1. Chemical Structure and Properties
Molecular Formula: C₈H₁₈O₄
Structural Formula:
CH₃CH₂O(CH₂CH₂O)₃H
A branched glycol ether composed of three ethylene oxide units linked to an ethyl group.
Physical Properties:
Appearance: Clear, colorless liquid with a mild, sweet odor.
Boiling Point: 255–260°C; Density: 1.02 g/cm³; Vapor Pressure: <0.01 mmHg at 25°C.
Solubility: Fully miscible with water, alcohols, and polar organic solvents; moderate solubility in hydrocarbons.
Chemical Properties:
Hydrophilic-Lipophilic Balance (HLB): ~6.5, balancing solvency for both polar and non-polar compounds.
Thermal Stability: Stable up to 200°C; decomposes above 300°C into aldehydes and carbon oxides.
Hydrolysis Resistance: Resistant to hydrolysis under neutral and mildly acidic/alkaline conditions.
2. Industrial Applications
Coatings & Inks:
High-Boiling Solvent: Enhances flow and leveling in waterborne coatings, UV-curable inks, and epoxy resin formulations.
Coalescing Agent: Improves film formation in latex paints and industrial finishes.
Electronics:
Photoresist Stripping: Cleans residues from semiconductor wafers without damaging silicon substrates.
Flux Remover: Used in PCB assembly to remove soldering residues.
Pharmaceuticals:
Reaction Medium: Solvent for synthesizing temperature-sensitive APIs (e.g., peptides, antibiotics).
Cleaning Formulations:
Industrial Degreaser: Effective in removing oils, greases, and adhesives from metal and plastic surfaces.
3. Safety and Toxicology
Health Hazards:
Acute Exposure:
Skin Contact: Mild irritation (rabbit skin LD₅₀: >2,000 mg/kg); prolonged exposure may cause defatting.
Inhalation: Low volatility minimizes risk (TLV-TWA: 10 ppm recommended); aerosolized mists may irritate the respiratory tract.
Ingestion: Low acute toxicity (oral LD₅₀ rat: >5,000 mg/kg).
Chronic Effects:
Reproductive Toxicity: No teratogenicity observed in OECD 414 studies.
Organ Toxicity: No significant hepatotoxicity or nephrotoxicity in subchronic rodent studies.
Protection Measures:
PPE: Nitrile gloves, safety goggles; local exhaust ventilation for high-temperature processes.
Storage: Stable in HDPE containers; store away from strong oxidizers and heat sources.
4. Environmental and Regulatory Compliance
Environmental Impact:
Aquatic Toxicity: LC₅₀ (fish, 96h): >100 mg/L; EC₅₀ (daphnia): >50 mg/L.
Biodegradability: Readily biodegradable (OECD 301F: >70% in 28 days).
Persistence: Low bioaccumulation potential (log Kow: 0.8).
Regulatory Frameworks:
EU:
REACH: Registered with no SVHC listing; CLP classification Not Hazardous.
USA:
EPA: Exempt from VOC regulations (40 CFR 51.100(s)(1)); TSCA-listed.
China:
GB 13690-2009: Classified as General Chemical (non-hazardous).
Transport:
UN Number: Non-hazardous; no special transport requirements.
5. Case Studies and Application Insights
Case 1: Sustainable Waterborne Coatings (Sherwin-Williams, 2023):
Application: Replaced 30% of ethylene glycol monobutyl ether (EGBE) with TEGEE in architectural paints.
Result: Achieved 20% lower VOC emissions while maintaining drying time and film hardness.
Case 2: Precision Cleaning in Aerospace (Boeing, 2022):
Process: TEGEE-based cleaner removed carbon deposits from turbine blades with 99.9% efficiency.
Cost Savings: Reduced solvent consumption by 40% through closed-loop recycling.
Comparative Analysis:
TEGEE vs. Triethylene Glycol Monomethyl Ether (TEGMME):
Pros: Higher solvency for hydrocarbons; better biodegradability.
Cons: Slightly higher viscosity (12 mPa·s vs. 8 mPa·s).