Mixed Xylenes (Technical Grade)
CAS 1330-20-7Mixed Xylenes (xylol, CAS 1330-20-7) is a technical-grade aromatic hydrocarbon solvent consisting of a mixture of ortho-, meta-, and para-xylene isomers.
Key Features
- ✓Preferred aromatic solvent for epoxy anti-corrosion primers — marine, offshore, industrial
- ✓Slower evaporation than toluene — improved leveling in epoxy and alkyd coating films
- ✓Higher TLV-TWA (100 ppm) vs. toluene (50 ppm) — better occupational exposure headroom
- ✓No reproductive toxicity Cat. 2 classification (unlike toluene) — preferred for routine use
- ✓Class II flammable (flash point 27–32°C) — less ignition hazard than acetone/MEK/toluene
Specifications
| Parameter | Value |
|---|---|
| Purity | ≥98.5% total xylenes by GC |
| Appearance | Clear, colorless liquid with aromatic odor |
| CAS Number | 1330-20-7 |
| Flash point | 27–32°C (ASTM D93) |
| Boiling range | 137–142°C |
| Density (20°C) | 0.864 g/cm³ |
| Relative evaporation rate | ~0.7 (n-BuAc = 1.0) |
FAQ
Xylene is preferred for several practical reasons: (1) Slower evaporation rate (xylene ~0.7 vs. toluene ~2.0 relative to n-BuAc) allows longer wet-edge time and better flow-out in epoxy primer films, reducing brush marks and roller texture in applied coatings; (2) Xylene's higher boiling range (137–142°C) provides better performance in hot application conditions where toluene evaporates too quickly; (3) Health and regulatory: xylene lacks the reproductive toxicity Category 2 classification of toluene, providing better regulatory and occupational health compliance, particularly in workplaces with mixed gender or pregnant worker exposure risks; (4) Regulatory requirements in some jurisdictions restrict toluene content in coating formulations, making xylene the compliant alternative. In some formulations, a xylene/MEK blend provides a better evaporation profile than either solvent alone.