Textbook Question
Show how the following compounds can be synthesized from benzene:
f. m-hydroxybenzoic acid
1962
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Ch. 18 - Reactions of Benzene and Substituted Benzenes
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
Chapter 19, Problem 55a
Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:
a. benzene, ethylbenzene, chlorobenzene, nitrobenzene, anisole
Verified step by step guidance1
Understand the concept of electrophilic aromatic substitution (EAS): This reaction involves the substitution of a hydrogen atom on an aromatic ring with an electrophile. The reactivity of the aromatic ring depends on the electronic effects of substituents already present on the ring, which can either activate or deactivate the ring toward EAS.
Classify the substituents on the aromatic rings: Substituents can be electron-donating groups (EDGs) or electron-withdrawing groups (EWGs). EDGs increase the electron density on the aromatic ring, making it more reactive toward electrophiles, while EWGs decrease the electron density, making the ring less reactive.
Analyze the substituents in the given compounds:
- Benzene: No substituents, so it is the baseline for reactivity.
- Ethylbenzene: The ethyl group is an EDG due to its inductive effect, slightly activating the ring.
- Chlorobenzene: The chlorine atom is an EWG due to its inductive effect, but it also has a resonance effect that slightly activates the ring.
- Nitrobenzene: The nitro group is a strong EWG, significantly deactivating the ring.
- Anisole: The methoxy group (-OCH₃) is a strong EDG due to its resonance effect, highly activating the ring.
Rank the compounds based on their reactivity: The order of reactivity is determined by the net effect of the substituents. Strong EDGs (anisole) will make the ring most reactive, followed by weaker EDGs (ethylbenzene). Benzene, with no substituents, is the baseline. Weak EWGs (chlorobenzene) will deactivate the ring slightly, and strong EWGs (nitrobenzene) will make the ring least reactive.
Final ranking from most reactive to least reactive: anisole > ethylbenzene > benzene > chlorobenzene > nitrobenzene. This ranking is based on the electronic effects of the substituents and their influence on the aromatic ring's reactivity toward electrophilic aromatic substitution.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilic Aromatic Substitution (EAS)
Electrophilic Aromatic Substitution is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. The reactivity of the aromatic compound is influenced by the nature of substituents already present on the ring, which can either activate or deactivate the ring towards further substitution.
Recommended video:
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03:07
EAS Review
Activating and Deactivating Groups
Substituents on an aromatic ring can be classified as activating or deactivating based on their electronic effects. Activating groups, such as -OH or -OCH3, increase the electron density of the ring, making it more reactive towards electrophiles. In contrast, deactivating groups, like -NO2 or -Cl, withdraw electron density, reducing reactivity.
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03:27Activating and deactivating groups
Resonance and Inductive Effects
Resonance and inductive effects are key to understanding how substituents influence the reactivity of aromatic compounds. Resonance involves the delocalization of electrons across the aromatic system, while inductive effects refer to the electron-withdrawing or donating ability of substituents through sigma bonds. These effects determine the stability of the carbocation intermediate formed during EAS.
Recommended video:
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01:47Understanding the Inductive Effect.
Related Practice
Textbook Question
Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:
b. 1-chloro-2,4-dinitrobenzene, 2,4-dinitrophenol, 1-methyl-2,4-dinitrobenzene
1219
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Textbook Question
Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:
e. p-methylnitrobenzene, 2-chloro-1-methyl-4-nitrobenzene, 1-methyl-2,4-dinitrobenzene, p-chloromethylbenzene
1236
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Textbook Question
For each horizontal row of substituted benzenes, indicate
c. the one that yields the highest percentage of meta product in an electrophilic aromatic substitution reaction.
3.
609
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Textbook Question
Show how the following compounds can be synthesized from benzene:
b. m-chloroethylbenzene
1801
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Textbook Question
Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:
f. bromobenzene, chlorobenzene, fluorobenzene, iodobenzene
1388
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