Acetyl cyanide is the
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
with the formula CH3C(O)CN. It is an
acyl cyanide
In organic chemistry, an acyl cyanide is a functional group with the Chemical formula, formula and Chemical structure, structure . It consists of an acyl group () attached to cyanide (). Examples include acetyl cyanide, formyl cyanide, and oxal ...
. Acetyl cyanide is a colorless liquid.
Structure
Its structure was determined through the use of
electron diffraction
Electron diffraction is a generic term for phenomena associated with changes in the direction of electron beams due to elastic interactions with atoms. It occurs due to elastic scattering, when there is no change in the energy of the electrons. ...
intensities and rotational spectroscopy.
Reactions
Two main types of reactions can occur with acetyl cyanide as a reactant; aldol condensation and enolate substitution. Aldol condensation can occur when acetyl cyanide reacts with (Z)-but-2-enal to form (2E,4E)-hexa-2,4-dienoyl cyanide:

The photochemical and thermal reactions of acetyl cyanide have been extensively studied. For example,
formyl cyanide does not undergo unimolecular decomposition to HCN and CO spontaneously. However, acetyl cyanide, also a member of this family, breaks down through this unimolecular decomposition at 470 °C. This reaction occurs through decarbonylation. This division of the molecule to a ketone and hydrogen cyanide were noted to be under competitive circumstances. This caused a study of the thermal unimolecular reactions that acetyl cyanide undergoes.
The unimolecular decompositions that acetyl cyanide undergo have been confirmed to be less energetically favorable than the molecule undergoing isomerization to acetyl isocyanide. However, through other photolysis experiments have resulted in the formation of a CN radical through acetyl cyanide decomposing into CH
3CO + CN or CH
3COCN.
Synthesis
Acetyl cyanide is prepared from acetyl chloride and cyanide sources, often in the presence of copper catalysts.
[ Acetyl cyanide is also synthesized at 350 °C from ]ketene
In organic chemistry, a ketene is an organic compound of the form , where R and R' are two arbitrary valence (chemistry), monovalent functional group, chemical groups (or two separate Substituent, substitution sites in the same molecule). The na ...
and hydrogen cyanide
Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...
.
References
Further reading
* Lide, David R., W. M. Haynes, and Thomas J. Bruno, eds. CRC Handbook of Chemistry and Physics. 93rd ed. Boca Raton, FL: CRC, 2012. Web. 17 October 2012.
* {{cite web, url=http://www.chemspider.com/Chemical-Structure.62638.html/, title=1737633 | C3H3NO, website=Chemspider.com, access-date=7 March 2022
Acyl cyanides
Nitriles