Aromatics

Question 1

Aromaticity

Answer 1

What makes a system aromatic or not aromatic.

Question 2

4 conditions of Aromaticity

Answer 2

1. Cyclic
2. Each carbon is sp2
3. Continuous loop of p-orbitals
4. Hachel’s Rule satisfied

Question 3

Hachel’s Rule

Answer 3

of e- in p-loop = 4n+2 or # of π e- = 4n + 2

Question 4

Parent name for simple compounds

Answer 4

Benzene

Question 5

Nitro

Answer 5

NO2

Question 6

NH2 attached to benzene

Answer 6

Aniline

Question 7

isopropyl attached to benzene

Answer 7

Cumene

Question 8

ethene attached to benzene

Answer 8

Styrene

Question 9

OH attached to benzene

Answer 9

Phenol

Question 10

Carbonyl attached to benzene

Answer 10

Benzaldehyde

Question 11

Carboxylic acid attached to benzene

Answer 11

Benzoic Acid

Question 12

Ether attached to Benzene

Answer 12

Anisole

Question 13

Ketone attached to Benzene

Answer 13

Acetophenone

Question 14

Dimethylbenzene

Answer 14

Zylene

Question 15

Electrophilic Aromatic Substitution, why does it include the word “substitution”?

Answer 15

Hydrogen is being substituted for electrophile.

Question 16

Electrophilic Aromatic Substitution Requirements

Answer 16

Strong Electrophile, Look at resonance (at least 3)

Question 17

Is the carbocation intermediate of the electrophilic aromatic substitution stable? Why?

Answer 17

It is stable, because it is resonance stabilized.

Question 18

Steps of Electrophilic Aromatic Substitution

Answer 18

1. Formation of Electrophile
2. Formation of Arenium Ion
3. Regeneration of Aromatic Ring

Question 19

halogens don’t like what?

Answer 19

positive charge

Question 20

Chlorination and Bromination Requirement

Answer 20

Requires Lewis Acid Catalyst

Question 21

Lewis Acid Catalysts

Answer 21

For Cl2: FeCl3 or AlCl3

For Br2: FeBr3 or AlBr3

Question 22

Nitric Acid

Answer 22

HNO3

Question 23

Which one is a stronger acid? Sulfuric Acid or Nitric Acid?

Answer 23

Sulfuric Acid (H2SO4) is a stronger acid than HNO3

Question 24

Bronsted Lowry Acid

Answer 24

Proton donor (not an acceptor like Lewis Acid)

Question 25

Bronsted Lowry Base

Answer 25

Proton Acceptor

Question 26

Required reagents for nitration

Answer 26

Nitric Acid, Sulfuric Acid, and heat

Question 27

Difference between nitration, sulfonation, and halogenation

Answer 27

Only difference is how you form electrophile.

Question 28

Required reagents for sulfonation

Answer 28

SO3 and H2SO4

Question 29

SO3

Answer 29

Sulfur Trioxide.

Question 30

Sulfonation resulting product

Answer 30

Benzene sulfonic Acid - SO3H added to Benzene

Question 31

Thing to remember about carbocations

Answer 31

LOOK FOR REARRANGEMENT

Question 32

How many products are generated from friedel-crafts alkylation?

Answer 32

2 without resonance, 1 without rearrangement (minor)

Question 33

Friedel-Crafts Alkylation Limitations

Answer 33

Rearrangement possibility and Electron withdrawing groups

Question 34

Why are electron withdrawing groups a limitation for Friedel-Crafts Alkylation?

Answer 34

Electron Withdrawing groups reduce the electron density of the ring and make it less likely that electrons will go to chloride, resulting in no reaction.

Question 35

Required Reagent for Friedel-Crafts Acylation

Answer 35

Acyl Chloride and AlCl3 like alkylation

Question 36

Limitation of Friedel-Crafts Acylation

Answer 36

Rearrangement still can occur.

Question 37

Electrophile used for Friedel-Crafts Acylation

Answer 37

Acylium ion

Question 38

What limitation does Friedel-Crafts Acylation resolve?

Answer 38

Electron withdrawing group results in no reaction - problem of Alkylation

Question 39

What does Clemmensen Reduction do?

Answer 39

Remove ketone after acylation.

Question 40

What we don't need to know about Clemmensen Reduction

Answer 40

its mechanism, just now its reagents.

Question 41

Where is the benzylic carbon?

Answer 41

First Carbon attached to Benzene

Question 42

Oxidation at Benzylic Carbon results in what?

Answer 42

Formation of Carboxylic group

Question 43

Oxidation at Benzylic Carbon requires what reagents?

Answer 43

KMnO4, heat, H3O+, and NaOH

Question 44

What leads to no reaction for oxidation at Benzylic Carbon?

Answer 44

Benzylic carbon has no hydrogens and no π bonds.

Question 45

Downside of oxidation at benzylic carbon

Answer 45

Difficult to control, affects multiple functional groups

Question 46

Oxidation at benzylic carbon further group terms for pi bonds

Answer 46

Alkenyl group, Alkynyl Group

Question 47

Ortho and Para products. Which on is major? Why?

Answer 47

Para, because of steric effect. (less steric hindrance)

Question 48

First substituent has what effect on the second substituent?

Answer 48

The first substituent has two effects on the second substituent: the first substituent can either be ortho/para directing or meta directing, and the first substituent can alter the rate of the second substituent. Activating = speeds up reaction, deactivating = slows down reaction.

Question 49

What mechanical way determines whether a substituent is ortho/para directing or meta directing?

Answer 49

Number of resonance structures and full octet.

Question 50

Ortho/para directors characteristics

Answer 50

Ortho/para directors have a lone pair of electrons and are electron donating.

Question 51

Meta director characteristics

Answer 51

Electron withdrawing (except halogens).

Question 52

Common ortho/para directors

Answer 52

-OR, -NR2, -R, -X (inappropriate films) - R=alkyl, acyl (carbonyl), H

Question 53

Activating Substituents characteristics

Answer 53

Usually ortho/para directors excluding halogens.

Question 54

Deactivating Substituents Characteristics

Answer 54

Electron withdrawing groups

Question 55

Why are most electron withdrawing groups deactivators?

Answer 55

Because they reduce electron density of the ring, slowing down the reaction.

Question 56

In order to add a third substituent, which substituent is the driving force behind determining where it will go?

Answer 56

Activating substituent is stronger than the deactivating substituent, so it will determine where the third substituent goes.

Question 57

TNT

Answer 57

2,4,6 - Trinitrotoluene