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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.
Synthesis 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.[1] It is produced by the reaction of hydrogen chloride with acetic anhydride:[2] - (CH3CO)2O + HCl CH3COCl + CH3CO2H
HCl impurities can be removed by distilling the crude product from dimethylaniline or by degassing the mixture by a stream of argon. It may also be synthesized from the catalytic carbonylation of methyl chloride.[3] Can containing a bottle of acetyl chloride Heating dichloroacetic chloride with acetic acid also gives acetyl chloride in 70% yield.[1] 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-CH3 CH3-COO-CH2-CH3 + H-Cl
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. 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 External links de:Acetylchlorid el: es:Cloruro de etanoilo fa: fr:Chlorure d' thanoyle id:Asetil klorida it:Cloruro di acetile hu:Acetil-klorid mk: nl:Acetylchloride ja: pl:Chlorek acetylu pt:Cloreto de acetila ru: sl:Acetilklorid sr:Acetil hlorid sv:Acetylklorid zh:
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