Formic anhydride

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

Formic anhydride
Names
Preferred IUPAC name
Formic anhydride[1]
Other names
Methanoic anhydride
Formyloxymethanone
Identifiers
3D model (JSmol)
1901016
ChEBI
ChemSpider
1041427
Properties
C2H2O3
Molar mass 74.035 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

Preparation

Formic anhydride can be obtained by reaction of formyl fluoride with excess sodium formate and a catalytic amount of formic acid in ether at −78 °C.[2] It can also be produced by reacting formic acid with N,N′-dicyclohexylcarbodiimide ((C
6H
11−N=)2C) in ether at −10 °C.[3] It can also be obtained by disproportionation of acetic formic anhydride.[4]

Properties

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] At room temperature and higher, it decomposes through a decarbonylation reaction into formic acid and carbon monoxide.[5] Due to its instability, formic anhydride is not commercially available and must be prepared fresh and used promptly.

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

References
  1. "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 909. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  2. George A. Olah, Yashwant D. Vankar; Massoud Arvanaghi; Jean Sommer (1979), Formic Anhydride. Angewandte Chemie International Edition Engl., volume 18, issue = 8, page = 614. doi:10.1002/anie.197906141.
  3. 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.
  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
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