1. Chemical Structure and Properties

Molecular Formula:

C₄H₁₁N

Structural Formula:

(CH₂CH₃)₂NH – A secondary aliphatic amine with two ethyl groups bonded to a central nitrogen atom.

Physical Properties:

• Appearance: Colorless to pale yellow liquid with a strong ammonia-like odor.
• Boiling Point: 56°C
• Density: 0.71 g/cm³
• Vapor Pressure: 250 mmHg at 20°C
• Solubility: Miscible with water, ethanol, and most organic solvents.

Chemical Properties:

• Basicity: Strong base (pKa = 10.98 in water), reacts exothermically with acids to form salts (e.g., diethylamine hydrochloride).
• Reactivity: Participates in alkylation, acylation, and condensation reactions; highly flammable (flash point: -23°C).

2. Industrial Applications

Pharmaceuticals:

• Intermediate in synthesizing local anesthetics (e.g., lidocaine) and antihistamines (e.g., diphenhydramine).

Agrochemicals:

• Key precursor for herbicides (e.g., atrazine) and fungicides (e.g., propiconazole).

Rubber Industry:

• Vulcanization accelerator in synthetic rubber production (e.g., neoprene).

Surfactants and Corrosion Inhibitors:

• Produces quaternary ammonium salts for detergents and oilfield chemicals.

Organic Synthesis:

• Catalyst in Grignard reactions and polymerization processes (e.g., polyurethane foams).

3. Safety and Toxicology

Health Hazards:

• Inhalation (≥25 ppm): Severe respiratory irritation, dizziness, and headache (TLV-TWA: 5 ppm).
• Skin Contact: Corrosive burns and dermatitis (rabbit skin LD50: 820 mg/kg).
• Eye Exposure: Permanent corneal damage.
• Ingestion: Highly toxic (oral LD50 rat: 540 mg/kg); causes gastrointestinal necrosis.

Acute Exposure:

• Chronic Effects: Potential liver and kidney damage (observed in animal studies).

Flammability and Explosion Risks:

• Extremely flammable liquid (flammability range: 1.7–10.1% vol in air).
• Reacts violently with oxidizers (e.g., nitric acid) and halogens.

Protection Measures:

• PPE: Neoprene gloves, chemical goggles, and NIOSH-approved respirators.
• Engineering Controls: Explosion-proof ventilation, inert gas blanketing.

4. Environmental and Regulatory Compliance

Environmental Impact:

• Aquatic Toxicity: LC50 (fish, 96h): 50 mg/L; EC50 (daphnia): 20 mg/L.
• Biodegradability: Readily biodegradable (OECD 301D: >70% in 28 days).
• Atmospheric Fate: Reacts with hydroxyl radicals (half-life ~6 hours); contributes to smog formation.

Regulatory Frameworks:

• GB 13690-2009: Listed as Class 3.1 Flammable Liquid and Class 8.2 Corrosive Substance.
• OSHA PEL: 25 ppm (8-hour TWA); EPA TRI: Reportable Quantity (RQ) = 1,000 lbs.
• CLP Regulation: Classified as Flammable Liquid (Category 1), Skin Corr. 1B (H314), and Acute Tox. 3 (H331).
• REACH: Requires SDS with exposure limits and disposal guidelines.

Transportation:

UN Number: UN 1154; Hazard Class: 3 (Flammable Liquid), Packing Group I.

5. Case Studies and Application Insights

Case 1: Lidocaine Synthesis

Process: DEA reacts with 2,6-dimethylaniline to form the intermediate for lidocaine, a widely used local anesthetic.

Efficiency: 85% yield at 60°C with catalytic acid (Pfizer’s optimized batch process).

Case 2: Oilfield Corrosion Inhibition

Application: Schlumberger uses DEA-derived imidazoline surfactants to protect pipelines from H₂S corrosion.

Performance: Reduces corrosion rates by 90% at 50 ppm dosage in acidic environments.

Comparative Analysis:

• Pros: DEA has lower cost and higher reactivity in alkylation reactions.
• Cons: TEA offers better thermal stability (up to 150°C) for high-temperature processes.