Anhydrous aluminium chloride (AlCl3) is a white solid that is an important Lewis acid catalyst. It is commonly used to catalyze Friedel-Crafts reactions and can introduce aldehyde groups or catalyze ene reactions. AlCl3 also catalyzes the addition of bromine to ketones in ether solvent to give 100% yields of bromoketones.

1. 7. Anhydrous aluminium chloride
Dr. Shivendra Singh
UGC-NET-JRF, PhD- IIT Indore
Assistant Professor
shivendrasngh0@gmail.com
Webpage: https://sites.google.com/view/drshivendrasingh/home
Youtube: https://bit.ly/2YM0QG0

2. 2
…Anhydrous aluminium chloride
Ø AlCl3, also known as aluminium trichloride, is a compounds with the
formula AlCl3(H2O)n (n = 0 or 6). Both are white solids, but samples are
often contaminated with iron(III) chloride, giving a yellow color.
Ø The anhydrous material is important commercially. It has a low melting
and boiling point. It is mainly produced and consumed in the production
of aluminium metal, but large amounts are also used in other areas of the
chemical industry.
Ø The compound is a Lewis acid.

3. 3
1. AlCl3 is a common used Lewis acid catalyst for Friedel-Crafts reactions, both
acylations and alkylations. In the general Friedel–Crafts reaction, an acyl chloride or
alkyl halide reacts with an aromatic system as shown;
…Anh AlCl3: Applications
Jonathan Clayden (University of Manchester), Nick Greeves (University of Liverpool), Stuart Warren (University of Cambridge); Organic
Chemistry, 2nd edition.

4. …Anh AlCl3: Applications
Jonathan Clayden (University of Manchester), Nick Greeves (University of Liverpool), Stuart Warren (University of Cambridge); Organic
Chemistry, 2nd edition.

5. …Anh AlCl3: Applications
Jonathan Clayden (University of Manchester), Nick Greeves (University of Liverpool), Stuart Warren (University of Cambridge); Organic
Chemistry, 2nd edition.

6. 6
2. Aluminium chloride can also be used to introduce aldehyde groups onto aromatic
rings, for example via the Gattermann-Koch reaction which uses carbon monoxide,
hydrogen chloride and a copper(I) chloride co-catalyst
…Anh AlCl3: Applications

7. The Gattermann reaction (Gattermann
formylation) is a chemical reaction in which
aromatic compounds are formylated by a mixture
of hydrogen cyanide (HCN) and hydrogen
chloride (HCl) in the presence of a Lewis acid
catalyst such as AlCl3. It is named for the German
chemist Ludwig Gattermann and is similar to the
Friedel-Crafts reaction.
The Gattermann-Koch reaction, named after
the German chemists Ludwig Gattermann
and Julius Arnold Koch, is a variant of the
Gattermann reaction in which carbon
monoxide (CO) is used instead of hydrogen
cyanide.
…Anh AlCl3: Applications
https://en.wikipedia.org

8. 8
3. Aluminium chloride finds a wide variety of other applications in organic
chemistry. For example, it can catalyse the "ene reaction", such as the
addition of 3-buten-2-one (methyl vinyl ketone) to carvone
…Anh AlCl3: Applications

9. …Anh AlCl3: Applications
The ene reaction (also known as Alder-ene reaction by its discoverer Kurt Alder in
1943) is a chemical reaction between an alkene with an allylic hydrogen (the ene) and a
compound containing a multiple bond (the enophile), in order to form a new σ-bond
with migration of the ene double bond and 1,5 hydrogen shift. The product is a
substituted alkene with the double bond shifted to the allylic position.
https://en.wikipedia.org

10. …Anh AlCl3: Applications
Ø Can be catalyzed by Lewis acids to increase electrophilicity of enophile.
Ø Intramolecular ene reaction.

11. 11
…Anh AlCl3: Applications
4. An unsymmetrical ketone gives 100% yield of the bromoketone with
catalytic AlCl3 in ether as solvent.
Jonathan Clayden (University of Manchester), Nick Greeves (University of Liverpool), Stuart Warren (University of Cambridge); Organic
Chemistry, 2nd edition.

12. 12
…Anh AlCl3: Applications
Jonathan Clayden (University of Manchester), Nick Greeves (University of Liverpool), Stuart Warren (University of Cambridge); Organic
Chemistry, 2nd edition.