26.4 - Carboxylic Acid Derivatives

Question 1

What is a carboxylic acid derivative?

Answer 1

A compound that can be hydrolysed to form the PARENT CARBOXYLIC ACID

All derivatives have an acyl group

Question 2

What are the 4 carboxylic acid derivatives?

Characteristics, naming

Answer 2

• ESTERS
  
  • suffix -oate
  • alkyl on the -O of the -COO is the prefix
• AMIDES
• ACID ANHYDRIDES
  
  • formed by the removal of H₂O from 2 carboxylic acids
• ACYL CHLORIDE

Question 3

Describe the process of esterification.

Answer 3

alcohol + carboxylic acid → ester

• alcohol warmed with CA & conc. H₂SO₄

alcohol + acid anydride

gives ester + carboxylic acid

R’OH + (RC(O))₂O → RCOOR’ + RCOOH

Question 4

Describe the 2 ester hydrolysis reactions.

Answer 4

Ester hydrolysed by either an acid or an alkali

ACID HYDROLYSIS (reverse esterification)

ester + water <> parent CA + alcohol

1. Heat ester under reflux with dilute aqeous acid
2. Ester broen down by water, acid is catalyst

ALKALI HYDROLYSIS (saponification)

Ester heated under reflux with aq OH^- ions

forms carboxylate salt + alcohol

IRREVERSIBLE

Question 5

What are the acyl chloride reactions?

Answer 5

• CA + SOCl₂ → acyl chloride + SO₂ + HCl
  
  • ^ Preparation of acyl chloride from parent carboxylic acid
• Acyl chlorides are usefule - as they are easily converted to CA derivatives
• acyl chloride + alcohol → ester
  
  • acyl chloride + phenol → ester
• acyl chloride + water → carboxylic acid
• acyl chloride + ammonia (AMINEs) → amides
  
  • gives a 1^o amide
  • nucleophile of ammonia donates lone pair from nitrogen

Question 6

What are acid anhydride reactions?

Answer 6

The same as acyl chlorides (+ alcohols; phenol; water; ammonia; amines)

Less reactive than acyl chloride