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Process for producing 3,4-enedioxy thiophene

A technology of ethylenedioxythiophene and ethyl, which is applied in 3 fields, can solve the problems of EDOT products such as dark color, high single impurity content, and heavy odor, so as to improve product color and storage stability, reduce single impurity content, reduce The effect of the type of impurity

Active Publication Date: 2009-05-13
APELOA PHARM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] The EDOT process reported in the current literature using thiodiglycolic acid as the starting material has the weakness of low yields in cycloetherification and decarboxylation reactions.
Especially for the decarboxylation reaction, if the solvents reported in the literature are used, the following problems generally exist: the color of the obtained EDOT product is dark, the peculiar smell is heavy (often with a smell different from the smell of EDOT), the residual solvent content is high, and the single impurity High content, low storage stability, etc., so it cannot meet the requirements of EDOT as an electronic product

Method used

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  • Process for producing 3,4-enedioxy thiophene
  • Process for producing 3,4-enedioxy thiophene
  • Process for producing 3,4-enedioxy thiophene

Examples

Experimental program
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Effect test

Embodiment 1

[0054] Preparation of 2,5-dicarboxylate-3,4-dihydroxy disodiumthiophene

[0055] 70g (0.466mol) thiodiglycolic acid, 1600mL methanol, 39g98% sulfuric acid and a small amount Molecular sieves were put into a 2000mL three-necked flask, and heated to reflux for 1-4 hours. The temperature was lowered to 0°C, and 50 g of sodium carbonate was slowly added to adjust the pH of the system to above 7.0. Methanol was distilled off under reduced pressure, and 800 mL of methanol was distilled off, and the residual solvent moisture was detected to control the moisture content below 0.5%. Raise the temperature to 25°C, add 10 g of anhydrous calcium chloride, and stir for 20 minutes. Filter, collect the filtrate, and cool the filtrate to 0°C. Add 432g of 25% sodium methoxide (2mol), add dropwise 99.8g (0.63mol) of diethyl oxalate, and control the temperature at 0-5°C. After the dropwise addition was completed, the temperature was raised to reflux for 1 hour, and then cooled to 0°C. Afte...

Embodiment 2

[0057] Preparation of 2,5-Diethyl Dicarboxylate-3,4-Dihydroxy Disodium Thiophene

[0058] 70g (0.466mol) thiodiglycolic acid, 1700mL ethanol, 25g trifluoroacetic acid and a small amount Molecular sieves were put into a 2000mL three-necked flask, and heated to reflux for 1-2 hours. Cool down to 0°C, slowly add 100 g of sodium carbonate solution in batches, and adjust the pH of the system to above 7.0. Ethanol was distilled off under reduced pressure, and 700 mL of ethanol was distilled off, and the residual solvent moisture was detected to control the moisture content below 0.5%. Raise the temperature to 25°C, add 15g of anhydrous calcium chloride, and stir for 20 minutes. Filter, collect the filtrate, and cool the filtrate to 0°C. Add 680 g of 20% sodium ethoxide (2 mol), add dropwise 99.8 g (0.63 mol) of diethyl oxalate, and control the temperature at 0-5°C. After the dropwise addition was completed, the temperature was raised to reflux for 1 hour, and then cooled to 0°C...

Embodiment 3

[0060] Preparation of 2,5-Diethyl Dicarboxylate-3,4-Dihydroxy Disodium Thiophene

[0061] 140g (0.932mol) thiodiglycolic acid, 2500mL ethanol, 25g sulfuric acid and a small amount Molecular sieves were put into a 2000mL three-necked flask, and heated to reflux for 2 hours. The temperature was lowered to 0°C, and 544 g (1.6 mol) of sodium carbonate solution was slowly added in batches to adjust the pH of the system to above 7.0. Ethanol was distilled off under reduced pressure, and after 1000mL of ethanol was distilled off, the residual system solvent moisture was detected, and the moisture content was controlled to be below 0.5%. Warm up to room temperature, add 50 g of anhydrous calcium chloride, and stir for 30 minutes. Filter, collect the filtrate, and cool the filtrate to 0°C. Add 1360g of 20% sodium ethoxide (4mol), add dropwise 200g (1.26mol) of diethyl oxalate, and control the temperature at 0-5°C. After the dropwise addition was completed, the temperature was rais...

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Abstract

The invention provides a method for preparing 3, 4-ethylenedioxythiophene (EDOT for short). Firstly, thiodiglycolic acid and methanol generate dimethyl 2, 2'-thiobisacetate through an esterification reaction under the catalysis of an acid, and then the dimethyl 2, 2'-thiobisacetate is condensed with diethy-aceto oxalate under the catalysis of sodium methoxide to obtain 2, 5-dimethyl carboxylate-3, 4-dihydroxy-thiophene; then the 2, 5-dimethyl carboxylate-3, 4-dihydroxy-thiophene and a cyclic esterification reagent are cyclic-esterified to generate 2, 5-dimethyl carboxylate-3, 4-ethylenedioxythiophene under the cocatalysis of copper powder or cuprous oxide and potassium carbonate, and 2, 5-dicarboxylic acid-3, 4-ethylenedioxythiophene is obtained through alkaline saponification and acid regulation; and finally a copper catalyst remained in the cyclic esterification reaction is used for catalytic decarboxylation in specific pyridine solvents, and the high-purity EDOT is obtained through reduced pressure distillation. The method has higher yield in the preparation of the EDOT, has low impurity content, and meets the requirement of electronic chemicals.

Description

technical field [0001] The invention relates to a preparation method of 3,4-ethylenedioxythiophene (hereinafter referred to as EDOT), which is a monomer of conductive polymer polyethylenedioxythiophene (PEDOT). Background technique [0002] Polyethylenedioxythiophene is a new type of conductive polymer, which was first synthesized by German Bayer company in 1991. It has the advantages of high conductivity, good environmental stability, easy film production and good transparency. It is used in antistatic packaging , Preparation of organic light-emitting diodes, preparation of organic solar cells, electrochemical capacitors and other fields have important applications, and are expected to be used as superconducting materials and information storage materials in the field of plastic electronic chip devices. Therefore, polyethylenedioxythiophene has become the focus in the field of conducting polymer research. Therefore, developing a suitable synthetic process to produce EDOT (...

Claims

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Application Information

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IPC IPC(8): C07D495/04
Inventor 厉昆李啸风厉云阳叶云生李铭东任红阳
Owner APELOA PHARM CO LTD
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