Triethylenediamine

Description

DABCO, short for1,4-diazabicyclo[2.2.2]octane, is one of a handful of molecules better known by their acronyms than by their full names1. It is also frequently referred to as triethylenediamine, or TEDA.
DABCO has been known for at least 100 years, originally under the name quinolidine. In 1943, Otto Hromatka* and Eva Engel at the University of Vienna synthesized it via the cyclization of the dihydrobromide salt of 1-(2-bromoethyl)piperazine2 or the dihydrochloride salt of 1-(2-chloroethyl)piperazine3. It is commercially produced by the catalytic thermolysis of ethylenediamine or 2-hydroxyethylamine.
Because of its two unhindered tertiary amine groups, DABCO is a strong base (pKa1 of its conjugate acid = 3.0) and nucleophile. It is used as an alkaline catalyst in the production of polyurethane foams. As a Lewis base, it forms crystalline adducts with hydrogen peroxide and sulfur dioxide.
This year, DABCO was featured as the catalyst in two new syntheses. In April, Silong Xu and co-workers at Xi’an Jiaotong University (China) showed that it catalyzes [4 + 2] annulation reactions between 5-methylenehex-2-ynedioates and electron-deficient olefins such as 2-benzylidene-1H-indene-1,3-(2H)-dione to form spirocyclohexadiene adducts in yields up to 90% under mild conditions. Alternative catalysts gave poor yields or no reaction.
In July, Cunde Wang and colleagues at Yangzhou University (China) reported the use of DABCO to promote another set of cyclization reactions. In their process, substituted 2-amino-4H-chromen-4-ones and substituted 2,6-dibenzylidenecyclohexan-1-ones react to form 7,8,9,10-tetrahydro-12H-chromeno[2,3-b]quinolin-12-ones, also under mild conditions and in optimized yields of >80%. As with the Xu process, other basic catalysts gave significantly poorer yields.
1. Another is TEMPO, which will appear as a Molecule of the Week later this year. 2. CAS Reg. No. 89727-93-5. 3. CAS Reg. No. 34782-06-4.

Description

DABCO is a caged tertiary diamine, and is generally described as a highly nucleophilic amine. DABCO can serve as an organic base, complexing ligand, or a catalyst.

Chemical properties

Triethylenediamine also known as DABCO or TEDA, is a highly symmetrical molecule with a cage structure. The colorless extremely hygroscopic crystals is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent in polymerization and organic synthesis.

The Uses of Triethylenediamine

An anti-fade reagent shown to scavenge free-radicals due to flurochrome excitation.

The Uses of Triethylenediamine

1,4-Diazabicyclo[2.2.2]octane is used as polyurethane catalyst, Balis-Hillman reaction catalyst complexing ligand and lewis base. It finds use in dye lasers and in mounting samples for fluorescence microscopy and as anti-fade reagent shown to scavenge free radicals due to flurochrome excitation of fluorochromes. Further, it is an oxidation and polymerization catalyst.

What are the applications of Application

1,4-Diazabicyclo[2.2.2]octane is an anti-fade reagent shown to scavenge free-radicals due to flurochrome excitation

Definition

ChEBI: Triethylenediamine is an organic heterobicylic compound that is piperazine with an ethane-1,2-diyl group forming a bridge between N1 and N4. It is typically used as a catalyst in polymerization reactions. It has a role as a catalyst, a reagent and an antioxidant. It is a bridged compound, a tertiary amino compound, a saturated organic heterobicyclic parent and a diamine.

Preparation

Triethylenediamine can be produced from ethylenediamine or ethanolamine, diethanolamine, or diethylenetriamine with a variety of different catalysts.

Reactions

Triethylenediamine reacts virtually quantitatively with bromine to give a 1/1 adduct. With alkyl halides it forms quaternary salts, even in nonpolar solvents. Apart from its highly nucleophilic nature, triethylenediamine exhibits catalytic activity in base-catalyzed reactions.

General Description

Dabco^?33-LV (Db) is a gelling catalyst and a bidentate ligand that forms a self-assembled monolayer (SAM) on a variety of substrates. It functionalizes the surface and immobilizes the surface atoms.

Hazard

Skin irritant.

Flammability and Explosibility

Flammable

Purification Methods

DABCO crystallises from 95% EtOH, pet ether or MeOH/diethyl ether (1:1). Dry it under vacuum over CaCl2 and BaO. It can be sublimed in vacuo, and readily at room temperature. It has also been purified by removal of water during azeotropic distillation of a *benzene solution. It is then recrystallised twice from anhydrous diethyl ether under argon, and stored under argon [Blackstock et al. J Org Chem 52 1451 1987]. [Beilstein 23/3 V 487.]