Chemistry:3,4-Ethylenedioxythiophene
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| Names | |
|---|---|
| Preferred IUPAC name
2,3-Dihydrothieno[3,4-b][1,4]dioxine | |
| Identifiers | |
PubChem CID
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| UNII | |
| Properties | |
| C6H6O2S | |
| Molar mass | 142.17 g·mol−1 |
| Appearance | colorless liquid |
| Density | 1.34 g/cm3[1] |
| Melting point | 10.5 °C (50.9 °F; 283.6 K)[1] |
| Boiling point | 225 °C (437 °F; 498 K)[1] |
| 2.1 g/L[1] | |
| Viscosity | 11 mPa·s[1] |
| Hazards | |
| Flash point | 104 °C (219 °F; 377 K)[1] |
| 360 °C (680 °F; 633 K)[1] | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
3,4-Ethylenedioxythiophene (EDOT) is an organosulfur compound with the formula C2H4O2C4H2S. The molecule consists of thiophene, substituted at the 3 and 4 positions with an ethylene glycolyl unit. It is a colorless viscous liquid.[2]
EDOT is the precursor to the polymer PEDOT, which is found in electrochromic displays, photovoltaics, electroluminescent displays, printed wiring, and sensors.[3][4]
Synthesis and polymerization
The original synthesis proceeded via the diester of 3,4-dihydroxythiophene-2,5-dicarboxylate.
EDOT is often prepared from C4 precursors such as butanediol and butadiene via routes that produce the thiophene and dioxane rings in separate steps. Representative is the reaction of 2,3-butanedione, trimethyl orthoformate, and ethylene glycol to form the dioxane. Sulfidization with elemental sulfur gives the bicyclic target.[5]
EDOT is converted into the conducting polymer PEDOT by oxidation. The mechanism for this conversion begins with production of the radical cation [EDOT]+, which attacks a neutral EDOT molecule followed by deprotonation. Further similar steps result in the dehydropolymerization. The idealized conversion using peroxydisulfate is shown
- n C2H4O2C4H2S + n (OSO3)22− → [C2H4O2C4S]n + 2n HOSO3−
For commercial purposes, the polymerization is conducted in the presence of polystyrenesulfonate.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Elschner, Andreas; Kirchmeyer, Stephan; Lovenich, Wilfried (2010). PEDOT: Principles and Applications of an Intrinsically Conductive Polymer. CRC Press. p. 51. ISBN 978-1-4200-6912-9. https://books.google.com/books?id=e12gOPc4lWAC&pg=PA51.
- ↑ Jonas, F.; Schrader, L. (1991). "Conductive Modifications of Polymers with Polypyrroles and Polythiophenes". Synthetic Metals 41 (3): 831–836. doi:10.1016/0379-6779(91)91506-6.
- ↑ Groenendaal, L. B.; Jonas, F.; Freitag, D.; Pielartzik, H.; Reynolds, J. R. (2000). "Poly(3,4-Ethylenedioxythiophene) and Its Derivatives: Past, Present, and Future". Adv. Mater. 12 (7): 481–494. doi:10.1002/(SICI)1521-4095(200004)12:7<481::AID-ADMA481>3.0.CO;2-C.
- ↑ 4.0 4.1 Kirchmeyer, S.; Reuter, K. (2005). "Scientific Importance, Properties and Growing Applications of Poly(3,4-Ethylenedioxythiophene)". J. Mater. Chem. 15 (21): 2077–2088. doi:10.1039/b417803n.
- ↑ Hachiya, I.; Yamamoto, T.; Inagaki, T. et al. (2014). "Two-Step Synthesis of 3,4-Ethylenedioxythiophene (EDOT) from 2,3-Butanedione". Heterocycles 88: 607–612. doi:10.3987/COM-13-S(S)8.
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