|Jmol-3D images||Image 1|
|Molar mass||78.49 g/mol|
|Density||1.104 g/ml, liquid|
|Melting point||−112 °C; −170 °F; 161 K|
|Boiling point||52 °C; 126 °F; 325 K|
|Solubility in water||Reacts with water|
|Dipole moment||2.45 D|
|EU classification||Flammable (F)
|R-phrases||R11 R14 R34|
|S-phrases||(S1/2) S9 S16 S26 S45|
|Flash point||4 °C; 39 °F; 277 K|
|Autoignition temperature||390 °C; 734 °F; 663 K|
|Related acyl chlorides||Propionyl chloride
|Related compounds||Acetic acid
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Acetyl chloride, CH3COCl, also known as ethanoyl chloride or acyl chloride, is an acid chloride derived from acetic acid. It belongs to the class of organic compounds called acyl halides. It is a colorless liquid.
The usual method involves the reaction of acetic acid with standard inorganic chlorodehydrating agents, such as by using PCl3, PCl5, SO2Cl2, or SOCl2. However, this usually gives acetyl chloride which is contaminated by phosphorus or sulfur impurities, which may interfere with the organic reactions.
- (CH3CO)2O + HCl → CH3COCl + CH3CO2H
Acetyl chloride is not expected to exist in nature, because contact with water would hydrolyze it into acetic acid and hydrogen chloride. In fact, if handled in open air it releases white "smoke" resulting from hydrolysis due to the moisture in the air. The smoke is actually small droplets of hydrochloric acid formed by hydrolysis.
It is a chemical for acetylation in the synthesis or derivatization of organic compounds. Examples of acetylation reactions include acylation processes such as esterification (see below) and the Friedel-Crafts reaction.
Frequently such acylations are carried out in the presence of a base such as pyridine, triethylamine, or DMAP, which act as catalysts to help promote the reaction and as bases neutralize the resulting HCl. Such reactions will often proceed via ketene.
For further information on the types of chemical reactions compounds such as acetyl chloride can undergo, see acyl halide.
- Merck Index, 11th Edition, 79.
- Leo A. Paquette (2005). "Acetyl chloride". Handbook of Reagents for Organic Synthesis, Activating Agents and Protective Groups. John Wiley & Sons. p. 16. ISBN 978-0-471-97927-2.
- Hosea Cheung, Robin S. Tanke, G. Paul Torrence “Acetic Acid” in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a01_045
- US 4352761