Acetyl bromide is an acyl bromide compound. As is expected, it may be prepared by reaction between phosphorus tribromide and acetic acid:

3 CH3COOH + PBr3 → 3 CH3COBr + H3PO3

As usual for an acid halide, acetyl bromide hydrolyzes rapidly in water, forming acetic acid and hydrobromic acid. It also reacts with alcohols and amines to produce acetate esters and acetamides, respectively.

Chemical formula:

C2H3BrO

Acetyl bromide appears as a colorless fuming liquid with a pungent odor that turns yellow in air. Vapors irritate eyes and mucous membranes. Corrosive to metals and tissue. It has a sharp, unpleasant odor and is used in making dyes and organic chemicals. Density 13.9 lb / gal.