Lecture Notes: Reactions of Carboxylic Acids

Overview

• Examination of four key reactions involving carboxylic acids:
  • With bases to form salts
  • With alcohols to form esters
  • With amines to form amides
  • With reducing agents to form primary alcohols

Reaction with Bases

• General Mechanism: Neutralization reaction producing a salt and possibly water and carbon dioxide.
• Example Reactions:
  • Metal Oxides: Sodium oxide + propanoic acid → Sodium propanoate + water
    • Salts from carboxylic acids have an "-oate" ending.
  • Metal Hydroxides: Lithium hydroxide + hexanoic acid → Lithium hexanoate + water
  • Metal Carbonates: Calcium carbonate + ethanoic acid → Calcium ethanoate + water + carbon dioxide

Reaction with Alcohols

• General Mechanism: Condensation reaction in the presence of concentrated sulfuric acid.
  • Produces water and an ester.
• Example:
  • Ethanoic acid + methanol → Methyl ethanoate + water
    • Naming esters: Alcohol name changes -ol to -yl, carboxylic acid to -oate.
    • Reaction is reversible; hydrolysis of methyl ethanoate regenerates methanol and ethanoic acid.

Reaction with Amines

• General Mechanism: Condensation reaction forming an amide.
• Example:
  • Propanoic acid + methyl amine → Amide (C=O NH linkage) + water

Reaction with Reducing Agents

• General Mechanism: Reduction of carboxylic acids to primary alcohols.
  • Common reducing agent: Lithium aluminium hydride.
• Example:
  • Ethanoic acid → Ethanol

Practice Problems

• Identify Products:
  1. Carboxylic acid + amine → Amide
  2. Carboxylic acid + base → Salt (e.g., sodium butanoate) + water
  3. Carboxylic acid + alcohol → Ester (e.g., pentyl propanoate)
  4. Reduction of carboxylic acid → Primary alcohol

Conclusion

• Encouragement to practice naming and drawing products.
• Reminder to engage with the channel for more educational content.