Textbook Question
What is the major product obtained from the acid-catalyzed hydration of each of the following alkenes?
a. CH3CH2CH2CH=CH2
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Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions
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. 6 - The Reactions of Alkenes • The Stereochemistry of Addition ReactionsProblem 10a,b,c
Bruice 8th EditionCh. 6 - The Reactions of Alkenes • The Stereochemistry of Addition ReactionsProblem 10a,b,cChapter 7, Problem 10a,b,c
Answer the following questions about the mechanism for the acid-catalyzed hydration of an alkene:
a. How many transition states are there?
b. How many intermediates are there?
c. Which step in the forward direction has the smallest rate constant?
Verified step by step guidance1
Step 1: Understand the reaction mechanism. The acid-catalyzed hydration of an alkene involves three main steps: (1) protonation of the alkene to form a carbocation intermediate, (2) nucleophilic attack by water on the carbocation, and (3) deprotonation of the oxonium ion to form the alcohol product. Each step may involve a transition state and/or an intermediate.
Step 2: Analyze the number of transition states. A transition state occurs at the highest energy point between two steps in a reaction. For this mechanism, there is a transition state for each of the three steps: (1) the protonation of the alkene, (2) the nucleophilic attack by water, and (3) the deprotonation of the oxonium ion. Therefore, there are three transition states.
Step 3: Determine the number of intermediates. An intermediate is a species that is formed during the reaction but is not the final product. In this mechanism, the carbocation formed after the protonation of the alkene and the oxonium ion formed after the nucleophilic attack by water are intermediates. Therefore, there are two intermediates.
Step 4: Identify the step with the smallest rate constant. The rate-determining step (RDS) is the slowest step in the reaction mechanism and has the smallest rate constant. In acid-catalyzed hydration, the formation of the carbocation (Step 1) is typically the slowest step because it involves breaking the π bond and forming a high-energy carbocation intermediate. This step has the smallest rate constant.
Step 5: Summarize the findings. There are three transition states, two intermediates, and the rate-determining step is the protonation of the alkene to form the carbocation, which has the smallest rate constant.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acid-Catalyzed Hydration Mechanism
The acid-catalyzed hydration of alkenes involves the addition of water across the double bond of an alkene in the presence of an acid. This process typically follows a Markovnikov addition pattern, where the hydrogen from the acid adds to the less substituted carbon, leading to the formation of a more stable carbocation intermediate. Understanding this mechanism is crucial for analyzing the number of transition states and intermediates involved.
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Acid-catalyzed hydration mechanism
Transition States and Intermediates
In a chemical reaction, a transition state represents a high-energy state during the conversion of reactants to products, while intermediates are stable species formed during the reaction pathway. In the acid-catalyzed hydration of alkenes, identifying the number of transition states and intermediates helps in understanding the reaction's kinetics and mechanism, as each transition state corresponds to a step in the reaction pathway.
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Rate Constants and Reaction Steps
The rate constant is a measure of the speed of a reaction step and is influenced by factors such as activation energy and temperature. In the context of the acid-catalyzed hydration of alkenes, determining which step has the smallest rate constant is essential for identifying the rate-determining step, which is the slowest step that controls the overall reaction rate. This understanding is key to predicting the reaction's behavior and efficiency.
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Related Practice
Textbook Question
What is the major product obtained from the acid-catalyzed hydration of each of the following alkenes?
d.
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Textbook Question
What alkene should be used to synthesize each of the following alkyl bromides?
c.
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Textbook Question
What is the major product of each of the following reactions?
3.
4.
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Textbook Question
The pKa of a protonated alcohol is about -2.5, and the pKa of an alcohol is about 15. Therefore, as long as the pH of the solution is greater than _______ and less than _______, more than 50% of 2-propanol (the product of the reaction on p. 244) will be in its neutral, nonprotonated form.
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Textbook Question
What alkene should be used to synthesize each of the following alkyl bromides?
d.
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