Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 22: Problem 1

Write the stepwise mechanism for sulfonation of benzene by hot, concentrated sulfuric acid. In this reaction, the electrophile is \(\mathrm{SO}_{3}\) formed as shown in the following equation. $$ \mathrm{H}_{2} \mathrm{SO}_{4} \rightleftharpoons \mathrm{SO}_{3}+\mathrm{H}_{2} \mathrm{O} $$

Short Answer

Expert verified
Question: Briefly explain the three key steps involved in the sulfonation of benzene using hot, concentrated sulfuric acid. Answer: The sulfonation of benzene involves: 1. Formation of the electrophile, SO3, by allowing hot, concentrated sulfuric acid to reach equilibrium with water. 2. Electrophilic attack on the benzene ring by SO3, creating a resonance-stabilized arenium ion intermediate. 3. Proton loss from the arenium ion to restore aromaticity and form the final product, benzene sulfonic acid (C6H5SO3).

Step by step solution

01

Formation of SO3

To form SO3, we need to take hot, concentrated sulfuric acid (H2SO4) and allow it to reach equilibrium with water (H2O): \(\mathrm{H}_{2} \mathrm{SO}_{4} \rightleftharpoons \mathrm{SO}_{3}+\mathrm{H}_{2} \mathrm{O}\). In this reaction, SO3 is the electrophile that reacts with benzene.
02

Electrophilic attack on benzene

In this step, the electrophile (SO3) attacks the π cloud (double bond) of the benzene ring, creating a positive charge on the ring (forming a carbocation). This intermediate species is called an arenium ion, and it is resonance stabilized as the positive charge can be delocalized across the ring. Here's the reaction representation: \(\mathrm{C}_{6} \mathrm{H}_{6} + \mathrm{SO}_{3} \rightarrow [ \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{SO}_{3}]^{+}\)
03

Proton loss to restore aromaticity

In this final step, the arenium ion loses a proton (H+) to become a neutral molecule while retaining the SO3 group. The reaction would look like this: \([ \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{SO}_{3}]^{+} \rightarrow \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3} + \mathrm{H}^{+}\) By completing the proton loss step, the benzene aromaticity is restored. The final product is benzene sulfonic acid (C6H5SO3).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Phenol is the starting material for the synthesis of \(2,3,4,5,6\)-pentachlorophenol, known alternatively as pentachlorophenol or more simply as penta. At one time, penta was widely used as a wood preservative for decks, siding, and outdoor wood furniture. Draw the structural formula for pentachlorophenol, and describe its synthesis from phenol.

Propose a synthesis for the antihistamine \(p\)-methyldiphenhydramine, given this retrosynthetic analysis. Is \(p\)-methyldiphenhydramine chiral? If so, how many of the possible stereoisomers are formed in this synthesis?

Show how to prepare each compound from 1-phenyl-1-propanone. CCC(=O)c1ccccc1 (a) CC(Br)C(=O)c1ccccc1 (b) CCC(=O)c1cccc(Br)c1 1-Phenyl-1-propanone (racemic)

Following is a retrosynthetic analysis for the acaracide (killing mites and ticks) and fungicide dinocap. CC=CC(=O)Oc1c(C(C)C)cc([N+](=O)[O-])cc1[N+](=O)[O-] CC(C)c1cc([N+](=O)[O-])cc([N+](=O)[O-])c1O O=[N+]([O-])c1ccc(O)c([N+](=O)[O-])c1 Oc1ccccc1 Dinocap (a) Given this analysis, propose a synthesis for dinocap from phenol and l-octene. (b) Is dinocap chiral? If so, which of the possible stereoisomers are formed in this synthesis?

Write a mechanism for the formation of tert-butylbenzene from benzene and tert-butyl alcohol in the presence of phosphoric acid.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

Organic Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Inorganic Chemistry

Read Explanation

Nuclear Chemistry

Read Explanation

Kinetics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free