Experiment 10: Friedel-Crafts Alkylation Reactions - A Greener Alternative

1. Synthesize and purify p-xylene as an example of Friedel-Crafts alkylation reaction

2. Understand the mechanism of Friedel-Crafts Alkylation

3. Utilize greener alternatives to the catalysts used in the traditional Friedel-Craft Alkylation reaction

Objectives of the experiment

Charles Friedel and James Crafts

Two people who discovered the alkylation reaction

1877

Year the Friedel-Crafts was discovered

Instillation of alkyl and acyl substituents on an aromatic ring

What the set of reactions allow for

Electrophilic aromatic substitution-type mechanism

Mechanism of the alkylation reaction

Lewis acid catalyst

Facilitates the conversion of the alkyl halide electrophile into a reactive carbocation

Alkyl halide will not be sufficiently electrophilic to react with aromatic rings

What happens without the conversion to a carbocation

Graphite to catalyze the alkylation of p-xylene by an alkyl halide (2-chrolorbutane or 2-bromobutane)

Greener alternative used for the experiment

Aluminum chloride catalyst

Traditional catalyst

1. Graphite can be reused

2. Aluminum chloride reacts with water rapidly to produce hydrogen chloride fumes

3. Less solvent used

Advantages of using graphite as a catalyst

1. Round bottom flask

2. Reflux setup apparatus

3. 2-chlorobutane

4. Graphite

5. P-xylene

6. Ice

7. Funnel

8. Erlenmeyer flask

9. Five 10 mL graduated cylinder

10. 25 mL graduated cylinder

11. Boiling stones

Materials used for the experiment

Flammable

Hazard of p-xylene and 2-chlorobutane