Triethylamine

Triethylamine
Names
Preferred IUPAC name
N,N-Diethylethanamine
Other names
(Triethyl)amine
Triethylamine (deprecated[1])
Identifiers
3D model (JSmol)
Abbreviations TEA[2]
605283
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.064
EC Number 204-469-4
KEGG
MeSH triethylamine
RTECS number YE0175000
UNII
UN number 1296
Properties[3]
C6H15N
Molar mass 101.19 g·mol−1
Appearance Colourless liquid
Odor Fishy, ammoniacal
Density 0.7255 g mL−1
Melting point −114.70 °C; −174.46 °F; 158.45 K
Boiling point 88.6 to 89.8 °C; 191.4 to 193.5 °F; 361.7 to 362.9 K
log P 1.647
Vapor pressure 6.899–8.506 kPa
66 μmol Pa−1 kg−1
Acidity (pKa) 10.75 (for the conjugate acid) (H2O), 9.00 (DMSO) [4]
-81.4·10−6 cm3/mol
1.401
Thermochemistry
216.43 J K−1 mol−1
−169 kJ mol−1
−4.37763 to −4.37655 MJ mol−1
Hazards
GHS pictograms
GHS signal word DANGER
H225, H302, H312, H314, H332
P210, P280, P305+351+338, P310
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasolineHealth code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
3
3
0
Flash point −15 °C (5 °F; 258 K)
312 °C (594 °F; 585 K)
Explosive limits 1.2–8%
2 ppm (8 mg/m3) (TWA), 
4 ppm (17 mg/m3) (STEL)
Lethal dose or concentration (LD, LC):
  • 580 mg kg−1 (dermal, rabbit)
  • 730 mg kg−1 (oral, rat)
1425 ppm (mouse, 2 hr)[5]
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 25 ppm (100 mg/m3)[6]
REL (Recommended)
 None established[6]
IDLH (Immediate danger)
 200 ppm[6]
Related compounds
Related amines
Related compounds
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

Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA is also a common abbreviation. It is a colourless volatile liquid with a strong fishy odor reminiscent of ammonia and is also the smell of the hawthorn plant.[7] Like diisopropylethylamine (Hünig’s base), triethylamine is commonly employed in organic synthesis.

Synthesis and properties

Triethylamine is prepared by the alkylation of ammonia with ethanol:[8]

NH3 + 3 C2H5OH → N(C2H5)3 + 3 H2O

The pKa of protonated triethylamine is 10.75,[4] and it can be used to prepare buffer solutions at that pH. The hydrochloride salt, triethylamine hydrochloride (triethylammonium chloride), is a colorless, odorless, and hygroscopic powder, which decomposes when heated to 261 °C.

Laboratory samples of triethylamine can be purified by distilling from calcium hydride.[9]

Applications

Triethylamine is commonly employed in organic synthesis as a base. For example, it is commonly used as a base during the preparation of esters and amides from acyl chlorides.[10] Such reactions lead to the production of hydrogen chloride which combines with triethylamine to form the salt triethylamine hydrochloride, commonly called triethylammonium chloride. This reaction removes the hydrogen chloride from the reaction mixture, which can be required for these reactions to proceed to completion (R, R' = alkyl, aryl):

R2NH + R'C(O)Cl + Et3N → R'C(O)NR2 + Et3NH+Cl−

Like other tertiary amines, it catalyzes the formation of urethane foams and epoxy resins. It is also useful in dehydrohalogenation reactions and Swern oxidations.

Triethylamine is readily alkylated to give the corresponding quaternary ammonium salt:

RI + Et3N → Et3NR+I−

Triethylamine is mainly used in the production of quaternary ammonium compounds for textile auxiliaries and quaternary ammonium salts of dyes. It is also a catalyst and acid neutralizer for condensation reactions and is useful as an intermediate for manufacturing medicines, pesticides and other chemicals.

Niche uses

Triethylamine is used to give salts of various carboxylic acid-containing pesticides, e.g. Triclopyr and 2,4-dichlorophenoxyacetic acid

Triethylamine is the active ingredient in FlyNap, a product for anesthetizing Drosophila melanogaster. Triethylamine is used in mosquito and vector control labs to anesthetize mosquitoes. This is done to preserve any viral material that might be present during species identification.

Also, the bicarbonate salt of triethylamine (often abbreviated TEAB, triethylammonium bicarbonate) is useful in reverse phase chromatography, often in a gradient to purify nucleotides and other biomolecules.

References

  1. ↑ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 671. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  2. ↑ X. Bories-Azeau, S. P. Armes, and H. J. W. van den Haak, Macromolecules 2004, 37, 2348 PDF
  3. ↑ The Merck Index (11th ed.). 9582.
  4. 1 2 David Evans Research Group Archived 2012-01-21 at the Wayback Machine.
  5. ↑ "Triethylamine". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  6. 1 2 3 "NIOSH Pocket Guide to Chemical Hazards #0633". National Institute for Occupational Safety and Health (NIOSH).
  7. ↑ The Hawthorn, BBC
  8. ↑ 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
  9. ↑ F.,, Armarego, W. L. Purification of Laboratory Chemicals. Chai, Christina Li Lin, (Seventh ed.). Amsterdam. ISBN 9780123821621. OCLC 820853648.
  10. ↑ Sorgi, K. L. (2001). "Triethylamine". Encyclopedia of Reagents for Organic Synthesis. Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rt217. ISBN 0471936235.
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