Properties of Butyric Acid (C4H8O2)
Butyric acid, also known as butanoic acid, is a short-chain fatty acid with a four-carbon alkyl chain. It is naturally occurring in some dairy products and is responsible for the distinctive smell and taste of rancid butter.
The following table provides a comprehensive list of butyric acid 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 | 88.106 g/mol |
| Density | 953 kg/m3 |
| Dynamic Viscosity | 1.54 mPa·s |
| Surface Tension | 26.51 mN/m |
| Thermal Properties | Metric |
| Melting Point | -5.1 °C |
| Boiling Point | 163.7 °C |
| Thermal Conductivity | 0.1506 W/m·K |
| Vapor Pressure (25°C) | 0.22 kPa |
| Critical Constants | Metric |
| Critical Temperature (Tc) | 350 °C |
| Critical Pressure (Pc) | 4 MPa |
| Critical Molar Volume (Vc) | 292 cm3/mol |
| Electrical Properties | Metric |
| Relative Permittivity (εr) (14°C) | 2.98 |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.398 |
| Hazardous Data | Metric |
| Flash Point | 72 °C |
| Autoignition Temperature | 443 °C |
| Lower Flammability Limit | 2% |
| Upper Flammability Limit | 10% |
| NFPA Rating (Health) | 3 |
| NFPA Rating (Fire) | 2 |
| NFPA Rating (Reactivity) | 0 |
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.