Reactions of carboxylic acids

Carboxylic Acids

• Carboxylic acids are a family of organic compounds containing carbon, hydrogen and oxygen.

• The general formula of carboxylic acids is C_nH_2n+1COOH (n = 0, 1, 2, 3, 4…)

• The functional group is the –COOH group.

• Carboxylic acids end with –oic acid.

Carboxylic acid

• Butanoic acid has 2 isomers.

• Formation of ethanoic acid

– Ethanoic acid is formed by the oxidation of ethanol.

• By using atmospheric oxygen:

• CH₃CH₂OH + O₂ --> CH₃COOH + H₂O

• By using acidified K₂Cr₂O₇.

• CH₃CH₂OH + 2[O] à CH₃COOH + H₂O

• The orange dichromate (VI) solution changes from orange to green.

• A vinegar smell is detected.

Reactions of carboxylic acids

• Two important reactions of carboxylic acids are :

– Acid reactions

– Esterification

Acid reactions

- A carboxylic acid is a weak acid. When dissolved in water, it dissociates to produce H⁺ ions.

^- Eg. CH₃COOH <--> CH₃COO^- + H⁺

Reactions of carboxylic acids

• Carboxylic acids react with bases to form salt and water only.

• Carboxylic acids react with carbonate to produce carbon dioxide gas.

Reaction of acid - Esterification

• In the presence of a catalyst concentrated sulfuric acid, carboxylic acids react with alcohols to form a sweet-smelling compound, called an ester.

• Eg. Ethanoic acid + ethanol --> ethyl ethanoate + water

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