Description

Acetyl Chloride is a colorless to pale yellow, fuming liquid with a pungent odor. It is used to make pharmaceuticals and pesticides.

Acyl halides, such as acetyl chloride, and acid anhydrides, such as acetic anhydride, are used exclusively as reagents rather than solvents. Consequently, their physical properties, such as boiling points and dielectric constants, are less interesting than those of other acyl derivatives. Because neither acyl halides nor acid anhydrides form intermolecular hydrogen bonds, their boiling points are similar to structurally related carbonyl compounds of approximately the same molecular weight.

Uses

Acetyl chloride is a powerful acetylating agent. It is use in the manufacture of aspirin, acetaminophen, and acetanilide. Liquid crystal compositions for optical display and memory devices frequently require acetyl chloride. Acetyl chloride is an efficient acetylating agent for alcohols and amines to produce esters and amides. It is essential in the synthesis of dyes and pharmaceuticals. In addition, Acetyl chloride is used in the Friedel-Craft acylation of benzene to yield acetophenone.

Acetyl chloride and pyridine at room temperature, or prolonged heating with acetic anhydride, can be used to acetylate lipids, but the mildest reagent is probably acetic anhydride in pyridine.

Application example

Acetyl chloride (35 g, 0.45 mol) was added dropwise to a slurry of octamethyltrisilane (40 g, 0.20 mol) and aluminum chloride (53 g, 0.40 mol) with stirring. A moderate exothermic reaction took place, and finally, the mixture became homogeneous. After the addition was completed, the mixture was stirred for 2 h. The product was simply removed from the mixture by distillation under reduced pressure. After fractionation through a 25-cm column packed with glass helicoils, 1,3-dichloro-1,1,2,2,3,3-hexamethyltrisilane (40 g, 84%) was obtained as a colorless pure liquid.