Alcohols & Glycols
REACH
1,3-propanediol
CAS Number
504-63-2
EC Number
207-997-3
FEMA Number
FEMA 4753
Abbreviation
PDO
What is 1,3-propanediol?
1,3-Propanediol (CAS 504-63-2), also known as trimethylene glycol or PDO, is a bifunctional diol used as a monomer, solvent, and humectant.
Where is 1,3-propanediol used?
- Polymer production: key monomer for polytrimethylene terephthalate (PTT), a polyester used in carpet fiber, apparel, and engineering plastics
- Personal care: humectant in skin creams, serums, and hair conditioners, supporting moisture retention and helping dissolve active ingredients
- Pharmaceuticals: carrier solvent in topical and oral formulations
- Industrial coatings and adhesives: cross-linking agent and reactive intermediate in polyurethane and UV-curable resin systems
- Its two terminal hydroxyl groups make it a reactive building block for polyesters and polyurethanes.
Good to know: Bio-based PDO, produced via fermentation, is commercially available and increasingly specified in sustainable formulation programs.
Commercial specifications
- Clear, colorless liquid in drum and IBC quantities, with bulk tanker options
- High-purity grades meeting USP and pharmaceutical specifications
Other Names (Synonyms)
trimethylene glycol|omega-propanediol|HOCH2CH2CH2OH|HO(CH2)3OH|CH2(CH2OH)2|beta-propylene glycol|2-deoxyglycerol|2-(hydroxymethyl)ethanol|PDO
What are the physical properties of 1,3-propanediol?
Melting Point -26.7 °C
Boiling Point 215 °C
Density 1.0538 g/cm³
Flash Point >230 °F
Appearance Colorless oil liquid; odorless. Soluble in water, alcohol, and ether. Combustible.
Color Clear
Form Oily Liquid
Water Solubility 100 g/L
Vapor Pressure 0.8 mm Hg ( 20 °C)
Refractive Index n 20/D 1.440(lit.)
pH 4.5-7.0 (100g/l, H2O, 20℃)
Log P -0.71 at 20℃
How is 1,3-propanediol classified and handled safely? Learn More
Warning
GHS07· Irritant
Hazard Statements
H315 Causes skin irritation
Precautionary Statements
P264 Wash … thoroughly after handling.
P280 Wear protective gloves/protective clothing/eye protection/face protection.
P321 Specific treatment (see … on this label).
P302+P352 IF ON SKIN: Wash with plenty of water.
P332+P317 Get emergency medical help.
P362+P364 Take off contaminated clothing and wash it before reuse.
Which trade and regulatory codes apply to 1,3-propanediol?
HS Code 29053980
Storage Class 10 - Combustible liquids
WGK (Germany) 1