Question

Alcl3 and acetyl chloride experimental reaction

Answer 1

Experiment 1: Friedel-Crafts Acylation
Background:
Goals: a) work with water-sensitive reagents; b) design experimental procedure and work-up;
and c) to assess the procedural design.
Electrophilic aromatic substitution reactions take place between the nucleophilic π electrons of
an aromatic ring and a strong electrophile. The intermediate carbocation rapidly loses H+ to
reform the aromatic system. In the case of Friedel-Crafts acylation, the electrophile is an
acylium ion, formed by the reaction of an acid chloride with aluminum chloride. The
mechanism is shown in Figure 1.
H3C
O
Cl
Al
Cl
Cl
Cl
H3C C O+ H3C C+ + O + AlCl4
-
CH3
C
O+
C+
(1)
(2)
(3)
H
O
CH3
H
C+
H
O
CH3
H
Cl
Cl Al
Cl
Cl
-
O
CH3
+ HCl + AlCl3
Figure 1: Mechanism for Friedel-Crafts Acylation
You will be assigned either toluene (methylbenzene), ethylbenzene, or anisole (methoxybenzene)
to acylate. The reaction is one that comes out of your organic chemistry textbook, so no
procedure is available. What variables should you consider when planning your reaction?