Textbook Question
Which compound has the greatest rate of hydrolysis at pH = 3.5: benzamide, o-carboxybenzamide, o-formylbenzamide, or o-hydroxybenzamide?
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Ch. 22 - Catalysis in Organic Reactions and in Enzymatic 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. 22 - Catalysis in Organic Reactions and in Enzymatic ReactionsProblem 32b
Bruice 8th EditionCh. 22 - Catalysis in Organic Reactions and in Enzymatic ReactionsProblem 32bChapter 23, Problem 32b
Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:
b. 
Verified step by step guidance1
Step 1: Analyze the reaction sequence provided in the image. The slow step involves the cleavage of the ester bond in the molecule, resulting in the formation of two products: a carboxylic acid and a phenol.
Step 2: Identify the type of catalysis occurring in the slow step. The presence of hydroxyl groups (OH) and the protonated intermediate suggests that acid catalysis is involved. Acid catalysis typically facilitates bond cleavage by protonating the ester oxygen, making it more electrophilic and susceptible to nucleophilic attack.
Step 3: Recognize the role of the catalyst in the reaction. In acid catalysis, the acid donates a proton to stabilize the transition state and lower the activation energy of the reaction, thereby accelerating the bond cleavage process.
Step 4: Observe the intermediate formed during the slow step. The protonated carboxylic acid intermediate indicates that the reaction mechanism involves proton transfer, which is characteristic of acid catalysis.
Step 5: Conclude that the slow step in this reaction sequence is an example of acid catalysis, as the reaction mechanism relies on protonation to facilitate the cleavage of the ester bond.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Catalysis
Catalysis refers to the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst. Catalysts work by providing an alternative reaction pathway with a lower activation energy, allowing the reaction to proceed more quickly. In organic chemistry, catalysts can be either homogeneous (in the same phase as the reactants) or heterogeneous (in a different phase). Understanding the type of catalysis involved is crucial for analyzing reaction mechanisms.
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Nucleophilic Catalysis Concept 1
Rate-Determining Step
The rate-determining step (RDS) is the slowest step in a reaction mechanism that determines the overall rate of the reaction. It is crucial to identify the RDS because it often involves the highest energy transition state and dictates the kinetics of the entire reaction sequence. In the context of the provided reaction, recognizing which step is slow helps in understanding the type of catalysis and the factors influencing the reaction rate.
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Acid-Base Catalysis
Acid-base catalysis involves the acceleration of a reaction through the transfer of protons (H+) or the acceptance of protons by a base. In organic reactions, this can involve the protonation of a reactant to make it more reactive or the deprotonation of a product to stabilize it. The presence of hydroxyl groups in the reaction sequence suggests that acid-base catalysis may be occurring, particularly in the slow step, where proton transfers can significantly influence the reaction pathway.
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Related Practice
Textbook Question
Which compound forms an anhydride more rapidly?
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Textbook Question
Co2+ catalyzes the hydrolysis of the lactam shown here. Propose a mechanism for the metal-ion catalyzed reaction.
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Textbook Question
The rate constant for the uncatalyzed reaction of two molecules of glycine ethyl ester to form glycylglycine ethyl ester is 0.6 M-1 s-1. In the presence of Co2+, the rate constant is 1.5 × 106 M-1 s-1. What rate enhancement does the catalyst provide?
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Textbook Question
The deuterium kinetic isotope effect (kH2O/kD2O) for the hydrolysis of aspirin is 2.2. What does this tell you about the kind of catalysis exerted by the ortho-carboxyl substituent? (Hint: It is easier to break an O–H bond than an O–D bond.)
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Textbook Question
Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:
a.
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