# Question #c84fc

Feb 8, 2017

It is probably a matter of cost of the acetyl halide.

#### Explanation:

All three compounds readily react with amines per the equation

$\text{RNH"_2 + "CH"_3"CO-X" → "RNH-COCH"_3 + "HX}$

The prices of the halides in US dollars are approximately

$\text{CH"_3"COCl"color(white)(m)"$100/L}$$\text{CH"_3"COBr"color(white)(m)"$300/L}$
$\text{CH"_3"COF"color(white)(mll)"$700/L}\$

Chemists like to choose the cheapest reactant that will do the job.

Hence, acetyl chloride is the reagent of choice.