Acetyl chloride

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Acetyl chloride
Acetyl chloride
General
Systematic name Ethanoyl chloride
Other names Acetyl chloride
Molecular formula CH3COCl
SMILES CC(=O)Cl
Molar mass 78.5 g/mol
Appearance colorless liquid
CAS number [75-36-5]
Properties
Density and phase 1.11 g/ml, liquid
Solubility in water Reacts
Melting point −112 °C
Boiling point 51 °C
Viscosity  ? cP at ? °C
Dipole moment  ? D
Hazards
MSDS External MSDS
EU classification Flammable (F)
Corrosive (C)
NFPA 704

3
3
2
W
R-phrases R11, R14, R34
S-phrases S1/2, S9, S16, S26, S45
Flash point 5 °C
Autoignition temperature 390 °C
Explosive limits 7.3–19%
RTECS number AO6390000
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related acyl chlorides Propionyl chloride
Butyryl chloride
Related compounds Acetic acid
Acetic anhydride
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Acetyl chloride, also known as ethanoyl chloride, is an acid chloride derived from acetic acid. It has the formula H3C-COCl and it belongs to the class of organic compounds called acyl halides. The chemical structure of acetyl chloride is shown at right. At room temperature and pressure, it is a clear colorless liquid. Acetyl chloride does not exist in nature, because contact with water would hydrolyze it into acetic acid and hydrogen chloride.

It is chemically synthesized by the reaction of thionyl chloride with acetic acid.

H3C-COO-H + O=SCl2 → H3C-COCl + SO2 + H-Cl

and is used as a reagent for acetylation in the synthesis or derivatization of chemical compounds. Examples of acetylation reactions include acylation processes such as esterification (see below) and the Friedel-Crafts reaction).

H3C-COCl + HO-CH2-CH3H3C-COO-CH2-CH3 + H-Cl

Frequently such acylations are carried out in the presence of a base such as pyridine, triethylamine, or DMAP, which as catalysts help to promote the reaction and as bases neutralize the resulting HCl.

Acetylation is the introduction of an acetyl group via acylation using a reactant such as acetyl chloride or acetic anhydride. An acetyl group is an acyl group having the formula
-C(=O)-CH3.

For further information on the types of chemical reactions compounds such as acetyl chloride can undergo, see acyl halide.

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