What Is Triethanolamine?
Triethanolamine, belonging to the aliphatic amine family, is also known as trihydroxytriethylamine. This organic compound presents as a clear, colorless, viscous liquid at room temperature, transforming into a white crystalline solid at lower temperatures. It emits an ammoniacal odor and is flammable, classified as a Class 4 hazardous substance.
Synthesis of triethanolamine involves reacting ethylene oxide with an aqueous ammonia solution, producing monoethanolamine and diethanolamine. The ratio of these products can be controlled by adjusting the reactants.
Applications of Triethanolamine
As a base catalyst in organic synthesis and an auxiliary agent in synthetic detergents, triethanolamine’s versatility extends to electronic material cleaners, metal corrosion inhibitors, cement additives, agrochemicals, polyurethane foaming agents, antifreeze additives, rust inhibitors, and cutting agents. It is integral to personal care products like shampoos, body soaps, and cosmetics, including emulsions, lotions, lipsticks, and eye shadows, for pH adjustment or emulsification. Furthermore, its inclusion in intravenous injections and topical preparations highlights its role as a dissolution aid and pharmaceutical additive.
Properties of Triethanolamine
Triethanolamine exhibits a basic nature, with a 0.1 N aqueous solution pH of approximately 10.5. Its melting point is around 20°C, and it boils at about 340°C. While triethanolamine’s utility spans various applications, it necessitates caution due to potential safety risks. Inhalation can irritate the respiratory tract, and prolonged exposure may harm the body, especially when aerosolized solutions are inhaled or in contact with mucous membranes.
Despite ongoing investigations into its carcinogenic potential, with a Group 3 classification by IARC, its safety, particularly regarding cancer, remains unconfirmed.
Structure of Triethanolamine
The molecular structure of triethanolamine, represented as (HOCH2CH2)3N, features a nitrogen atom bonded to three ethanol groups, making it a tertiary amine. This structure endows it with high water solubility and chelating abilities, enabling it to stabilize and chelate metal ions in water.
Other Information on Triethanolamine
Triethanolamine Regulations
Included in “Schedule 3, Part B” of the Chemical Weapons Convention and designated as a “Class II Designated Substance,” triethanolamine is regulated to prevent its misuse in chemical weapons, underscoring the importance of careful handling and compliance with legal restrictions.