Synthesis method for 4-bromo-o-phenylenediamine

A technology of bromo-phthalic acid amide and o-phenylenediamine, which is applied in the field of synthesis of 4-bromo-o-phenylenediamine, can solve the problems of unsuitability for industrialized production, toxicity and corrosiveness, and high reactivity, and achieves utilization of The effect of high rate, low cost and safe reaction route

Inactive Publication Date: 2013-05-01
SHANGHAI RECORD PHARM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Liquid bromine is an easily volatile liquid with strong toxicity and corrosiveness, high reactivity, easy to obtain polybrominated by-products, and the utilization rate of bromine atoms using its brominated reaction is only 50%, so It is not the most ideal reagent for bromination; while using NBS bromination, although the reaction is relatively mild and the regioselectivity is good, the cost is too high and it is not suitable for industrial production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 80 grams of o-phenylenediamine and 640 mL of glacial acetic acid into a 1-liter bottle, stir vigorously until the solution is clear, add 158 grams of acetic anhydride dropwise under ice-cooling, heat up to 50 degrees, and react for 1 hour. The peak area of ​​amine is less than 0.5%; then after cooling down to 25 degrees, add 80 grams of sodium bromide, after stirring evenly, slowly add 92 grams of 30% hydrogen peroxide dropwise, after the addition is completed, stir at room temperature for 2 hours and heat up to 50 degrees React for 2 hours, follow the liquid phase until the peak area of ​​the intermediate is less than 1%; pour the above reaction solution into 2000 grams of ice water (containing 9 grams of sodium sulfite), stir until the red color disappears, filter to obtain a white solid, and dry to obtain 4- Bromo-phthalamide 165 grams, purity 98.5%.

[0022] Under the protection of nitrogen, put 122 grams of sodium hydroxide into a 3L four-necked bottle, add 1.2...

Embodiment 2

[0024] Add 160 grams of o-phenylenediamine and 1000 mL of glacial acetic acid into a 1-liter bottle, stir vigorously until the solution is clear, add 330 grams of acetic anhydride dropwise under ice bath, heat up to 50 degrees, react for 1-2 hours, and track the liquid phase until the raw materials The peak area of ​​phenylenediamine is less than 0.5%. After cooling down to 25 degrees, add 153 grams of sodium bromide. After stirring evenly, slowly add 167.7 grams of 30% hydrogen peroxide dropwise. After the addition, stir at room temperature for 1 hour and raise the temperature to 60 degrees for 3 hours. When the peak area of ​​the solid is reduced to 6%, it will not change anymore. Pour the above reaction solution into 3000 grams of ice water (containing 15 grams of sodium sulfite), stir until the red color disappears, filter to obtain a white solid, and obtain 4-bromo-o-phenylene after drying. 325 grams of diacetamide, purity 95.6%.

[0025] Under the protection of nitrogen...

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PUM

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Abstract

The invention discloses a synthesis method for 4-bromo-o-phenylenediamine. The synthesis method comprises the following synthesis steps of: A, enabling o-phenylenediamine to react with a bromo reagent in acetic acid and acetic oxide to obtain 4-bromo-o-phenyl diacetyl amide; B, dissolving the 4-bromo-o-phenyl diacetyl amide in methyl alcohol, then, adding 5N sodium hydroxide aqueous solution, and hydrolyzing to obtain the 4-bromo-o-phenylenediamine, wherein the bromo reagent in the step A comprises sodium bromide and hydrogen peroxide. According to the synthesis method disclosed by the invention, the sodium bromide and the hydrogen peroxide are used as the bromo reagent instead of liquid bromine, and therefore, the reaction route is safe and environmentally friendly, the cost is low, the reaction condition is mild, the regioselectivity is high, and the bromine atom use ratio is high. A crude product generated by the invention is recrystallized by using tert-butyl methyl ether, and the obtained 4-bromo-o-phenylenediamine is high in purity.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a synthesis method of 4-bromo-o-phenylenediamine. Background technique [0002] 4-Bromo-o-phenylenediamine is an important chemical raw material, which can not only be used as an analytical reagent, but also be used to prepare various benzimidazoles and quinolines. These two types of compounds are widely used in medicine, pesticides and polymers. [0003] There are literatures that use o-nitroaniline to generate 4-bromo-o-nitroaniline under the action of liquid bromine, and then reduce the obtained 4-bromo-o-phenylenediamine. When this method is brominated, it is easy to obtain polybrominated by-products, which brings trouble to the post-treatment; and iron powder or SnCl is required for reduction. 2 , The post-treatment requires a large amount of reagents, and the industrial production cost is relatively high. [0004] There are also literature reports on the bromin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/62C07C209/84
Inventor 许伟长张芳江甘建刚
Owner SHANGHAI RECORD PHARM CO LTD
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