Carbonyl chemistry

Question 1

What are the simplest carbonyl compounds?

Answer 1

Formaldehydes

Question 2

What is resonsance?

Answer 2

Movement of electrons

Question 3

The more resonance form a compound has the more stable it is. True or False?

Answer 3

True

Question 4

The net charge between resonance forms stays the same. True or False?

Answer 4

True

Question 5

What are the physical properties of carbonyls?

Answer 5

Polar
High Bp
Soluble in water

Question 6

Why are the peaks located where they are?

Answer 6

This is because of bond strength, the stronger the bond strength the harder it is to pull, so higher the wavenumber

Question 7

What is the IR spectrum wavenumber for carbonyl compounds C=O?

Answer 7

1600-1800

Question 8

When conjugation occurs, more resonance is formed? True or False?

Answer 8

TRUE

Question 9

What is conjugation?

Answer 9

Reduces carbonyl (double bond) characters

Question 10

The larger the k value to more the equilibrium lies to the products and vice versa for smaller k value. True or False?

Answer 10

True

Question 11

Bulkier carbonyls are more stable than bulkier normal alcohol groups due to steric hendrice. True or False?

Answer 11

True

Question 12

What type of reactions do carbonyl compounds undergo under the reagents of water, cyanide and alcohols?

Answer 12

Nucleophilic addition.

Question 13

What is the name of the intermediate that is obtained from a nucleophilic addition of carbonyls with cyanide ion?

Answer 13

Cyanohydrin

Question 14

What is obtained when aldehydes and ketones react with alcohols?

Answer 14

Hemiacetyle - the aldehyde hemiacetyle is favoured because there less steric hendrice (less bulkier) than a ketone hemiacetyle.

Question 15

What type of reactions does organometallic and grignard reagent perform with carbonyls?

Answer 15

Addition reactions

Question 16

What do grignard and organometallic reagents provide during the nucleophilic addition?

Answer 16

Provide R-

Question 17

Name the two steps involved when carbonyl is reacted with organolithium reagent?

Answer 17

Step 1- nucleophilic addition

Step 2- Protonation (using aqueous acid)

Question 18

What are the two good R groups and X leaving groups?

Answer 18

Alkyl and Alkenyl

Cl, Br , I

Question 19

Why is the carbonyl and organolithium reaction required in two steps?

Answer 19

Water will damage the organometallic/grignard reagent

Question 20

How are primary and secondary alcohols synthesised?

Answer 20

Aldehyde and organometallic reagent to produce primary alcohol or Aldehyde and grignard to produce secondary alcohols

Question 21

How are tertiary alcohols synthesised?

Answer 21

Ketone and organometallic reagent

Question 22

Give examples of functional groups that contain the C=O?

Answer 22

Carboxylic acids 
Amides
Esters
Acid chloride
Acid anahydride

Question 23

What is the IR stretch of C=O in carboxylic acids and O-H stretch in carboxylic acids?

Answer 23

C=O 1710cm shifted by conjugation

O-H 3100cm (broad)

Question 24

What are the two peaks that acid anhydridres form and give reasoning to this?

Answer 24

1833 and 1767

Due to symmetrical and unsymmetrical stretching modes

Question 25

How can carboxylic be formed?

Answer 25

CO2 and grignard reagent - via nucleophilic addition and protonation using aqueous acid

Question 26

What is the firscher esterification reaction?

Answer 26

Craboxylic acid and alcohol to give water and ester

Question 27

What is the name of the reaction for fischer esterification?

Answer 27

Addition - elimination reaction

Question 28

How can you form an ester without breaking the C-O bond?

Answer 28

Using diazomethane to methylate the carboxylic acid and the carboxylic acid is then methylated to form the carboxylate anion whic via an Sn2 reaction will form an ester.

Question 29

What are the draw backs of using diazomethane?

Answer 29

1. Toxic 2. it only methylates acrboxylic acids 3. Explosive

Question 30

What are the names of the reactions that occurs during methylation of carboxylic acid and formation of an ester?

Answer 30

Step 1- Deprotonation - a nucleophile and a methylating agent is formed Step 2- Sn2 reaction to form an ester

Question 31

How many resonance forms does diazomethane have ?

Answer 31

3

Question 32

What is the process for obtaining amides from carboxylic acids?

Answer 32

Amine + carboxylic acid = ammonium salt | Ammonium salt + heat = Amide + H20

Question 33

What is the name of the second step in formation of amides from carboxylic acids?

Answer 33

Dehydration process

Question 34

How to form anhydrides from carboxylic acids?

Answer 34

Carboxylate anion + acid chloride = anhydride

Question 35

What reagent can be used to convert carboxylic acid to an acid chloride in formation of anydrides?

Answer 35

Thionyl chloride (SOCL2)

Question 36

What is the name of the reaction for converting COOH to Anhydride?

Answer 36

Addition - elimination?

Question 37

How do acyl groups defer from acids?

Answer 37

They have a good Cl leaving groups while acids have an OH group.

Question 38

Give examples of Acyl compounds?

Answer 38

``` Esters Acid chlorides Amides Anhydrides Acid bromides ```

Question 39

What is the most important mechanism of acyl compounds?

Answer 39

Addition elimination reaction

Question 40

In addition elimination of acyl compounds, L is replaced but L can itself act as a nucleophile, therefore this is an equilibrium reaction. TRUE OR FALSE?

Answer 40

TRUE

Question 41

What are the physical properties of acyl compounds?

Answer 41

They can H bond and form dimers/ which gives them a high Bp

Question 42

Cl- are good leaving groups. True or False?

Answer 42

True

Question 43

With acid chloride reactions/ by product is always HCL. True or False?

Answer 43

True

Question 44

What do you get from reacting esters and organometallic reagents, with an addition elimination process?

Answer 44

Tertiary alcohols

Question 45

Esters and amides are more stable than aldehydes and due to greater resonance stabilization. True or False?

Answer 45

True