CAS 57-55-6: Propylene Glycol (C3H8O2)
Identity
| CAS Number | 57-55-6 |
| Molecular Formula | C3H8O2 |
| IUPAC Name | propane-1,2-diol |
| Molecular Weight | 76.09 g/mol |
| SMILES | CC(O)CO |
| Synonyms | PG, 1,2-propanediol, 1,2-propylene glycol, monopropylene glycol |
2D Structure
Physical Properties
| Density | 1.036 g/mL at 25°C |
| Boiling Point | 188.2°C |
| Melting Point | -59.0°C |
| Flash Point | 99.0°C |
| Vapor Pressure | 0.01 kPa at 20°C |
| Refractive Index | nD = 1.433 |
| Dielectric Constant | ε = 32.0 |
Safety & GHS Classification
Storage: Store in tightly sealed containers. Hygroscopic. Very low toxicity — GRAS (Generally Recognized as Safe). Keep away from strong oxidizers.
Material Compatibility Matrix
Plastics
| Material | Rating |
|---|---|
| PTFE | Excellent |
| PVC | Good |
| PE | Good |
| PP | Excellent |
| PEEK | Excellent |
| PVDF | Excellent |
Rubbers
| Material | Rating |
|---|---|
| Viton | Good |
| NBR | Good |
| EPDM | Excellent |
| Silicone | Good |
| FKM | Good |
Metals
| Material | Rating |
|---|---|
| Stainless 316 | Excellent |
| Aluminum | Good |
| Copper | Good |
| Brass | Good |
Applications
- E-cigarette liquid (PG/VG mixture)
- Food additive (E1520 — humectant, solvent)
- Pharmaceutical solvent and carrier
- Antifreeze (food-grade applications)
- Cosmetics and personal care
- Unsaturated polyester resin production
- De-icing fluid
- Paint and coating additive
External References: PubChem