Chapter 17 Carboxylic Acids and Esters

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Chapter 17Carboxylic Acids and Esters

• Carboxylic Acids

Carboxyl carbon
Carboxyl functional group -COOH
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Nomenclature

• Find longest chain that contains COOH
• Replace -e (from alkane) with oic acid
• Carboxyl carbon is 1
• Carboxyl group takes priority over other
  functional groups
• Benzene carboxylic acid benzoic acid
• NOTE Common names use Greek letters starting
  with
• a (alpha) as carbon 1 and continuing to ?
  (omega)

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Examples
1-propanoic acid
3-ethyl-5-methyl-benzoic acid
2-hydroxy-4-methyl-pentanoic acid
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Physical Properties

• Relatively high boiling points compared to
  alcohols,ketones, aldehydes and ethers
• Water-soluble
• Why?
• H-bonds!

Boiling points decrease as length of carbon
chain increases. Why?
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Boiling Points and Solubility
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H-bonds

• Hydrogen bonds between water and alcohol
• increase solubility in water
• raises boiling points

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Organic (carboxylic) acids are weak acids

• Q. What is an acid?
• A. Species that donates H
• Q. What is weak acid?
• A. An acid that does not completely ionize

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Ionization of Carboxylic Acids
Salt
Acid
Examples Propanoic acid base Sodium
Propanoate H2O Benzoic acid base
Sodium Benzoate H2O
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Carboxylic Acids, Esters, and Other Acid
Derivatives contd

• Table 16.3

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Carboxylic Acids in MetabolismThe Citric Acid
Cycle
a-Ketoglutaric acid
Oxaloacetic acid
Citric acid
Succinic acid
Malic acid
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Esters Derivatives of Carboxylic Acids

• Esterification
• Carboxylic acid alcohol ? ester

Naming esters I Alkyl part of ALCOHOL
CARBOXYLATE part of acid
Methyl propionate
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Naming Esters II
Pentanoic acid 1-propanol propyl pentanoate
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Properties of Esters

• Acid Hydrolysis
• Base Hydrolysis (saponification)