Triethylamine

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Triethylamine
Skeletal formula of triethylamine
Ball and stick model of triethylamine Spacefill model of triethylamine
Identifiers
Abbreviations TEA[1]
CAS number 121-44-8 YesY
PubChem 8471
ChemSpider 8158 YesY
UNII VOU728O6AY YesY
EC number 204-469-4
UN number 1296
KEGG C14691 YesY
MeSH triethylamine
ChEBI CHEBI:35026 YesY
ChEMBL CHEMBL284057 YesY
RTECS number YE0175000
Beilstein Reference 605283
Jmol-3D images Image 1
Properties[3]
Molecular formula 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
kH 66 μmol Pa−1 kg−1
Acidity (pKa) 10.75 (for the conjugate acid) (H2O), 9.00 (DMSO) [2]
Refractive index (nD) 1.401
Thermochemistry
Specific
heat capacity
C
216.43 J K−1 mol−1
Std enthalpy of
formation
ΔfHo298
−169 kJ mol−1
Std enthalpy of
combustion
ΔcHo298
−4.37763–−4.37655 MJ mol−1
Hazards
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H225, H302, H312, H314, H332
GHS precautionary statements P210, P280, P305+351+338, P310
EU Index 612-004-00-5
EU classification Highly Flammable F Corrosive C
R-phrases R11, R20/21/22, R35
S-phrases (S1/2), S3, S16, S26, S29, S36/37/39
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., gasoline) Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −15 °C (5 °F; 258 K)
Explosive limits 1.2–8%
LD50
  • 580 mg kg−1 (dermal, rabbit)
  • 730 mg kg−1 (oral, rat)
Related compounds
Related amines
Related compounds
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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.[4] Like diisopropylethylamine (Hünig’s base), triethylamine is commonly encountered in organic synthesis.

Synthesis and properties[edit]

Triethylamine is prepared by the alkylation of ammonia with ethanol:[5]

NH3 + 3 C2H5OH → N(C2H5)3 + 3 H2O

The pKa of protonated triethylamine is 10.75,[2] and it can be used to prepare buffer solutions for that pH. The hydrochloride salt, triethylamine hydrochloride (triethylammonium chloride), is a colorless, odorless, and hygroscopic powder, which decomposes when heated to 261 °C.

Applications[edit]

Triethylamine is commonly employed in organic synthesis as a base, most often in the preparation of esters and amides from acyl chlorides.[6] 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 is 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 used to give salts of various carboxylic acid-containing pesticides, e.g. Triclopyr and 2,4-dichlorophenoxyacetic acid

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[edit]

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[edit]

  1. ^ X. Bories-Azeau, S. P. Armes, and H. J. W. van den Haak, Macromolecules 2004, 37, 2348 PDF
  2. ^ a b David Evans Research Group
  3. ^ The Merck Index (11th ed.). 9582. 
  4. ^ The Hawthorn, BBC
  5. ^ 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
  6. ^ Sorgi, K. L. (2001). "Triethylamine". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rt217. 

External links[edit]