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

9. Alkenes and Alkynes

Dehydration Reaction

Organic Chemistry

9. Alkenes and Alkynes

Dehydration Reaction

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2:58 minutes

Problem 44b

Textbook Question

Identify two different alcohols that can be dehydrated (one without rearrangement) to form the alkene shown.

Verified step by step guidance

Analyze the given alkene structure and identify the possible positions where the double bond is located. This will help determine the potential alcohol precursors.

Recall that alcohol dehydration involves the elimination of a water molecule, typically under acidic conditions, to form an alkene. The hydroxyl group (-OH) is removed along with a hydrogen atom from an adjacent carbon.

For the first alcohol (without rearrangement), identify a structure where the hydroxyl group is directly attached to one of the carbons involved in the double bond. Ensure that no carbocation rearrangement is necessary during the dehydration process.

For the second alcohol (with potential rearrangement), consider a structure where the hydroxyl group is attached to a carbon that, upon dehydration, could lead to a carbocation intermediate. This intermediate may rearrange to form a more stable carbocation before the double bond is formed.

Draw the structures of the two alcohols and verify that each can undergo dehydration to yield the given alkene. Ensure that the reaction mechanism aligns with the expected pathway (E1 or E2) for each case.

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Key Concepts

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

Dehydration of Alcohols

Dehydration of alcohols is a chemical reaction where an alcohol loses a water molecule, resulting in the formation of an alkene. This process typically requires an acid catalyst and can occur through either an E1 or E2 mechanism, depending on the structure of the alcohol. Understanding this reaction is crucial for identifying which alcohols can yield a specific alkene.

Rearrangement in Dehydration

Rearrangement refers to the structural change that can occur during the dehydration of alcohols, particularly in E1 mechanisms. This can lead to the formation of more stable carbocations, resulting in different alkene products. Recognizing when rearrangement occurs helps in selecting alcohols that will dehydrate without altering the desired product structure.

Types of Alcohols

Alcohols can be classified as primary, secondary, or tertiary based on the carbon atom to which the hydroxyl group (-OH) is attached. This classification affects their reactivity in dehydration reactions; for instance, tertiary alcohols typically dehydrate more readily than primary alcohols. Identifying the type of alcohol is essential for predicting the dehydration outcome and ensuring the correct alkene is formed.

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