The salt formed acts as a deactivating group and hence the electrophilic substitution cannot happen. Hence, aniline does not undergo Friedel — Crafts reaction. Skip to content Lifehacks. May 2, Joe Ford. Table of Contents. Benzenesulfonic acids are also used in the synthesis of detergents, dyes, and sulfa drugs. Bezenesulfonyl Chloride is a precursor to sulfonamides, which are used in chemotherapy. Draw an energy diagram for the nitration of benzene.
Draw the intermediates, starting materials, and products. Label the transition states. For questions 1 and 2 see Electrophilic Aromatic Substitution for hints. Sulfuric acid is needed in order for a good electrophile to form. Sulfuric acid protonates nitric acid to form the nitronium ion water molecule is lost. The nitronium ion is a very good electrophile and is open to attack by benzene. Without sulfuric acid the reaction would not occur. Nitration of Benzene The source of the nitronium ion is through the protonation of nitric acid by sulfuric acid, which causes the loss of a water molecule and formation of a nitronium ion.
Sulfuric Acid Activation of Nitric Acid The first step in the nitration of benzene is to activate HNO 3 with sulfuric acid to produce a stronger electrophile, the nitronium ion. Mechanism Resonance forms of the intermediate can be seen in the generalized electrophilic aromatic substitution. Sulfonation of Benzene Sulfonation is a reversible reaction that produces benzenesulfonic acid by adding sulfur trioxide and fuming sulfuric acid.
Mechanism To produce benzenesulfonic acid from benzene, fuming sulfuric acid and sulfur trioxide are added. Reverse Sulfonation Sulfonation of benzene is a reversible reaction.
Further Applications of Nitration and Sulfonation Nitration is used to add nitrogen to a benzene ring, which can be used further in substitution reactions. On the other hand any procedure which requires acid will protonate the amine, resulting in an ammonium group.
What might be the major product in case of chlorination? Actually I had thought that Cl would go ortho to amino group, but one of our Chemistry faculties at school insists that Cl should go ortho to CH3 group, ie meta to NH2 in order to avoid steric repulsion with amino group… which would, in his opinion, decrease the resonance energy of the benzene ring, by sending NH2 out of the ring, ie.
Please help! This is incorrect. The repulsion difference between the amino and nitro group is marginal, so the electronic effects are predominant here and amino-group is a way stronger activating EDG than a methyl, so the substitution will go ortho to amine. Hate it with passion! I really appreciate you adding the comment, however! I really appreciate for what you are doing. Regarding this post, I just need the link of your next post where you have talked about one more case of Ipso Substitution other with SO3H.
Yes, protonated SO3 is the electrophile. Acids and Lewis acids tend to make electrophiles even more electrophilic. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Notify me via e-mail if anyone answers my comment.
This site uses Akismet to reduce spam. Learn how your comment data is processed. Advanced References and Further Reading 1. Recap: The Three Stages Of Electrophilic Aromatic Substitution Reactions In the previous post on halogenation via electrophilic aromatic substitution , we saw that this electrophilic aromatic substitution reaction proceeded in three distinct stages: Activation.
The activated electrophile is attacked by the aromatic ring, resulting in a carbocation intermediate this is the rate determining step, and Step 1 in the generic mechanism of electrophilic aromatic substitution.
The carbocation intermediate is deprotonated by a weak base, restoring aromaticity Step 2 in the generic mechanism of electrophilic aromatic substitution. Nitration of Benzene In contrast to nitration of alcohols, the nitration of benzene produces relatively stable nitro compounds that are much more difficult to detonate. Click to see an image of the mechanism ] 4.
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