17.4 Esters of Carboxylic Acids

1
Chapter 17 Carboxylic Acids And Esters

• 17.4 Esters of Carboxylic Acids
• 17.5 Naming Esters
• 17.6 Properties of Esters

2
Esters

• In an ester, the H in the carboxyl group is
  replaced by an alkyl group.
• O
• ??
• CH3COCH3
• CH3COOCH3
• ester group

3
Esterification

• An ester is produced by the reaction of a
  carboxylic acid and alcohol in the presence of an
  acid catalyst.
• O
• ?? H
• CH3COH HOCH2CH3
• O
• ??
• CH3COCH2CH3 H2O

4
Ester Products

• Aspirin
• Is used to relieve pain and reduce inflammation.
• Is an ester of salicylic acid and acetic acid.
• Oil of wintergreen
• Is used to soothe sore muscles.
• Is an ester of salicylic acid and methanol.

5
Naming Esters

• Esters are named with the alkyl name of the
  alcohol followed by the carboxylate name from the
  acid.
• from acid from alcohol
• O
• ?? methyl
• CH3COCH3
• Ethanoate methyl ethanoate (IUPAC)
• (Acetate) methyl acetate (common)

6
Some Esters In Nature

• Esters give fruits their pleasant fragrances and
  flavors.

7
Hydrolysis

• In hydrolysis
• An ester reacts with water to produce a
  carboxylic acid and an alcohol.
• An acid catalyst is required.
• O
• ?? H
• HCOCH2CH3 H2O
• O
• ??
• HCOH HOCH2CH3

8
Base Hydrolysis (Saponification)

• In base hydrolysis or saponification, an
  ester reacts with a strong base to produce the
  salt of the carboxylic acid and an alcohol.
• O
• CH3COCH2CH3 NaOH
• O
• ?? CH3CO Na HOCH2CH3
• salt of carboxylic acid
  alcohol

9
Base Hydrolysis of Fatty Acids Produces Soaps

10
Cleaning Action of Soap

• A soap
• Contains a nonpolar carbon end that dissolves in
  nonpolar fats and oils, and a polar end that
  dissolves in water.
• Forms groups of soap molecules called micelles
  that dissolve in water and are washed away.