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Method for producing 3-bromothiophene by reducing 2,3,5-three bromine thiophene by using acid-metal system

A technology of tribromothiophene and bromothiophene, which is applied in the direction of organic chemistry, and can solve the problems of less synthesis steps and difficult separation of 3-bromothiophene

Inactive Publication Date: 2015-04-22
白银摩尔化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Using thiophene as a raw material to synthesize 2-bromothiophene first, and then isomerizing 2-bromothiophene to obtain 3-bromothiophene, this process has fewer synthesis steps and higher yield, but unreacted 2-bromothiophene and 3-bromothiophene in the product Bromothiophene is difficult to separate

Method used

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  • Method for producing 3-bromothiophene by reducing 2,3,5-three bromine thiophene by using acid-metal system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] a. Put 80L of water, 24.5kg of 85% concentrated phosphoric acid, 32.0kg of zinc powder, and 52.6kg of 2,3,5-tribromothiophene into the reaction kettle 1, and heat it to reflux under stirring. The gas is condensed by the reflux condenser 5 and then returned to Flow into the reactor 1, and the reflux reaction time is 6 hours.

[0020] b. After the reaction, put the mixture in the reaction kettle 1 into the steam distillation kettle 2, and pass superheated steam into the steam distillation kettle 2 to carry out steam distillation.

[0021] c. The distillate is condensed by the steam distillation condenser 6 and then collected into the extraction drying kettle 3, extracted with 80L ethyl acetate, and the water phase is released, and the organic phase is dried with 5 kg of anhydrous sodium sulfate.

[0022] d. Put the dried organic phase into the distillation kettle 4 for distillation, and the gas passes through the distillation condenser I7 and the distillation condenser II...

Embodiment 2

[0024] a. Put 80L of water, 60kg of 31% hydrochloric acid, 32.0kg of zinc powder, and 52.6kg of 2,3,5-tribromothiophene into the reaction kettle 1, heat it under stirring, and return the gas to the reaction kettle 1 after being condensed by the reflux condenser 5 , the reflux reaction time was 3 hours.

[0025] b. After the reaction, put the mixture in the reaction kettle 1 into the steam distillation kettle 2, and pass superheated steam into the steam distillation kettle 2 to carry out steam distillation.

[0026] c. The distillate is condensed by the steam distillation condenser 6 and then collected into the extraction drying kettle 3, extracted with 80L ethyl acetate, and the water phase is released, and the organic phase is dried with 5 kg of anhydrous sodium sulfate.

[0027] d. Put the dried organic phase into the distillation kettle 4 for distillation, and the gas passes through the distillation condenser I 7 and the distillation condenser II 8 successively to collect t...

Embodiment 3

[0029] a. Put 80L of water, 24.5kg of 85% concentrated phosphoric acid, 30kg of reduced iron powder and 52.6kg of 2,3,5-tribromothiophene into the reaction kettle 1, heat under stirring, and the gas is condensed by the reflux condenser 5 and then flows back into the reaction vessel In kettle 1, the reflux reaction time was 7 hours.

[0030] b. After the reaction, put the mixture in the reaction kettle 1 into the steam distillation kettle 2, and pass superheated steam into the steam distillation kettle 2 to carry out steam distillation.

[0031] C, the distillate is collected in the extraction drying kettle 3 after being condensed by the steam distillation condenser 6, extracted with 80L ethyl acetate, and the water phase is released, and the organic phase is dried with 5 kg of anhydrous sodium sulfate;

[0032] d. Put the dried organic phase into the distillation kettle 4 for distillation, and the gas passes through the distillation condenser I 7 and the distillation condenser...

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Abstract

The invention relates to a method for producing 3-bromothiophene by reducing 2,3,5-three bromine thiophene by using an acid-metal system. The method is characterized by comprising the following specific steps that strong phosphoric acid or hydrochloric acid, zinc powder or reduced iron powder or magnesium powder and the 2,3,5-three bromine thiophene are put into a reaction still 1, and the mole ratio of strong phosphoric acid or hydrochloric acid to zinc powder or reduced iron powder or magnesium powder to 2,3,5-three bromine thiophene is 3:6:2; water with the volume two times of the strong phosphoric acid or the hydrochloric acid is added in the reaction still 1, heating reflux is performed on reaction mixture under stirring, and the reaction mixture reacts for three to seven hours. After reaction is completed, steam distillation is performed, distillate is extracted by adding ethyl acetate with the same volume of the water, water phases are released, organic phases are dried by adding an anhydrous sodium sulfate drying agent into an extraction dying still 3, the dried organic phases are put into a distillation still 4 to be distilled, and the colourless liquid 3-bromothiophene is obtained by distilling and collecting distillate at the temperature ranging from 159 DEG C to 161 DEG C. The method has the advantages that the purity of a product is high, the content is higher than 99.0% (GC), the productive rate of a by-product 2-bromothiophene is less than 5%, the production cost is low, the post-processing is simple, and the environmental pollution is small.

Description

technical field [0001] The invention relates to a method for producing 3-bromothiophene, more specifically to a method for producing 3-bromothiophene by reducing 2,3,5-tribromothiophene with an acid-metal system. Background technique [0002] 3-Bromothiophene is an important organic intermediate. As a derivative of β-thiophene, it has important application value in the synthesis of thiophene polymers and the synthesis of new drugs. [0003] The main production methods of 3-bromothiophene include isomerization and reduction. [0004] (1) Isomerization method [0005] Using thiophene as a raw material to synthesize 2-bromothiophene first, and then isomerizing 2-bromothiophene to obtain 3-bromothiophene, this process has fewer synthesis steps and higher yield, but unreacted 2-bromothiophene and 3-bromothiophene in the product Bromothiophene is difficult to separate. [0006] (2) Reduction method [0007] 2,3,5-Tribromothiophene is debrominated in the presence of a reducing ...

Claims

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Application Information

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IPC IPC(8): C07D333/28
CPCC07D333/28
Inventor 王发森许新兵
Owner 白银摩尔化工有限责任公司