EAS reactions

Question 1

Mechanism in EAS:

1. electrophile reagent + catalyst
2. The more reactive electrophile attacks aromatic ring – formation of sigma complex or stabilized carbocation
3. Loss of proton – regeneration of pi bonds and aromatic ring

Answer 1

Mechanism in EAS:

1. electrophile reagent + catalyst
2. The more reactive electrophile ATTACKED BY aromatic ring – formation of sigma complex or stabilized carbocation
3. Loss of proton – regeneration of pi bonds and aromatic ring

Question 2

Mechanism in EAS:

1. electrophile reagent + catalyst
2. The more reactive electrophile attacks aromatic ring – formation of sigma complex or stabilized carbocation
3. Loss of proton – regeneration of pi bonds and aromatic ring

Answer 2

Mechanism in EAS:

1. electrophile reagent + catalyst
2. The more reactive electrophile ATTACKED BY aromatic ring – formation of sigma complex or stabilized carbocation
3. Loss of proton – regeneration of pi bonds and aromatic ring

Question 3

What are the EAS reaction?

Answer 3

-Halogenation: Bomination, Chlorination, Iodination
-Nitration
-Sulfonation
-Freidel Crafts: Alkylation
-Freidel Crafts:
Acylation

Question 4

Bromination:

• Electrophilic reagent
• Catalyst
• product

Answer 4

Br2
FeBr3
Bromobenzene

Question 5

Chlorination:

• Electrophilic reagent
• Catalyst
• product

Answer 5

Cl2
FeCL3
Chlorobenzene

Question 6

Iodonation:

• Electrophilic reagent
• Catalyst
• product

Answer 6

I2 /oxidation w HNO3 catalyst = I+

Iodobenzene

Question 7

Nitration:

• Electrophilic reagent
• Catalyst
• product

Answer 7

E reagent prepared by sulfuric acid H2SO4 w/ nitric acid HNO3 to form the Ereagent nitronium ion electrophile.

Product: Nitrobenzene

Question 8

Formation of Aminobenze

Answer 8

Reaction with Zn, tin Sn, or Fe in dilute acid like HCl forms amino benzene

Question 9

Sulfonation:

• Electrophilic reagent
• Catalyst
• product

Answer 9

SO3
H2SO4
Benzenesulofnic acid

Question 10

Friedel–Crafts Alkylation:

• Electrophilic reagent
• Catalyst
• product

Answer 10

Alkyl halide (C-X)
AlCl3 lewis acid which produces the carbocation = electrophile

Product depend on the alkyl halide

Question 11

Friedel–Crafts Acylation:

• Electrophilic reagent
• Catalyst
• product

Answer 11

Carbocation from C-X + Lewis acid = Acylium ion (RC--O)
AlCl3
Phenyl Ketone (RCR)

Question 12

Alkylation by Protonation of Alkenes

Alkene is protonated by?

Answer 12

HF, hydroflouride. Weak nucleophile and will not react to the carbocation.

Question 13

Protonation of Alcohol

Catalyst?
Product

Answer 13

H2SO4 = Electrophile used is carbocation CH3CH2 protonated C

Ethylbenzene

Question 14

What are the EAS reaction?

Answer 14

-Halogenation: Bomination, Chlorination, Iodination
-Nitration
-Sulfonation
-Freidel Crafts: Alkylation
-Freidel Crafts:
Acylation

Question 15

Bromination:

• Electrophilic reagent
• Catalyst
• product

Answer 15

Br2
FeBr3
Bromobenzene

Question 16

Chlorination:

• Electrophilic reagent
• Catalyst
• product

Answer 16

Cl2
FeCL3
Chlorobenzene

Question 17

Iodonation:

• Electrophilic reagent
• Catalyst
• product

Answer 17

I2 /oxidation w HNO3 catalyst = I+

Iodobenzene

Question 18

Nitration:

• Electrophilic reagent
• Catalyst
• product

Answer 18

E reagent prepared by sulfuric acid H2SO4 w/ nitric acid HNO3 to form the Ereagent nitronium ion electrophile.

Product: Nitrobenzene

Question 19

Formation of Aminobenze

Answer 19

Reaction with Zn, tin Sn, or Fe in dilute acid like HCl forms amino benzene

Question 20

Sulfonation:

• Electrophilic reagent
• Catalyst
• product

Answer 20

SO3
H2SO4
Benzenesulofnic acid

Question 21

Halogens: Activating or Deactivating? What is the orientation?

Answer 21

Deactivating but the orientation ortho and para.

Question 22

Friedel–Crafts Acylation:

• Electrophilic reagent
• Catalyst
• product

Answer 22

Carbocation from C-X + Lewis acid = Acylium ion (RC--O)
AlCl3
Phenyl Ketone (RCR)

Question 23

Alkylation by Protonation of Alkenes

Alkene is protonated by?

Answer 23

HF, hydroflouride. Weak nucleophile and will not react to the carbocation.

Question 24

Protonation of Alcohol

Catalyst?
Product

Answer 24

H2SO4 = Electrophile used is carbocation CH3CH2 protonated C

Ethylbenzene

Question 25

Limitations of Friedel–Crafts Reaction fails if benzene has a substituent that is less deactivating than halogens

Answer 25

False. | Reaction fails if benzene has a substituent that is MORE deactivating than halogens.

Question 26

Limitations of Friedel–Crafts Rearrangement causes Mixture of products

Answer 26

True. Formation of carbocation due to lone pairs. Results to low yield of monosubti benzene

Question 27

Effect of substituents on EAS reactions

Answer 27

Reactivity (act or deact) and direction of Orientation (o, m, p) of the electrophilic attack.

Question 28

Orientations

Answer 28

Ortho - 1,2 Meta - 1, 3 Para - 1, 4

Question 29

What is activating group?

Answer 29

Donating E, has high reactivity. Has Ortho and Para direction

Question 30

Alkyl groups stabilize sigma complex by resonance.

Answer 30

False. by INDUCTION. | Donates electron density through sigma bond.

Question 31

Lone pair of e- stabilize sigma complex by resonsance.

Answer 31

True.

Question 32

What is deactivating group?

Answer 32

Has low reactivity. Directs to meta position. It deactivates all positions on the ring but less in the meta position.

Question 33

For multiple substituents. Reaction is where?

Answer 33

In the position of the strongest activating substituent. Product could be mixtures.