Aminoethylethanolamine (AEEA) - CAS 111-41-1
Aminoethylethanolamine (AEEA) - Properties, Applications, and Safety
Aminoethylethanolamine (AEEA, CAS 111-41-1), also known as N-(2-hydroxyethyl)ethylenediamine or 2-(2-aminoethylamino)ethanol, is a bifunctional alkanolamine containing both primary and secondary amine groups as well as a hydroxyl group. This unique combination of functional groups makes it a versatile intermediate in the production of epoxy curing agents, chelating agents, surfactants, corrosion inhibitors, and various other industrial chemicals. AEEA is a clear, colorless to pale yellow, hygroscopic liquid with a mild ammonia-like odor.
Chemical and Physical Properties
AEEA has the molecular formula C₄H₁₂N₂O and a molecular weight of 104.15 g/mol. It is a viscous liquid with a density of approximately 1.03 g/cm³ at 25°C. Its boiling point is 238–243°C at atmospheric pressure, with a melting point below -18°C. The flash point is approximately 132°C (closed cup), classifying it as a combustible liquid. AEEA is very soluble in water, ethanol, and acetone. The pH of a 111 g/L aqueous solution is 11.8, indicating strong alkalinity. Its vapor pressure is very low, typically <0.01 hPa at 20°C, which significantly reduces the risk of inhalation exposure compared to volatile amines like ethylenediamine. The compound is hygroscopic and may absorb moisture and carbon dioxide from the air.
Mechanism of Action and Applications
The combination of primary and secondary amine groups with a hydroxyl group provides AEEA with a distinct reactivity profile, enabling selective derivatization and broad process compatibility. The primary amine is highly reactive toward epoxides, isocyanates, and carbonyl compounds. The secondary amine and hydroxyl group provide additional sites for further reactions, including crosslinking and chelation.
Epoxy Curing Agent: AEEA is widely used as an epoxy resin curing agent. It serves as a low-temperature hardener with significantly lower toxicity than ethylenediamine – approximately 6–7 times less acutely toxic and over 3,500 times less volatile. AEEA is compatible with epoxy resins and is extensively used for bonding metal and non-metal parts, formulating corrosion-resistant epoxy coatings, and casting cable joints and electrical components.
Chelating Agent Intermediate: AEEA is formulated as an intermediate to form polycarboxylic acids and their salts, and chelating agents. The multiple nitrogen and oxygen atoms confer strong chelating properties, making it valuable in coordination chemistry and catalysis.
Corrosion Inhibitor and Fuel Additives: Used in the production of corrosion inhibitors for oil and gas production, as well as fuel and lubricant additives. AEEA is used in the production of chlorinated polybutene based fuel additives as a dispersant-detergent additive.
Surfactants and Textile Auxiliaries: Serves as a building block for fabric softeners and surfactants, making textiles "softer" and more pleasing to the touch. Also used in dyeing assistants and modifying agents for textiles.
Other Applications: Chemical intermediate for detergents and emulsifiers, mining chemicals, gasoline stabilizers, latex paints, and gas processing chemicals.
Safety and Toxicology
AEEA is classified as a corrosive substance with significant health hazards. It causes severe skin burns and eye damage (Skin Corr. 1B, Eye Dam. 1). It is a skin sensitizer (Skin Sens. 1). Based on animal studies, AEEA may damage fertility and cause birth defects (Repr. 1B). The oral LD50 in rats is approximately 3000 mg/kg, while the dermal LD50 in rabbits is >2000 mg/kg.
The compound is combustible; its lower explosive limit is 3.3% and upper explosive limit is 10.1% (v/v). Combustion produces toxic oxides of nitrogen. AEEA is hygroscopic and may react with acids, isocyanates, epoxides, and strong oxidizers. No airborne exposure limits have been established by OSHA or ACGIH. However, due to its low vapor pressure, skin exposure represents the primary hazard in most applications. Workers must be properly instructed and supervised in handling AEEA, and appropriate personal protective equipment should be used.
Storage and Handling
AEEA should be stored in tightly sealed containers, protected from moisture and strong oxidizing agents. It is hygroscopic and readily absorbs water and carbon dioxide from the air. Storage temperatures should be maintained between 2–30°C. Containers should be kept closed when not in use, and the substance should be stored in a corrosive-resistant area.
Conclusion
Aminoethylethanolamine is a versatile chemical intermediate with a unique combination of amine and hydroxyl functionalities. Its role as an epoxy curing agent, chelating agent intermediate, corrosion inhibitor, and surfactant precursor makes it a valuable component in numerous industrial applications. While its low vapor pressure and reduced volatility offer handling advantages over more volatile amines, its corrosive nature, skin sensitization potential, and reproductive toxicity require strict adherence to safety protocols and proper personal protective equipment.