Properties of Acetaldehyde (C2H4O)
Acetaldehyde is a colorless, volatile organic compound with the chemical formula C2H4O. It is the simplest aldehyde and is characterized by a pungent, fruity odor. Acetaldehyde is produced in various natural and industrial processes, including in the human body during alcohol metabolism.
The following table provides a comprehensive list of acetaldehyde properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).
Click on the icon to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Molar Mass | 44.052 g/mol |
| Density | 784 kg/m3 |
| Dynamic Viscosity | 0.21 mPa·s |
| Surface Tension | 21.2 mN/m |
| Thermal Properties | Metric |
| Melting Point | -123.4 °C |
| Boiling Point | 20.8 °C |
| Thermal Conductivity | 0.19 W/m·K |
| Vapor Pressure | 100 kPa |
| Critical Constants | Metric |
| Critical Temperature (Tc) | 188 °C |
| Critical Pressure (Pc) | 5.6 MPa |
| Critical Molar Volume (Vc) | 154 cm3/mol |
| Electrical Properties | Metric |
| Relative Permittivity (εr) | 21 |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.332 |
| Hazardous Data | Metric |
| Flash Point | -39 °C |
| Autoignition Temperature | 175 °C |
| Lower Flammability Limit | 4% |
| Upper Flammability Limit | 60% |
| NFPA Rating (Health) | 2 |
| NFPA Rating (Fire) | 4 |
| NFPA Rating (Reactivity) | 2 |
Unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)
Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017. 3) Yaws, Carl L. The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals. Netherlands: Elsevier Science, 2015. 4) Fire Protection Guide to Hazardous Materials, 14th Edition. United States: National Fire Protection Association, 2010.