What Is DABCO?
DABCO is a white crystalline powder of tertiary amines.
Its IUPAC name is 1,4-diazabicyclo [2,2,2] octane, also known as 1,4-ethylenepiperazine, DABCO, and TEDA.
DABCO is a registered trademark (No. 551479) of Air Products & Chemicals, Inc. DABCO is not subject to any major national regulations.
Applications of DABCO
1. Foaming Catalyst for Polyurethane Foam
DABCO is mainly used as a catalyst for polyurethanation reactions. It is dissolved in crystalline form or with diprovylene glycol, etc., and the polyaddition reaction and the foaming reaction proceed in a well-balanced manner. Soft, hard, semi-hard, urethane paints and urethane elastomers can be produced.
2. Low-Molecular-Weight Organic Synthesis Reaction
DABCO is used as a bulky base in small-molecule organic synthetic chemical reactions. A well-known example of its use is the Morita-Baylis-Hillman reaction. DABCO is a nucleophilic catalyst in the reaction.
When aldehydes or imines react with alkenes substituted with electron-withdrawing groups in the presence of DABCO, new carbon-carbon bonds are formed. The reaction proceeds by a Michael-Aldol-like mechanism.
In addition, it is used as a catalyst for metal complex salt formation, dehalogenation agent, cyanoethylation catalyst, ester exchange catalyst, and epoxy resin curing catalyst.
Properties of DABCO
The chemical formula is C6H12N2 and the molecular weight is 112.17. The CAS number is 280-57-9.
Its melting point is 158 °C and its boiling point is 174 °C. It is hygroscopic and sublimates and exists as a solid at room temperature. The compound has an ammonia-like odor and is well soluble in water, ethanol, acetone, and chloroform.
It has a pH of 10.8, which indicates the degree of acidity or alkalinity, and acid dissociation constants (pKa) of 3.0 and 8.6. The acid dissociation constant is a quantitative measure of the strength of an acid; a smaller pKa indicates a stronger acid.
The basicity of DABCO is comparable to other tertiary amines, but it has high nucleophilicity due to its fixed structure, which leaves unshared electron pairs exposed.
Other Information on DABCO
1. Production Method of DABCO
DABCO is synthesized by cyclization of amine compounds using zeolite as a catalyst. Ethylenediamine,monoethanolamine, diethanolamine, and diethylenetriamine can be used as amine compounds.
2. Handling and Storage Precautions
Handling Precautions
Avoid contact with strong oxidizing agents. There is a risk of respiratory irritation. Use in a draft chamber with local exhaust ventilation. Wear personal protective equipment when using.
In Case of Fire
Thermal decomposition may release corrosive and toxic gases and vapors. Use water spray, foam, powder extinguisher, carbon dioxide, or extinguishing sand to extinguish fire.
For Storage
DABCO may be altered by light. During storage, place in polypropylene or polyethylene containers and seal tightly. Store locked up in a well-ventilated and as cool a place as possible, away from direct sunlight.