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 lowtemperature, low - pressure distillation, but decomposes on heating above room temperature. It decomposes into formic acid and carbon monoxide.
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′- di cyclo hexyl carbo di imide ((C6H11- N =)2C) in ether at -10 °C. It can also be obtained by disproportionation of acetic formic anhydride. The decomposition of formic anhydride may be catalyzed by formic acid.
Formic anhydride can be detected in the gas phase reaction of ozone with ethylene. The molecule is planar in the gas phase.
