Carboxylic Acid Derivatives

Question 1

How do you name carboxylic acids?

Answer 1

Alkanoic acid

Question 2

How do you name carboxylic ester?

Answer 2

Alkyl alkanoate

Question 3

How do you name acyl (acid) chloride?

Answer 3

Alkanoyl chloride

Question 4

How do you name acid anhydride?

Answer 4

Alkanoic anhydride

Question 5

How do you name amide?

Answer 5

Alkanamide

Question 6

How do you make acyl chlorides?

Answer 6

Add SOCl2 to RCOOH

Question 7

RCOOH + SOCl2

Answer 7

ROCl + SO2 + HCl

Question 8

How do you make acid anhydrides?

Answer 8

Add P2O5 to RCOOH

Question 9

CH3COOH + P2O5

Answer 9

CH3COOCOCH3 (symmetrical anhydride) + H3PO4

Question 10

How do you make ester?

Answer 10

Add alcohol and carboxylic acid with acid catalyst

Question 11

RCOOH + ROH

Answer 11

RCOOR + H2O

Question 12

How do you make amides?

Answer 12

RCOOH + RNH2

Question 13

RCOOH + RNH2?

Answer 13

RCONHR + H2O

Question 14

What is the mechanism for nucleophilic addition?

Answer 14

Start off with ketone

Add nucleophile -> electron donated to delta positive C of C=O

Electrons from double bond donated to O -> O gains a negative charge

Add acid -> H+ ion joins to O-

Addition reaction to form alcohol

Question 15

What is the mechanism for nucleophilic acyl subsitution?

Answer 15

Same first step (nucleophile) donates electron to delta positive carbon and electron from double bond donated to oxygen for negative charge

Intermediate forms where the electrons from the oxygen donated back to C-O bond and electron from C-Leaving group donated to leaving group

Forms carboxylic derivative

Question 16

Which is the slow step for nucleophilic acyl substitution?

Answer 16

The initial step in which the carboxylic acid forms the intermediate with negatively charged oxygen

Question 17

What is the order of reactivity for carboxylic acid derivatives?

Answer 17

Fastest

Acyl chlorides

Acid anhydrides

Esters

Amides

Slowest

Question 18

How does leaving group strength affect reactivity of carboxylic acid derivatives?

Answer 18

It does not

Question 19

What affects the reactivity of carboxylic acid derivatives?

Answer 19

The size of the partial positive charge on carbon -> therefore electronegativity of substituent group

This is because the rate determining step of nucleophilic acyl substitution involves the nucleophile and the carboxylic acid derivative

Question 20

How does the electronegativity of the substituent group of carboxylic acid derivatives affect reactivity?

Answer 20

If the substituent group is electron donating, the carbon becomes less partially positive meaning it is less reactive

If the substituent group is electron withdrawing, the carbon becomes more partially positive meaning it is more reactive

Question 21

What reactions can acyl chlorides undergo?

Answer 21

Acyl chlorides are very reactive due to the electron withdrawing chloride group

Therefore it can form all carboxylic acid derivatives:

• carboxylic acid
• acid anhydride
• amide
• ester

Question 22

How do you form amide from acyl chlorides?

Answer 22

By adding amine

Question 23

How do you form ester from acyl chlorides?

Answer 23

By adding alcohol

Question 24

How do you form anhydride from acyl chlorides?

Answer 24

By adding carboxylic acid

Question 25

How do you form carboxylic acid from acyl chlorides?

Answer 25

By adding water

Question 26

What is the byproduct formed from nucleophilic acyl substitution of acyl chlorides?

Answer 26

HCl

Question 27

How do you make an unsymmetrical anhydride?

Answer 27

By adding an acyl chloride of different length to a carboxylic acid

Question 28

What carboxylic acid derivatives can anhydrides form?

Answer 28

Esters Amides Carboxylic acids NOT acyl halides as they are more reactive

Question 29

What is the byproduct formed from nucleophilic acyl substitution of anhydrides

Answer 29

Carboxylic acid

Question 30

What carboxylic acid derivatives can esters form?

Answer 30

Amides Carboxylic acids NOT acyl halides and anhydrides as they are more reactive

Question 31

How do you hydrolyse esters?

Answer 31

Add water with base or acid (either) Not as reactive as acyl chlorides and anhydrides therefore requires acid or base

Question 32

What carboxylic acid derivatives can amides form?

Answer 32

Only carboxylic acids

Question 33

How do you form carboxylic acid from amides?

Answer 33

Add 70% (concentrated) sulfuric acid with heat to amide to form protonated amine and carboxylic acid Adding base to protonated amine will form amine and water

Question 34

What happens when you do nucleophilic acyl substitution using a strong nucleophile in excess?

Answer 34

nucleophilic acyl substitution occurs first then nucleophile added to partial positive carbon form nucleophilic addition in which a nucleophile is added then acid is added to form the alcohol group

Question 35

What happens when you add LiAlH4 to acyl chloride?

Answer 35

Forms an aldehyde RCOH

Question 36

What happens when you add LiAlH4 and acid to an aldehyde?

Answer 36

Nucleophilic addition occurs to form ROH

Question 37

How do you make a tertiary alcohol from an acyl chloride?

Answer 37

Add grignard reagent to form a ketone (nucleophilic acyl substitution) Add grignard reagent with acid (nucleophilic addition) to form tertiary alcohol