Triethylamine

Triethylamine is the chemical compound with the formula N(CH₂CH₃)₃, commonly abbreviated Et₃N. It is a commonly encountered in organic synthesis probably because it is the simplest symmetrically trisubstituted amine, i.e. a tertiary amine, that is liquid at room temperature. It possesses a strong fishy odor reminiscent of ammonia. Diisopropylethylamine (Hünig’s base, CAS # 7087-68-5) is a widely used relative of triethylamine. Triethylamine is also the smell of the hawthorn plant, and semen, among others ^[1]

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Triethylamine is commonly employed in organic synthesis as a base, most often in the preparation of esters and amides from acyl chlorides.^[2] 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 readily alkylated to give the corresponding quaternary ammonium salt:

RI + Et₃N → Et₃NR⁺I^-

References

1. ^ The Book of General Ignorance, Lloyd, John, Faber and Faber Limited, 2006, p236
2. ^ Sorgi, K. L. "Triethylamine" in Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons, New York. DOI: 10.1002/047084289X.rt217