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2, 5-dichloro thiophene preparation method

A technology of dichlorothiophene and thiophene, which is applied in the field of preparation of 2,5-dichlorothiophene, can solve problems such as environmental pollution, and achieve the effects of clean preparation method, reduced dosage, and improved yield

Inactive Publication Date: 2016-04-13
CHONGQING TIANYI HENGHUA TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In view of the above-mentioned problems in the prior art, the present invention proposes a preparation method of 2,5-dichlorothiophene, which solves the existing technology that 2,5-dichlorothiophene will pollute the environment during the production process question

Method used

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  • 2, 5-dichloro thiophene preparation method

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Embodiment 1

[0020] A preparation method of 2,5-dichlorothiophene comprises: adding 231g of carbon tetrachloride and 84g of thiophene in a 1000ml three-necked flask, heating up to reflux, and adding 200g of N-chlorobutyl in batches under the condition of reflux Diimide, backflow obtains reaction solution after 3.5 hours; The reaction solution in step 1 is cooled to room temperature, filters and removes impurity, then concentrates and recovers the carbon tetrachloride in the filtrate to obtain remaining reaction solution; Step 2 The temperature of the remaining reaction solution was raised to 100°C, and rectification under reduced pressure was carried out. The fraction at 100°C was collected, and the fraction at 100°C was collected as the target product of 2,5-dichlorothiophene to obtain 97g of 2,5-dichlorothiophene, 2, The yield of 5-dichlorothiophene was 63.4%, and the purity was 98%.

Embodiment 2

[0022] A preparation method of 2,5-dichlorothiophene comprises: adding 300g of carbon tetrachloride and 84g of thiophene in a 1000ml three-necked flask, heating up to reflux, and adding 270g of N-chlorobutyl in batches under the condition of reflux Diimide, reflux obtains reaction solution after 4 hours; The reaction solution in step 1 is cooled to room temperature, filters and removes impurity, then concentrates and recovers the carbon tetrachloride in the filtrate to obtain remaining reaction solution; Step 2 The temperature of the remaining reaction solution was raised to 100°C, and rectification under reduced pressure was carried out. The fraction at 100°C was collected, and the fraction at 100°C was collected as the target product of 2,5-dichlorothiophene to obtain 145g of 2,5-dichlorothiophene, 2, The yield of 5-dichlorothiophene was 95%, and the purity was 98.5%.

Embodiment 3

[0024] A preparation method of 2,5-dichlorothiophene comprises: adding 385g carbon tetrachloride and 84g thiophene in a 1000ml three-necked flask, heating up to reflux, and adding 334gN-chlorobutyl in batches under the condition of reflux Diimide, reflux obtains reaction solution after 4.5 hours; The reaction solution in step 1 is cooled to room temperature, filters and removes impurity, then concentrates and recovers the carbon tetrachloride in the filtrate to obtain remaining reaction solution; Step 2 The temperature of the remaining reaction solution was raised to 100°C, and rectification under reduced pressure was carried out. The fraction at 100°C was collected, and the fraction at 100°C was collected as the target product of 2,5-dichlorothiophene to obtain 145g of 2,5-dichlorothiophene, 2, The yield of 5-dichlorothiophene was 95%, and the purity was 98.5%.

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Abstract

The present invention discloses a 2, 5-dichloro thiophene preparation method comprising the following steps: (1) an organic solvent and thiophene are added into a reaction vessel and warmed to reflux, under reflux conditions, batches of added N-chlorosuccinimide are added for refluxing for 3 to 5 hours to obtain a reaction solution; (2) the reaction solution of the step (1) is cooled to room temperature, impurities are filtered out, the organic solvent in the filtrate is concentrated and recovered to obtain the remaining reaction solution; (3) the remaining reaction solution of the step (2) is heated to 100 DEG C for vacuum rectification, a fraction of 100 DEG C is collected, namely a 2, 5-dichloro thiophene desired product is collected. The N-chlorosuccinimide and the thiophene are reacted in carbon tetrachloride, the reaction process does not produce gases polluting the environment, the reactants can be more fully reacted in the case of use of the carbon tetrachloride as a solvent, the product yield is higher, after the reaction, the carbon tetrachloride can easily be separated and recovered, and the product purity is higher.

Description

technical field [0001] The invention relates to a preparation method of 2,5-dichlorothiophene. Background technique [0002] 2,5-dichlorothiophene is an important intermediate in the synthesis of new drugs. At present, 2,5-dithiophene is produced by the reaction of thiophene and sulfuryl chloride. Since sulfuryl chloride is used as the reactant, during the reaction process, there will be A large amount of sulfur dioxide waste gas is produced. Sulfur dioxide is a gas with a strong pungent smell. It is easily dissolved in human blood and other viscous liquids. Not only does it do great harm to the human body, but also sulfur dioxide is easy to form acid rain. Buildings are extremely corrosive, and affect the normal growth of plants, causing serious pollution to the environment, making it impossible to realize industrial production. Contents of the invention [0003] In view of the above-mentioned problems in the prior art, the present invention proposes a preparation method...

Claims

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Application Information

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IPC IPC(8): C07D333/28
CPCC07D333/28
Inventor 郑伟唐勇
Owner CHONGQING TIANYI HENGHUA TECH CO LTD
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