Chapter 18- Reaction of Aromatics (Part I)

Question 1

Electrophilic Aromatic Substitution

Answer 1

The addition of a strong electrophile to a ring.

Question 2

Examples of Electrophilic Aromatic Substitution

Answer 2

-Halogenation
-Nitration
-Sulfonation
-Alkylation
-Acylation

Question 3

The three steps of Electrophilic Aromatic Substituion

Answer 3

Step 1: Formation of electrophile (E+), aka Super Electrophile.
Step 2: Attack on electrophile forms the sigma complex. This makes a C-E bond. (Slow step, high activation energy (Ea).
Step 3: Loss of a proton gives a substitution aromatic product. (Fast step).

Question 4

Reactants for Nitration

Answer 4

-Benzene ring
-HNO3
-H2SO4

Question 5

How do you make a nitronium ion? (Hint: Draw it out!)

Answer 5

Question 6

How is a nitro group reduced? What molecule is attached to the benzene ring now?

Answer 6

To reduce a nitro group use Zn, Sn or Fe in HCl and then use NaOH. This then forms an NH2 group on the benzene ring.

Question 7

What is an alternative to reducing a nitro group without the transition metals?

Answer 7

H2 and Pd/C or Pt (if you have money lol)

Question 8

What reactants are needed for the bromination of a benzene?

Answer 8

-Br2
-FeBr3 or AlBr3

Question 9

Provide the preliminary step of a bromination of a benzene. (Hint: Draw it out!)

Answer 9

Question 10

Can fluorination occur with benzene?

Answer 10

No, the reaction is too violent.

Question 11

Reactants of Iodination

Answer 11

-1/2 I2
-HNO3

Question 12

What are the reactants of Sulfonation?

Answer 12

-SO3 (Sulfur Trioxide)
-H2SO4

Question 13

Write out the mechanism and product for the following reaction:

Answer 13

Question 14

Write out the mechanism and product for the following reaction:

Answer 14

Question 15

What reactants are involved in desulfonation?

Answer 15

-Benzenesulfonic acid
-H2)
-H+
-Heat