What Is Triethylamine?
Triethylamine is a tertiary amine with three ethyl groups (C2H5) attached to the nitrogen and is a clear, colorless liquid with a strong ammonia odor. Its chemical formula is (C2H5)3N, commonly abbreviated as TEA.
Triethylamine is a strong base that is easily dissolved in common organic solvents such as ethanol and acetone and is used in various industrial and laboratory applications.
It is also widely used industrially, especially in the fields of pharmaceuticals and dye intermediates.
On the other hand, triethylamine has a foul odor, is highly irritating to the skin and eyes, and is a flammable liquid classified as a hazardous material in Class 4, Petroleum No. 1. Therefore, when handling triethylamine, safety measures are required to prevent leakage, contact with the human body, fire, and explosion.
Applications of Triethylamine
Triethylamine is a type of tertiary amine widely used in synthetic reactions because it is a soluble base in a wide range of organic solvents such as acetone, toluene, and chloroform.
Industrially, it is used as an intermediate in pharmaceuticals and dyes, polymer synthesis, and agrochemicals. It is also used as a catalyst in the gas-curing reaction of phenol resin and isocyanate resin (cold box method).
In the food industry, triethylamine is also present in squid and fish, and is added to meat products and frozen dairy products in Europe and the United States to enhance flavor.
Properties of Triethylamine
Triethylamine is very soluble in water, ethanol, and most organic solvents. It has a boiling point of 89°C, a melting point of -114.7°C, and a density of 0.726 g/mL at 20°C. Triethylamine has a strong pungent odor, often described as similar to that of ammonia or fish.
Its chemical properties are primarily due to the presence of an amine functional group consisting of two hydrogen atoms bonded to a nitrogen atom. Because of the single pair of electrons on the nitrogen atom, Triethylamine is a strong base.
Triethylamine is also known to be a strong nucleophile, donating an electron pair to form a new chemical bond with an electrophile. For this reason, triethylamine is widely used as a reagent in organic synthesis.
Although triethylamine is not highly toxic, it can be harmful if ingested or inhaled in large quantities. Triethylamine is also flammable and should be handled with care.
Structure of Triethylamine
Triethylamine is a tertiary amine, having three ethyl groups (-C2H5) bonded to a nitrogen atom (-N).
The nitrogen atom has a lone pair of electrons, which characterizes the properties of triethylamine. Triethylamine is a strong base because the nitrogen atom can accept a proton (H+) to form the positively charged ammonium ion (C2H5)3NH+.
Other Information on Triethylamine
1. Triethylamine Safety and Legal Regulations
Triethylamine is corrosive to the skin and eyes and is classified as Class 1 for specific target organ toxicity (single exposure) and central nervous system. In addition, as mentioned above, the substance emits a strong unpleasant odor like ammonia or rotten fish. Therefore, when using triethylamine, it is necessary to wear protective equipment and to take measures to prevent leakage.
Triethylamine is classified under various regulatory laws. Before using triethylamine, it is recommended that the hazards of the operation be assessed and that disposal procedures be clearly defined.
2. Triethylamine Production Method
Triethylamine is produced primarily from ethylene, ammonia, and ethanol.
The process proceeds in the following steps
(1) Synthesis of Intermediate (Ethylenediamine)
Ethylenediamine is formed by mixing ethylene and ammonia at a temperature of approximately 200-250°C and a pressure of approximately 1-5 MPa. When this mixture is passed over a catalyst such as alumina or silica-alumina, ethylenediamine is formed.
H2C=CH2 + NH3 → H2NCH2CH2NH2
(2) Triethylamine Synthesis
Triethylamine is formed by reacting ethylenediamine with ethanol in the presence of another catalyst such as Lewis acid.
H2NCH2CH2NH2 + 2C2H5OH → (C2H5)3N + H2O + C2H4
TEA can then be separated from the reaction mixture by distillation or extraction.