Ethanolamine: Properties, Production, Applications, and Safety

Ethanolamine, also known as monoethanolamine (MEA), is an organic chemical compound that serves as both an alcohol and an amine. With the chemical formula C₂H₇NO, ethanolamine is a colorless, viscous liquid at room temperature and plays a vital role in a wide range of industrial and commercial applications.

It is widely used in the production of detergents, emulsifiers, pharmaceuticals, chemical intermediates, and as a gas treatment agent for removing acid gases. Thanks to its unique chemical structure and reactivity, ethanolamine has become a cornerstone compound in numerous sectors including agriculture, petrochemicals, and consumer goods.

Chemical Structure and Properties

• IUPAC Name: 2-Aminoethanol
  
  

• Common Name: Ethanolamine
  
  

• Chemical Formula: C₂H₇NO
  
  

• Molecular Weight: 61.08 g/mol
  
  

• CAS Number: 141-43-5
  
  

• Appearance: Colorless to pale yellow viscous liquid
  
  

• Odor: Slight ammonia-like
  
  

• Melting Point: 10.3 °C (50.5 °F)
  
  

• Boiling Point: 170 °C (338 °F)
  
  

• Density: 1.018 g/cm³
  
  

• Solubility: Completely miscible with water, alcohol, and acetone
  
  

Ethanolamine is a hydroxyalkylamine, featuring both a hydroxyl group (-OH) and an amine group (-NH₂) on a two-carbon backbone. This dual functionality makes it highly reactive and useful in both nucleophilic and hydrogen-bonding chemical environments.

Production and Manufacturing

1. Industrial Synthesis

The most common industrial method for producing ethanolamine is through the reaction of ethylene oxide with ammonia:

mathematica

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C₂H₄O + NH₃ → C₂H₇NO (Ethanolamine)

This reaction also produces diethanolamine (DEA) and triethanolamine (TEA) as by-products depending on the stoichiometry and conditions of the reaction.

2. Separation Process

After synthesis, the mixture is distilled to separate the three ethanolamines:

• Monoethanolamine (MEA) – primary product
  
  

• Diethanolamine (DEA) – secondary amine
  
  

• Triethanolamine (TEA) – tertiary amine
  
  

Each has distinct chemical properties and applications.

Applications of Ethanolamine

Ethanolamine is one of the most versatile chemicals in industry. Its applications are diverse and widespread:

1. Gas Treatment (Amine Scrubbing)

MEA is extensively used in the removal of acidic gases like carbon dioxide (CO₂) and hydrogen sulfide (H₂S) from natural gas and refinery process streams. This process is known as amine scrubbing or gas sweetening.

2. Surfactants and Detergents

Due to its amphiphilic nature (having both polar and non-polar properties), ethanolamine is used in the manufacture of anionic and nonionic surfactants for:

• Shampoos
  
  

• Soaps
  
  

• Household cleaners
  
  

• Dishwashing liquids
  
  

3. Pharmaceuticals and Cosmetics

Ethanolamine serves as a pH buffer and emulsifying agent in cosmetic formulations and pharmaceutical products. It is often found in:

• Skin creams
  
  

• Lotions
  
  

• Shaving products
  
  

• Medicinal ointments
  
  

4. Agricultural Chemicals

Ethanolamine is used as a base in herbicide and pesticide formulations, improving solubility and delivery. It is often neutralized with acid herbicides to form stable, water-soluble salts.

5. Cement and Concrete Additives

As a grinding aid and setting time controller, ethanolamine improves the production efficiency of cement and concrete, making it useful in the construction industry.

6. Textile and Leather Industry

Used in dyeing processes and as a softening agent for leather and textiles.

7. Chemical Intermediates

Ethanolamine is used in the production of:

• Morpholine (used in corrosion inhibitors and rubber chemicals)
  
  

• Ethylene amines
  
  

• Emulsifiers
  
  

• Plasticizers
  
  

Health and Safety Considerations

1. Toxicity

While ethanolamine is generally considered low in acute toxicity, it can cause irritation to the skin, eyes, and respiratory tract:

• Inhalation: May cause respiratory discomfort and coughing
  
  

• Skin Contact: Can cause redness, irritation, and chemical burns on prolonged exposure
  
  

• Eye Contact: Severe irritation or even eye damage
  
  

• Ingestion: Harmful, may lead to gastrointestinal irritation or systemic toxicity
  
  

Chronic exposure can affect the liver and kidneys. Workers handling ethanolamine should use protective gloves, eye protection, and work in well-ventilated areas.

2. Flammability and Reactivity

• Flash point: ~85 °C (185 °F) – combustible but not highly flammable
  
  

• Reactivity: Can react with acids, oxidizing agents, and some metals (e.g., aluminum)
  
  

3. Environmental Impact

Ethanolamine is biodegradable and generally considered to pose low environmental risk when handled properly. However, spills in large quantities can affect aquatic organisms due to changes in pH and oxygen levels.

Regulatory bodies like the EPA, OSHA, and REACH have established guidelines for the safe handling and disposal of ethanolamine.