Formic anhydride

Formic anhydride, also called methanoic anhydride, is an organic compound with the chemical formula C2H2O3 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. It can also be produced by reacting formic acid with N,N′-dicyclohexylcarbodiimide ((C6H11−N=)2C) in ether at −10 °C. It can also be obtained by disproportionation of acetic formic anhydride.Formic anhydride is a liquid with boiling point 24 °C at 20 mmHg. It is stable in diethyl ether solution. It can be isolated by low-temperature, low-pressure distillation, but decomposes on heating above room temperature. It decomposes into formic acid and carbon monoxide.