purity target product is obtained; and this process avoids the use of hydrobromic acid, and the reaction conditions are mild. Since the hydrolysis reaction is an open system, it is conducive to the release of nitrogen generated during hydrolysis, so that the reaction balance is carried out towards the reaction direction under hydrolysis, which is beneficial to the reaction. Yield improvement.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation method of m-bromophenol. Background technique [0002] Meta-bromophenol is a key intermediate used in the synthesis of analgesic drug tramadol hydrochloride. Due to the increase of cancer patients in recent years, the supply of tramadol hydrochloride has increased. Since tramadol hydrochloride has certain adverse reactions after taking it, the requirements for the purity of the intermediate are quite high, so as to reduce the adverse reactions after taking the finished medicine. m-bromophenol is generally made of m-aminophenol as a raw material. After diazotization reaction, hydrobromic acid and cuprous bromide are used for bromination reaction to obtain the target product. Since the bromination reaction is based on the SN1 mechanism, the bromination can obtain a higher yield, but there is still competition with the hydroxyl group, so the yield of the pro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/045C07C39/27
CPCC07C37/045C07C245/20C07C39/27
Inventor 王力倪协屏孙乐达
Owner 开封缘润药业有限公司