Acetyl chloride

Acetyl chloride[1]
Identifiers
CAS number 75-36-5 Y
ChemSpider 6127 Y
UNII QD15RNO45K Y
ChEBI CHEBI:37580 Y
RTECS number AO6390000
Jmol-3D images Image 1
Properties
Molecular formula CH3COCl
Molar mass 78.49 g/mol
Appearance colorless liquid
Density 1.104 g/ml, liquid
Melting point

-112 °C, 161 K, -170 °F

Boiling point

52 °C, 325 K, 126 °F

Solubility in water Reacts
Structure
Dipole moment 2.45 D
Hazards
EU classification Flammable (F)
Corrosive (C)
R-phrases R11 R14 R34
S-phrases (S1/2) S9 S16 S26 S45
Autoignition
temperature
390 °C
Explosive limits 7.3–19%
Related compounds
Related acyl chlorides Propionyl chloride
Butyryl chloride
Related compounds Acetic acid
Acetic anhydride
Acetyl bromide
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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. Acetyl chloride does not exist in nature, because contact with water would hydrolyze it into acetic acid and hydrogen chloride. In fact, if handled in open air it gives off white smoke owing to the hydrolysis from the moisture in the air. The "smoke" is actually small droplets of hydrochloric acid formed by hydrolysis.

Contents

Synthesis

Acetyl chloride is produced by the reaction of hydrogen chloride with acetic anhydride:[2]

(CH3CO)2O + HCl → CH3COCl + CH3CO2H

It may also be synthesized from the catalytic carbonylation of methyl chloride.[3]

Uses

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.

CH3COCl + HO-CH2-CH3CH3-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. Such reactions will often proceed via ketene.

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.

References

  1. ^ Merck Index, 11th Edition, 79.
  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
  3. ^ US 4352761 

External links