Textbook Question
Which of the following alcohols dehydrates the fastest when heated with acid?
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Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
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Bruice 8th EditionCh. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing CompoundsProblem 14(b)
Bruice 8th EditionCh. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing CompoundsProblem 14(b)Chapter 11, Problem 14(b)
What is the major product obtained when each of the following alcohols is heated in the presence of H2SO4?
b. 
Verified step by step guidance1
Step 1: Recognize the reaction type. Heating an alcohol in the presence of H2SO4 typically leads to an elimination reaction (E1 mechanism), resulting in the formation of an alkene. This occurs via dehydration, where water is removed from the alcohol.
Step 2: Identify the structure of the alcohol. The given alcohol is a secondary alcohol attached to a cyclopentane ring with a double bond present in the ring. Secondary alcohols undergo elimination reactions readily under acidic conditions.
Step 3: Protonation of the alcohol group. In the presence of H2SO4, the hydroxyl group (-OH) is protonated to form a better leaving group, water (H2O). This step increases the reactivity of the molecule.
Step 4: Formation of the carbocation intermediate. After the water molecule leaves, a carbocation is formed at the carbon where the hydroxyl group was attached. The stability of the carbocation is crucial in determining the major product. In this case, the carbocation is stabilized by the cyclopentane ring.
Step 5: Rearrangement and elimination. The carbocation undergoes elimination of a proton from a β-carbon (adjacent to the carbocation), leading to the formation of the most stable alkene. The major product will be determined by Zaitsev's rule, which states that the more substituted alkene is favored.
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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 common reaction in organic chemistry where an alcohol loses a water molecule, typically in the presence of an acid catalyst like sulfuric acid (H2SO4). This process often leads to the formation of alkenes or ethers, depending on the structure of the alcohol and the reaction conditions. Understanding this reaction is crucial for predicting the products formed when heating alcohols.
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Mechanism of Acid-Catalyzed Dehydration
The mechanism of acid-catalyzed dehydration involves protonation of the alcohol's hydroxyl group, making it a better leaving group. This is followed by the formation of a carbocation intermediate, which can rearrange to a more stable form if possible. Finally, a water molecule is eliminated, resulting in the formation of an alkene. Recognizing this mechanism helps in determining the major product based on the stability of the carbocation formed.
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Carbocation Stability
Carbocation stability is a key concept in organic chemistry that influences the outcome of reactions involving carbocations. Tertiary carbocations are more stable than secondary, which are more stable than primary due to hyperconjugation and inductive effects. In the context of dehydration reactions, the stability of the carbocation intermediate will dictate the major product formed, as more stable carbocations are favored in the reaction pathway.
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Related Practice
Textbook Question
Propose a mechanism for each of the following reactions:
a.
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Textbook Question
Show how 1-propanol can be converted into the following compounds by means of a sulfonate ester:
b.
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Textbook Question
Heating an alcohol with sulfuric acid is a good way to prepare a symmetrical ether such as diethyl ether.
b. How would you synthesize ethyl propyl ether?
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Textbook Question
Heating an alcohol with sulfuric acid is a good way to prepare a symmetrical ether such as diethyl ether.
a. Explain why it is not a good way to prepare an unsymmetrical ether such as ethyl propyl ether.
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Textbook Question
What is the major product obtained when each of the following alcohols is heated in the presence of H2SO4?
a.
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