A Complete Gide to Ethanolamine Series

The ethanolamine series refers to a class of organic compounds that possess both amino and hydroxyl groups on an ethane backbone. As important derivatives resulting from the reaction of ethylene oxide with ammonia, this series exhibits the dual chemical properties of both alcohols and amines, is capable of neutralization reactions with acids, and possesses good hygroscopicity and basicity. It primarily includes the following three core products: 2-Aminoethanol; Diethanolamine (DEA); and Trolamine.

2-Aminoethanol (MEA)

2-Aminoethanol (CAS 141-43-5), commonly abbreviated as MEA, is an organic compound that is miscible with water, ethanol, and acetone, and slightly soluble in diethyl ether and carbon tetrachloride. It is used as a chemical reagent, pesticide, pharmaceutical, solvent, dye intermediates, rubber accelerators, corrosion inhibitors, and surfactants, among others. It is also used as an acid gas absorbent, emulsifier, plasticizer, rubber vulcanizing agent, textile brightener, and fabric moth repellent. Additionally, it serves as a plasticizer, vulcanising agent, accelerator, and foaming agent for synthetic resins and rubber, as well as an intermediate in the production of pesticides, pharmaceuticals, and dyes.

Properties

Diethanolamine (DEA)

Diethanolamine (DEA) cas 111-42-2, is an organic compound that possesses the chemical properties of both an alcohol and an amine. It is highly soluble in water and ethanol but insoluble in diethyl ether and benzene. At room temperature, the pure compound is a white solid; however, due to its tendency to absorb moisture and undergo supercooling, it typically appears as a colorless to pale yellow viscous liquid. It has a faint ammonia-like odor and is primarily used as an absorbent for acidic gases such as CO₂, H₂S, and SO₂, as well as a nonionic surfactant, emulsifier, polishing agent, industrial gas purifier, and lubricant. It serves as an intermediate in the production of the herbicide glyphosate, is used as a gas purifier, and also serves as a raw material for the synthesis of pharmaceuticals and in organic synthesis. It is corrosive and irritating to the skin and eyes and can corrode copper, aluminum, and their alloys.

Properties

Triethanolamine

Triethanolamine (CAS 102-71-6) is a colorless to pale yellow, transparent, viscous liquid with a faint ammonia-like odor; it is hygroscopic, its color gradually darkens when exposed to air. It is an organic compound that can be regarded as the trihydroxy derivative of triethylamine. Similar to other amine compounds, triethanolamine exhibits weak basicity due to the presence of a lone pair of electrons on the nitrogen atom and can react with inorganic or organic acids to form salts.

Properties

When should you choose which alkanolamine?

In industrial applications—particularly in natural gas purification, refinery gas desulfurisation, and carbon capture (CCUS), as well as in the consumer chemicals and metal processing sectors—the selection of an alkanolamine depends primarily on its absorption selectivity for acidic gases (CO₂ and H₂S), reaction rate, energy consumption requirements, and corrosion control.

MEA is the most basic agent, with an extremely fast reaction rate and virtually no kinetic resistance; it exhibits a very strong affinity for acidic gases. 2-Aminoethanol should be selected in scenarios where thorough and rapid removal of CO₂ or H₂S is required and system pressure is low (such as carbon capture from coal-fired flue gas and low-pressure flare gas purification).
DEA’s performance falls between that of MEA and MDEA, with a relatively fast reaction rate; Compared to MEA, its corrosiveness is significantly reduced, allowing for higher solution concentrations (up to 30–35 wt%), which increases cycle capacity and reduces energy consumption. DEA is selected for high-pressure, medium-load gas purification (such as natural gas and refinery gas desulfurisation), particularly in scenarios where the use of MEA is not permitted due to severe corrosion or where the feed gas contains significant amounts of COS and CS₂.
TEA is extremely weakly basic, mild, and non-irritating. It possesses excellent metal chelating and rust-inhibiting properties as well as surface activity. It is rarely used in modern industrial gas desulfurisation (having been replaced by MDEA) but is widely used in cement grinding aids, household and cosmetic detergents (as a pH adjuster/emulsifier), and metalworking fluids (as a rust inhibitor in cutting oils).

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