1. Chemical Structure and Properties

Molecular Formula: C₃H₁₀ClN

Structural Formula: (CH₃)₃N·HCl

A tertiary amine hydrochloride formed by neutralizing trimethylamine (TMA) with hydrochloric acid.

Physical Properties:
 Appearance: White crystalline powder or hygroscopic solid.
 Melting Point: 260–265°C (decomposes).
 Solubility: Highly soluble in water (>500 g/L at 25°C), ethanol, and methanol; insoluble in non-polar solvents.
 Odor: Odorless (unlike volatile TMA gas).
 Hygroscopicity: Absorbs moisture rapidly; requires airtight storage.

Chemical Properties:
 Stability: Stable under dry conditions; decomposes upon heating to release TMA gas and HCl.
 Reactivity: Acts as a weak acid (pKa ≈ 9.8); regenerates TMA when treated with strong bases.

2. Industrial Applications

Pharmaceuticals:
 - Intermediate for antihistamines (e.g., tripelennamine) and neurological drugs (e.g., donepezil for Alzheimer’s).
 - Salt Formation: Improves solubility and shelf-life of APIs (e.g., betaine HCl).

Agrochemicals:
 - Herbicide precursor: Participates in glyphosate and paraquat synthesis.
 - Pesticides: Intermediate in neonicotinoid production (e.g., imidacloprid).

Organic Synthesis:
 - Catalyst for alkylation and quaternization reactions (e.g., choline chloride formation).
 - Surfactant precursor: Converts into trimethylamine oxide used in detergents and softeners.

Electronics:
 - Etching/Cleaning Agent: Removes organic residues on silicon wafers during chip fabrication.

3. Safety and Toxicology

Health Hazards:
 - Potential liver/kidney toxicity (limited data); not classified as carcinogenic (IARC).
 - Skin/Eye Contact: Causes irritation and chemical burns (rabbit skin LD50 ~600 mg/kg).
 - Inhalation: Dust or decomposition fumes irritate respiratory tract; handle as TMA hazard.
 - Ingestion: Moderately toxic (oral LD50 rat: ~1,500 mg/kg); causes GI tract irritation.

Handling Precautions:
 - PPE: Nitrile gloves, protective goggles, and N95 respirator.
 - Storage: Store in airtight, moisture-resistant containers in cool, dry environment.
 - First Aid: Rinse exposed areas thoroughly with water; seek medical attention for severe exposure.

4. Environmental and Regulatory Compliance

Environmental Impact:
 - Aquatic Toxicity: LC50 (fish, 96h): 200–400 mg/L; EC50 (daphnia): 100–200 mg/L.
 - Biodegradability: Readily biodegradable (OECD 301D: >70% in 28 days).
 - Persistence: Low due to hydrolysis in aqueous environments.

Regulatory Frameworks:
 - GB 13690-2009 (China): Classified as General Chemical; follow standard safety practices.
 - OSHA (USA): No established PEL; general duty clause applies.
 - EPA: Listed on TSCA Inventory.
 - CLP (EU): Classified as Skin Irrit. 2 (H315), Eye Irrit. 2 (H319), Acute Tox. 4 (H302).
 - REACH (EU): Registered with full SDS obligations for transport and disposal.

Transport:
 - UN Number: Not classified as hazardous; general cargo transport allowed (non-DG).

5. Case Studies and Application Insights

Case 1: Choline Chloride Production
 - Process: TMA HCl reacts with ethylene oxide to produce choline chloride.
 - Efficiency: 95% yield at 80°C using zeolite catalyst (BASF proprietary process).

Case 2: Semiconductor Wafer Cleaning
 - Application: Intel uses aqueous TMA HCl to remove organic residues during 10nm process.
 - Performance: 99.9% removal efficiency without damaging substrate.

Comparative Analysis:
 - Pros: Solid form reduces volatility and flammability risks; safer storage and transport.
 - Cons: Requires chemical regeneration (e.g., basification) to access free TMA for reactions.