DABCO
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| Names | |||
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| IUPAC name
1,4-Diazabicyclo[2.2.2]octane
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| Other names
triethylenediamine, TEDA
DABCO |
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| Identifiers | |||
280-57-9  |
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| ChemSpider | 8882 |
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| 2577 | |||
| Jmol 3D model | Interactive image Interactive image |
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| PubChem | 9237 | ||
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| Properties | |||
| C6H12N2 | |||
| Molar mass | 112.18 g·mol−1 | ||
| Appearance | White crystalline powder | ||
| Melting point | 156 to 160 °C (313 to 320 °F; 429 to 433 K) | ||
| Boiling point | 174 °C (345 °F; 447 K) | ||
| Soluble, hygroscopic | |||
| Acidity (pKa) | 3.0, 8.8 (in water)[1] | ||
| Vapor pressure | {{{value}}} | ||
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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| Infobox references | |||
DABCO is the acronym for the organic compound 1,4-diazabicyclo[2.2.2]octane, with the formula N2(C2H4)3. This colorless solid is a highly basic amine, which is used as a catalyst and reagent in polymerization and organic synthesis.[2]
Contents
Reactions and applications
The pKa of [HDABCO]+ (the protonated derivative) is 8.8, which is almost the same as ordinary alkylamines. The nucleophilicity of the amine is high because the amine centers are unhindered. It is sufficiently basic to promote C-C coupling of terminal acetylenes, for example, phenylacetylene couples with electron-deficient iodoarenes.
Catalyst
DABCO is used as a base-catalyst for:
- formation of polyurethane from amines and isocyanates. In factDABCO is a registered trademark of Air Products & Chemicals Inc for this application.[3]
- Baylis-Hillman and Morita-Baylis-Hilman reactions of aldehydes and unsaturated ketones and aldehydes.[4]
Lewis base
As an unhindered amine, it is a strong ligand and Lewis base. it forms a crystalline 2:1 adduct with hydrogen peroxide[5] and sulfur dioxide.[6]
Quencher of singlet oxygen
DABCO and related amines are quenchers of singlet oxygen and effective antioxidants,[7] and can be used to improve the lifetime of dyes. This makes DABCO useful in dye lasers and in mounting samples for fluorescence microscopy (when used with glycerol and PBS).[8] DABCO can also be used to demethylate quaternary ammonium salts by heating in dimethylformamide (DMF).[9]
Production
It is produced by thermal reactions of compounds of the type H2NCH2CH2X (X = OH, NH2, NHR) in the presence of zeolitic catalysts. An idealized conversion is shown for the conversion from ethanolamine:[10]
- 3 H2NCH2CH2OH → N(C2H4)3N + NH3 + 3 H2O
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Uppuluri V. Mallavadhani, Nicolas Fleury-Bregeot "1,4-Diazabicyclo [2.2.2]octane" Encyclopedia of Reagents for Organic Synthesis, 2010, John Wiley & Sons, Ltd. doi:10.1002/047084289X.rd010m.pub2
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Baylis, A. B.; Hillman, M. E. D. German Patent 2155113, 1972.
- ↑ P. Dembech, A. Ricci, G. Seconi, and M. Taddei "Bis(trimethylsilyl) Peroxide" Org. Synth. 1997, volume 74, pp. 84. doi:10.15227/orgsyn.074.0084
- ↑ Ludovic Martial and Laurent Bischoff "Preparation of DABSO from Karl-Fischer Reagent" Org. Synth. 2013, volume 90, pp. 301. doi:10.15227/orgsyn.090.0301
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a02_001
Further reading
- Lua error in package.lua at line 80: module 'strict' not found..
