Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

19. Reactions of Aromatics: EAS and Beyond

EAS:Friedel-Crafts Acylation Mechanism

Organic Chemistry

19. Reactions of Aromatics: EAS and Beyond

EAS:Friedel-Crafts Acylation Mechanism

Previous problemNext problem

2:14 minutes

Problem 30c

Textbook Question

Show how Friedel–Crafts acylation might be used to synthesize the following compounds.
c. n-butylbenzene

Verified step by step guidance

Step 1: Understand the Friedel–Crafts acylation reaction. This reaction involves the introduction of an acyl group (RCO-) into an aromatic ring using an acyl halide (RCOCl) and a Lewis acid catalyst, such as AlCl₃. The product is an aromatic ketone.

Step 2: Identify the target compound, n-butylbenzene. This compound consists of a benzene ring attached to a straight-chain butyl group (CH₂CH₂CH₂CH₃). Note that Friedel–Crafts acylation cannot directly introduce an alkyl group, but it can introduce an acyl group, which can later be reduced to an alkyl group.

Step 3: Choose the appropriate acyl halide for the reaction. To synthesize n-butylbenzene, you need to introduce a butanoyl group (CH₃CH₂CH₂CO-) onto the benzene ring. The acyl halide to use is butanoyl chloride (CH₃CH₂CH₂COCl).

Step 4: Perform the Friedel–Crafts acylation. React benzene with butanoyl chloride in the presence of a Lewis acid catalyst, such as AlCl₃. This will yield butanophenone (C₆H₅COCH₂CH₂CH₃), an aromatic ketone.

Step 5: Reduce the ketone to an alkyl group. Use a reducing agent such as zinc amalgam (Zn/Hg) in concentrated HCl (Clemmensen reduction) or hydrazine (NH₂NH₂) with a base (Wolff–Kishner reduction) to convert the butanophenone into n-butylbenzene (C₆H₅CH₂CH₂CH₂CH₃).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Friedel–Crafts Acylation

Friedel–Crafts acylation is an electrophilic aromatic substitution reaction that introduces an acyl group into an aromatic ring. This reaction typically involves the use of an acyl chloride and a Lewis acid catalyst, such as aluminum chloride, to generate the acylium ion, which then reacts with the aromatic compound. The result is a ketone that retains the aromatic character of the starting material.

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. The aromatic system's stability allows it to undergo substitution rather than addition, preserving its aromaticity. Understanding the mechanism of EAS is crucial for predicting the outcomes of reactions involving aromatic compounds, such as the Friedel–Crafts acylation.

n-Butylbenzene

n-Butylbenzene is an aromatic compound consisting of a benzene ring substituted with a butyl group. The presence of the butyl group influences the reactivity and orientation of further substitutions on the aromatic ring. In the context of Friedel–Crafts acylation, the n-butyl group can direct the acylation to specific positions on the benzene ring, affecting the final product's structure and properties.

Watch next

Master Friedel-Crafts Acylation with a bite sized video explanation from Johnny

Start learning