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

Side-Chain Oxidation

Organic Chemistry

19. Reactions of Aromatics: EAS and Beyond

Side-Chain Oxidation

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Problem 48h

Textbook Question

Draw the product(s) of each of the following reactions:
h. m-xylene + Na₂Cr₂O₇ + HCl + ∆

Verified step by step guidance

Step 1: For reaction g (ethylbenzene + Br2/FeBr3), recognize that this is an electrophilic aromatic substitution reaction. The FeBr3 acts as a Lewis acid catalyst, helping to generate the bromonium ion (Br⁺) from Br2, which is the electrophile in this reaction.

Step 2: Identify the directing effects of the ethyl group on the benzene ring. The ethyl group is an electron-donating group, which activates the ring and directs substitution to the ortho and para positions relative to itself.

Step 3: Predict the major product of the reaction. Due to steric hindrance, the para position is typically favored over the ortho position. Draw the brominated product at the para position relative to the ethyl group, and optionally include the minor ortho product.

Step 4: For reaction h (m-xylene + Na2Cr2O7 + HCl + ∆), recognize that this is an oxidation reaction. Sodium dichromate (Na2Cr2O7) in acidic conditions (HCl) and heat (∆) is a strong oxidizing agent that converts benzylic positions (positions adjacent to the benzene ring) with at least one hydrogen into carboxylic acids.

Step 5: Analyze the structure of m-xylene. It has two methyl groups attached to the benzene ring in the meta positions. Each methyl group has benzylic hydrogens, so both will be oxidized to carboxylic acids. Draw the product, which is m-phthalic acid (benzene ring with two carboxylic acid groups in the meta positions).

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Key Concepts

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

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. In the case of ethylbenzene reacting with Br2 in the presence of FeBr3, the bromine acts as the electrophile, leading to the substitution of a hydrogen atom on the benzene ring, resulting in brominated products.

Oxidation of Aromatic Compounds

The oxidation of aromatic compounds involves the addition of oxygen or the removal of hydrogen, often resulting in the formation of carboxylic acids or ketones. In the reaction of m-xylene with Na2Cr2O7 and HCl, the m-xylene undergoes oxidation, which can lead to the formation of phthalic acid or other oxidized products, depending on the reaction conditions.

Reagents and Reaction Conditions

Understanding the role of reagents and reaction conditions is crucial in organic reactions. In the provided reactions, FeBr3 serves as a catalyst for the bromination of ethylbenzene, while Na2Cr2O7 is a strong oxidizing agent that facilitates the oxidation of m-xylene. The presence of HCl and heat (∆) further influences the reaction pathway and product formation.

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