DABCO


DABCO is an organic compound with the formula N23. This colorless solid is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent in polymerization and organic synthesis.
Quinuclidine has a similar structure, with one of the nitrogen atoms replaced by a carbon atom.

Reactions and applications

The pKa of + 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:
As an unhindered amine, it is a strong ligand and Lewis base. It forms a crystalline 2:1 adduct with hydrogen peroxide and sulfur dioxide.

Ionic monomer synthesis

DABCO can be used to synthesize doubly-charged styrenic monomers. These ionic monomers allow synthesis of polyelectrolytes and ionomers with two cyclic quaternary ammonium cations on each ionic pendant group.

Quencher of singlet oxygen

DABCO and related amines are quenchers of singlet oxygen and effective antioxidants, and can be used to improve the lifetime of dyes. This makes DABCO useful in dye lasers and in mounting samples for fluorescence microscopy. DABCO can also be used to demethylate quaternary ammonium salts by heating in dimethylformamide.

Production

It is produced by thermal reactions of compounds of the type H2NCH2CH2X in the presence of zeolitic catalysts. An idealized conversion is shown for the conversion from ethanolamine: