1. Chemical Structure and Properties
Molecular Formula: C₁₀H₂₂O₃
Structural Formula:
CH₃(CH₂)₃O-(CH₂CH(CH₃)O)₂H
A branched glycol ether composed of two propylene oxide units linked to a butyl ether group.
Physical Properties:
Appearance: Clear, colorless liquid with a mild ether-like odor.
Boiling Point: 235–240°C; Density: 0.92–0.94 g/cm³; Vapor Pressure: <0.01 mmHg at 25°C.
Solubility: Partially miscible with water (1% w/w at 25°C); fully miscible with alcohols, esters, and hydrocarbons.
Chemical Properties:
Hydrolysis Stability: Resistant to hydrolysis under neutral and mildly acidic/alkaline conditions.
Thermal Stability: Stable up to 200°C; decomposes above 250°C, releasing aldehydes and propylene oxide derivatives.
Flammability: Combustible (flash point: ~90°C).
2. Industrial Applications
Coatings & Inks:
High-Boiling Solvent: Enhances flow and leveling in automotive and industrial coatings (e.g., epoxy, polyurethane).
Coalescing Agent: Improves film formation in waterborne latex paints.
Cleaning Products:
Heavy-Duty Degreaser: Removes oils, greases, and waxes in aerospace and automotive maintenance.
Personal Care:
Emollient & Stabilizer: Used in cosmetics and lotions for its low volatility and skin compatibility.
Chemical Synthesis:
Intermediate: Produces surfactants and plasticizers via ethoxylation or esterification.
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: Not established; handle as nuisance vapor).
Ingestion: Low toxicity (oral LD₅₀ rat: >5,000 mg/kg); gastrointestinal discomfort.
Chronic Effects:
Reproductive Toxicity: No teratogenicity observed in OECD 414 studies.
Organ Toxicity: Negligible hepatotoxicity or nephrotoxicity in subchronic rodent studies.
Protection Measures:
PPE: Nitrile gloves, safety goggles, and general ventilation.
Storage: Stable in HDPE containers; store away from strong oxidizers.
4. Environmental and Regulatory Compliance
Environmental Impact:
Biodegradability: Moderate (OECD 301F: 40–60% in 28 days).
Aquatic Toxicity: LC₅₀ (fish, 96h): >100 mg/L; EC₅₀ (daphnia): >50 mg/L.
Bioaccumulation: Low (log Kow: ~1.5).
Regulatory Frameworks:
EU:
REACH: Registered with no SVHC listing; CLP classification Not Hazardous.
USA:
EPA: Exempt from VOC status under 40 CFR 51.100(s)(1); TSCA-listed.
China:
GB 13690-2009: Classified as General Chemical (non-hazardous).
Waste Management:
Incinerate in approved facilities; landfill disposal permitted for small quantities.
5. Case Studies and Application Insights
Case 1: Green Automotive Coatings (BASF, 2023):
Challenge: Reduce solvent emissions in waterborne automotive primers.
Solution: Dipropylene glycol butyl ether replaced 15% of ethylene glycol-based solvents.
Result: Achieved 25% lower VOC emissions (ASTM D6886) while maintaining adhesion (ASTM D3359).
Case 2: Sustainable Industrial Cleaners (Ecolab, 2022):
Process: Formulated a bio-based degreaser using dipropylene glycol butyl ether and citrus terpenes.
Impact: Reduced solvent waste by 40% and met EU Ecolabel criteria.
Comparative Analysis:
Dipropylene Glycol Butyl Ether vs. Ethylene Glycol Monobutyl Ether (EGBE):
Pros: Lower toxicity, higher biodegradability, and better compatibility with hydrophobic substrates.
Cons: Higher viscosity (~25 mPa·s vs. 3 mPa·s) limits use in spray applications.
Dipropylene Glycol Butyl Ether vs. Propylene Glycol Methyl Ether (PGME):
Pros: Improved thermal stability and reduced dermal absorption risks.
Cons: PGME offers faster evaporation for quick-drying formulations.
Specifications:
A slow-evaporating, hydrophobic glycol ether with excellent surface tension-lowering ability and coalescing properties. It has a near mid-range balance of hydrophobic and hydrophilic characteristics, and it offers significant water solubility. It is one of our most efficient coalescents in water-borne latex systems. It combines a number of properties that contribute to very high latex film quality: 1) high polymer plasticizing efficiency, 2) large molecular size and therefore greater polymer mobility contribution, 3) strong partitioning to the polymer phase, and 4) relatively slow evaporation rate. This product is compatible with many different resin types. It also provides excellent surface tension lowering ability, and is useful in cleaning products by itself or when blended with other products. Used alone in cold metal cleaning, it is a good solvent for removing oils and greases. An excellent choice for coatings applications, this product provides outstanding coalescing and film properties. INCI Name: Dipropylene glycol n-butyl ether