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Method for preparing bromophenol

A technology for bromophenol and phenol, applied in the field of preparing bromophenol, can solve the problems of cumbersome catalyst preparation process, low para-selectivity of bromide, environmental pollution of hydrogen bromide, etc., and achieves short preparation cycle, low cost, improved The effect of catalytic activity

Inactive Publication Date: 2008-09-17
LIAOCHENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional phenol bromination method uses inorganic acid or metal halide (such as anhydrous aluminum trichloride) as a catalyst, and directly uses liquid bromine as a raw material. It is low in performance, and half of the bromine is converted into hydrogen bromide during production, which is wasted. At the same time, the discharge of hydrogen bromide causes environmental pollution, and after the reaction, the catalyst is not easy to separate
The oxidative bromination method developed later, that is, in the process of phenol bromination, hydrogen bromide is selected as the bromine source, and hydrogen peroxide is used as the oxidant to brominate phenol. This method has good para-selectivity, but the conversion of the bromide The rate is low and can only reach about 30%, and the unreacted hydrogen bromide also causes environmental pollution; in order to avoid the waste and pollution caused by the hydrogen bromide generated in the bromination reaction, potassium bromide is selected as the bromine source and acidified with nitric acid Carbon nanotubes are used as catalysts to catalyze the oxidation of brominated phenol, and the conversion rate can reach 90%, but the preparation process of the catalyst is cumbersome, the acidification time is long, and the method requires a long bromination reaction time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1: prepare brominated phenol:

[0022] (1) Catalyst preparation: add a certain amount of activated carbon of 200 to 400 microns to 10% HNO 3 In the solution, heat and reflux for 1.5 hours until the activated carbon is just submerged, then cool, wash the activated carbon particles with water until the pH is neutral, filter with suction, dry at 120°C for 3 hours, and cool in a desiccator. Add 4g of activated carbon to 4g of phosphomolybdenum tungsten heteropoly acid aqueous solution with a mass concentration of 15%, soak overnight, dry in a drying oven at 90°C for 3h, and then cool in a desiccator to obtain phosphorus with a loading capacity of 15% activated carbon. Molybdenum tungsten heteropolyacid catalyst.

[0023] (2) Get above-mentioned catalyst 10g, mix with 2mol phenol, 2.2mol potassium bromide respectively, then add 4L mass concentration and be 99.5% acetic acid and 2.2mol mass concentration be 30% hydrogen peroxide (the molar number of hydrogen perox...

Embodiment 2

[0024] Embodiment 2: prepare bromophenol:

[0025] (1) Catalyst preparation: add a certain amount of activated carbon of 200 to 400 microns to 10% HNO 3 In the solution, heat and reflux for 1.5 hours until the activated carbon is just submerged, then cool, wash the activated carbon particles with water until the pH is neutral, filter with suction, dry at 120°C for 3 hours, and cool in a desiccator. Add 4g of activated carbon to 4g of 15% silicon-molybdenum-tungsten heteropoly acid aqueous solution, soak overnight, dry in a drying oven at 90°C for 3 hours, and then cool in a desiccator to obtain silicon with a loading capacity of 15% activated carbon. Molybdenum tungsten heteropolyacid catalyst.

[0026] (2) Get above-mentioned catalyst 10g, mix with 2mol phenol, 2.2mol potassium bromide respectively, then add 6L mass concentration and be 99.5% acetic acid and 3mol mass concentration be 30% hydrogen peroxide, stir vigorously at room temperature, react 5 After 1 hour, filter, ...

Embodiment 3

[0027] Embodiment 3: prepare bromophenol:

[0028] (1) Catalyst preparation: add a certain amount of activated carbon of 200 to 400 microns to 10% HNO 3 In the solution, heat and reflux for 1.5 hours until the activated carbon is just submerged, then cool, wash the activated carbon particles with water until the pH is neutral, filter with suction, dry at 120°C for 3 hours, and cool in a desiccator. 4g of activated carbon is added to 4g of phosphomolybdenum heteropoly acid aqueous solution with a mass concentration of 15%, soaked overnight, dried at 90°C for 3h in a drying oven, and then cooled in a desiccator to obtain a 15% activated carbon-loaded phosphomolybdenum heteropolyacid catalyst.

[0029] (2) Get above-mentioned catalyst 8g, mix with 2mol phenol, 2.2mol potassium bromide respectively, then add 2L mass concentration and be 99.5% acetic acid and 4mol mass concentration be 30% hydrogen peroxide, stir vigorously at room temperature, react 5 After 1 hour, filter, wash,...

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Abstract

The invention discloses a method of preparing bromophenol. The method comprises the following steps: supported heteropoly acid is used as a catalyst, potassium bromide is used as bromo source, and peroxide is used as oxidizer to bromize phenol, and then neutralization, washing, extraction, and drying are performed in sequence to obtain the bromophenol. The supported heteropoly acid is formed by carriers which load heteropoly acid, wherein, the grain diameter of the carriers ranges from 75 to 800 micrometres, and the weight of the heteropoly acid ranges from 1 to 50 percent. In the method, the phenol percent conversion is high, and the selectivity of contraposition phenol bromo-compounds is high; the adopted catalyst has simple preparation, high reactivity and wide loading range, is easy to process after the reaction, can be used repeatedly, and has wide application prospect.

Description

technical field [0001] The invention relates to a method for preparing brominated phenol, in particular to a method for brominating phenol by using a loaded heteropolyacid as a catalyst. Background technique [0002] Aromatic brominated compounds are important intermediates for the synthesis of various biologically active substances, especially p-bromophenol, which can be used as intermediates for medicine, pesticides, flame retardants, etc., so the synthesis of p-bromophenol is very important. Very important. The traditional phenol bromination method uses inorganic acid or metal halide (such as anhydrous aluminum trichloride) as a catalyst, and directly uses liquid bromine as a raw material. Low performance, because half of the bromine is converted into hydrogen bromide during production, which is wasted. At the same time, the discharge of hydrogen bromide causes environmental pollution, and after the reaction, the catalyst is not easy to separate. The oxidative brominati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/27C07C37/62
CPCY02P20/52
Inventor 龚树文尹汉东崔庆新刘丽君
Owner LIAOCHENG UNIV
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