Propylene oxide
CAS Number
75-56-9
EC Number
200-879-2
Abbreviation
PO
What is Propylene oxide?
Propylene oxide (CAS 75-56-9), commonly abbreviated as PO, is a reactive epoxide monomer and industrial solvent. Also referenced as methyl oxirane in technical and regulatory contexts.
Where is Propylene oxide used?
- Polyurethane foam: key feedstock for polyether polyols, covering rigid insulation panels, flexible seating and automotive interiors
- Polyols and propylene glycols: primary commercial building block
- Food and pharmaceutical processing: fumigant and sterilizing agent for spices and cocoa
- Medical equipment: sterilizing agent where heat sterilization is not viable
- Antifreeze and industrial coolants: primary component
- Electron microscopy: fixative and dehydration agent in sample preparation
- Propylene glycol from hydration of PO feeds food-grade humectants and cosmetic carriers.
Good to know: Buyers sourcing for food or pharmaceutical sterilization should confirm compliance with regional regulatory standards. Proper handling is required due to its low boiling point and volatility.
Commercial specifications
- Purity commonly 99.5% or higher for polyol synthesis and chemical manufacturing
Other Names (Synonyms)
propene oxide|methyl oxirane|methyl ethylene oxide|2,3-epoxypropane|1,2-propylene oxide|1,2-epoxy propane|2-methyloxirane|Oxirane, methyl-|PO
What are the physical properties of Propylene oxide?
Melting Point -112.13 °C
Boiling Point 34.23 °C
Density 0.8 g/cm³
Flash Point −35 °F
Appearance Propylene oxide is a colorless liquid. Ethereal odor.
Color Clear
Odor Ethereal; characteristic; sweet, alcoholyc; like natural gas.
Form Liquid
Water Solubility 40 g/100 mL (20 ºC)
Vapor Pressure 29.43 psi ( 55 °C)
Refractive Index n 20/D 1.366(lit.)
Log P 0.030
How is Propylene oxide classified and handled safely? Learn More
Danger
GHS02· Flammable GHS06· Toxic GHS08· Health Hazard GHS07· Irritant GHS05· Corrosive
Hazard Statements
H224 Extremely flammable liquid and vapor
H302 Harmful if swallowed
H311 Toxic in contact with skin
H312 Harmful in contact with skin
Precautionary Statements
P203 Obtain, consult and follow expert instructions for use.
P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
P233 Keep container tightly closed.
P240 Ground and bond container and receiving equipment.
Which trade and regulatory codes apply to Propylene oxide?
HS Code 29102000
UN Number 1280
ADR Class 3
Packing Group I
Storage Class 3 - Flammable liquids
WGK (Germany) 3