DERIVATIVES OF CARBOXYLIC ACIDS

1
DERIVATIVES OF CARBOXYLIC ACIDS
VIDEO 1
2
Reactions of carboxylic acid derivatives
i. Hydrolysis of acid chlorides
H2O
HCl
acid chloride
carboxylic acid
ii. Hydrolysis of acid anhydrides
H2O
2
carboxylic acid
acid anhydride
VIDEO 2
3
Reactions of carboxylic acid derivatives
iii. Hydrolysis of esters
4
Example
H2O
benzoyl chloride
H2O
ethanoic anhydride
5
Example
H2O H
methyl ethanoate
6
Relative Reactivity Of Carboxylic Acid Derivatives

• The reactivity of a carboxylic acid derivative
  depends on the basicity of the substituent
  (leaving group) that attached to the acyl group
• The less basic the substituent, the more reactive
  the carboxylic acid derivative.

7
Relative basicities of the leaving group
(substituent)
Cl lt RCOO lt RO lt HO lt NH2
acid chloride
acid anhydride
ester
carboxylic acid
amide
reactivity increases
VIDEO 3
8
ACYL CHLORIDE

• Acyl chloride is the most reactive because of
  its electropositive carbonyl group is attach to
  the electronegative Cl atom (which is a releasing
  group).

9
ANHYDRIDE ACID

• Anhydride acid is more reactive than ester and
  amide because the carboxyl group of anhydride is
  attached to the carbonyl carbon.
• This makes the carbonyl carbon becomes more
  electropositive and can be easily attack by
  nucleophile.

10
ESTER

• Ester is less reactive towards nucleophile
  because the delocalization of electron makes the
  positive charge of carbon can be shifted to
  oxygen.
• That makes the carbonyl carbon less
  electropositive.

11
AMIDE

• Amide is the least reactive because, NH2 group is
  an electron-donating group that makes the
  carbonyl less electropositive.
• The resonance structure of amide shows that the
  carbonyl carbon is not electropositive.

12
The Uses of Carboxylic Acid