Propionic anhydride

From Sciencemadness Wiki
Jump to: navigation, search
Propionic anhydride
Names
IUPAC name
Propanoic anhydride
Other names
Propanoic acid, anhydride
Propanoyl propanoate
Properties
C6H10O3
(CH3CH2CO)2O
Molar mass 130.14 g/mol
Appearance Colorless liquid
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)
Slowly hydrolyzes
Solubility Miscible with chloroform, diethyl ether, ethanol, isopropanol, methanol
Slightly soluble in CCl4
Vapor pressure 1.36 mm Hg at 25 °C
Hazards
Safety data sheet Sigma-Aldrich
Flash point 63 °C (145 °F; 336 K)
Lethal dose or concentration (LD, LC):
2,360 mg/kg (rat, oral)
Related compounds
Related compounds
Acetic anhydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Propanoic anhydride or propionic anhydride is an organic compound with the formula (CH3CH2CO)2O.

Properties

Chemical

Propanoic anhydride slowly hydrolyzes in water to propionic acid.

Physical

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.

Availability

Propionic anhydride is sold by chemical suppliers.

In US, is it classified as List I compound, due to its use in the illicite 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.

Preparation

Propionic anhydride can be easily prepared by dry distilling a mixture of dry calcium propionate and propionyl chloride.

Alternatively, distilling a mixture propionic acid and oxalyl chloride will produce propionic anhydride, with an yield of 51%.[1]

Propanoic anhydride also be obtained by dehydration of dry propionic acid using ethenone.

2 CH3CH2CO2H + CH2=C=O → (CH3CH2CO)2O + CH3CO2H

Another routes is the Reppe carbonylation of ethylene with propionic acid and nickel carbonyl as the catalyst:[2]

CH2=CH2 + CH3CH2CO2H + CO → (CH3CH2CO)2O

Projects

  • Make esters

Handling

Safety

Propanoic anhydride is strong smelling and corrosive, and will cause burns on contact with skin. Vapour can burn eyes and lungs.

Storage

In closed bottles, away from moisture.

Disposal

Can be neutralized by adding it in a diluted NaOH or KOH solution, which causes it to hydrolyze to propionic acid and finally sodium propionate, which is harmless and can be poured down the drain or dumped in soil.

References

  1. https://www.prepchem.com/synthesis-of-propionic-anhydride
  2. https://onlinelibrary.wiley.com/doi/10.1002/14356007.a22_223.pub4

Relevant Sciencemadness threads