What Is Monoethanolamine (MEA)?
Monoethanolamine, abbreviated MEA, is an organic compound with the formula HOCH2CH2NH2 and a CAS number of 141-43-5. It contains both a primary amine group and a hydroxyl group, which makes it strongly basic, fully water-soluble, and highly reactive toward acids and acidic gases. These properties make MEA one of the most versatile building blocks in the chemical industry.
Gas Sweetening and Carbon Dioxide Capture
The largest use of MEA is in gas sweetening. In natural gas and refinery streams, MEA selectively absorbs hydrogen sulfide and carbon dioxide through a reversible reaction, forming salts that can be regenerated by heating. Industry data indicate that roughly 60 percent of global MEA consumption is dedicated to desulfurization, with demand growing in shale gas development. MEA is also the benchmark solvent in post-combustion carbon dioxide capture, where it can achieve capture rates above 90 percent, although energy consumption and solvent degradation remain key challenges.
Surfactants and Personal Care Products
MEA reacts with fatty acids to form ethanolamine soaps, such as cocamide MEA, which are widely used as foam boosters and thickeners in detergents, shampoos, and body washes. In personal care formulations, MEA adjusts pH and acts as an emulsifier to stabilize creams and lotions. These applications benefit from MEA's low irritation profile and its ability to regulate the acidity of finished products.
Metalworking, Pharmaceutical, and Agricultural Uses
In metalworking, MEA is added to cutting fluids and rust inhibitors, where it forms a protective layer on metal surfaces and stabilizes coating quality in plating baths. In pharmaceutical synthesis, MEA is a key intermediate for local anesthetics such as lidocaine and is involved in the production of certain antihistamines and antibiotics. In agriculture, MEA serves as a pesticide emulsifier that improves the adhesion of spray solutions, and it can react with phosphoric acid to form ethanolamine phosphate, a foliar fertilizer that supplies nitrogen and phosphorus.
Electronics and Emerging Applications
In semiconductor manufacturing, dilute MEA solutions are used to remove photoresist residues after etching. Compared with strong acids and bases, MEA is milder and reduces the risk of damage to silicon wafers. Emerging research is exploring stabilized MEA formulations that reduce solvent degradation and energy demand in carbon capture systems, which would expand the role of MEA in decarbonization projects.
Frequently Asked Questions
What is the main use of MEA?
The main use of MEA is gas sweetening, where it removes hydrogen sulfide and carbon dioxide from natural gas and refinery streams, accounting for about 60 percent of global consumption.
Is MEA used in shampoos?
Yes. MEA-derived surfactants such as cocamide MEA are common foam boosters and thickeners in shampoos, body washes, and detergents.
What is the CAS number of MEA?
The CAS number of monoethanolamine is 141-43-5.
Can MEA capture carbon dioxide?
Yes. MEA is the benchmark solvent for post-combustion CO2 capture and can achieve capture rates above 90 percent in optimized systems.
Is MEA used in medicine?
MEA is used as an intermediate in the synthesis of pharmaceuticals such as lidocaine, antihistamines, and some antibiotics.
Is MEA corrosive to metals?
MEA itself acts as a corrosion inhibitor in metalworking fluids, but concentrated solutions are alkaline and must be handled with appropriate protective equipment.
