| IUPAC name
| Other names
Propanoic acid, anhydride
|Molar mass||130.14 g/mol|
|Odor||Pungent, rancid odor|
|Density||1.015 g/cm3 (20 °C)|
|Melting point||−42 °C (−44 °F; 231 K)|
|Boiling point||167–170 °C (333–338 °F; 440–443 K)|
|Solubility|| Miscible with chloroform, diethyl ether, ethanol, isopropanol, methanol|
Slightly soluble in CCl4
|Vapor pressure||1.36 mm Hg at 25 °C|
|Safety data sheet||Sigma-Aldrich|
|Flash point||63 °C (145 °F; 336 K)|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
|2,360 mg/kg (rat, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Propanoic anhydride or propionic anhydride is an organic compound with the formula (CH3CH2CO)2O.
Propanoic anhydride slowly hydrolyzes in water to propionic acid.
Propionic anhydride is a colorless liquid, with a strong pungent smell, which is insoluble in water, but slowly hydrolyzes upon contact. It is miscible with most organic solvents.
Propionic anhydride is sold by chemical suppliers.
In the US, is it classified as a List I compound, due to its use in the illicit manufacturing of fentanyl and its analogues. As such it cannot be acquired by private individuals, and a license is required to purchase and use the compound.
- 2 CH3CH2CO2H + CH2=C=O → (CH3CH2CO)2O + CH3CO2H
- CH2=CH2 + CH3CH2CO2H + CO → (CH3CH2CO)2O
- Make esters
Propanoic anhydride is strong smelling and corrosive and will cause burns on contact with skin. Vapour can burn the eyes and lungs.
In closed bottles, away from moisture.
Can be neutralized by adding it in a diluted NaOH or KOH solution, which causes it to hydrolyze to propionic acid and finally sodium or potassium propionate, respectively, which is harmless and can be poured down the drain or dumped in soil.