1. Chemical Structure and Properties

Molecular Formula:

C₃H₉N

Structural Formula:

(CH₃)₃N

Tertiary amine with a trigonal pyramidal geometry, featuring three methyl groups attached to a central nitrogen atom.

Physical Properties:

• State: Colorless gas at standard conditions; commonly stored as a 40% aqueous solution (boiling point of solution: ~85°C).
• Density: 0.63 g/cm³ (gas), 0.67 g/cm³ (liquid).
• Odor Profile: Pungent, ammonia-like odor detectable at 0.002 ppm (olfactory threshold).

Chemical Behavior:

• Basicity: Strong base (pKa = 9.8 in water), reacts exothermically with acids to form salts (e.g., trimethylamine hydrochloride).
• Reactivity: Combustible (flash point: -7°C) and forms explosive peroxides upon prolonged exposure to air.

2. Industrial Applications

Chemical Manufacturing:

• Choline Derivatives: Primary feedstock for choline chloride (animal feed additive, global production >600,000 t/year).
• Pharmaceuticals: Building block for antihistamines and neurological drugs.

Gas Processing:

• Acid Gas Removal: Utilized in amine scrubbing systems (e.g., Shell’s ADIP process).

Surfactants:

• Production of trimethylamine oxide (TMAO) for detergents and personal care products.

Agriculture:

• Intermediate in glyphosate herbicide synthesis.

3. Safety and Toxicology

Hazard Profile:

• Inhalation (≥50 ppm): Severe respiratory irritation, pulmonary edema.
• Skin Contact (liquid): Frostbite risk.

Acute Exposure:

• Chronic Effects: Potential liver/kidney damage.

Flammability:

Class 1 flammable gas (NFPA 704 rating: Health 3, Flammability 4).

Protection Protocols:

• Engineering Controls: Explosion-proof ventilation, gas detectors.
• PPE: SCBA, neoprene gloves.

Regulatory Limits:

OSHA PEL: 10 ppm (8-hour TWA); IDLH: 500 ppm.

4. Environmental and Regulatory Compliance

Ecotoxicology:

• Aquatic Toxicity: LC50 (fish): 80 mg/L; EC50 (algae): 25 mg/L.
• Biodegradation: Rapid in aerobic conditions (half-life <24 hours).
• Atmospheric Impact: Contributes to secondary aerosol formation via NOx reaction.

Global Regulations:

• EU: CLP Regulation (H221: Flammable gas; H331: Toxic if inhaled).
• US EPA: Listed as a TRI chemical.
• China: GB 13690-2009, Category 2.1 hazardous chemical.

Transportation:

UN 1083 (anhydrous), UN 1296 (aqueous solution); Class 2.1 hazard label required.

5. Case Studies and Comparative Analysis

Case 1: Choline Chloride Production

Process: TMA reacts with ethylene oxide to form choline, then neutralized with HCl.

Efficiency: 95% yield at 80°C with zeolite catalysts (BASF method).

Case 2: Natural Gas Sweetening

Application: ADIP-X process uses TMA-based solvents to reduce H₂S to <4 ppm.

Operational Data: 20% energy savings vs. MEA systems.

Alternative Comparison:

• Cost: TMA is 30% cheaper but requires stricter safety protocols.
• Performance: DMA has higher selectivity for CO₂ but lower reaction kinetics.