Acetic oxalic anhydride

Acetic oxalic anhydride is an organic compound with a chemical formula of C
6
H
6
O
6
and a structural formula of (H3C-(C=O)-O-(C=O)-)2. It can be viewed as a mixed anhydride, formally derived from acetic acid (H3C-(C=O)OH) and oxalic acid ((-(C=O)OH)2), in 2:1 molecular ratio, by the loss of two water molecules.

Acetic oxalic anhydride
Ball-and-stick model of the acetic oxalic anhydride molecule
Names
Preferred IUPAC name
Diacetic oxalic dianhydride
Other names
Diacetyl oxalate
Identifiers
3D model (JSmol)
ChemSpider
UNII
  • InChI=1S/C6H6O6/c1-3(7)11-5(9)6(10)12-4(2)8/h1-2H3 checkY
    Key: XRMBFFGBVGXJJF-UHFFFAOYSA-N checkY
  • CC(OC(C(OC(C)=O)=O)=O)=O
Properties
C6H6O6
Molar mass 174.108 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation

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Unlike some other anhydrides, Acetic oxalic anhydride cannot be obtained directly from the acids. It was synthesized in 1953 by W. Edwards and W. M. Henley, by reacting silver oxalate (Ag
2
C
2
O
4
) suspended in diethyl ether with acetyl chloride at temperatures below −5 °C and distilling off the solvent under low pressure. It can also be obtained by reacting anhydrous oxalic acid with ketene (H
2
C
=C=O).[1]

Properties

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Acetic oxalic anhydride is an unstable colorless crystalline solid, soluble in diethyl ether, that decomposes at about −3 °C into acetic anhydride (H
3
C
-(C=O)-)2O, carbon dioxide (CO
2
) and carbon monoxide (CO). It is hydrolyzed by water into acetic and oxalic acids.[1]

Acetic oxalic anhydride was conjectured to be an intermediate in the decomposition of anhydrous oxalic acid by acetic anhydride.[1]

See also

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References

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  1. ^ a b c W. R. Edwards and Walter M. Henley (1953), Acetic Oxalic Anhydride. J. Am. Chem. Soc., volume 75, issue 14, pages 3857-3859. doi:10.1021/ja01110a505