Formic anhydride

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Formic anhydride
Structural formula of formic anhydride
Ball-and-stick model of the formic anhydride molecule
Preferred IUPAC name
Formic anhydride[1]
Other names
Methanoic anhydride
3D model (JSmol)
Molar mass 74.04 g·mol−1
Appearance Colorless gas
Boiling point 24 °C (75 °F; 297 K) at 20 mmHg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Formic anhydride, also called methanoic anhydride, is an organic compound with the chemical formula C
and a structural formula of (H(C=O)−)2O. It can be viewed as the anhydride of formic acid (HCOOH).


Formic anhydride can be obtained by reaction of formyl fluoride with sodium formate in ether at −78 °C.[2] It can also be produced by reacting formic acid with N,N′-dicyclohexylcarbodiimide ((C
−N=)2C) in ether at −10 °C.[3] It can also be obtained by disproportionation of acetic formic anhydride.[4]


Formic anhydride is a liquid with boiling point 24 °C at 20 mmHg.[3] It is stable in diethyl ether solution. It can be isolated by low-temperature, low-pressure distillation, but decomposes on heating above room temperature.[3] It decomposes into formic acid and carbon monoxide.[5]

The decomposition of formic anhydride may be catalyzed by formic acid.[3]

Formic anhydride can be detected in the gas-phase reaction of ozone with ethylene.[6] The molecule is planar in the gas phase.[3]

See also[edit]


  1. ^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 909. ISBN 978-0-85404-182-4. doi:10.1039/9781849733069-FP001. 
  2. ^ George A. Olah, Yashwant D. Vankar; Massoud Arvanaghi; Jean Sommer (1979), Formic Anhydride. Angewandte Chemie Int. Ed. Engl., volume 18, issue = 8, page = 614. doi:10.1002/anie.197906141.
  3. ^ a b c d e G. Wu, S. Shlykov, F. S. Van Alseny, H. J. Geise, E. Sluyts, B. J. Van der Veken (1995), Formic Anhydride in the Gas Phase, Studied by Electron Diffraction and Microwave and Infrared Spectroscopy, Supplemented with Ab-Initio Calculations of Geometries and Force Fields. J. Phys. Chem., volume 99, issue 21, pages 8589–8598 doi:10.1021/j100021a022
  4. ^ R. Schijf, J. W. Scheeren, A. van Es, W. Stevens (1965) Mixed carboxylic acid anhydrides: IV. formic anhydride. Recueil des Travaux Chimiques des Pays-Bas, volume 84, issue 5, pages 594–596. doi:10.1002/recl.19650840510
  5. ^ Boogaard, A.; H. J. Geise; F. C. Mijlhoff (July 1972). "An electron diffraction investigation of the molecular structure of formic anhydride". Journal of Molecular Structure. Elsevier Science. 13 (1): 53–58. doi:10.1016/0022-2860(72)87031-5. Retrieved 9 September 2011. 
  6. ^ A. Vaccani, A. Bauder and Hs. H. Günthar (1975), The Microwave Spectrum of Formic Anhydride. Abstracts of OSU International Symposium on Molecular Spectroscopy 1970-1979