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Process for synthesizing 3, 4-dimethoxythiophene

A technology of dimethoxythiophene and a synthesis method, applied in the direction of organic chemistry and the like, can solve problems such as affecting the quality and use of EMOT products, high residual bromide ion content, unfavorable industrial production, etc., achieving convenient industrial production and safe and reliable synthesis process. , the effect of easy industrial production

Inactive Publication Date: 2013-08-21
QINGDAO HECHENG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process uses more expensive thiophene and highly corrosive bromine, and the residual content of bromide ions in EMOT products is relatively high, thus affecting the quality and use of EMOT products
At present, there are reports in China that react with diacetyl and methyl orthoformate, and then react with sulfur dichloride to synthesize EMOT, but in this method, the intermediate 2,3-dimethoxy-1,3-butadiene does not Stable and easy to polymerize, the raw material sulfur dichloride is highly corrosive, which is not conducive to industrial production, so the process is still in the laboratory research stage

Method used

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  • Process for synthesizing 3, 4-dimethoxythiophene
  • Process for synthesizing 3, 4-dimethoxythiophene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add 552.3 g (2.0 mol) of sodium 2,5-dicarboxylate-3,4-thiophenediol to 1600 g of N,N-dimethylformamide, stir at room temperature, and dropwise add 216.2 g of dimethyl carbonate ( 2.4mol), heat up to reflux, and react for 4 hours; after the reaction is completed, evaporate the solvent and add 2000g (5.0mol) of sodium hydroxide solution with a mass concentration of 10% to mix evenly, heat to 85°C, react for 2 hours, and the reaction is complete Finally, acidify with sulfuric acid with a mass concentration of 50% at room temperature until the pH is 1 to 2, filter, add 1200 g of ethylene glycol solvent to the filter residue, add 6.4 g (0.04 mol) of copper sulfate under stirring, and heat to 100 ° C , heat preservation reaction for 3 hours, after the reaction was completed, 211.8g of the product, namely 3,4-dimethoxythiophene, was obtained by rectification under reduced pressure, with a content of 99.0% and a total yield of 72.7%. The ethylene glycol can be reused after recov...

Embodiment 2

[0030] Add 552.3 g (2.0 mol) of sodium 2,5-dicarboxylate-3,4-thiophenediol to 1100 g of N,N-dimethylformamide, stir at room temperature, and dropwise add 540.4 g of dimethyl carbonate ( 6.0mol), heated to reflux, and reacted for 2 hours; after the reaction was completed, evaporate the solvent and add 2400g (6.0mol) of sodium hydroxide solution with a mass concentration of 10%, mix evenly, heat to 90°C, react for 2 hours, and the reaction was completed Finally, acidify with sulfuric acid with a mass concentration of 50% at room temperature to a pH of 1 to 2, filter, add 1600 g of ethylene glycol solvent to the filter residue, add 16.0 g (0.1 mol) of copper sulfate under stirring, and heat to 120 ° C , heat preservation reaction for 6 hours, after the reaction was completed, 232.8g of the product was obtained by vacuum distillation, that is, 3,4-dimethoxythiophene, the content was 98.5%, the total yield was 79.5%, and the ethylene glycol could be reused after recovery.

Embodiment 3

[0032] Add 552.3 g (2.0 mol) of sodium 2,5-dicarboxylate-3,4-thiophenediol to 1,400 g of N,N-dimethylformamide, stir at room temperature, and dropwise add 234.2 g of dimethyl carbonate ( 2.6mol), heated to reflux, and reacted for 3 hours; after the reaction was completed, evaporate the solvent to dryness and add 2200g (5.5mol) of sodium hydroxide solution with a mass concentration of 10% to mix evenly, heated to 82°C, reacted for 2 hours, and the reaction was completed Finally, acidify with sulfuric acid with a mass concentration of 50% at room temperature until the pH is 1 to 2, filter, add 1400 g of ethylene glycol solvent to the filter residue, add 63.8 g (0.4 mol) of copper sulfate under stirring, and heat to 110 ° C , heat preservation reaction for 5 hours, after the reaction was completed, 222.3g of the product, namely 3,4-dimethoxythiophene, was obtained by vacuum distillation, with a content of 98.2% and a total yield of 75.7%. The ethylene glycol can be reused after re...

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Abstract

The invention discloses a process for synthesizing 3, 4-dimethoxythiophene. The process comprises the steps that (1) 2, 5-dimethyl formate-3,4-thiophene disodium alkoxide is dissolved in N, N-dicarboxylic thiophene to obtain 2, 5-dicarboxylic formate-3, 4-dimethoxy thiophene crude product by adding an alkylating reagent and based on heating reflux; (2) sodium hydroxide solution is added into the 3, 4-dimethoxy-2, 5-dicarboxylic thiophene crude product to obtain 3, 4-methoxy-2, 5-dicarboxylic thiophene crude product; (3) decarboxylation catalyst is added into a mixture of the 3, 4-dimethoxy-2, 5-dicarboxylic thiophene crude product and ethylene glycol solvent to obtain 3, 4-dimethoxythiophene finished product based on heating decarboxylation and rectification. The ethylene glycol solvent can be repeatedly used; and the process for synthesizing 3, 4-dimethoxythiophene has an environment-friendly process route, the production raw materials are easily obtained, the post treatment method is simple, the yield of the product obtained according to the process is high, the cost is low, and the quality is stable.

Description

technical field [0001] The invention relates to a synthesis method of heterocyclic compounds, in particular to a synthesis method of 3,4-dimethoxythiophene. Background technique [0002] The polymer PEMOT of 3,4-dimethoxythiophene (EMOT) has many advantages such as high conductivity, good transparency, high stability, and easy processing, and is used in organic thin film solar cell materials, solid capacitors, conductive inks, OLED materials, electrochromic materials, antistatic materials, new electromagnetic shielding materials and other fields, so the market demand for 3,4-dimethoxythiophene is increasing. [0003] The synthesis method of EMOT is mainly obtained by thiophene bromination, selective reduction, and oxyalkylation. This process uses more expensive thiophene and highly corrosive bromine, and the residual content of bromide ions in EMOT products is relatively high, thus affecting the quality and use of EMOT products. At present, there are reports in China that ...

Claims

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Application Information

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IPC IPC(8): C07D333/32
Inventor 杜法富
Owner QINGDAO HECHENG PHARMA
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