Substance profile
Propylene
Propylene is a colorless gas and is odorless.
01 · Identification
What Propylene is
Propylene is a colorless gas and is odorless. Its molecular formula is C3H6 and its molecular weight is 42.08 g/mol. It boils at -47.7 °C, melts at -185 °C.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 4th degree.
Other names for Propylene
- propene
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
03 · Physical and chemical properties
Propylene properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -47.68 °C (-53.8 °F) | HSDB | |
| -47.72 °C (-53.9 °F) | at 760 mmHg | CAMEO | |
| -48 °C (-54.4 °F) | ICSC | ||
| Melting point | -185.3 °C (-301.5 °F) | HSDB | |
| -185.22 °C (-301.4 °F) | CAMEO | ||
| -185 °C (-301 °F) | ICSC | ||
| Density | 0.5 g/cm³ | ICSC | |
| 0.5139 g/cm³ | at 20 °C, liquid | HSDB | |
| 0.505 g/cm³ | at 25 °C, at 760 mmHg | HSDB | |
| Solubility | Very soluble in water | HSDB | |
| In water, 44.6 mL gas/100 mL at 20 °C | at 20 °C | HSDB | |
| In water, 200 mg/L at 25 °C | at 25 °C | HSDB | |
| Vapor pressure | 7600 mmHg | at 19.8 °C | HSDB |
| 8690 mmHg | at 25 °C | HSDB | |
| 8686 mmHg | at 25 °C | ICSC | |
| Flash point | -107.78 °C (-162 °F) | HSDB | |
| Autoignition temperature | 455 °C (851 °F) | HSDB | |
| 460 °C (860 °F) | ICSC | ||
| Lower explosive limit (LEL) | 2.4 % by volume | HSDB | |
| 2 % by volume | CAMEO | ||
| Upper explosive limit (UEL) | 10.3 % by volume | HSDB | |
| 10.1 % by volume | HSDB | ||
| 11.1 % by volume | CAMEO | ||
| Vapor density | 1.5 (air = 1) | ICSC | |
| 4.46 (air = 1) | OSHA | ||
| 1.46 (air = 1) | at 0 °C, Air = 1.0 | HSDB | |
| Odor threshold | ... between 39.6 and 116.27 mg/cu m. | HSDB | |
| Propylene has odor thresholds of 10-50 mg/cu m (detection) and about 100 mg/cu m (recognition), and an organoleptic limit of 0.5 mg/L. | HSDB | ||
| Odor Threshold Low: 23.0 [ppm] | Haz-Map | ||
| Critical temperature and pressure | 91.75 °C (197.2 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Propylene
Storage conditions
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Propylene ... reacts vigorously with oxidizing materials. Under unusual conditions, eg, 96.8 MPa (995 atm) and 600 K, it explodes. It reacts violently with NO2, N2O4, and N2O. Explosions have been reported when liquid propylene contacts water at 315-348 K.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
During an experiment to produce lactic acid by oxidizing PROPYLENE with nitrogen peroxide, a violent explosion occurred. These mixtures (olefins and nitrogen peroxide) form extremely unstable nitrosates or nitrosites (Comp. Rend. 116:756 1893). Contact of very cold liquid propylene with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid propylene contacts water in a closed container.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Propylene in the storage compatibility matrix →