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

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1:11 minutes

Problem 30b

Textbook Question

Show how Friedel–Crafts acylation might be used to synthesize the following compounds.
b. benzophenone

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 chloride (RCOCl) and a Lewis acid catalyst, typically aluminum chloride (AlCl₃). The reaction proceeds via electrophilic aromatic substitution.

Step 2: Identify the target compound, benzophenone. Benzophenone has two phenyl groups attached to a carbonyl group (C=O). This means one phenyl group will act as the aromatic ring undergoing acylation, while the other phenyl group will be part of the acyl group.

Step 3: Choose the appropriate acylating agent. To synthesize benzophenone, the acylating agent should be benzoyl chloride (C₆H₅COCl), which contains the phenyl group attached to the carbonyl group.

Step 4: Set up the reaction. Combine benzene (C₆H₆) as the aromatic substrate with benzoyl chloride (C₆H₅COCl) in the presence of a Lewis acid catalyst, such as AlCl₃. The AlCl₃ activates the benzoyl chloride by forming a complex, making the carbonyl carbon more electrophilic and susceptible to attack by the benzene ring.

Step 5: Complete the reaction mechanism. The benzene ring donates electrons to the electrophilic carbonyl carbon, forming a sigma complex. The AlCl₃ catalyst helps stabilize the intermediate, and a proton is lost to regenerate the aromaticity of the benzene ring. The final product is benzophenone (C₆H₅COC₆H₅).

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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. This method is valuable for synthesizing ketones from aromatic compounds.

Benzophenone Structure

Benzophenone is an organic compound characterized by two phenyl groups attached to a carbonyl group (C=O). Its structure can be represented as Ph-CO-Ph, where 'Ph' denotes a phenyl group. Understanding the structure of benzophenone is crucial for recognizing how Friedel–Crafts acylation can be applied to synthesize it from simpler aromatic precursors.

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a fundamental reaction mechanism in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. This process is essential for the synthesis of various aromatic compounds, including benzophenone. The stability of the aromatic system is maintained during the reaction, making EAS a key concept in understanding how acylation can modify aromatic compounds.

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