Ethylene vs Propylene
Ethylene and Propylene are commonly confused, and 3 measured properties separate them — boiling point most clearly.
Ethylene vs Propylene
Ethylene
C2H4
The highest-tonnage organic chemical made anywhere, and a plant hormone that ripens fruit — the same molecule doing both.
Propylene
C3H6
Ethylene's more useful sibling and its perpetual shortage — one carbon longer, and the source of polypropylene.
| Property | Ethylene | Propylene |
|---|---|---|
| Boiling point | -103.7 °C | -47.6 °C higher |
| Density Only one of the two has a figure we can stand behind, so there is nothing to compare. | 0.00126 g/cm³ | Not known |
| Melting point | -169.2 °C higher | -185.2 °C |
| Molar mass | 28.05 g/mol | 42.08 g/mol higher |
Why these get confused
one carbon apart, made in the same plant, and the difference decides whether the product is polyethylene or polypropylene
The confusion is a real and documented one, not a resemblance we have invented.