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Method for preparing 2-bromine-4-methylphenol

A technology of methylphenol and p-cresol, which is applied in the field of preparation of 2-bromo-4-methylphenol, can solve the problems of large amount of solvent, difficult separation of monobromophenol, limited application, etc., and achieve the goal of avoiding dibromo Produce, reduce production costs, and avoid strong corrosion effects

Inactive Publication Date: 2012-11-07
SHANDONG MORIS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main defect of this technique is: (1) select 40% hydrobromic acid as the bromination agent for use, which has strong corrosion to equipment
(2) The reaction process is prone to produce dibromo compounds, which are difficult to separate from monobromophenol
(3) The amount of solvent is large, and at least 6.5 tons of solvent are needed to produce one ton of p-cresol
Due to the above reasons, the industrial application of this method is limited.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Add 220g (2.00 moles) of p-cresol and 146.7g (1.23 moles) of chloroform into a 1000mL four-neck flask, add 336.33g (2.10 moles) of bromine and 228.8g (1.91 moles) of chloroform into a constant pressure dropping funnel, well mixed. Start stirring, lower the temperature to 0~5°C, start to add the mixed solution of bromine and chloroform dropwise, control the rate of addition, keep dropping at a constant speed, and control the temperature, the time is 7 hours, and the reaction ends. Add 400 g of water to the reaction flask to wash the hydrogen bromide with water, separate the water layer, and wash the organic layer with water again, generally about 3 times until neutral. The organic layer was distilled to 100°C under normal pressure, then to 55°C at -0.09MPa, and the chloroform was recovered for the next experiment. After the organic layer was evaporated to remove the solvent, 376.88g of finished monobromophenol was obtained. , through gas spectrum analysis, it can be see...

Embodiment 2

[0017] Add 110g (1.00 mol) of p-cresol and 52.11g (0.61 mol) of dichloromethane into a 500mL four-neck flask, add 168.24g (1.05 mol) of bromine, and 80.83g of dichloromethane ( 0.95 mol), mix well. Start stirring, lower the temperature to -5~5°C, start to drop the mixed solution of bromine and dichloromethane, control the dropping speed, about 1 second, keep dropping at a constant speed, and control the temperature, the time is 7.5 hours, the reaction is over. Add 200 g of water to the reaction flask to wash the hydrogen bromide with water, separate the water layer, and wash the organic layer with water again (3 times in total). Distill the organic layer to 80°C under normal pressure and then to 33°C at -0.09MPa to recover dichloromethane for the next experiment. After the organic layer is evaporated to remove the solvent, the finished monobromophenol can be obtained 189.39g, through gas spectrum analysis, it can be seen that in addition to dichloromethane, the composition of...

Embodiment 3

[0019] Add 220g (2.00 moles) of p-cresol and 300.11g (2.51 moles) of chloroform into a 1000mL four-neck flask, add 368.69g (2.30 moles) of bromine and 448.17g (3.75 moles) of chloroform into a constant pressure dropping funnel, well mixed. Start stirring, lower the temperature to -5~0°C, start dropwise adding the mixed solution of bromine and chloroform, control the rate of addition, keep dropping at a constant rate, and control the temperature, the time is 7 hours, and the reaction is completed. Add 400 g of water to the reaction flask to wash the hydrogen bromide with water, separate the water layer, and wash the organic layer with water again, generally about 3 times until neutral. The organic layer was distilled to 100°C under normal pressure, then to 55°C at -0.09MPa, and the chloroform was recovered for the next experiment. After the organic layer was evaporated to remove the solvent, 376.76g of finished monobromophenol was obtained. , through gas spectrum analysis, it ...

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PUM

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Abstract

The invention provides a method for preparing 2-bromine-4-methylphenol, wherein p-cresol serves as the raw material. The method is characterized in that p-cresol and methyl chloride solvents are added into a reactor, methyl chloride solution added with bromine dropwise is subjected to bromination reaction, then the solvents are recovered through distilling, and finally the product of 2-bromine-4-methylphenol is obtained. By using the method to produce 2-bromine-4-methylphenol, purity and yield are high, consumption of the raw material and the solvents is low, and reaction conversion rate is high.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a preparation method of 2-bromo-4-methylphenol. Background technique [0002] 2-bromo-4-methylphenol (hereinafter referred to as monobromophenol) is an important intermediate in the synthesis of many drugs and broad-spectrum spice vanillin. At present, the more advanced method of preparing monobromophenol is to prepare p-cresol as raw material through bromination oxidation. "Synthesis of 2-bromo-4-methylphenol" and other articles published in the fifth issue of "Chemical Research and Application" in 2004 introduced this process. It can be seen from the above article that the main steps of this process are: add p-cresol and methylene chloride to the reactor, mix well, add hydrobromic acid, and control the temperature at -5~-10°C, add hydrogen peroxide dropwise, After the reaction was completed, it was washed with water and distilled under reduced pressure to o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/27C07C37/62
Inventor 李建业段学伟于文智王德强葛芹芹宫雪红
Owner SHANDONG MORIS TECH