Monoethanolamine (MEA), with the chemical formula C₂H₇NO and CAS No. 141-43-5, is a primary amine containing two reactive functional groups — an amino group (–NH₂) and a hydroxyl group (–OH).
It appears as a colorless, viscous liquid with a strong ammonia-like odor.
Due to its unique chemical reactivity, MEA is widely used in gas treatment, detergents, oil and gas, cement additives, catalyst production, and personal care formulations.

Chemical Structure

IUPAC Name: 2-Aminoethan-1-ol
Molecular Structure: Bifunctional molecule containing –NH₂ and –OH groups
Chemical Family: Simplest member of the ethanolamines

Physical and Chemical Properties

Property	Typical Value
Appearance	Colorless, viscous liquid with ammonia-like odor
Density (20°C)	1.0117 g/cm³
Melting Point	10.3°C
Boiling Point	170°C
Vapor Pressure (20°C)	≈ 64 Pa
pKa (25°C)	9.50
Water Solubility	Fully miscible with water and alcohols
Viscosity (20°C)	23.2 mPa·s
Refractive Index (nD)	1.4539

Key Advantages

Efficient absorber of acid gases (CO₂ and H₂S) in gas sweetening units
Adjustable neutralizing and emulsifying agent for detergents and personal care products
Versatile chemical intermediate in the synthesis of polymers, pharmaceuticals, dyes, and resins
Catalyst in polyurethane foam production and other industrial reactions

Limitations and Precautions

Highly corrosive and irritating – causes severe burns to skin and eyes on contact
Vapor irritation – may affect respiratory system with prolonged exposure
Oral toxicity: LD₅₀ (rat) ≈ 3320 mg/kg → moderate toxicity
Environmental hazard: harmful to aquatic life; neutralization or dilution required prior to disposal

Applications

1. Gas Treatment (Gas Sweetening)

Used for removing CO₂ and H₂S from natural gas, process gases, and flue gases in power plants.

2. Detergents and Cleaners

Functions as an emulsifier and pH regulator in industrial, cosmetic, and household formulations.

3. Cement and Construction

Acts as an additive to improve cement fluidity and reduce permeability.

4. Chemical Intermediate

Used in the synthesis of EDTA, pharmaceuticals, dyes, resins, and surfactants.

Safety and Handling

GHS Classification:

H314: Causes severe skin burns and eye damage
H335: May cause respiratory irritation

Personal Protective Equipment (PPE):

Chemical-resistant clothing
Nitrile gloves
Safety goggles or face shield
Respiratory protection in confined areas

Storage Conditions:

Store in a cool, dry, well-ventilated area
Keep away from heat sources, sparks, and oxidizing agents
Use tightly sealed containers with clear labeling

Emergency Measures:

Skin contact: Rinse immediately with plenty of water
Eye contact: Flush for at least 15 minutes and seek medical attention
Inhalation: Move to fresh air immediately
Spillage: Absorb with dry inert material and prevent vapor release

Monoethanolamine (MEA) is a key industrial chemical valued for its reactivity, versatility, and neutralizing properties.
It plays a critical role in gas purification systems, detergents, and chemical synthesis, provided that proper safety and handling measures are observed.