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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3:20 minutes

Problem 48c

Textbook Question

Draw the product(s) of each of the following reactions:
c. p-xylene + acetyl chloride + AlCl₃ followed by H₂O

Verified step by step guidance

Step 1: For part (c), recognize that the reaction involves Friedel-Crafts acylation. This reaction uses acetyl chloride (CH3COCl) and AlCl3 as a Lewis acid catalyst to introduce an acyl group (-COCH3) onto an aromatic ring. p-Xylene (1,4-dimethylbenzene) is the aromatic compound in this case.

Step 2: Identify the positions on the aromatic ring where substitution is likely to occur. The methyl groups on p-xylene are electron-donating groups, which activate the aromatic ring and direct substitution to the ortho and para positions relative to themselves. Since the para position is already occupied, the acyl group will be introduced at one of the ortho positions relative to a methyl group.

Step 3: Write the intermediate formed after the acylation step. The acyl group attaches to one of the ortho positions, and the AlCl3 catalyst temporarily forms a complex with the aromatic ring. After hydrolysis (H2O step), the catalyst is regenerated, and the final product is obtained.

Step 4: For part (d), recognize that the reaction involves electrophilic aromatic substitution between o-methylaniline (an aromatic amine with a methyl group ortho to the amino group) and benzenediazonium chloride (C6H5N2+Cl−). This is an example of an azo coupling reaction, which forms an azo compound (-N=N-).

Step 5: Determine the site of coupling on o-methylaniline. The amino group (-NH2) is an electron-donating group, activating the aromatic ring and directing substitution to the ortho and para positions relative to itself. Since the ortho position is already occupied by a methyl group, the coupling occurs at the para position. The product is an azo compound where the diazonium group (-N=N-) is attached to the para position of o-methylaniline.

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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 a reaction that introduces an acyl group into an aromatic ring using an acyl chloride and a Lewis acid catalyst, such as AlCl3. In this process, the aromatic compound (like p-xylene) reacts with the acyl chloride to form a ketone, which retains the aromaticity of the ring. The reaction is important for synthesizing aromatic ketones and understanding electrophilic aromatic substitution.

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 preserves the aromaticity of the compound and is crucial for modifying aromatic systems. The nature of the substituents on the ring can influence the reactivity and orientation of the substitution, making it essential to consider when predicting products.

Diazonium Salts

Diazonium salts are highly reactive intermediates formed from primary aromatic amines and nitrous acid. They are key in various coupling reactions, particularly in the synthesis of azo compounds. In the presence of nucleophiles, such as phenols or other aromatic compounds, diazonium salts can undergo electrophilic substitution, leading to the formation of colored azo dyes, which are significant in both organic synthesis and industrial applications.

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