Acetic formic anhydride
Acetic formic anhydride is an organic compound with the, which can be viewed as the mixed anhydride of acetic acid and formic acid. It is used on a laboritory-scale as a formylating agent. Preparation
Acetic formic anhydride can be produced by reacting sodium formate with acetyl chloride in anhydrous diethyl ether between 23–27 °C. It can also be prepared by the reaction of acetic anhydride and formic acid at 0 °C. Properties
While more stable than formic anhydride, acetic formic anhydride is thermally unstable and gradually decomposes above about 60℃, with the evolution of carbon monoxide. Impurities such as pyridine or residual acid can promote this, resulting in decomposition commencing as low as 0°C. Crude material has been successfully purified by distillation at ≤30°C under reduced pressure. Applications
Acetic formic anhydride is a formylation agent for amines, amino acids, and alcohols. It is also a starting material for other compounds such as formyl fluoride. See also
 Formic anhydride
 Acetic anhydride
 Acetic oxalic anhydride

References 

Carboxylic anhydrides