1. Chemical Structure and Properties

Molecular Formula: C₆H₁₄O₃
      Structural Formula:
      HO-(CH₂CH(CH₃)O)₂H
      A branched glycol ether composed of two propylene oxide units linked by ether bonds, terminated with hydroxyl groups.

Physical Properties:
     Appearance: Clear, colorless liquid with a mild, slightly sweet odor.
     Boiling Point: 230–235°C; Density: 1.02–1.04 g/cm³; Vapor Pressure: <0.01 mmHg at 25°C.
     Solubility: Fully miscible with water, alcohols, and most organic solvents (e.g., acetone, ethyl acetate).

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 propylene oxide derivatives.
     Flammability: Combustible (flash point: ~120°C).

2. Industrial Applications

Coatings & Inks:
     Coalescing Agent: Enhances film formation in waterborne paints and latex adhesives.
     Solvent: Dissolves resins and pigments in high-performance industrial coatings.

Cleaning Products:
     Heavy-Duty Degreaser: Removes oils, greases, and waxes in aerospace and automotive industries.

Personal Care:
     Humectant & Emollient: Used in cosmetics and lotions for moisture retention and skin compatibility.

Chemical Synthesis:
     Intermediate: Produces plasticizers, surfactants, and specialty polymers.

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 studies.

Protection Measures:
     PPE: Nitrile gloves, safety goggles, and general ventilation.
     Storage: Stable in HDPE containers; store away from 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: ~0.2).

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: Sustainable Paint Formulation (Sherwin-Williams, 2023):
     Challenge: Reduce VOC emissions in architectural paints without compromising drying time.
     Solution: Dipropylene glycol ether (8% w/w) replaced ethylene glycol-based coalescents.
     Result: Achieved 25% lower VOC emissions (ASTM D6886) and maintained scrub resistance (ASTM D2486).

Case 2: Green Electronics Cleaning (Samsung, 2022):
     Process: Implemented dipropylene glycol ether in PCB flux cleaning for 5G devices.
     Impact: Reduced solvent waste by 30% and met EU RoHS standards.

Comparative Analysis:
     Dipropylene Glycol Ether vs. Ethylene Glycol Monobutyl Ether (EGBE):
     Pros: Lower toxicity, higher biodegradability, and better water solubility.
     Cons: Higher viscosity (~20 mPa·s) limits spray applications.
     Dipropylene Glycol Ether vs. Glycerin:
     Pros: Superior solvency for non-polar contaminants; lower hygroscopicity.
     Cons: Glycerin is non-toxic but less effective in high-temperature processes.

Specifications:
Di(propylene glycol) methyl ether is an organic solvent with a variety of industrial and commercial uses. It finds use as a less volatile alternative to propylene glycol methyl ether and other glycol ethers. The commercial product is typically a mixture of four isomers.