1. Chemical Structure and Properties

Molecular Formula: C₂H₇NO

Structural Formula: HO–CH₂–CH₂–NH₂ — A primary alkanolamine containing both hydroxyl (-OH) and amino (-NH₂) groups.

Physical Properties:

• Appearance: Colorless to pale yellow viscous liquid with ammonia-like odor

• Boiling Point: 170 °C

• Density: 1.01 g/cm³ (20 °C)

• Viscosity: ~24 mPa·s at 20 °C

• Solubility: Fully miscible with water, ethanol, and polar solvents; strongly hygroscopic

Chemical Properties:

• Basicity: Weak base (pKa ≈ 9.5), readily forms salts (e.g., MEA hydrochloride)

• Reactivity: Can undergo esterification, alkylation, carbamate formation, and chelation

• Stability: Thermally stable below 140 °C, but degrades under oxidative or thermal stress

2. Industrial Applications

Gas Treatment:

• Widely used in amine scrubbing for removal of CO₂ and H₂S from natural gas, syngas, and flue gas.

• Typical operation: 30 % aqueous MEA solution, capturing up to 90% CO₂ at 40–60 °C.

Personal Care & Surfactants:

• Intermediate in producing cocamide MEA and lauramide MEA, common in shampoos, conditioners, and lotions for foam boosting and emulsification.

Agrochemicals:

• Serves as a neutralizing agent and carrier in pesticide and herbicide formulations (notably in glyphosate products).

Pharmaceuticals:

• Used as a chemical intermediate in synthesis of antihistamines and local anesthetics.

Textiles:

• Employed as a pH regulator in dyeing and finishing, particularly for wool and silk.

3. Safety and Toxicology

Health Hazards:

• Skin/Eyes: Corrosive; causes burns and severe irritation.

• Inhalation: Irritant at ≥10 ppm; high exposure may cause pulmonary edema.

• Ingestion: Harmful if swallowed; causes gastrointestinal irritation and potential organ damage.

Toxicological Data:

• Oral LD₅₀ (rat): ~2,000 mg/kg

• Inhalation LC₅₀ (rat, 4h): ~2,000 ppm

• Dermal LD₅₀ (rabbit): ~2,000 mg/kg

Flammability:

• Combustible liquid

• Flash point: 93 °C

• Autoignition: ~410 °C

Protective Measures:

• Use gloves (nitrile), protective goggles, and local exhaust ventilation.

• Emergency: Flush exposed area with water for ≥15 minutes; seek medical help immediately.

4. Environmental and Regulatory Compliance

Environmental Impact:

• Aquatic Toxicity: LC₅₀ (fish, 96h): ~1,000 mg/L; EC₅₀ (daphnia): ~800 mg/L

• Biodegradability: Readily biodegradable; >90% degraded in 28 days (OECD 301B)

• Atmospheric Fate: Short half-life (~1 day) via OH radical reaction

Regulatory Status:

• EU: CLP Regulation — Skin Corr. 1B (H314), Eye Dam. 1 (H318)

• USA: OSHA PEL = 3 ppm (8-hour TWA); EPA TRI-listed substance

• China: Classified as Class 8.2 Corrosive (GB 13690-2009)

• Transport: UN 2491, Hazard Class 8 (Corrosive), Packing Group III

5. Case Studies and Application Insights

Case 1: CO₂ Capture in Power Plants

• Example: Boundary Dam Power Station (Canada) uses MEA scrubbing to capture ~1 million tons CO₂/year.

• Challenge: High regeneration energy demand (3–4 GJ per ton CO₂).

Case 2: Personal Care Formulations

• MEA derivatives (cocamide MEA) widely used in shampoos like Garnier Fructis®.

• Benefit: Improves foam stability and viscosity by up to 30% compared to sulfate-free formulations.

Comparative Analysis:

• Pros: High CO₂ absorption capacity (0.5 mol CO₂/mol MEA), versatile reactivity.

• Cons: Oxidative degradation leads to higher solvent replacement costs compared to alternatives like DEA or MDEA.