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

13. Alcohols and Carbonyl Compounds

Oxidizing Agent

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Oxidizing Agent

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1:31 minutes

Problem 11e

Textbook Question

Show how you would synthesize the following carboxylic acids, using the indicated starting materials.
(e) p-xylene → terephthalic acid

Verified step by step guidance

Step 1: Recognize the structure of p-xylene. p-Xylene is a benzene ring with two methyl groups attached at the para positions (1,4-positions). The target molecule, terephthalic acid, is a benzene ring with two carboxylic acid groups at the para positions.

Step 2: Plan the oxidation of the methyl groups. To convert the methyl groups into carboxylic acid groups, you can use a strong oxidizing agent such as potassium permanganate (KMnO₄) or chromic acid (H₂CrO₄). These reagents are effective at oxidizing alkyl side chains on aromatic rings to carboxylic acids.

Step 3: Write the reaction conditions. Treat p-xylene with an aqueous solution of KMnO₄ under heat. The reaction proceeds through the oxidation of each methyl group (-CH₃) to a carboxylic acid group (-COOH). Ensure the reaction is carried out under acidic or neutral conditions to facilitate the oxidation.

Step 4: Consider the mechanism. The oxidation involves the formation of intermediate species such as benzyl alcohol and benzaldehyde, which are further oxidized to the carboxylic acid. However, under the strong oxidizing conditions, the reaction proceeds directly to the carboxylic acid stage.

Step 5: Verify the product. After the reaction, terephthalic acid (benzene-1,4-dicarboxylic acid) is formed. The two carboxylic acid groups are located at the para positions, confirming the successful synthesis from p-xylene.

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Key Concepts

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

Carboxylic Acid Synthesis

Carboxylic acids can be synthesized through various methods, including oxidation of alcohols, carbonylation of alkenes, and the Kolbe electrolysis. Understanding these pathways is crucial for determining how to convert starting materials into the desired carboxylic acid. In this case, the transformation of p-xylene to terephthalic acid involves specific reactions that introduce carboxyl groups to the aromatic ring.

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. This concept is essential for understanding how functional groups can be introduced to aromatic compounds like p-xylene. The reaction conditions and the nature of the electrophile significantly influence the position and efficiency of substitution, which is key in synthesizing terephthalic acid.

Oxidation Reactions

Oxidation reactions involve the loss of electrons or an increase in oxidation state, often resulting in the formation of carboxylic acids from hydrocarbons. In the synthesis of terephthalic acid from p-xylene, oxidation is a critical step that converts the methyl groups on the aromatic ring into carboxylic acid groups. Understanding the types of oxidizing agents and their mechanisms is vital for successfully carrying out this transformation.

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