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What it is. Triethanolamine (TEA) is a viscous, colorless-to-pale-yellow liquid with a faint ammonia-like odor, supplied as 98% reagent grade in a 1-gallon size. It is a tertiary amine and triol used as a buffer, masking agent, emulsifier, and pH adjuster.
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Chemical identity. Triethanolamine (2,2',2''-nitrilotriethanol, CAS 102-71-6, C6H15NO3, 149.19 g/mol) combines a basic nitrogen with three hydroxyl groups. It mixes completely with water and dissolves in alcohols, acetone, and chloroform.
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Physical properties. TEA has a density of about 1.12 g/mL, melts near 21 °C, and boils with decomposition near 335 °C. Its flash point is high, about 179-190 °C. Because it can solidify in cool rooms, warm it gently if it thickens or crystallizes.
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A weak base and buffer. Triethanolamine is a weak base; a 0.1 N aqueous solution has a pH of about 10.5. Its conjugate acid buffers in the mildly alkaline range, so biochemists and analytical chemists use TEA-based buffers.
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Masking agent in titrations. In complexometric titrations, triethanolamine masks iron, aluminum, and manganese by binding them so they do not interfere with EDTA determinations of calcium and magnesium. It is also used to dissolve Eriochrome Black T for indicator solutions.
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Emulsifier and formulation ingredient. Neutralized with fatty acids, triethanolamine forms soaps that act as emulsifiers, which is why it appears in cosmetics, lotions, cutting fluids, and cleaning formulations as a pH adjuster and emulsifying agent.
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Industrial uses. TEA is used as a cement grinding aid, corrosion inhibitor, gas-scrubbing absorbent for acid gases, and intermediate in surfactant production.
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Buffer preparation. To prepare a TEA buffer, dilute triethanolamine in water and titrate to the target pH with hydrochloric acid. TEA buffers are used in enzyme assays and as alkaline media for some colorimetric methods.
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Handling at a glance. Triethanolamine causes serious eye irritation and is hygroscopic. Wear safety glasses and gloves, keep the container closed, and store it at room temperature away from strong acids and oxidizers. Related titration products include Lab Pro's Eriochrome Black T Indicator and EDTA Titrant 0.1 N / 0.05 M.
Technical Specifications
| Chemical Name |
Triethanolamine |
| CAS Number |
102-71-6 |
| EC Number |
203-049-8 |
| Synonyms |
TEA, 2,2',2''-nitrilotriethanol, tris(2-hydroxyethyl)amine, trolamine |
| Formula |
C6H15NO3 (N(CH2CH2OH)3) |
| Molecular Weight |
149.19 g/mol |
| Grade |
Reagent |
| Assay |
98% (nominal) |
| Density |
About 1.12 g/mL |
| Melting Point |
About 21 °C |
| Boiling Point |
About 335 °C (decomposes) |
| Flash Point |
About 179 to 190 °C |
| Refractive Index |
About 1.484 to 1.486 |
| pH (0.1 N aqueous) |
About 10.5 |
| Appearance |
Colorless to pale yellow viscous liquid |
| Solubility |
Miscible with water; soluble in alcohol, acetone, chloroform |
| Hazard Statement |
H319 (causes serious eye irritation) |
| DOT |
Not regulated (comparable products) |
| Package Size |
1 gallon |
Applications / Common Uses
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Masking agent: Masks Fe, Al, and Mn in EDTA titrations.
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Buffers: Prepares mildly alkaline TEA buffers.
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Indicator preparation: Dissolves Eriochrome Black T.
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Emulsifier: Forms soaps with fatty acids.
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Industrial processing: Serves as a grinding aid and corrosion inhibitor.
Storage, Handling & Shipping
Store tightly closed at room temperature, away from strong acids and oxidizers. Triethanolamine is hygroscopic and can solidify below about 21 °C; warm gently and mix if it thickens or crystallizes.
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Incompatible materials: Strong acids, strong oxidizers, and copper and its alloys.
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Personal protection: Safety glasses and gloves.
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Spill response: Absorb with inert material and place in a closed container for disposal.
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First aid: Eyes: rinse with water for several minutes and seek medical advice if irritation persists.
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GHS signal word: Warning (eye irritation).
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DOT / shipping: Not regulated (confirm on SDS).
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